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A  MANUAL 


PRACTICAL  HYGIENE 


STUDENTS,  PHYSICIANS,  AND  MEDICAL  OFFICERS. 


BY 


CHARLES  HARRINGTON,  M.D, 

Pkofessor  of  Hygiene  in  the  Medical  School  of  Harvard  University. 


THIRD  EDITION,   REVISED  AND  ENLARGED. 


ILLUSTRATED  WITH   TWELVE   PLATES  IN   COLORS  AND   MONOCHROME, 
AND  ONE  HUNDRED  AND    EIGHTEEN   ENGRAVINGS. 


LEA   BROTHERS   &   CO., 

PHILADELPHIA   AND  NEW  YORK. 


Entered  according  to  Act  of  Congress,  in  the  j-ear  1905,  by 

LEA  BROTHERS   &  CO., 

In  the  Office  of  the  Librarian  of  Congress.    All  rights  reserved. 


WESTOOTT    &.    THOMSON,  WILLIAM    J.    DOBNAN, 

ELEOTROTYPERS,    PHILADA.  PRINTER,   PHILADA. 


PREFACE  TO  THE  THIRD  EDITION. 


In  the  preparation  of  this  third  edition,  matter  rendered  obsolete 
by  research  and  study  conducted  since  the  appearance  of  the  second 
edition  has  been  replaced  with  material  in  accordance  with  present 
knowledge,  and  other  advances  have  been  noted  in  their  appropriate 
places.  In  addition,  a  chapter  on  the  increasingly  important  subject 
of  Immunity  has  been  introduced,  which,  it  is  hoped,  may  serve  a 
useful  purpose. 

The  author  extends  hearty  thanks  to  those  who  have  aided  him 

with  friendly  criticism  and  suggestions. 

C.  H. 

688  BoYLSTON  St.,  Boston. 
May,  1905. 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/manualofpracticaOOharr 


CONTENTS 


CHAPTER  I. 

PAGE 

FOODS. 17 

§  1.     General  Considerations , 17 

The  nutritive  value  of  foods,  17.  Amount  of  food  necessaiy,  18.  Composi- 
tion of  foods,  19.  Proteids,  19.  Fats,  21.  Carbohydrates,  21.  Organic 
acids,  22.     Inorganic  salts,  23. 

§  2.    Animal  Foods  :  Meats,  Fish,  Eggs,  and  Meat  Products  .......      23 

Meats,  24.     Digestibility,  24.     Flavor,  24.     Texture,  25.     Effects  of  cooking, 

25.  Characteristics  of  good  meat,  26.     Compai-ative  digestibility  of  meats, 

26.  Eed  meat  and  white  meat,  27.  Composition  of  meats,  27.  Beef,  28. 
Pork,  29.  Veal,  30.  Mutton,  30.  Lamb,  30.  Poultry,  31.  Horse  meat,  31. 
Meat  preparations,  32.  Sausages,  32.  Fish,  34.  Digestibility,  35.  Keeping 
qualities,  35.  Composition,  35.  Meat  and  fish,  and  parasitic  disease,  37. 
Transmission  of  disease  by  meat  and  fish,  42.  Tuberculosis,  43.  Typhoid 
fever  and  cholera,  49.  Poisoning  by  meat  and  fish,  54.  Poisoning  due  to 
substances  normally  present  in  the  living  organism,  54.  Poisoning  due  to 
bacterial  products  in  meats  and  fish,  54.  Onset  and  course  of  symptoms,  57. 
Nature  of  symptoms,  57.  Post-mortem  appearances,  58.  Character  of  meats 
which  cause  peisoning,  58.  Cases  illustrative  of  poisoning  by  fish  and  meats, 
60.  Poisoning  by  mussels,  60.  Poisoning  by  herrings,  61.  Poisoning  by 
salmon,  63.  Poisoning  by  oysters,  63.  Poisoning  by  veal,  64.  Poisoning  by 
pork,  66.  Poisoning  by  beef,  70.  Poisoning  by  horse  meat,  73.  Poisoning 
by  sausages,  74.  Poisoning  by  kid  meat,  76.  Meat  inspection  and  slaughter- 
ing, 76.     Eggs,  78.     Lard,  81. 

§  3.     Milk  and  Milk  Products .........      82 

Composition  of  cows'  milk,  82.  Fat,  83.  Milk  sugar,  84.  Proteids,  84. 
Mineral  matter,  85.'  Specific  gravity,  85.  Reaction,  85.  Appearance,  85. 
Taste,  86.  Presence  of  alcohol,  86.  Colostrum,  87.  Changes  produced  in 
milk  by  boiling,  87.  Changes  due  to  bacterial  action,  88.  Preservation  of 
milk,  91.  Adulteration  of  milk,  94.  Condensed  milk,  95.  Koumiss  and 
kefir,  95.  Cream,  96.  Milk  as  a  factor  in  the  spread  of  disease,  96.  Poison- 
ous milk,  96.  Milk  from  diseased  cows,  98.  Milk  contaminated  from  with- 
out with  organisms  related  to  human  diseases,  104.  Diphtheria,  105. 
Cholera,  105.  Scarlet  fever,  106.  Typhoid  fever,  107.  Cholera  infantum, 
108.  Analysis  of  milk,  110.  Determination  of  specific  gravity,  111. 
Dctci-iiiination  of  fat,  112.  Determination  of  total  solids,  115.  Determina- 
tion of  milk  sugar,  116.  Determination  of  nsh,  117.  Determination  of  pro- 
teids, 117.     Detection  of  added  coloring  matters,  118.     Detection  of  preserva- 

5 


t)  CONTENTS. 

PAGE 

tives,  120.  Methods  of  distinguishing  between  raw  and  cooked  milk,  122. 
Detection  of  gelatin  in  cream,  123.  Butter,  124.  Butter  as  a  carrier  of  dis- 
ease, 127.  Analysis  of  butter,  128.  Cheese,  132.  Composition  of  cheese, 
134.  Adulteration  of  cheese,  135.  Analysis  of  cheese,  135.  Cheese  as  a 
cause  of  poisoning,  136. 

§  4.     Vegetable  Foods 186 

Farinaceous  seeds,  137.  Cereals,  137.  "Wheat,  137.  Composition  of  wheat, 
138.  Wheat  flour,  139.  Preparations  of  wheat  flour,  bread,  140.  Macaroni, 
spaghetti,  and  vennicelli,  142.  Adulteration  of  flour,  143.  Eye,  144. 
Barley,  144.  Oats,  145.  Corn,  146.  Eice,  147.  Buckwheat,  148.  Legumes, 
148.  Peas,  149.  Beans,  150.  Lentils,  151.  Farinaceous  preparations,  151. 
Sago,  151.  Tapioca,  151.  Arrowroot,  152.  Fatty  seeds  (Nuts),  152. 
Almonds,  152.  Cocoanuts,  152.  "Walnuts,  152.  Peanuts,  153.  Chestnuts, 
153.  Vegetable  fats,  154.  Olive  oil,  154.  Cotton-seed  oil,  154.  Tubers  and 
roots,  154.  Potatoes,  154.  Sweet  potatoes,  157.  Artichokes,  157.  Boots, 
157.  Herbaceous  articles,  158.  Fruit  products  used  as  vegetables,  158. 
Fruits,  159.  Apples,  159.  Peare,  160.  Peaches,  160.  Apricots,  160. 
Plums,  160.  Cherries,  160.  Oranges,  160.  Grapes,  161.  Melons,  161. 
Bananas,  162.  Figs,  162.  Berries,  162.  Edible  fungi,  163.  Mushrooms, 
163.  Truffles,  163.  Saccharine  preparations,  163.  Cane  sugar,  163.  ]\Iaple 
sugar,  164.  Glucose,  dextrose,  164.  Molasses,  165.  Honey,  165.  Confec- 
tionery, 167.     Jellies  and  jams,  168. 

§  5.    Beverages 168 

Stimulant  beverages  containing  alkaloids,  168.  Tea,  168.  Adulteration  of 
tea,  170.  Coffee,  171.  Cocoa,  173.  Fermented  alcoholic  beverages,  175. 
Beer,  175.  Process  of  manufacture  of  beer,  177.  Substitutes  for  barley  malt, 
178.  Substitutes  for  hops,  179.  Physical  properties  and  chemical  composi- 
tion of  beer,  180.  Adulteration  of  beer,  180.  Analysis  of  beer,  181.  Tables 
showing  percentage  of  alcohol  by  weight  and  by  volume,  182.  Detection  of 
preservatives,  188.  "Wines,  189.  Classification  of  wines,  191.  Composition 
of  wines,  191.  Adulteration  of  wines,  192.  Analysis  of  wines,  194.  Detec- 
tion of  preservatives,  195.  Cider,  196.  Perry,  197.  Distilled  alcoholic 
beverages,  197.  Brandy,  198.  "Whiskey,  199.  Eum,  200.  Gin,  201. 
Liqueurs,  201. 

§  6.     Condiments,  Spices,  and  Bakers'  Chemicads 202 

Vinegar,  202.  Lemon  juice  and  lime  juice,  204.  Salt,  204.  Mustard,  205. 
Pepper,  205.  Cloves,  205.  Cinnamon  and  cassia,  206.  Allspice,  206. 
Ginger,  206.  Nutmeg,  206.  Mace,  206.  Cayenne  pepper,  206.  Baking 
powders,  206. 

§  7.     Food  Preservation 208 

Cold,  209.  Drying,  209.  Salting,  209.  Smoking,  209.  Canning,  209.  Chemical 
treatment,  211.  Boric  acid  and  borax,  213.  Salicylic  acid,  216.  Sulphites, 
217.  Formaldehyde,  217.  Hydrogen  peroxide,  218.  Sodium  fluoride,  219. 
Sodium  bicarbonate,  219. 

§  8.     CoNTAjvnNATioN  OP  FooDS  BY  ^Ietals 219 

Copper,  219.  Lead,  221.  Zinc,  222.  Nickel,  222.  Tin,  222.  Metallic  con- 
tamination from  kitchen  utensils,  222. 


CONTENTS.  7 

CHAPTER  II. 

PAGE 

AIE 224 

Oxygen,  224.  Nitrogen;  226.  Argon,  227.  Hydrogen,  227.  Carbon  dioxide, 
227.  Ozone,  229.  Peroxide  of  hydrogen,  230.  Ammonia,  230.  Nitrogen 
acids,  230.  Aqueous  vapor,  231.  Dust  and  micro-organisms,  233.  Carbon 
monoxide,  235.  "  Sewer  gas,"  237.  Organic  matters,  240.  Effects  of  vitiated 
air,  240.  The  air  as  a  carrier  of  infection,  244.  Influence  of  fog,  251. 
Examination  of  air,  251.  Determination  of  aqueous  vapor,  252.  Deter- 
mination of  relative  humidity,  253.  Glaishei-'s  table,  254.  Table  of 
tensions,  255.  Determination  of  carbon  dioxide,  257.  Deteimination  of 
carbon  monoxide,  265.  Determination  of  ozone,  266.  Determination  of 
dust,  267.     Bacteriological  examination,  268. 

CHAPTER  III. 

THE  SOIL  . 270 

Tlie  soil,  270.  Constituents  of  the  soil,  272.  Physical  properties  of  soils, 
273.  Pore-volume,  273.  Permeability  of  soils,  274.  Capacity  for  water,  and 
water-retaining  capacity,  278.  Soil  temperature,  280.  Changes  in  the  char- 
acter of  soils  due  to  chemical  and  biological  agencies,  282.  Soil-air,  283. 
Soil-water,  286.  Sources  of  soil-water,  289.  Loss  of  soil  moisture  by  evapora- 
tion, 289.  Influence  of  vegetation  on  soil  moisture,  290.  Other  effects  of 
vegetation  upon  the  soil,  291.  Pollution  of  the  soil,  292.  Bacteria  of  the  soil, 
294.  Soil  and  disease,  296.  Soil  dampness  and  disease  in  general,  296.  Soil 
and  pulmonary  tuberculosis,  297.  Typhoid  fever,  297.  Cholera,  300.  Bubonic 
plague,  300.  Diphthei-ia,  301.  Malaria,  302.  Yellow  fever,  302.  Tetanus 
and  malignant  oedema,  303.  Anthrax,  303.  Uncinariasis,  304.  Goitre,  305. 
Epidemic  diarrhoea,  307.  Examination  of  soils,  307.  Pore-volume,  308. 
Permeability  to  air,  309.  Permeability  to  water,  310.  Water  capacity,  312. 
Capillarity,  312.  Moisture,  312.  Organic  and  volatile  matters,  313.  Deter- 
mination of  COj  in  soil-air,  313.     Bacteriological  examination  of  soil,  315. 

CHAPTER  IV. 

WATER 316 

Introductory,  316.  Eain,  316.  Surface-waters,  317.  Ground-waters,  318. 
Physical  and  chemical  characteristics  of  water,  320.  Appearance,  321.  Ee- 
action,  322.  Odor,  322.  Substances  found  normally  in  water,  324.  Gases, 
324.  Carbon  dioxide,  325.  .  Organic  matter,  325.  Ammonia,  326.  Albumi- 
noid ammonia,  328.  Nitrites  and  nitrates,  328.  Mineral  matters,  330.  Salt, 
330.  Hardness,  331.  Bacteria  in  water,  332.  Water  supplies,  335.  Stored 
rain,  335.  Surface-waters,  337.  Ground-waters,  338.  Springs,  338.  Wells, 
339.  Driven  wells,  340.  Drainage  area  of  wells,  344.  Filter  galleries,  346. 
Classification  of  waters  from  the  sanitary  standpoint,  347.  Purification  of 
water,  .349.  Oxidation,  349.  Dilution,  350.  Sedimentation,  350.  Bacterial 
action,  350.  Vegetation,  350.  Methods  of  purification,  351.  Chemical  treat- 
ment, 351.  Boiling  and  distillation,  355.  Filtration,  355.  Domestic  filters, 
355.  Filtration  of  public  supplies,  357.  "  Mechanical  filtration,"  363.  De- 
struction of  alg;e,  363.  Eemoval  of  hardness,  364.  Removal  of  iron,  364. 
Action  of  water  on  lead  and  other  metals,  365.     Action  on  iron,  369.     Action 


8  CONTENTS. 

PAGE 

on  zinc,  369.  Action  on  tin,  370.  "Water  and  disease,  371.  Disorders  con- 
nected with  mineral  matter,  372.  Disorders  connected  with  organic  pollution, 
374.  Typhoid  infection  of  water  supplies,  376.  Influence  of  introduction  of 
public  water  supplies  on  typhoid  rates,  377.  Examples  of  typhoid  fever 
epidemics  and  of  limited  outbi-eaks  traced  to  infected  water,  379.  Asiatic 
cholera,  386.  The  propagation  of  cholera  in  India,  388.  Parasites  and  drink- 
ing-water, 391.  Ice,  393.  Chemical  examination  of  water,  394.  Collection 
of  samples,  394.  Determination  of  free  and  albuminoid  ammonia,  395.  De- 
termination of  other  nitrogen  compounds,  400.  Nitrites,  400.  Nit'-at„s,  401. 
Determination  of  chlorine,  402.  Determination  of  residue,  403.  Determina- 
tion of  hardness,  403.  Determination  of  "  Oxygen  required,"  404.  Determina- 
tion of  color,  405.     Determination  of  odor,  405.     Determination  of  reaction, 

405.  Determination  of  turbidity,  406.     Detection  and  determination  of  lead, 

406.  Detection  of  tin,  409.  Detection  and  determination  of  iron,  409.  Infer- 
ences as  to  character  of  water  from  the  results  of  sanitary  chemical  analysis,  409. 
Bacteriological  examination  of  water,  412.  Collection  of  samples,  413.  Plant- 
ing of  samples,  413.  Quantitative  determination,  414.  Qualitative  deter- 
mination, 415.  Comparative  value  of  chemical  and  bacteriological  analysis 
of  water,  417. 

CHAPTER  V. 

HABITATIONS,  SCHOOLS,  ETC 420 

§  1.    Generax  Considerations 420 

Aspect,  420.  Construction  and  arrangement,  420.  Care  of  habitations,  421. 
Schools,  421.     School  furniture,  422.     Legislation  concerning  schools,  423. 

§  2.     Ventilation  and  Heating 423 

Ventilation  and  heating,  423.  Amount  of  space  required  for  good  ventilation, 
425.  Natural  forces  in  ventilation,  426.  Diffusion  and  gravity,  427.  Peri- 
flation  and  aspiration,  429.  Natural  ventilation,  431.  Inlets  and  outlets,  432. 
Mechanical  ventilation,  435.  Artificial  heating  in  its  relation  to  ventilation, 
435.  Eadiation,  436.  Conduction,  436.  Convection,  436.  Methods  of 
warming,  437.  Open  fires,  437.  Stoves,  437.  Furnaces,  439.  Hot-water 
pipes,  439.  Steam  pipes,  439.  Begulation  of  temperature,  440.  Necessity 
of  providing  moisture.  441.     Determination  of  rates  of  ventilation,  443. 

§  3.     Lighting ■ 445 

Natural  lighting,  445.  Artificial  lighting,  447.  Luminosity  of  flame,  447. 
Gas  burners,  448.  Varieties  of  illuminating  gas,  449.  Coal-gas,  449.  Water- 
gas,  449.  Acetylene  gas,  450.  Gasolene  gas,  451.  Impurities  given  off"  in 
lighting,  451.     Gas  pipes,  451.     Fixtures,  452.     Electric  lighting,  452. 

§  4.     Plfmbing 452 

Plumbing,  452.  The  soil-pipe  and  main  drain,  454.  Waste  pipes,  459.  Traps, 
460.  Grease  traps,  464.  Loss  of  seal,  466.  Non-siphoning  traps,  468.  Water- 
closets,  470.  The  pan  closet,  473.  The  plunger  closet,  474.  Hopper  closets, 
475.  Open  wash-out  closets,  475.  Siphon  closets,  476.  Flushing  apparatus, 
478.  Water-closet  connections,  479.  Urinals,  480.  AVash  basins,  480.  Bath- 
tubs, 482.  Sinks,  484.  Laundry  tubs,  485.  House  service  tanks,  485.  Service 
pipes,  486.     Testing  plumbing,  487. 


CONTENTS.  9 

CHAPTER  VI. 

PAGE 

DISPOSAL  OF  SEWAGE 488 

Sewage,  488.  Methods  of  sewage  disposal,  491.  Discharge  into  the  sea,  491. 
The  pail  system,  492.  Chemical  treatment,  493.  Action  of  sewage  effluents 
on  fish  life,  494.  Sewage  irrigation,  494.  Influence  of  sewage  irrigation  on 
health,  498.  The  Waring  system  of  irrigation,  499.  Sewage  filti-ation,  500. 
Other  biological  processes,  502.  Dibdin's  bacteria  filter,  502.  Cameron's 
septic  tank,  504.     The  Scott-Moncrieff  system,  505. 

CHAPTER  VII. 

DISPOSAL  OF  GAEBAGE 507 

Garbage,  507.  Methods  of  disposal  of  garbage,  508.  Incineration,  508.  Ee- 
duction,  509. 

CHAPTER  VIII. 

DISINFECTANTS  AND  DISINFECTION 511 

Disinfectants,  511.  Physical  agents,  511.  Light,  511.  Heat,  514.  Dry  heat, 
515.  Steam,  515.  Boiling  water,  519.  Cold,  519.  Chemical  agents,  520. 
Oxygen,  522.  Ozone,  522.  Hydrogen  peroxide,  523.  Chlorine,  524.  "  Chloride 
of  lime,"  524.  Sodium  hypochlorite,  526.  Bromine  and  iodine,  526.  Sul- 
phur dioxide,   526.     Lime,  527.     Ferrous   sulphate,   528.     Ferric   sulphate, 

529.  Ferric  chloride,  529.  Zinc  chloride,  529.  Aluminum  chloride,  529. 
Potassium   permanganate,  530.     Copper   sulphate,  530.     Mercuric   chloride, 

530.  Mineral  acids,  532.  Organic  substances,  532.  Carbolic  acid,  phenol, 
phenic  acid,  532.  Cresols,  534.  CreoKn,  535.  Lysol,  536.  Bacillol,  536. 
Lysoform,  536.  Saprol,  536.  Solveol,  536.  Solutol,  537.  Alcohol,  537. 
Essential  oils,  538.  Soaps,  538.  Medicated  soaps,  541.  Formaldehyde,  542. 
Formaldehyde  apparatus,  543.  Germicidal  properties,  549.  Power  of  pene- 
tration, 552.  Conditions  favoring  action,  553.  Toxicity,  554.  Amount  neces- 
sary for  room  disinfection,  556.  Disadvantages,  556.  Other  applications  of 
formaldehyde,  557.  Prevention  of  dissemination  of  infectious  material: 
Practical  disinfection,  557.  Disinfection  of  fteces,  558.  Urine,  559.  Sputum, 
559.  Discharges  from  the  mouth,  etc.,  559.  Eating  utensils,  559.  Bed  linen 
and  clothing,  559.  Hands,  560.  Air,  560.  Eoom  disinfection,  561.  Disin- 
fection of  books,  564.    Disinfection  of  watei'-closets,  564. 

■  CHAPTER  IX. 

MILITAEY  HYGIENE 565 

Introductory,  565.  The  recruit,  567.  Age,  568.  Height,  571.  Weight,  572. 
Examination  of  the  recruit,  572.  Chest  capacity,  573.  Gi-ounds  for  rejection, 
573.  Hygiene  of  the  soldier,  575.  Personal  cleanliness,  575.  Contentment 
and  cheerfulness,  575.  Clothing  of  the  soldier,  576.  Wool,  576.  Cotton 
and  linen,  576.  Shoddy,  576.  Color,  577.  Military  dress  coats,  577.  Gaiters 
and  leggings,  577.  Head  covering,  577.  Stockings,  578.  Boots,  578.  Under- 
clothing, 579.  Abdominal  bands,  579.  Waterproof  blankets,  580.  The  sol- 
diei-'s  exercise  and  work,  580.  Marching,  580.  Care  of  the  feet  on  the  march, 
585.     Care  of  other  jiarts,  .>S0.     Tlie  Soulier's  food ;"  rations,"  587.     Alcohol 


10  CONTENTS. 

PAGE 

in  the  ration,  589.  Preparation  of  food,  591.  Is  the  U.  S.  ration  adequate  in 
amount  and  composition?  591.  Is  the  U.  S.  ration  suited  to  the  tropics?  593. 
Tropical  dietaries,  595.  Posts  and  camps,  597.  Barracks,  599.  Tents.  601. 
Water  supply,  604.  Sewerage,  604.  Sinks  and  latrmes,  605.  Inspections,  606. 
Sanitary  police,  607.  The  diseases  of  the  soldier,  613.  Typhoid  fever,  614. 
Dysentery,  615.  Malaria,  615.  Measles,  616.  Diarrhoeal  diseases  in  general, 
616.     Sunstroke,  616.    Venereal  diseases,  617. 

CHAPTER   X. 

NAVAL  AND  MAKIXE  HYGIENE 618 

Naval  recruits,  618.  The  naval  ration,  619.  "Water  supply,  620.  The  sailor's 
sleeping  quarters,  621.  The  diseases  of  the  sailor,  622.  Ventilation  of  vessels, 
623.     General  hygiene  of  ships,  624. 

CHAPTER  XL 

TKOPICAL   HYGIENE 627 

The  soldier  and  tlie  civilian  in  the  tropics,  627.  Habits  of  life,  629.  Diet, 
620.  The  use  of  alcohol  in  the  tropics,  631.  Clothing,  633.  Care  of  the 
person,  634.     Tropical  diseases,  634. 

CHAPTER   XII. 

THE  EELATION  OF  INSECTS  TO  HUMAN  DISEASES 636 

Introductory,  636.  Flies,  637.  Fleas,  640.  Bedbugs,  640.  Mosquitoes,  641. 
Mosquitoes  and  malaria,  642.  The  malarial  parasite,  645.  Preventive 
measures,  651.  Mosquitoes  and  yellow  fever,  652.  The  yellow  fever  mos- 
quito, 654.  Preventive  measures,  656.  Mosquitoes  and  filarial  disease,  657. 
Mosquitoes  and  dengue,  659.     Mosquitoes  and  distomiasis,  660. 

CHAPTER   XIII. 
HYGIENE  OF  OCCUPATION     661 

Introductory,  661.  Classification  of  occupations,  666.  Occupations  involving 
exposure  to  air  vitiated  by  respiration,  668.  Occupations  involving 
exposure  to  irritating  and  poisonous  gases  and  fumes,  668.  Occupations 
involving  exposure  to  irritating  and  poisonous  dusts,  674.  Occupations 
involving  exposure  to  infective  matter  in  dust,  680.  Occupations  involving 
the  inhalation  of  ofifensive  gases  and  vapors,  681.  Occupations  involving 
exposure  to  extremes  of  heat,  682.  Occupations  involving  exposure  to 
dampness,  682.  Occupations  involving  exposure  to  abnormal  atmospheric 
pressure,  682.  Occupations  involving  constrained  attitude,  683.  Occupa- 
tions involving  overexercise  of  parts  of  the  body,  684.  Occupations  involv- 
ing sedentary  life,  684.  Prophylaxis  in  general,  684.  Employment  of 
women  and  children,  685. 

CHAPTER  XIV. 

VITAL  STATISTICS 686 


Introductoiy,  686.     The  census,  687.     Estimated  population,  689.     Increase 
of  population,  690.     Population  constitution,  690.     Eegistrars'  returns,  691. 


CONTENTS.  11 

PAGE 

Marriage-rates,  692.  Birth-rates,  6(i3.  Death-rates,  695.  Influence  of  sex, 
695.  Influence  of  age,  695.  Influence  of  race,  696.  Influence  of  density, 
697.  Weekly  death-rates,  etc.,  698.  Zymotic  death-rate,  698.  Infantile 
death-rate,  698.  High  and  low  death-rates,  700.  Correction  of  death-rates, 
701.  Classification  of  causes  of  death,  702.  Registration  of  sickness,  702. 
Duration  of  life,  703.  Probable  duration  of  life,  703.  Mean  dui-ation  of 
life,  703.     Expectation  of  life,  703.     Life  tables,  704. 

CHAPTER   XV. 

PERSONAL  HYGIENE 706 

§  1.     Care  of  the  Person.     Baths 706 

§  2.     Regulation  op  the  Diet 708 

§  3.     Rest  and  Recreation 708 

§'4.     Physical  Exercise 709 

Effects  of  active  exercise,  709.  Circulation  and  respiration,  709.  Skin,  710. 
Nervous  system,  710.  Digestive  apparatus,  711.  Kidneys,  711.  Efl'ect  of 
exercise  on  weight,  711.  Amount  of  exercise  required,  712.  Kinds  of  exer- 
cise, 713.     Golf,  713.     Wheeling,  714.     Tennis,  etc.,  714.     Rowing,  714. 

§  5.     Clothing    .    .- 714 

Color,  714.  Texture,  714.  Heat  conductivity,  715.  Hygroscopicity,  715. 
Materials,  715.  Wool,  716.  Silk,  717.  Cotton,  718.  Linen,  719.  Rubber, 
719.  Leather,  720.  Fur,  720.  Felt,  720.  Adulteration  of  clothing,  720. 
Chemical  analysis,  721.  Microscopical  examination,  721.  Poisonous  dyes, 
721.     Selection  of  clothing,  722. 


CHAPTER   XVI. 

INFECTION,    SUSCEPTIBILITY,    IMMUNITY 724 

Exciting  causes  of  disease,  724.  Channels  of  infection,  724.  Infection  and 
contagion,  725.  Susceptibility,  725.  Ehrlich's  theory,  727.  Toxins  and  anti- 
toxins, 727.  Bacteriolysis,  732.  Hsemolysis,  733.  Complements,  737.  Im- 
mune bodies,  739.  Agglutinins,  740.  Precipitins,  742.  Metschnikoff's 
theory,  744.  Practical  applications  of  the  results  of  studies  in  immunity, 
745.  Diphtheria,  746.  Tetanus,  748.  Hay  fever,  748.  Dysentery,  749. 
Typhoid  fever,  749.  Asiatic  cholera,  751.  Bubonic  plague,  751.  Anti- 
streptococcus  serums,  753.     Tuberculosis,  754. 

CHAPTER  XVII. 
VACCINATION   AND  SMALLPOX 755 


12  CONTENTS. 

CHAPTER   XVIII. 

PAGE 

QUAEAXTINE .    761 

Quarantine,  761.  Law  of  1893,  763.  Interstate  quarantine,  767.  State  quar- 
antine, 767.  Sanitary  cordon,  769.  Municipal  quarantine,  769.  Camps  of 
detention,  770. 

CHAPTER  XIX. 

DISPOSAL    OF   THE    DEAD 771 

Earth  burial,  771.  Sites  for  cemeteries,  773.  Cremation,  773.  History  of 
modern  cremation,  775.     TaVjle  of  cremations  in  tlie  L'nited  States,  776. 


PRACTICAL  HYGIENE. 


CHAPTER  I. 

FOODS. 

Section  1.     GENERAL   CONSIDERATIONS. 

Foods  may  be  said  to  include  everything  taken  into  the  system 
capable  of  being  utilized  directly  or  indirectly  to  build  up  normal 
structure,  repair  waste,  or  produce  energy  in  any  form,  but  in  the 
common  acceptation  of  the  term  they  include  only  those  substances 
which  can  be  oxidized  in  the  system,  thus  excluding  water  and  air, 
without  which  the  functions  of  the  body  can  not  be  performed.  Diet 
is  a  mixture  of  food  materials  of  various  kinds  habitually  taken  in  such 
quantity  as  is  needed  to  maintain  or  improve  the  condition  of  the  system. 

The  Nutritive  Value  of  Foods. 

The  potential  energy  of  food  is  measured  by  the  amount  of  heat 
which  can  be  obtained  by  its  complete  combustion,  and  is  expressed  in 
units  of  heat  or  calories.  The  amount  of  energy  required  to  raise  the 
temperature  of  1  kilogram  of  water  1  °  C.  is  known  as  a  large  calorie ; 
that  required  to  raise  the  temperature  of  1  gram  to  the  same  extent 
is  known  as  a  small  calorie;  thus,  1  >rge  calorie  equals  1000  small 
calories.  When  the  term  is  used  without  qualification,  large  calories 
are  understood.  These  heat  units  correspond  to  425.5  units  of  work; 
that  is  to  say,  the  same  amount  of  energy  required  to  raise  the  tempera- 
ture of  the  given  weight  of  water  1°  C.  is  sufficient  to  raise  425.5 
times  the  weight  one  meter.  The  amount  of  work  done  is  expressed 
in  kilogram-meters. 

The  heat  unit  of  the  English  system  is  the  amount  of  energy  required 
to  raise  the  temperature  of  a  pound  of  water  1  °  F.,  and  its  mechanical 
equivalent  is  772  units  of  work ;  that  is  to  say,  the  same  amount  of 
energy  will  raise  772  pounds  one  foot.  According  to  the  English 
method,  work  done  is  expressed  in  foot  tons  rather  than  in  foot 
j)onn(ls. 

The  calorimetric  values  of  different  food  materials  express  also  their 

2  17 


18  FOODS. 

physiological  values  as  nutriment.     Rubner^   determined   the  calori- 
metric  value  of  the  proximate  principles  as  follows  : 


One  gi-am  of  proteids  =  4.1  calories. 

One  gram  of  carbohydrates  =  4.1       " 
One  gi-am  of  fat  =  9.3       " 


In  the  system,  the  carbohydrates  and  fats  are  burned  completely  to 
carbonic  acid  and  water,  but  the  proteids  leave  a  residue  of  urea  incapa- 
ble of  still  further  oxidation.  It  is  estimated  that  the  physiological 
value  of  the  proteids  averages  only  about  75  per  cent,  of  their  calori- 
metric  value. 

The  calorimetric  value  of  different  foods  of  the  several  classes  is 
not  to  be  understood  as  bemg  exactly  the  same.  Thus,  two  kinds  of 
sugar  or  two  kinds  of  fat,  or  two  kinds  of  proteid  have  not  exactly  the 
same  calorimetric  values,  and  the  figures  above  given  are  to  be  under- 
stood only  as  fair  averages.  Rubner  ^  has  determined  by  actual  ex- 
perimentation the  relative  calorimetric  values  of  certain  food  materials, 
and  has  shown  that  100  grams  of  fat  are  equivalent  to  225  of  syntonin, 
or  232  of  starch,  or  234  of  cane  sugar,  or  243  of  muscle  fiber,  or  256  of 
grape  sugar.  In  other  words,  these  several  amounts  of  food  material  are 
isodynamic. 

Amount  of  Food  Necessary. 

For  the  maintenance  of  a  proper  degree  of  health  and  strength,  the 
individual  must  ingest  an  amount  of  food  sufficient  to  meet  the  dailv 
loss  of  nitrogen  and  carbon.  This  must  necessarily  vary  accordmg  to 
circumstances,  and  hence  no  rule  can  be  laid  down  to  fit  all  cases.  Tlie 
best  that  can  be  done  is  to  make  certain  general  rules  based  on  the 
amoimt  of  work  performed,  for  the  greater  the  amount  of  work  done, 
the  greater  the  amount  of  food  required  to  meet  the  necessary  consump- 
tion of  fuel  and  to  repair  the  tissues.  When  performing  heavy  labor, 
the  naturally  increased  desire  for  food  is  shown  particularly  in  the 
direction  of  fats,  and  secondarily  of  proteids. 

For  many  years  Voit's  estimate,  that  a  man  of  154  to  165  pounds, 
working  at  moderately  hard  labor  9  or  10  hours  a  day,  requires  118 
grams  of  proteid,  56  of  fat,  and  500  of  carbohydrates,  the  whole  yield- 
ing 3054.6  calories,  has  been  generally  accepted  as  correct.  Recently, 
however,  Chittenden^  has  demonstrated  conclusively  by  experiments 
extending  over  many  months,  the  subjects  being  men  engaged  in  intel- 
lectual pursuits,  soldiers,  and  athletes  in  training,  that  half  the  stated 
amount  of  proteids  is  ample  for  the  real  physiological  needs  of  the  body 
under  ordinary  conditions  of  life,  and  that  a  fuel  value  of  3000  cal- 
ories is  not  necessary,  the  diminution  in  the  proteid  intake  requiring  no 
additional  amount  of  non-nitrogenous  substances. 

Knowing  the  composition  of  a  given  article  of  food,  the  proteid,  fat, 
and  carbohydrate  value  of  a  given  weight  can  easily  be  determined  ; 
and  thus  one  can  construct  standard  dietaries  for  the  various  conditions 

1  Lehrbuch  der  Hygiene,  Leipsic,_1900,  p.  438^  ''  Ibidem,  p.  430. 

^  Physiological  Economy  in  Nutrition,  New  York.  1904. 


COMPOSITION  OF  FOODS.  19 

of  bare  subsistence,  rest,  and  performance  of  various  amounts  of  daily 
labor.  Up  to  the  present  time  it  has  been  customary  to  prescribe  the 
constituents  of  the  standard  diets  in  the  following  proportions  :  For 
each  part  of  proteids,  two-thirds  of  a  part  of  fat,  three  and  one-sixth 
parts  of  carbohydrates,  and  one-fourth  of  a  part  of  mineral  matter, 
the  proportion  of  1  part  of  nitrogen  to  15  of  carbon  being  maintained 
as  nearly  as  possible.  In  view,  however,  of  Chittenden's  results,  these 
proportions  should  be  changed,  not  only  on  account  of  the  fact  that  an 
excess  of  proteids  is  a  burden  to  the  system,  but  also  for  economical 
administration,  since  the  nitrogenous  foods  are,  as  a  class,  by  far  the 
most  expensive. 

In  any  dietary,  nutritive  value  must  not  be  the  sole  consideration, 
for  taste  and  variety  are  highly  important  and  the  palate  must  be  flat- 
tered. 

Composition  of  Foods. 

The  constituents  of  food  materials  are  partly  organic  and  partly  in- 
organic. The  organic  constituents  include  proteids,  fats,  carbohydrates, 
and  organic  acids ;  the  inorganic  include  water  and  mineral  salts. 

Proteids. — The  proteids  are  the  most  important  constituents  of  both 
animal  and  vegetable  foods,  and  their  presence  is  necessary  for  the 
carrying  on  of  all  the  phenomena  of  life.  They  are  very  complex 
colloid  substances  composed  of  carbon,  oxygen,  hydrogen,  nitrogen,  and 
sulphur,  possessing  common  properties  and  connected  in  very  close 
genetic  relationship.  They  are  divided  into  animal  proteids  and  vege- 
table proteids,  but  between  the  members  of  the  one  class  and  those  of 
the  other  there  are  no  important  chemical  differences,  and  they  are 
about  equal  in  nutritive  value.  Some  of  the  vegetable  proteids  are  not 
colloids,  for  according'  to  Schmiedeberg,  Weyl,  Maschka,  and  others, 
they  are  found  in  crystalline  form  in  the  tissues  of  certain  plants,  and 
notably  in  the  bean,  pea,  lentil,  and  various  nuts. 

Proteids  when  completely  split  up  by  acids  yield  as  end  products 
ammonia,  nitrogen,  organic  bases,  and  amido  acids.  They  are  never 
completely  absent  from  animal  and  vegetable  tissues,  but  their  amount 
in  different  substances  is  very  widely  variable,  some  foods  being  very 
rich  in  them,  while  in  others  they  exist  only  in  traces. 

Ingested  in  great  excess  of  the  needs  of  the  system,  they  are  likely 
to  cause  general  disturbance,  diarrhoea  and  albuminuria,  while  a  diet 
from  which  they  are  practically  excluded  will  cause  rapid  loss  of 
strength,  anaemia,  great  prostration,  and  greatly  diminished  resistance 
to  invasion  by  specific  diseases,  especially  tuberculosis  and  pneumonia. 

The  animal  proteids  are  more  rapidly  digested  than  the  vegetable 
proteids,  some  of  which  are  largely  wasted  through  imperfect  digestion. 
The  proteids,  whatever  their  source,  yield  in  the  main  the  same  prod- 
ucts of  digestion,  and  consequently  may  replace  each  other  in  the 
diet. 

The  most  com])letc  classification  of  proteids  is  that  of  Wroblewski,^ 
\)y  whom  they  are  divided  '\\\io  three  groups  as  follows  : 

'  Berichte  der  deutschen  chemischen  Gesellschaft,  1897,  30,  pp.  3045,  3052. 


20  FOODS. 

Geoup  I.     Albuminous  bodies  closely  related  to  q^^  albumin. 

1.  Albumins.  Soluble  in  water.  Egg  albumin,  senun  albumin, 
lactalbumin,  muscle  albumin,  vegetable  albumin. 

2.  Globulins.  Insoluble  in  water,  soluble  in  diliue  salt  solution. 
Egg  globulin  (vitellin),  serum  globulin,  lactoglobuliu,  fibrinogen,  mvo- 
sin,  vegetable  globulin. 

3.  Proteids  soluble  in  alcohol.  Substances  vers'  slightly  soluble  in 
water  and  salt  solutions,  soluble  in  dilute  alcohol,  some  in  strong  alco- 
hol.     Chiefly  of  vegetable  origin.     Very  rich  in  carbon. 

4.  Albuminates.  Products  of  the  action  of  alkalies  on  albumins. 
Slightly  soluble  in  water,  easily  soluble  in  alkalies. 

5.  Acid  albumins.  Products  of  the  action  of  acids  on  albumins. 
Soluble  in  ver^'  dilute  acids  and  alkalies.     Syntonin,  etc. 

6.  Coagulated  albumins.  Proteid  substances  coagulated  by  the 
action  of  heat  or  enzymes.      Fibrin,  para-casein,  etc. 

Group  II.  Compoimd  proteids  composed  of  molecules  which  consist 
of  an  albumin  group  (a^  plus  another  group,  usually  of  a  non- 
proteid  nature. 

1.  Glyco-proteids.     a^  plus  a  car1)ohydrate  group.     Mucin,  etc. 

2.  Haemoglobins,     a^  plus  a  coloring-matter  group. 

3.  Xucleo-albimiins.     Oj  plus  a  nuclein  group. 

4.  Caseins.  They  contain  no  tnie  nuclein  group.  With  rennet 
they  give  a  chai^acteristic  coagulation  reaction.  They  are  not  coagulated 
by  heat  like  albumin  nor  l:)y  enzyme  action  like  fibrin.  Milk  casein, 
legumin,  etc. 

5.  Xucleins.     Oj  plus  a  nuclein  acid  group. 

6.  Amyloids. 

GRorp  III.     Albuminoids. 
a,  Frame-work  substances. 

1.  Keratins.  Constituents  of  horn.  Attacked  with  difficulty  Ijy 
pepsin  and  tn-jisin.  They  contain  much  sulphur  and  yield  much 
t}'rosin. 

2.  Elastins.  Constituents  of  elastic  tissue.  They  contain  less  sul- 
phur and  yield  less  t^Tosin. 

3.  Collagens.  Constituents  of  connective  tissue,  bone,  and  caitilage. 
They  contain  very  httle  sulphur,  and  yield  no  aromatic  amido-acids. 
Gelatin,  isinglass,  chondrin.  collagen,  etc. 

h.  Albumoses  and  Peptones.  Products  of  hydrolytic  splitting  of 
various  proteid  substances.  Their  molecides  are  much  smaller  than 
those  of  the  albumins. 

c.  Enz^'mes.  Bodies  which  when  present  in  very  small  amounts  have 
the  property  of  lireaking  up  very  large  amounts  of  certain  other  sub- 
stances, including  proteids,  fats,  starches,  etc. 

The  albumins  are  not  precipitated  by  alkaline  carbonates,  common 
salt,  or  dilute  acids,  but  they  are  coagulated  by  being  heated  to  65°— 
73°  C.  Casein,  legumin.  conglutin.  syntonin,  and  aibiuninates,  on  the 
contrary,  are  not  coagulable  by  heat,  but  are  precijtitated  by  common 
salt,  sodium   acetate,  and   trisodium    phosphate.     The    albumoses    are 


COMPOSITIOy   OF  FOODS.  21 

widely  distributed  throughout  the  vegetaljle  kingdom,  and  are  found 
largelv  in  the  cereals.  In  the  animal  kingdom,  they  are  intermediate 
products  of  the  action  of  pepsin  on  ordinar\^  proteids,  becoming  even- 
tually conyerted  to  peptones.  The  collagens  are  ver\-  rich  in  nitrogen, 
Ijut  Lave  an  inferior  nutritive  value.  Gelatin,  for  instance,  contains 
17-18  per  cent.,  while  the  albumins  contain  but  16. 

Fats. — The  fats  are  compounds  of  the  triatomic  alcohol,  glycerin, 
with  fatty  acids,  mainly  stearic,  palmitic,  and  oleic.  These  several 
compounds  are  known  as  stearin,  palmitin,  and  olein.  The  t^vo  first 
mentioned  are  solids  at  usual  temperatures,  while  olein  is  a  liquid. 
Most  fats  are  combinations  of  tvvo  or  all  of  these  substances,  and  some, 
as,  for  example,  butter,  contain  additional  glycerides  in  small  amount. 
Stearin  and  palmitin  being  solids,  and  olein  liquid,  the  consistency  of 
a  fat  is  dependent  upon  the  proportions  in  which  these  substances  are 
present.  Stearin  is  a  component  of  most  animal  fats,  but  never  is 
found  in  vegetable  fats.  The  chief  constituent  of  animal  fats  is  pal- 
mitin, and  this  occurs  also  in  nearly  all  vegetable  fats.  Olein  exists 
in  both.  Butyrin,  caprin,  caproin,  and  caprylin  are  glycerides  of 
volatile  fatty  acids  present  in  the  fat  of  milk. 

Fats  consist  of  carbon,  hydrogen,  and  oxygen,  and  contain  no  nitro- 
gen. The  hydrogen  and  oxygen  are  not  present  in  the  proportions  in 
which  they  exist  in  water  and  in  carbohydrates,  the  oxygen  being  de- 
ficient. ' 

As  taken  in  food,  fats  are  chiefly  in  the  form  of  neutral  substances, 
but  more  or  less  free  fatty  acid  is  always  present,  and  in  some  foods 
which  have  been  kept  for  a  time,  particularly  in  well-ripened  cheese, 
fatty  acids  may  be  present  in  a  free  state  in  quite  large  proportion. 

The  fats  play  an  important  part  in  the  maintenance  of  animal  heat 
and  mechanical  energy.  When  hard  labor  is  being  performed,  an  excess 
of  fat  is  instinctively  taken. 

Carbohydrates. — The  carbohydrates  include  the  starches,  sugars, 
and  cellulose. 

The  Starches,  though  presenting  very  different  appearance-  under 
the  microscope  according  to  source,  are  of  equal  value  as  food-,  and 
have  the  same  composition.  Starch  is  insoluble  in  water,  but,  heated 
with  it  to  72°  C,  the  cells  swell  and  burst,  and  produce  a  sort  of 
mucilage.  Heated  with  dilute  mineral  acids,  it  is  converted  into  dex- 
trose.     Suljjected  to  the  action  of  diastase,  it  is  converted  into  maltose. 

Starch  is  found  almost  exclusively  in  vegetable  cells.  It  forms  the 
chief  part  of  the  seeds  of  the  cereals  and  of  the  dried  residue  of  certain 
other  vegetable  products,  such  as  potatoes.  A  form  of  starch  known 
as  animal  starch  or  glycogen  is  found  in  the  liver  and  muscles,  and  also 
in  some  of  the  mollusca.  Dextrin  is  an  artificial  ])rriduct  formed  from 
starch  by  the  action  of  ferments  or  r.f  dilute  acid^  and  lipfit. 

The  Sugars  are  of  vegetable  and  animal  oi'iLiiii,  and  indnd  ■  the 
following : 

1.  Sucrose,  cane  sugar.  A  disaccharid.  From  sugarcane,  mi-mIhiih, 
sugar  maple,  sugar  beet,  and  some  other  vegetable  sources.      Jii:~'i]ul)lo 


22  FOODS. 

in  strong  alcohol,  does  not  reduce  copper ;  not  directly  fermentable. 
Boiled  with  dilute  acids,  is  converted  to  invert  sugar,  a  mixture  of 
dextrose  and  Isevulose. 

2.  Dextrose,  glucose,  grape  sugar.  A  monosaccharid.  Found  in 
many  fruits  and  flowers.  Formed  from  cane  sugar,  maltose,  starch, 
and  dextrin  by  boiling  with  dilute  acids.  In  the  presence  of  decom- 
posing proteids,  splits  into  two  molecules  of  lactic  acid.  Fermented 
with  yeast,  splits  into  alcohol  and  carbonic  acid. 

3.  Maltose,  malt  sugar.  A  disaccharid.  (Two  molecules  of  dex- 
trose.)    Formed  from  starch  by  the  action  of  diastase. 

4.  Lsevulose,  fruit  sugar.  A  monosaccharid.  Found  in  honey  and 
various  fruits.  Rotates  the  ray  of  polarized  light  to  the  left.  Does 
not  form  crystals.      Isomeric  with  dextrose. 

5.  Lactose,  milk  sugar.  A  disaccharid.  (Dextrose  and  galactose.) 
Found  only  in  milk.      Behaves  like  dextrose. 

6.  Galactose.  A  monosaccharid.  Formed  from  lactose  by  boiling 
Avith  dilute  mineral  acids. 

7.  luosite,  muscle  sugar,  phaseomannite.  Found  in  certain  animal 
tissues,  as  the  heart's  muscle,  and  in  certain  plants,  as  peas,  beans,  and 
grapes.  Has  no  rotatoiy  power,  does  not  reduce  copper,  and  is  not  fer- 
mentable. It  contains  the  benzene  ring,  and  hence  is  not  a  true  sugar. 
In  the  presence  of  decomposing  jjroteids,  it  is  converted  into  lactic  and 
butyric  acids. 

Cellulose. — Cellulose,  while  of  value  as  a  food  for  herl)ivora,  has  no 
nutritive  value  for  man.  It  is  converted  to  dextrose  by  boiling  with 
dilute  sulphuric  acid. 

Pectin. — Pectin  is  a  substance  not  uncommonly  classified  as  a  car- 
bohydrate. It  is  composed  of  carbon,  hydrogen,  and  oxygen,  but  its 
precise  composition  is  unknown.  It  is  found  in  various  fleshy  fruits 
and  in  roots,  and  is  believed  to  be  formed  from  pectose  by  the  action 
of  vegetable  acids.      It  is  known  also  as  vegetable  jelly. 

Pectose. — Pectose  is  an  insolul:)le  substance  found  in  unripe  fruits 
and  roots  :  an  earlier  stage  of  pectin. 

The  carbohydrates  play  an  imj)ortant  part  in  the  maintenance  of 
heat  and  the  production  of  force.  They  lessen  the  need  of  fat  and 
form  fatty  tissue.  Excessive  ingestion  interferes  with  the  metamor- 
phosis of  nitrogenous  tissue,  causes  deposition  of  fat  in  excess,  and  is 
likely  to  produce  digestive  disturbances.  Deprivation  for  a  time  can 
be  borne,  provided  the  system  receives  sufficient  fatty  food,  but  not 
otherwise. 

Organic  Acids. — The  organic  acids  exist  in  foods  either  in  the  free 
state  or  in  combination  as  salts.  In  the  system  they  are  converted  to 
carbonates,  which  exercise  a  most  important  influence  in  controlling 
the  alkalinity  of  the  blood  and  other  fluids.  Deprivation  leads  to  a 
peculiar  disturbance  of  the  system  resulting  in  scurvy.  They  include 
malic,  acetic,  lactic,  oxalic,  citric,  and  tartaric  acids.  Malic  acid  is  a 
constituent  of  apples,  pears,  and  some  other  fruits.  Acetic  acid  is  the 
essential    element  of  vinegar.     Oxalic  acid  is    found  in  considerable 


ANIMAL  FOODS:   MEATS,  FISH,   EGGS,  AND  MEAT  PRODUCTS.    23 

amounts  in  spinach,  tomatoes,  strawberries,  sorrel,  and  rhubarb.  Lactic 
acid  is  present  in  fresh  meats  and  in  milk.  The  two  most  important 
acids  are  citric  and  tartaric.  The  former  is  found  in  oranges,  lemons, 
limes,  and  other  fruits ;  the  latter  largely  in  grapes. 

Not  all  vegetables  contain  these  acids,  and,  therefore,  not  all  have 
antiscorbutic  properties.  Potatoes,  cabbage,  and  roots  are  very  effici- 
ent in  this  respect,  while  peas  and  beans  are  notable  examples  to  the 
contrary. 

Inorganic  Salts. — The  important  inorganic  salts  taken  into  the 
system  with  food  include  sodium  and  potassium  chlorides,  sodium, 
potassium,  magnesium  and  calcium  phosphates,  and  compounds  of  iron. 
The  sulphates  are  of  minor  importance  and  are  ingested  m  only  small 
amounts.  The  sulphur  essential  to  growth  is  taken  into  the  system  in 
combination  in  the  proteids.  The  chlorides  keep  the  globulins  of  the 
blood  and  other  fluids  of  the  body  in  solution,  and  are  the  source  of  the 
hydrochloric  acid  of  the  gastric  juice.  The  phosphates  are  very  essential 
to  the  growth  of  bone  and  to  the  nervous  system,  and  iron  is  needed  for 
the  haemoglobin  of  the  blood.  Deficiency  of  calcium  and  magnesiiun 
salts  leads  to  rickets  and  other  abnormal  conditions. 


Section  2.     ANIMAL   FOODS:   MEATS,   FISH,   EGGS, 
AND  MEAT   PRODUCTS. 

The  foods  of  animal  origin  used  by  man  include  the  flesh  and  various 
organs  of  the  herbivora  and  swine,  domestic  and  wild  fowl,  eggs,  fish 
and  shellfish,  milk  and  milk  products.  The  flesh  of  all  carnivorous 
animals  except  fish  is  unpalatable,  and,  therefore,  undesirable  as  food, 
though  under  stress  of  circumstances  it  may  be  borne.  Thus,  during 
the  siege  of  Paris,  about  5,000  cats  and  1,200  dogs  are  said  to  have 
been  eaten  when  the  food  supply  had  become  so  meagre  that  anything 
in  the  form  of  flesh  was  acceptable.  In  Germany,  according  to  a  com- 
munication of  Consul-General  Guenther  to  the  State  Department  at 
AVashington,  under  date  of  May  26,  1900,  the  statistical  year-book 
shows  that,  on  account  of  the  high  price  of  other  meats,  not  only  horses, 
iHit  also  dogs  are  much  used  as  food.  At  Breslau,  Chemnitz,  Dresden, 
Leipzig,  Zwickau,  and  other  places,  dogs  are  slaughtered  extensively 
for  this  purpose  and  regularly  inspected. 

PirP  reports  that  in  Saxony  during  1894,  295  ;  in  1895,  388  ;  in 
1896,  399;  and  in  1897,  474  dogs  were  slaughtered  and  inspected. 
In  Dessau,  between  1893  and  1898,  the  number  averaged  251  yearly, 
and  inspection  showed  that  one  in  202  was  trichinous.  According 
to  Tempel,^  of  289  killed  at  Chemnitz  during  1897,  1.391  per  cent., 
and  of  147  killed  during  the  first  half  of  the  year  1898,  2.04  per 
cent,  were  found  to  be  trichinous.  The  meat  is  eaten  chiefly  in  the 
roasted  state,  but  also,  in  many  parts  of  Saxony,  raw,  but  highly  sea- 

'  Zcitsfhrirt  fiir  Flcisch-  und  Milchhygiene,  X.,  No.  1. 
'  Ibidem,  IX.,  No.  1. 


24  FOODS. 

soned.  The  same  animals  are  commonly  eaten  by  the  Chinese,  and  the 
Canada  lynx  and  the  skunk  are  rated  as  delicacies  by  the  North  Ameri- 
can Indians. 

MEATS. 

The  value  of  meat  as  food  depends  upon  the  presence  of  proteids, 
fat,  and  mineral  salts.  The  nitrogenous  extractive  matters  (creatin, 
etc.),  sometimes  called  "  meat  bases,"  formed  by  cleavage  of  the  pro- 
teids,  give  flavor,  but  have  little  value  as  foods.  The  carbohydrates 
play  but  an  insignificant  part,  being  present  chiefly  as  muscle  sugar  and 
to  only  a  very  small  extent.  All  meat,  however  lean,  contains  fat,  some 
of  which  is  visible  and  some  indistinguishable  from  the  muscle  fibres  by 
which  it  is  surrounded.  The  visible  fat  varies  widely  in  amount. 
Very  fat  beef  may  contain  considerably  more  than  a  quarter  of  its 
weight  of  visible  fat,  and  fat  pork  meat  more  than  a  half,  while  chicken 
and  veal  contain  comparatively  little. 

The  content  of  water  varies  very  widely  and  in  general  may  be  said 
to  be  governed  by  the  richness  in  fat,  for,  while  the  proteids  are 
fairly  constant  in  amount,  the  remainder  is  almost  wholly  water  and 
fat,  and  the  greater  the  amount  of  the  one,  the  less  the  amount  of 
the  other.  The  less  fat  a  meat  contains,  the  less,  therefore,  its  relative 
nutritive  value. 

Digestibility. — While  the  amount  of  nutriment  contamed  in  meats 
chiefly  determines  their  food  value,  the  latter  is  to  no  inconsiderable 
extent  dependent  upon  the  ability  of  the  alimentary  tract  to  digest  and 
absorb  them.  Gastric  digestion  is  by  no  means  to  be  accepted  as  a 
measure  of  the  true  digestibility  of  a  food,  and  the  same  is  true  of  the 
results  of  artificial  laboratory  experiments  ;  hence  many  of  the  accepted 
statements  bearing  on  this  subject,  based  upon  the  oft-quoted  experi- 
ments on  Alexis  St.  Martin  and  upon  test-tube  observations,  may  be 
wholly  disregarded. 

Raw  meat  is  digested  more  easily,  but  less  completely,  than  that 
which  has  undergone  the  process  of  cooking,  and  roasted  meat  is  more 
completely  digested  than  that  which  has  been  boiled.  Fat  meats,  as 
beef  and  mutton,  and  especially  pork,  require  more  time  for  digestion 
than  those  which,  like  chicken  and  veal,  contain  but  little  fat.  In 
general,  it  may  be  said  that  meats  are  assimilated  more  easily  than  vege- 
table foods. 

Flavor. — The  flavor  of  meats  depends  largely  upon  the  nature  and 
amounts  of  nitrogenous  extractives  which  they  contain,  and  is  greatly 
modified  by  the  condition  of  the  animal  when  killed,  its  age,  sex,  and 
the  character  of  its  food.  The  high  flavor  of  birds  and  game  is  due  to 
the  richness  in  extractives,  while  in  the  case  of  meats  deficient  in  these 
substances,  as,  for  example,  mutton  and  pork,  the  flavor  is  due  largely 
to  their  contained  fats.  Most  meats  are  improved  in  flavor  by  being 
kept  for  a  time,  during  which,  additional  flavors,  due  to  decompo- 
sition products  similar  to  the  extractives,  are  developed.  The  meat 
of  young   animals    is  flavored  less  highly  than    that  of  adults,    and 


MEATS.  25 

that  of  females  than  that  of  males,  though  in  the  case  of  the  goose 
this  condition  is  reversed,  and  in  that  of  swine  no  diiference  is  ob- 
servable. 

Asexualization  by  spaying  or  castration  produces  a  fatter,  more 
tender,  and  better  flavored  meat.  Thus,  the  flesh  of  oxen  is  far  pre- 
ferable to  that  of  bulls  or  cows,  and  that  of  capons  and  poulards  to 
that  of  cocks  and  hens. 

Texture. — Whether  a  given  meat  is  tough  or  tender  depends  upon 
the  character  of  the  walls  of  the  muscle  tubes  and  upon  the  amount  of 
connective  tissue  present.  The  tube  walls  are  thin  and  delicate,  and 
the  connective  tissue  is  small  in  amount  in  the  young  and  well-fed,  but 
as  the  animal  becomes  older  or  is  made  to  work,  the  tubes  thicken  and 
become  hard,  the  connective  tissue  increases  in  amount,  the  fat  may 
diminish,  and  the  result  is  a  coarser  flesh.  Very  young  animals  have 
a  very  watery,  gelatinous,  and  flavorless  flesh. 

The  texture  of  meat  undergoes  very  considerable  change  after 
slaughter.  When  freshly  slaughtered,  it  is  tender  and  juicy,  bvit  as 
rigor  mortis  supervenes,  it  becomes  hardened  and  tough.  The  stage 
of  rigor  is  succeeded  by  the  first  stage  of  decomposition,  during  which 
lactic  acid  is  formed.  This  acts  upon  the  connective  tissue  and  causes 
softening  and  tenderness,  and  as  the  process  of  decomposition  proceeds 
within  proper  limits,  increase  of  flavor  is  developed. 

Effects  of  Cooking". — When  meat  is  cooked,  the  connective  tissue 
is  softened,  the  bundles  of  fibrillae  are  loosened  from  each  other,  the 
albumin  is  coagulated,  flavors  are  improved  and  new  ones  developed, 
parasites  and  micro-organisms  are  destroyed,  and  the  whole  mass  is 
rendered  more  acceptable  to  the  eye  and  palate.  In  the  process  of 
roasting  or  broiling,  considerable  shrinkage  due  to  loss  of  water  occurs. 
The  heat  to  which  the  meat  is  subjected  should  be  sufficiently  intense  to 
produce  speedy  coagulation  of  the  exterior  and  prevent  the  meat  juices 
from  becoming  dried  up.  In  order  that  the  surface  shall  not  be  burned, 
the  meat  must  be  basted  from  time  to  time  with  hot  melted  fat,  which 
forms  a  protective  coating.  The  heat  employed  should  be  less  intense 
with  large  joints  than  with  small  ones,  since  before  the  heat  can  pene- 
trate well  into  the  interior,  the  outer  parts  will  become  burned. 

In  boiling,  the  temperature  of  the  water  into  which  the  meat  is  im- 
mersed varies  according  to  the  object  sought.  If  a  rich  broth  is  de- 
sired, the  meat  is  placed  in  cold  water,  which  then  is  heated  gradually. 
During  the  heating  process,  the  soluble  albumins  together  with  a  por- 
tion of  the  salts  and  the  extractives  are  dissolved  out.  When  the  tem- 
perature reaches  134°  F.,  the  albumin  begins  to  coagulate,  and  above 
160°,  the  connective  tissue  is  changed  to  gelatin  and  dissolved.  The 
solution  of  certain  of  the  constituents  is  assisted  by  the  small  amounts 
of  lactic  acid  formed. 

If,  on  the  other  hand,  it  is  desired  to  have  the  juices  and  flavors  re- 
tained within  the  mass,  the  meat  chould  be  plunged  into  boiling  water, 
which  fjiiickly  coagulntes  the  albumins  at  tlu;  surfiiccand  ciuises  thereby 
the  formation  of  a  protective  cf^ating.     After   this  is  fornied,  the  tern- 


26  FOODS. 

perature  should  be  lowered  to  about  180°  F.,  for  otherwise  the  meat  be- 
comes tough,  even  to  the  center.  The  shrinkage  in  meat  that  has  been 
properly  boiled  amounts  to  from  20  to  40  per  cent,  of  its  weight. 

In  frying,  the  meat  is  dropped  into  very  hot  fat,  as  lard  or  vegetable 
oil,  which  causes  speedy  coagulation  of  the  surface,  such  as  is  brought 
about  in  the  process  of  boiling,  whereby  all  the  flavors  and  juices  are 
retained.  It  is  essential  that  the  fat  be  very  hot,  since  otherwise  it 
Avill  penetrate  the  tissues  and  cause  the  meat  to  become  greasy  and  un- 
palatable. 

In  stewing,  the  meat  is  cut  into  small  pieces  and  placed  in  cold  water, 
which  then  is  heated  slowly  to  about  180°  F.,  at  which  temperature 
the  whole  is  kept  for  several  hours.  If  heated  above  180°,  the  meat 
becomes  tough,  stringy,  unpalatable,  and  of  diminished  digestibility. 

Characteristics  of  Good  Meat. — Meat  should  have  a  uniform  color, 
neither  abnormally  pale  nor  inclined  to  purplish.  It  should  have  little 
or  no  odor,  and  such  as  it  has  should  give  no  disagreeable  impression 
such  as  the  sickly  cadaveric  smell  characteristic  of  diseased  or  decom- 
posing flesh.  It  should  be  firm  and  elastic,  and  should  not  pit  nor  crackle 
on  pressure.  On  being  handled,  it  should  scarcely  moisten  the  fingers, 
and  with  keeping,  the  exterior  should  become  dry  rather  than  wet. 
There  should  be  no  evidence  whatever  of  the  presence  of  parasites. 

Beef  has  a  bright  red  color  and  a  marbled  appearance,  due  to  the 
presence  of  fat  between  the  bundles  of  muscular  fibers.  This  marbling 
is  much  less  apparent  in  the  flesh  of  animals  that  have  not  been  well 
fed  and  of  old  cows  and  bulls.  Bull  meat  is  darker  than  that  of  oxen 
and  cows,  and  is  coarse,  stringy,  and  of  strong  flavor. 

Veal  is  much  paler  than  beef  and  less  firm  to  the  touch,  and  coming 
from  a  very  young  animal,  "  bob-veal,"  it  is  flabby  and  watery,  and  its 
fat  has  a  tallowy  appearance. 

Mutton  should  be  of  a  dull-red  color  and  firm  to  the  touch.  Its  fat 
is  white,  sometimes  yellowish,  and  hard. 

Lamb  is  somewhat  less  firm  to  the  touch  and  has  a  decidedly  lighter 
color  than  mutton. 

Pork  is  much  less  firm  to  the  touch  than  beef  and  mutton,  and  its 
fat  is  quite  soft  in  comparison. 

Horse  meat,  the  use  of  which  is  increasing  rapidly  abroad  and  to  a 
much  greater  extent  in  this  country  than  is  commonly  believed,  is 
darker  and  coarser  than  beef  and  possesses  a  very  different  odor.  TKs 
fat  is  yellow  and  oily  and  has  a  rather  disagreeable  odor. 

The  flesh  of  birds  is  not  marbled  like  that  of  mammals.  That  of 
Avild  fowl  that  feed  on  fish  has  a  strong  flavor,  which  is  not  improved 
by  keeping. 

Comparative  Digestibility  of  Meats. — Beef  is  commonly  and  cor- 
rectly regarded  as  one  of  the  most  digestible  of  meats,  but  according  to 
the  experience  and  testimony  of  many  victims  of  dyspepsia  it  is  mterior 
in  this  respect  to  mutton.  Pork  is,  without  doubt,  digested  with 
greater  difficulty  than  any  other  meat,  on  account  of  its  high  content 
of  fat.     The  evidence  as  to  veal  is  most  conflicting,  some  holding  that 


ME  A  TS.  27 

it  is  digested  very  easily,  while  others  maiutaiu  the  contrary  view. 
Certain  it  is  that  many  persons  bear  it  very  l^adly.  The  white  meat 
of  chickens,  fowls,  and  turkeys,  is  more  delicate  and  is  digested  more 
easily  than  the  dark  meat,  probably  by  reason  of  its  smaller  amount 
■of  fat.  The  flesh  of  ducks  and  geese  is  harder,  richer,  and  more  diffi- 
■cult  of  digestion.  Game  birds  are  less  fat  than  poultry  and  are  often 
much  better  borne.  Their  habits  of  life  are  unfavorable  to  the  depo- 
sition of  much  fat.  Liver,  kidneys,  and  heart  are  generally  regarded 
■as  unsuitable  as  foods  for  persons  with  weak  stomachs,  but  tripe  and 
sweetbreads  are  usually  easily  borne. 

*'  Red  Meat  "  and  "  White  Meat." — The  prohibition  of  red  meats 
(beef,  mutton,  venison)  to  patients  with  gouty  and  rheumatic  tendencies 
dates  from  the  time  of  Sydenham,  whose  dietetic  rules  allowed  only 
the  white  meats  (veal,  goat,  young  pig,  chicken)  and  fish  to  such 
persons.  Today,  many  practitioners  extend  this  prohibition  to  those 
with  diseases  of  the  stomach,  intestines,  and  kidneys,  and  various 
neuroses.  The  foundation  of  this  prejudice  against  the  red  meats  is  the 
supposed  presence  in  them  of  a  greater  percentage  of  the  nitrogenous 
extractives  (creatin,  xanthin,  guanin,  etc.),  which  are  believed  to  exert 
injurious  action  in  two  ways  :  First,  locally,  by  irritating  the  kidneys 
during  the  process  of  their  elimination  from  the  body ;  and  second,  in 
cases  of  impaired  functional  activity  of  the  kidneys,  by  causing  systemic 
intoxication.  Unfortunately,  however,  for  the  stability  of  this  belief, 
exact  analysis  has  shown  that  the  very  small  amounts  of  these  sub- 
stances present  are  practically  the  same  in  both  red  and  white  meats, 
with  the  single  exception  of  venison,  which  contains  them  not,  as  would 
be  surmised,  in  highest  percentage,  but,  in  fact,  in  lowest.  Further- 
more, these  extractives  are  not  eliminated  as  such,  but  as  the  normal  ulti- 
mate product  of  metamorphosis,  urea.  It  has  been  supposed,  too,  that 
the  non-nitrogenous  extractives  (lactic,  butyric,  and  acetic  acids,  etc.)  are 
present  to  a  greater  extent  in  red  than  in  white  meats  and  may  cause 
disturbance ;  but  as  a  matter  of  fact,  these  are  present  in  extremely 
small  amounts  in  both  red  and  white  meat,  and  cannot  possibly  be 
regarded  as  harmful,  in  view  of  the  fact  that  appreciable  amounts  exert 
no  influence  on  the  system. 

Composition  of  Meats. — In  the  following  tables,  showuig  the  com- 
position of  the  ediljle  portions  of  meats,  the  figures  given  are  taken, 
unless  otherwise  stated,  from  Bulletin  No.  28  (revised  edition)  of  the 
Office  of  Experiment  Stations  of  the  U.  S.  Department  of  Agriculture  : 
The  Chemical  Composition  of  American  Food  Materials. '^ 
^  Government  Printing  Office,  Washington,  1899. 


28 


FOODS. 
BEEF. 


Cut. 

SI 

u 

2 
'S 

o 

1^ 

< 

t>  O  t! 

p  So 
^  p.— 

Brisket,  medium  fat 

Chuck,  including  shoulder. 

3 

1 
2 

4 
4 
2 

54.6 

73.8 
71.3 
68.3 
62.3 
53.2 

15.8 

22.3 
20.2 
19.6 
18.5 
17.2 

28.5 

3.9 

8.2 
11.9 
18.8 
29.0 

0.9 

0.8 
1.0 
0.9 
0.9 
0.9 

1495 
580 

lean 

medium  fat 

720 
865 

fat 

very  fat 

1135 
1555 

Average 

13 

65.0 

19.2 

15.4 

0.9 

1005 

Chuck  rib,  very  lean , 

lean 

medium  fat 

1 

11 

7 

2 

21 

75.8 
71.3 
62.7 
52.0 

22.2 
19.5 
18.5 
16.6 

1.4 

8.3 
18.0 
31.1 

1.1 
1.0 
1.0 

0.8 

470 

715 

1105 

fat 

1620 

Average 

66.8 

19.0 

13.4 

1.0 

920 

Flank,  very  lean 

lean 

medium  fat  .    .    .        

fat 

3 
3 
5 
3 
2 

70.7 
67.8 
60.2 
54.2 
34.7 

25.9 
20.8 
18.9 
17.1 
14.0 

3.3 
11.3 
21.0 

28  4 
51.8 

1.2 
1.0 
0.9 
0.8 
0.7 

620 

865 

1240 

1515 

very  fat 

2445 

Average 

16 

59.3 

19.6 

21.1 

0.9 

1255 

3 

12 

32 

6 

3 

70.8 
67.0 
60.6 
54.7 
49.7 

24.6 
19.7 
18.5 
17.5 
17.8 

3.7 

12.7 
20.2 
27.6 
32.3 

1.3 
1.0 
1.0 
0.9 
0.9 

615 

900 

medium  fat 

fat                  

1190 
1490 

1695 

56 

61.3 

19.0 

19.1 

1.0 

1155 

Porterhouse  steak 

7 

21 

1 

6 

60.0 
61.9 
42.2 
59.2 

21.9 

18.9 
13.8 
16.2 

20.4 
18.5 
43.7 
24.4 

1.0 
1.0 
0.8 
0.8 

1270 
1130 

Top  of  sirloin 

2100 

Tenderloin 

1330 

4 

6 

15 

9 

1 

65.7 
67.9 
55.5 
48.5 
45.9 

21.9 
19.6 
17.5 
15.0 
14.6 

1.1 
12.0 
26.6 
35.6 

38.7 

0.7 
1.0 
0.9 
0.7 
0.6 

455 

870 

1450 

fat 

1780 

very  fat    ...    .        

1905 

Average 

35 

57.0 

17.8 

24.6 

0.9 

1370 

Eib  rolls,  very  lean 

lean 

medium  fat 

2 
3 
4 
2 

73.7 
69.0 
63.9 
51.5 

20.8 
20.2 
19.3 
17.2 

5.0 
10.5 
16.7 
31.3 

1.0 

1.0 
0.9 
0.8 

600 

820 

1065 

fat 

1640 

Average 

11 

64.8 

19.4 

15.5 

0.9 

1015 

Round,  very  lean 

6 
31 
18 

5 

2 

73.6 
70.0 
65.5 
60.4 
55.9 

22.6 
21.3 
20.3 
19.5 

18.2 

2.8 

7.9 

13.6 

19.5 

26.2 

1.3 
1.1 
1.1 

1.0 
0.8 

640 
730 
950 

fat 

1185 

very  fat 

1445 

62 

67.8 

20.9 

10.6 

1.1 

835 

Round,  second  cut 

2 

69.8 

20.4 

8.6 

1.1 

740 

Rump,  very  lean 

lean 

medium  fat 

fat 

4 
4 
10 
5 
1 

71.2 
65.7 
56.7 
47.1 
40.2 

23.0 
20.9 
17.4 
16.8 
15.0 

5.1 
13.7 
25.5 
35.7 
44.3 

1.2 

1.0 
0.9 
0.8 

0.8 

645 

965 

1400 

1820 

very  fat 

2150 

24 

57.9 

18.7 

23.1 

0.9 

1325 

MEATS. 


29 


BEEF. — Continued. 


Cut. 

<4-l 

O  w 

S 
2 

1 

< 

Beef  heart 

Kidney  (carbohydrates  0.4)     ... 
Liver  (carbohydrates  1.5)    .... 
Marrow 

2 
3 

6 

1 
3 
1 
9 

62.6 
76.7 
71.2 
3.3 
70.8 
79.7 
13.7 

16.0 
16.6 
20.7 

2.2 
18.9 
16.4 

4.7 

20.4 
4.8 
4.5 

92.8 
9.2 
3.2 

81.8 

1.0 
1.2 
1.6 
1.3 
1.0 
1.0 
0.3 

1160 
520 
605 

3955 
740 

440 

Suet      

3540 

Eoast  beef  (cut  not  specified)  .   .    . 

Sirloin  steak,  baked 

Broiled  tenderloin      

7 

1 

6 

18 

48.2 
63.7 
54.8 
63.0 

22.3 
23.9 
23.5 
27.6 

28.6 
10.2 
20.4 

7.7 

1.3 
1.4 

1.2 
1.8 

1620 
875 

1300 
840 

Canned  corned  beef 

Canned  roast  beef 

Canned  whole  tongue 

Canned  tripe 

15 
4 
5 

2 

51.8 
58.9 
51.3 
74.6 

26.3 
25.9 
19.5 

16.8 

18.7 
14.8 
23.2 

8.5 

4.0 
1.3 
4.0 
0.5 

1280 

1105 

1340 

670 

Corned  beef  (all  cuts) 

Tongues,  pickled 

Tripe  (carbohydrates  0.2)      .... 

10 

2 
4 

53.6 
62.3 

86.5 

15.6 
12.8 
11.7 

26.2 

20.5 

1.2 

4.9 
4.7 
0.3 

1395 

1105 

270 

POEK. 


Cut. 

-2 

2 
0 

Ph 

< 

•g§.2 

Ham,  fresh,  lean 

medium  fat 

fat 

2 

10 

5 

3 

1 

19 

4 

11 

19 

8 

3 

2 

1 

60.0 
53.9 
38.7 
64.5 
60.3 
52.0 
41.8 
66.5 
51.2 
50.7 
43.3 
77.8 
71.4 

25.0 
15.3 
12.4 
19.2 
20.3 
16.6 
14.5 
18.9 
13.3 
8.3 
19.5 
15.5 
21.3 

14.4 
28.9 
50.0 
16.2 
19.0 
30.1 
44.4 
13.0 
34.2 
17.4 
33.8 
4.8 
4.5 

1.3 
0.8 
0.7 
0.9 
1.0 
1.0 
0.7 
1.0 
0.8 
0.4 
3.3 
1.2 
1.4 

1075 
1505 
2345 

visible  fat  largely  removed  .    . 
Xioin  (chops),  lean 

medium  fat 

fat . 

Tenderloin 

Shoulder  

1040 
1180 
1580 
2145 
900 
1690 

Feet      

1090 

Head  cheese 

1790 

Kidney     

Liver  (carbohydrates  1.4)    .... 

490 
615 

Ham,  smoked,  lean 

medium  fat 

fat 

3 

14 
4 

2 
8 
2 
7 
4 
2 
17 

53.5 
40.3 

27.9 
51.3 
45.0 
26.5 
7.9 
19.9 
31.8 
18.8 

19.8 

16.3 

14.8 

20.2 

15.9 

15.1 

1.9 

8.4 

15.5 

9.9 

20.8 
38.8 
52.3 
22.4 
32.5 
53.6 
86.2 
67  1 
42.6 
67.4 

5.5 
4.8 
3.7 
6.1 
6.7 
5.2 
3.9 
5.7 
11.0 
4.4 

1245 
1940 

2485 

smoked,  boiled 

Shoulder,  smoked,  medium  fat    .    . 
fat 

1320 
1665 
2545 

Salt  pork,  fat 

lean  ends     

Bacon,  smoked,  lean 

medium  fat 

3670 

'     2985 

2085 

3030 

30 


FOODS. 
VEAL. 


Cut. 


Breast,  lean  .    . 

medium  fat 

Leg,  lean  .  .  . 
medium  fat 
cutlets    .    . 

Loin,  lean  .  . 
medium  fat 
fat   ...    . 

Heart     .... 

Kidney  .... 

Liver      .... 


«4H 

1 

O   M 

m 

t-  s 

u 

-c 

="  £. 

^x^ 

S. 

<s 

'S 

to 

as 

^ 

g 

f^ 

< 

^< 

Qh 

5 

72.1 

21.7 

5.6 

1.1 

7 

66.0 

19.5 

14.0 

1.0 

9 

73.5 

21.3 

4.1 

1.2 

10 

70.0 

20.2 

9.0 

1.2 

3 

70.7 

20.3 

7.7 

1.1 

5 

73.3 

20.4 

5.6 

1.2 

6 

69.0 

19.9 

10.8 

1.0 

2 

61.6 

18.7 

18.9 

1.0 

1 

73.2 

16.8 

9.6 

1.0 

2 

75.8 

16.9 

6.4 

1.3 

2 

73.0 

19.0 

5.3 

1.3 

3  C  m 
>  O  M. 

aj  t.  oj 


640 
955 
570 
755. 
705 
615 
825 
1145. 
720 
585 
575 


MUTTON. 


Cut. 


Hind  leg,  lean 

medium  fat 

fat 

Loin,  medium  fat  without  kitlney  and  tallow 

fat  without  kidney  and  tallow    .... 

very  fat  without  kidney  and  tallow  .    . 

Fore  quarter 

Hind  quarter 

Koast  leg,  cooked 

Kidney 

Liver  (carbohydrates  5.0) 


<*H 

2 

j3 

< 

PL( 

3 

67.4 

19.8 

12.4 

1.1 

11 

62.8 

18.5 

18.0 

1.0 

1 

55.0 

17.3 

27.1 

0.9 

13 

50.2 

16.0 

33.1 

0.8 

3 

43.3 

14.7 

41.7 

0.8 

1 

30.8 

10.6 

58.7 

0.5 

10 

52.9 

15.6 

30.9 

0.9 

10 

54.8 

16.7 

28.1 

0.8 

2 

50.9 

25.0 

22.6 

1.2 

1 

69.5 

16.9 

12.6 

0.9 

2 

61.2 

23.1 

9.0 

1.7 

<t>Ti-> 


^5.2 

>  c  >- 

O  t,  oj 

E  OO 


890 
1105 
1465 
1695 
2035 
2675 
1595 
1495 
1420 
845 
905 


LAMB. 


Cut. 


Hind  leg,  medium  fat     .... 

fnt 

very  fat 

Loin,  without  kidney  and  tallow 

Fore  quarter 

Hind  quarter 

Broiled  chops 

Roast  leg 


cw 

Om 

m 

>^  S 

-a 

%>! 

O 

Ol 

Is 

A 

3  =* 

^ 

o 

^ 

< 
1.1 

0 

63.9 

19.2 

16.5 

1 

54.6 

18.3 

27.4 

0.9 

1 

51.8 

17.6 

30.1 

0.9 

4 

53.1 

18.7 

28.3 

1.0 

1 

55.1 

18.3 

25.8 

1.0 

1 

60.9 

19.6 

19.1 

1.0 

4 

47.6 

21.7 

29.9 

1.3 

1 

67.1 

19.7 

12.7 

0.8 

0  i_  ca 

1  055 
1495 
1595 
1540 
1430 
1170 
1665 

900 


ME  A  'IX 


31 


POULTRY. 


Cut. 


O  M 

t-4 

to 

3 
is 

< 

;S^ 

FLl 

3 

74.8 

21.5 

2.5 

1.1 

26 

63.7 

19.3 

16.3 

1.0 

1 

46.7 

16.3 

36.2 

0.8 

3 

55.5 

21.1 

22.9 

1.0 

1 

69.3 

22.4 

4.2 

1.7 

1 

73.8 

19.6 

5.8 

1.0 

5-5 1J 


Broiler  chickens 

Fowls 

Young  goose 

Turkey  

Chicken  liver  (carbohydrates  2.4) 
Goose  liver 


505 

1045 

1830 

18GU 

640 

610 


Horse  Meat. — The  mean  of  twelve  analyses  of  horse  meat  as  given 
by  Konig  '  is  as  follows  : 

Water 74.27 

Proteicls       21.71 

Fat 2.55 

Ash 1.01 

The  objection  to  the  use  of  horsefle.sh  as  food  is  very  largely  senti- 
mental. It  has  not  the  pleasant  flavor  of  beef,  to  which  we  are  accus- 
tomed, but  when  eaten  in  ignorance  of  its  true  character,  it  makes  no 
unpleasant  impression.  Its  use  is  increasing  steadily  in  Europe,  and 
is  finding  favor  in  America.  In  Paris,  during  1898,  21,667  horses, 
52  mules,  and  310  donkeys  were  slaughtered  for  food,  and  of  these  but 
734  horses,  1  mule,  and  7  donkeys  were  condemned  as  unsalable.  The 
meat  was  disposed  of  in  193  shops,  where  the  best  cuts  brought  about 
a  franc  (19.3  cents),  and  the  inferior  parts  10  centimes  (2  cents)  per 
pound.  During  1896,  822  horses  and  mules  were  slaughtered  in 
Strassburg,  and  in  1898  the  number  rose  to  1,099.  In  Vienna,  where 
the  sale  of  the  meat  was  permitted  first  in  1854,  there  were  slaughtered, 
in  1899,  25,646  horses  and  58  donkeys.  In  the  whole  of  Prussia, 
there  were  slaughtered,  in  1897,  at  367  abattoirs,  58,484  horses,  and 
in  the  following  year  tlie  number  rose  to  63,531.  In  Frankfort,  where, 
in  1847,  the  first  horse-meat  dinner  ever  given  occurred,  about  a  thou- 
sand horses  are  slaughtered  annually,  at  a  special  abattoir.  In  the 
United  States,  during  1899,  3,232  horses  were  slaughtered  and  offi- 
cially inspected  with  other  food  animals. 

It  is  said  that,  unless  the  fat  of  some  other  animal  or  some  starchy 
food  is  eaten  with  it,  horse  meat  may  cause  diarrhoea.  Whatever 
causes  this  disturbance  is  soluble  in  water,  and  may  thus  be  removed 
partially  when  the  meat  is  boiled.  From  water  in  which  horse-meat 
had  been  boiled,  E.  Pfliiger  ^  separated  jecorin,  lecithin,  and  (probably) 
neurin.  He  recommends  the  addition  of  about  25  grams  of  beef  or 
mutton  kidney-fat  to  each  kilogram  of  the  meat  when  a  mince  is  to 
be  made,  and  that,  in  whatever  form  it  is  consumed,  it  be  served  with 
a  fat  gravy. 

'  Zusammcnsetzung  der  menschlichen  Nahrungs-  und  Genussmittel,  Berlin,  1882. 
'  Archiv  fur  die  gesamrnte  riiysiologie,  1900,  Bd.  80,  p.  111. 


32  FOODS. 

Meat  Preparations. — Meat  Extracts. — These  are  preparations 
which  are  supposed  often  erroneously  to  contam  all  the  nutritive  parts 
of  the  meats  from  which  they  are  made,  but  they  are  to  be  regarded  as 
stimulants  rather  than  foods,  since  they  represent  the  extractives  and 
not  the  substances  which  determine  the  true  food  value.  In  point  of 
fact,  so  far  as  their  nutritive  properties  are  concerned,  it  has  been 
shown  that  animals  will  die  more  quickly  of  starvation  when  fed  ex- 
clusively upon  these  stimulating  preparations  than  when  entirely  de- 
prived of  food.  They  are,  however,  of  considerable  value  in  their 
proper  place,  particularly  in  conditions  of  great  fatigue  and  exhaustion. 

Meat  Powder. — jSIeat  may  easily  be  treated  so  as  to  retain  all  of  its 
nutriment  and  yet  have  a  very  much  diminished  volume.  The  lean 
parts  are  cut  into  small  strips,  dipped  for  a  few  minutes  into  very  hot 
fat  (fried),  drained,  and  then  slowly  dried  in  an  oven.  When  com- 
pletely dry,  they  are  ground  in  an  ordinary  spice  mill  or  coffee  mill  to 
a  fine  powder,  which  keeps  well,  has  an  agreeable  taste  and  a  pleasant 
odor,  is  digested  easily,  and  may  be  used  in  a  great  many  different  ways. 

Sausages. — Sausage  is  understood  generally  to  mean  an  article  of 
food  consisting  chiefly  of  finely  chopped  meat,  mainly  pork  and  beef, 
with  or  without  the  addition  of  a  small  amount  of  meal,  highly  sea- 
soned with  spices,  herbs,  and  other  flavorings,  and  stuffed  into  casings 
made  from  cleaned  and  prepared  intestines.  Their  nutritive  value  is, 
therefore,  about  the  same  as  that  of  average  meat.  As  may  be  supposed, 
the  best  cuts  of  meat  are  not  used  in  their  manufacture,  but  only  such 
parts  as  cannot  be  disposed  of  in  pieces  of  fair  size  and  of  attractive 
appearance.  But  there  are  sausages  and  sausages.  There  are  those 
made  from  meat  of  good  quality  and  others  from  materials  which 
would  not  be  salable  in  any  other  form. 

Many  of  the  so-called  Frankforters,  sold  at  veiy  low  rates,  and  the 
cheap  Bolognas  are  said  to  consist  largely  of  horse  meat,  immature 
veal,  and  the  flesh  of  cows  that  are  no  longer  in  condition  to  produoe 
milk.  Certain  it  is  that  a  not  inconsiderable  number  of  persons  gain 
a  fair  livelihood  by  going  about  in  the  country  buying  up  newly  born 
calves  and  decrepit  cows,  tuberculous  and  otherwise,  and  horses,  and 
that  these  animals  are  not  taken  to  comfortable  stables  and  inviting 
pastures,  but  to  small  slaughtering  establishments,  the  output  of  which 
is  not  very  largely  butchers'  meat.  To  the  cheap  grades  of  sausages 
the  saying  of  Jean  Paul,  "  Only  a  god  can  eat  sausage,  for  only  such 
can  know  of  what  it  is  made,"  applies  very  aptly.  Even  sausages 
made  from  pork,  especially  those  which  have  undergone  a  process  of 
cooking  before  being  stuffed,  are  not  always  beyond  suspicion,  for  the 
trichinous  pork  condemned  by  government  inspectors  at  public  abat- 
toirs is  neither  destroyed  nor  converted  into  fertilizers,  but  is  allowed 
to  be  sold  after  being  subjected  to  a  heat  suflicient  to  kill  the  parasites ; 
and  cooked  pork  is  not  commonly  to  be  found  on  sale  as  such. 

Horse  meat  is  said  to  combine  two  advantages  in  the  preparation  of 
sausage  :  it  is  inexpensive,  and  it  lends  a  firmness  which  increases  as 
the  sausage  is  boiled.     A  number  of  chemical  processes  have  been  pro- 


MEATS.  33 

posed  for  its  detection,  and  among  them  the  following :  Dr.  Notel  ^ 
covers  coarsely  chopped  horsemeat  with  a  0.1  per  cent,  solution  of 
sodium  hydroxide,  lets  the  mixture  stand  3  hours  at  37°  C,  and  then 
separates  the  liquid  through  cheese  cloth.  The  liquid  is  injected,  in 
<loses  of  8  to  10  cc,  subcutaneously  into  a  rabbit  at  intervals  of  2  or 
3  days  until  10  or  12  injections  have  been  given.  Six  days  after  the 
last  injection,  the  animal  is  bled  and  its  serum  serves  as  a  reagent. 
The  suspected  food  is  chopped  finely,  covered  with  0.1  per  cent,  sodium 
hydroxide,  allowed  to  stand  2  hours  in  a  warm  room,  and  filtered.  A 
few  drops  of  the  filtrate  are  mixed  in  a  test-tube  with  about  an  equal 
amount  of  the  serum,  and  other  tubes  containing  filtrate  alone  are  used 
as  controls.  The  tubes  are  incubated  at  37°  C,  and  if  the  suspected 
article  contains  horsemeat,  the  tubes  containing  the  serum  will  become 
cloudy  in  from  10  to  40  minutes. 

A  number  of  tests  which  depend  upon  the  reaction  of  iodine  with 
glycogen,  which  is  a  normal  constituent  of  horsemeat,  are  criticised  by 
Niebel  ^  as  uncertain,  on  account  of  the  presence  of  glycogen  in  liver, 
meat  extract,  and  very  young  veal. 

In  the  manufacture  of  all  grades  of  sausage,  scrupulous  care  should 
be  observed  to  secure  cleanliness  of  the  casings,  which  require  more 
thorough  treatment  than  the  mere  passage  of  water  through  them.  Dr. 
Schilling^  reports  the  examination  of  prepared  intestines  which  yielded 
5  grams  of  excrement  per  meter. 

Owing  to  the  occurrence  of  a  gray  color,  which  is  said  by  Meyer  ^  to 
he  due  to  the  passage  of  salt  by  diffusion  from  the  contents  to  the 
casing,  which  is  rich  in  water  and  poor  in  salt,  the  commercial  value 
of  certain  varieties  of  sausage  is  impaired,  and  hence  it  becomes  neces- 
sary to  apply  artificial  colors,  or  so  to  treat  the  stuffing  that  the  change 
in  color  shall  not  occur.  The  very  red  appearance  which  so  often  sug- 
gests the  presence  of  coal-tar  products  may  be  due  to  the  action  of 
harmless  preservatives,  like  niter,  or  the  haemoglobin  of  swine  blood. 
In  such  case,  the  extract  with  alcohol,  glycerin,  or  amyl  alcohol  will 
not  dye  wool,  and  the  color  cannot  be  precipitated  as  a  lake. 

According  to  J.  Haldane,^  the  red  color  of  cooked  salted  meats  is 
■due  to  the  presence  of  NO-hoemochromogen  produced  by  the  decomposi- 
tion of  NO-hsemoglobin,  which  is  formed  by  the  action  of  a  nitrite  on 
the  NO-hsemochromogen  in  the  absence  of  oxygen  and  presence  of  re- 
ducing agents.  The  nitrite  is  formed  by  reduction,  within  the  raw 
meat,  of  the  niter  used  in  salting. 

Certain  of  the  artificial  sausage  colors,  as  "Orange  II.,"  the  sodium 
salt  of  ^9-naphtholazobenzene,  are  extracted  easily  with  acidulated 
water,  and  will  dye  woolen  fibers  immersed  therein. 

'  Zeitsc:hrift  fiir  Hygiene  und  Infeetionskrankheiten,  XXXIX.,  p.  373. 

'■'Zeitsclirift  fur  Fleish-  und  Milchliygiene,  1895,  p.  86. 

"  Deutsche  mediciniHche  Wochenschrift,  1900,  p.  602. 

*r'herniker  Zeitung,  1900,  p.  3. 

*. Journal  oi  Hygiene,  1901,  Vol.  I.,  p.  115. 

3 


34  FOODS. 


FISH. 


In  the  ordinary  sense  of  the  word,  fish  inckides,  in  addition  to  the 
varieties  of  fish  in  its  narrow  sense,  molkisks  (clams,  oysters,  mussels, 
etc.)  and  crustaceans  (lobsters,  crabs,  crawfish,  and  shrimps). 

Many  prejudices  have  existed  from  the  earliest  times,  and  to  a  cer- 
tain extent  still  exist,  against  the  use  of  fish  in  the  diet.  The  ancient 
belief  that  a  fish  diet  is  a  common  cause  of  leprosy  still  obtains  to  a 
certain  extent,  even  among  enlightened  people,  in  spite  of  all  scientific 
evidence  to  the  contrary.  Thus,  Mr.  Jonathan  Hutchinson  ^  main- 
tains that  this  disease  is  so  caused,  especially  if  the  fish  is  poorly  cooked 
or  partially  decomposed.  He  asserts  that  the  disease  prevails  near  the 
sea  and  is  disappearing  before  the  advance  of  agriculture ;  but  op- 
posed to  this  is  the  fact  that,  in  the  interior  of  India,  the  disease  is  very 
common  among  people  whose  religion  forbids  the  use  of  fish,  and  who 
cannot  obtain  it  even  if  it  were  desired. 

Some  varieties  of  fish  cannot  be  eaten,  because  of  their  inherent 
poisonous  properties.  Bat  few  of  these  are,  however,  found  north  of 
the  tropics.  Some  of  them  are  always  poisonous,  and  others  only  at 
certain  times  ;  and  in  some  cases,  individuals  of  certain  species  may  be 
and  others  may  not  be  noxious.  Some  varieties  of  fish  are  the  hosts 
of  parasites,  some  of  which  are  injurious  to  man,  but  unless  eaten  in 
the  raw  state  they  are  not  likely  to  produce  harm. 

There  is  a  belief  that  fish  is  particularly  valuable  as  a  brain  food,  on 
account  of  the  supposed  high  percentage  of  phosphorus  that  it  contains. 
The  amount  of  phosphorus  is,  however,  so  far  as  is  known,  no  higher 
in  fish  than  in  meat  and,  moreover,  this  element  is  no  more  essential 
to  the  brain  and  nervous  system  than  any  others  which  are  present. 
If  there  were  any  truth  in  this  common  belief,  we  should  expect 
naturallv  to  find  men  of  commanding  intellect  among  those  whose 
diet  consists  mainly  of  fish,  but,  as  is  well  known,  such  people  are  of  a 
low  order  of  intelligence,  though  not  by  reason  of  their  diet. 

In  spite  of  the  large  amount  of  nutriment  contained,  fish  has  not  the 
same  satisfying  properties  that  belong  to  meats,  but  it  is  an  exceed- 
ingly valuable  food,  and  in  many  parts  of  northern  countries  is  the 
principal  animal  food.  The  flavor  of  fish  is  influenced  greatly  by  the 
nature  of  the  food  supply  and  by  the  content  of  fat.  Generally  speak- 
ing, salt-water  fish  from  deep  water,  where  the  current  is  strong,  are 
better  than  those  from  shallow,  warm,  and  quiet  water,  and  both  salt- 
water and  fresh-water  fish  taken  from  rocky  and  sandy  bottoms  are 
preferred  to  those  from  muddy  bottoms. 

Condition  is  dependent  upon  a  variety  of  circumstances.  Some  fish 
are  regarded  most  highly  during  their  spawning  season  (shad  and 
smelts),  while  others  are  looked  upon  with  disfavor  at  this  period. 
Fish  caught  by  the  gills  in  gill  nets  die  slowly,  but  decompose  rapidly, 
and  such  are  of  inferior  flavor  and  value.  Fish  taken  from  the  water 
'  Archives  of  Surgery,  April,  1899. 


FISH.  35 

alive  and  killed  at  once  remain  firm  and  retain  their  flavor  longer  than 
those  allowed  to  die  slowly. 

Digestibility. — So  far  as  is  known,  the  digestibility  of  fish  and  meat 
is  about  equal,  but,  as  is  true  of  meats,  different  varieties  of  fish  are 
differently  digestible.  Thus,  those  w^hich  contain  the  greatest  per- 
centages of  fat,  as  salmon,  eels,  and  mackerel,  are  the  most  difficult  of 
digestion.  The  processes  of  drying,  smoking,  salting,  and  pickling 
lessen  digestibility,  and  fish  so  treated  are,  in  consequence,  less  suited 
to  the  needs  of  invalids  and  dyspeptics.  The  mollusks  are  regarded 
generally  as  most  digestible,  while  the  crustaceans  are  believed  to  tax 
the  digestive  powers  much  more  than  any  other  animal  food.  Many 
persons  are  unable  to  digest  them  in  any  form,  and  others  who  suffer 
no  inconvenience,  so  far  as  digestion  is  concerned,  are  obliged  to  prac- 
tise self-denial,  because  of  idiosyncrasy,  which  manifests  itself  in  dis- 
tressing eruptive  disorders  of  the  skin,  dizziness,  and  other  nervous 
symptoms.  Lobster  and  crabs  are  much  alike,  but  the  former  is  less 
likely  to  disagree.  The  claws  of  the  lobster  are  more  tender  and  deli- 
cate than  the  tail,  which  is  firmer  and  much  closer  grained.  Shrimps 
are  rated  generally  as  more  difficult  of  digestion  than  lobsters  and 
crabs,  but  with  many  they  are  borne  more  easily. 

The  mollusks  are  more  digestible  in  the  raw  state  than  w^hen  cooked. 
The  comparatively  tough  part  of  the  oyster,  the  adductor  muscle,  is 
very  trying  to  some  persons,  and  for  such  it  is  best  removed  and 
rejected. 

Keeping  Qualities. — Fish  flesh  differs  very  greatly  from  meats  in 
keeping  qualities.  While  the  latter  are  improved  up  to  a  certain  point 
by  hanging,  fish  should  be  eaten  while  fairly  fresh,  since  decomposition 
sets  in  very  quickly.  Some  varieties,  as  halibut,  cod,  haddock,  and 
turbot,  may  be  kept  a  week  or  more  when  properly  cared  for,  while 
others  begin  to  deteriorate  almost  immediately.  So  long  as  the  flesh 
is  firm  and  stiff,  all  fish  is  edible,  but  when  it  is  crushed  readily  by 
gentle  pressure  between  the  fingers,  it  is  unsound  and  should  be  re- 
jected. Mollusks  and  crustaceans  decompose  very  quickly,  and  the 
latter  when  boiled  a  short  time  after  natural  death  have  but  little 
flavor. 

Composition. — In  proteids,  fish  rank  nearly  as  high  as  meats,  but 
they  are  very  much  poorer  in  fat,  only  a  few  varieties  yielding  over  10 
per  cent.  These  include  salmon,  turbot,  lamprey  eels,  eels,  butterfish, 
lake  trout,  and  herring,  and  are  followed  by  shad  and  Spanish  mack- 
erel, with  over  9  per  cent.  The  great  majority  of  species  contain  less 
than  5  per  cent.,  and  many  of  the  commoner  kinds  even  less  than  1 
per  cent.  In  fact,  most  fish  flesh  yields  more  mineral  matter  than  fat. 
Sliellfish  are  fairly  rich  in  proteids  and  contain  notable  amounts  of 
carl)ohydrates,  l)ut  they  are  very  poor  in  fat. 

The  chemical  composition  of  the  edible  portions  of  many  varieties  of 
American  fish  is  given  in  the  following  table  compiled  from  the  report 
of  the  U.  S.  Commissioner  of  Fish  and  Fislieries  for  1888  : 


36 


FOODS. 


Kinds  of  fish. 


In  flesh. 

Proteids. 

Fat. 

Ash. 

Total. 

Water. 

Fuel  value 
per  pound. 

per  ct. 

per  ct. 

per  ct. 

per  ct. 

per  ct. 

Calories. 

17.46 

17.87 

1.06 

36.39 

63.61 

1,080 

15.82 

18.74 

0.93 

35.49     64.51 

1,085 

20.77 

12.09 

1.38 

34.24  '  65.76 

895 

20.97 

9.43 

1.50 

31.90     68.10 

790 

18.22 

11.38 

1.26 

30.86     69.14 

820 

22.06 

6.49 

1.62 

30.17     69.83 

685 

17.81 

11.03 

1.14 

29.98 

70.02 

795 

18.55 

9.48 

1.35 

29.38 

70.62 

745 

14.93 

13  29 

0.66 

28.88 

71.12 

840 

12.92 

14.41 

1.28 

28.61 

71.39 

850 

18.77 

8.21 

1.40 

28.38 

71.62 

695 

18.19 

8.02 

1.69 

27.90 

72.10 

675 

18.65 

7.57 

1.00 

27.22 

72.78 

665 

19.17 

4.92 

1.47 

25.56 

74.44 

565 

21.50 

2.44 

1.24 

25.18 

74.82 

505 

18.35 

5.18 

1.05 

24.58 

75.42 

560 

19.54 

3.69 

1.22 

24.45 

75.55 

520 

19.03 

4.07 

1.19 

24.29 

75.71 

525 

21.65 

0.78 

1.55 

23.98 

76.02 

435 

19.12 

3.48 

1.25 

23.85 

76.15 

505 

19.63 

2.54 

1.57 

23.74 

76.26 

470 

18.31 

2.83 

1.16 

22.30 

77.70 

460 

18.97 

2.10 

1.21 

22.28 

77.72 

440 

19.20 

1.03 

1.31 

21.54 

78.46 

400 

19.02 

1.25 

1.27 

21.54 

78.46 

405 

19.24 

0.96 

1.19 

21.39 

78.61 

400 

17.90 

2.35 

1.19 

21.44 

78.56 

430 

17.96 

1.90 

1.43 

21.29 

78.71 

415 

18.82 

0.93 

1.43 

21.18 

78.82 

390 

17.45 

2.39 

1.19 

21.03 

78.97 

425 

18.47 

1.35 

1.08 

20.90 

79.10 

400 

17.36 

1.80 

1.68 

20.84 

79.16 

400 

18.66 

0.95 

1.18 

20.79 

79.21 

385 

18.75 

0.49 

1.44 

20.68 

79.32 

370 

18.80 

0.60 

1.15 

20.55 

79.45 

375 

18.49 

0.70 

1.29 

20.48 

79.52 

375 

18.42 

0.47 

1.37 

20.26 

79.74 

360 

18.64 

0.50 

1.18 

20.32 

79.68 

370 

17.26 

0.76 

1.13 

19.15 

80.85 

355 

17.10 

0.26 

1.25 

18.61 

81.39 

330 

17.08 

0.38 

0.99 

18.45 

81.55 

335 

16.68 

0.53 

1.23 

18.44  1  81.56 

335 

16.92 

0.17 

0.90 

17.99  !  82.01 

320 

16.00 

0.30 

1.24 

17.54 

82.46 

310 

15.24 

0.67 

0.98 

16.89 

83.11 

310 

13.82 

0.69 

1.28 

15.79 

84.21 

285 

14.01 

0.44 

1.20 

15.65 

84.35 

280 

18.52 

3.60 

1.14 

23.26 

76.74 

495 

17.24 

2.98 

1.24 

21.46 

78.54 

445 

California  salmon 

Eel 

Salmon 

Spanish  mackerel 

Lake  trout 

Whitefish 

Butterfish 

Shad 

Lamprey  eel 

Turbot 

Mackerel 

Herring 

Pompano 

Alewife 

Small-mouthed  black  bass  . 

Halibut 

Sheepshead  

AVhite  perch 

Pollock 

Cisco 

Muskellunge 

Striped  bass 

Brook  trout 

Ped  snapper 

Bluefish    

Large-mouthed  black  bass  . 
Small-mouthed  red-horse  .    . 

Sturgeon  

Skate 

^'eakfish 

Blackfish  

Smelt 

Kingfish 

Sea  bass 

Grouper 

Yellow  perch 

Pike  perch,  Wall-eyed  pike 

Pickerel 

Pike  perch,  Gray  pike  .    .    . 

Haddock 

Tomcod 

Ped  bass 

Cusk 

<:;od 

Hake 

Common  flounder 

"Winter  flounder 

Spent  fish. 

Spent  salmon 

Spent  land-locked  salmon   . 


MEAT  AND  FISH  AND  PARASITIC  DISEASE. 


37 


Edible  portion. 

'6 
5 

o 

Nutrients. 

. 

Fish. 

i 

'2  ■ 
'53 

•  'S 

.a 

t 

cc 

o 

Oh 

f^ 

< 

o 

k 

perct. 

per  ct. 

per  ct. 

per  ct. 

per  ct. 

Calor. 

per  ct. 

Desiccated  codfish  (fish  meal)     .    . 

74.46 

1.90 

5.41 

84.75 

15.25 

1,465 

2m 

Salt  codfish         .    . 

21.42 

0.34 

1.62 

46.42 

53.58 

410 

23.04 

Salt  mackerel 

18.88 

25.12 

2.59 

56.99 

43.01 

1,410 

10.40 

Smoked  haddock 

33.68 

0.17 

1.53 

27.44 

72.56 

445 

2.06 

Smoked  halibut 

20.57 

15.03 

2.06 

50.62 

49.38 

1,015 

12.96 

Smoked  herring 

36.44 

15.82 

1.53 

65.45 

34.55 

1,345 

11.66 

Canned  salmon  . 

20.06 

15.70 

1.32 

38.12 

61.88 

1,035 

1.04 

Canned  mackerel 

19.91 

8.68 

1.30 

31.82 

68.18 

735 

1.9a 

Canned  tunny     . 

21.52 

4.05 

1.69 

27.26 

72.74 

570 

Fish. 


s 

'3 
g 

Si 

< 

"3 
o 

9.78 

2.05 

5.89 

1.98 

19.70 

1.48 

0.03 

0.75 

2.13 

4.39 

7.41 

2.07 

3.95 

1.31 

14.74 

14.55 

1.79 

2.94 

2.76 

22.04 

17.73 

2.89 

1.59 

3.16 

25.37 

11.59 

0.74 

7.21 

2.22 

21.76 

16.70 

1.27 

4.14 

2.33 

24.44 

12.51 

1.67 

5.42 

1.73 

21.33 

14.75 

0.17 

3.38 

1.38 

19.68 

14.49 

1.84 

1.71 

18.13 

1.07 

2.47 

16.64 

1.96 

3.13 

15.80 

1.55 

1.94 

25.38 

1.00 

2.58 

21.23 

3.47 

1.02 

19.84 

0.53 

1.20 

Oysters 

Oyster  liquor  .... 
Canned  oysters  .  .  . 
Long  clams  .... 
Long  clams  (canned) 
Kound  clams  .... 
Kound  clams  (canned) 

Mussels 

Scallops 

Lobster 

Lobster  (canned)     .    . 

Crab 

Crab  (canned)      .    .    . 
Shrimps  (canned)    .    . 

Terrapin 

Green  turtle    .... 


80.30 
95.61 
85.26 
77.96 
74.6S 
78.24 
75.56 
78.67 
80.32 


Meat  and  Fish  and  Parasitic  Disease. 

Man  is  often  the  host  of  parasites  through  ingestion  of  infested  meat 
and  fish.  Of  these,  the  most  common  is  the  tapeworm,  of  which  at 
least  ten  species  are  l?:nown,  though  only  three  have  been  demonstrated 
as  having  any  connection  with  food.  These  are  Taenia  saginata  (T. 
mediocanellata)  due  to  measly  beef,  Taenia  solium  to  measly  pork,  and 
Bothriocephalus  latus  to  infested  sturgeon,  pike,  perch,  and  salmon. 
The  latter  is  very  rare  in  this  country,  though  not  uncommon  along 
the  Baltic.  Of  the  large  number  of  worms  which  infest  fish,  this  is  the 
only  one  known  to  he  conveyed  to  man.  It  is  killed  very  quickly  if 
the  fish  is  cooked  properly. 

The  larval  forms  of  T.  saginata  and  T.  solium  exist  in  beef  and 
pork  respectively  as  Cysticercus  bovis  and  C.  cellulosae.  The  latter 
is  found  rarely  also  in  mutton.      Meats  infested  with  these  forms  are 


38  FOODS. 

knowD  as  "  measly  "  or  "  measled,"  and  the  animals  from  which  the 
meats  are  derived  are  known  as  the  intermediate  hosts,  man  being 
the  final  host.  The  life  history  of  the  tapeworm  is  much  more  simple 
than  that  of  many  other  parasites.  Beginning  with  the  adult  tape- 
worm in  man,  the  cycle  is  as  follows  :  From  each  individual  segment, 
which  is  possessed  of  a  complete  reproductive  system,  great  numbers 
of  eggs  are  discharged.  The  latter  are  expelled  from  the  intestine  with 
the  feces,  and  some  of  them  eventually  may  enter  the  digestive  tract  of 
cattle  or  swine  through  the  food  or  water.  In  the  intestine,  the  embryos 
become  liberated  from  the  eggs,  and  they  then  make  their  way  in  large 
numbers  to  the  muscular  tissues,  brain,  liver,  and  other  parts,  where 
they  come  to  rest  and  develop  as  bladder  worms.  The  bladders  are 
variable  in  size,  the  smallest  being  about  -^  inch,  and  the  largest  about 
^  inch  across,  and,  in  the  flesh,  are  embedded  between  the  muscular 
fibers.  The  living  animal  shows  nothing  in  its  appearance  to  indicate 
the  presence  of  the  parasite,  excepting  when  the  cyst  can  be  seen  in  the 
under  side  of  the  tongue  or  between  the  tongue  and  the  lower  jaw.  If 
now  the  animal  is  slaughtered  and  the  meat  is  eaten  raw  or  imperfectly 
cooked,  the  Cysticercus  is  freed  from  its  enveloping  capsule  and  pro- 
ceeds to  develop  into  an  adult  tapeworm,  and  the  cycle  is  complete. 
The  Cysticercus  bovis  dies  within  two  or  three  weeks  after  the 
slaughter  of  its  host,  and,  therefore,  measled  beef,  kept  for  three  weeks 
in  cold  storage,  becomes  incapable  of  producing  harmful  effects.  It  is 
killed  within  24  hours  by  pickling  solutions  of  common  salt,  when 
brought  into  intimate  contact.  The  Cysticercus  cellulosse  lives  rather 
longer  in  cold  storage  :  probably  a  month  or  more,  Both  of  these 
larv?e  are  killed  by  exposure  to  a  temperature  of  140°  F.  for  5 
minutes,  and  as  this  is  lower  than  the  temperature  in  the  interior  of 
well-cooked  meat,  it  is  necessary  only  to  make  sure  that  the  meat  is 
IJroperly  cooked  to  escape  danger.  Neither  ])arasite  is  destroyed  by 
ordinary  smoking  or  salting,  but  both  are  killed  by  hot  smoking. 

The  sale  of  measled  meat  is  permitted  in  many  countries  of  Europe, 
but  it  must  be  sold  as  such  and  only  in  specially  designated  places.  It 
finds  a  ready  market  at  a  low  price,  and  the  purchasers  are  warned 
that  it  should  be  cooked  thoroughly.  According  to  Yirchow,  since  the 
introduction  of  systematic  meat  inspection,  the  proportion  of  tapeworm 
in  the  human  subject  dissected  in  Berlin  has  fallen  from  1  in  31  to  1 
in  280. 

A  parasite  of  far  greater  importance  is  the  Trichina  spiralis,  which 
is  found  almost  exclusively  in  pork  and  only  occasionally  in  the  flesh 
of  other  mammals  and  of  birds  and  frogs.  Trichinae  are  small,  thread- 
like worms,  much  longer  than  one  would  suppose  on  passing  examina- 
tion of  fairly  thick  microscopic  preparations,  since  they  are  coiled  with 
several  turns  within  the  minute  cysts  in  which  they  are  lodged.  In 
Plate  I.,  Fig.  1,  is  shown  one  of  the  parasites  in  the  free  state.  In  the 
pig  the  worm  infests  both  the  fat  and  the  voluntary  muscles,  but  chiefly 
the  latter,  and  especially  the  diaphragm,  the  intercostals,  and  the  mus- 
cles of  the  jaw.     When  encapsulated  in  the  flesh,  their  location  may  be 


PLATE  I. 


Free  Trichina.     X  38 


Trichinae    in    Human    Muscle.     /  7S. 


MEAT  AND  FISH  AND  PARASITIC  DISEASE.  39 

evident  to  the  naked  eye  as  small  white  specks.  Thin  sections  of 
muscles,  treated  a  few  minutes  in  weak  caustic  potash  solution  (1  :  10), 
are  soon  made  sufficiently  clear  to  reveal  the  coiled  worm  under  a  lens 
of  low  power.  If  very  much  fat  is  present  or  if  the  capsule  has 
become  calcareous  and  thick,  it  may  be  necessary  to  employ  ether  or 
acetic  acid  before  applying  the  potash.  When  the  parasites  are  very 
numerous,  the  flesh  is  both  speckled  and  pale. 

Our  first  knowledge  of  the  serious  eifects  which  may  result  from 
eating  infested  pork  dates  back  only  to  1860,  although  the  parasite  had 
been  discovered  in  the  muscles  of  a  human  subject  by  James  Paget  in 
1833  and  named  by  Richard  Owen.  It  long  was  regarded  as  a  harm- 
less parasite  and  curiosity,  and  its  effects  were  mistaken  for  rheuma- 
tism, typhoid  fever,  and  other  diseases  of  common  occurrence.  The 
case  which  finally  revealed  its  capacity  for  harm  was  that  of  a  young 
woman  admitted  to  the  hospital  at  Dresden  suffering,  it  was  supposed, 
from  typhoid  fever.  In  a  short  time,  a  train  of  symptoms  quite  unlike 
those  of  that  disease  apj^eared,  the  most  marked  one  being  very  acute 
pain  involving  the  entire  muscular  system,  and  intensified  on  attempting 
to  move.  On  account  of  the  agony  induced,  extension  of  the  arms 
and  legs  was  quite  impossible.  Pneumonia  supervened,  and  in  a  few 
days  the  victim  died.  The  autopsy  revealed  the  parasite  in  vast  numbers 
in  the  muscles,  and  this  led  to  further  investigation,  which  showed 
that,  four  days  before  the  first  symptoms  of  illness  ajipeared,  she  had 
eaten  freshly  killed  pork.  Some  of  this  was  secured  in  the  form  of  ham 
and  sausage,  and  examination  demonstrated  the  presence  of  the  parasite. 

The  first  extensive  outbreak  which  caused  the  disease  to  be  looked 
upon  as  one  of  great  importance  occurred  in  Prussia  in  1863,  when 
more  than  20  persons  died  within  a  month  after  a  dinner  in  which  103 
had  participated,  and  at  which  smoked  sausages  made  from  an  infested 
pig  had  been  served.  The  parasites  were  discovered  in  the  muscles 
of  those  who  died  and  in  the  sausages  that  remained.  Since  that 
time,  it  has  been  customary  in  most  large  slaughtering  establishments 
to  examine  pork  for  evidence  of  the  parasite,  before  passing  it  as  fit  for 
food.  But  examination  is  not  always  a  safeguard,  even  in  countries 
where  it  is  observed  most  carefully.  In  Germany,  for  instance,  where 
all  meats  are  supposed  to  be  examined  with  scrupulous  care,  particu- 
larly those  from  the  United  States,  the  disease  is  very  common. 

In  1883,  on  account  of  the  alleged  dangers  which  lurked  in  Ameri- 
can meats,  importation  was  interdicted  for  a  time,  but  in  the  succeed- 
ing 15  years  there  were  in  Prussia  alone  3,003  cases  and  207  deaths, 
not  one  of  which  could  be  traced  to  American  meat  either  salted, 
})ickled,  canned,  or  made  into  smoked  sausages.  Over  40  per  cent, 
of  the  cases  were  traced  to  European  meat  which  had  been  passed  as 
free  from  trichinae,  and  the  rest  to  European  meat  wliich  liad  been 
found  to  contain  the  parasite,  but  had,  nevertheless,  been  handled  by 
the  trade.  During  1899,  the  parasites  were  found  by  the  microscopists 
of  the  U.  S.  Department  of  Agriculture  in  41,659  of  the  2,227,740 
hogs  examined. 


40  FOODS. 

It  is  probable,  as  stated  by  Charles  W.  Stiles/  who  collected 
about  900  reported  cases  which  had  occurred  in  this  country  during 
the  36  years  1860—1895,  that  the  disease  is  more  common  in  the 
United  States  than  generally  is  supposed.  It  is  accepted  commonly 
that  1  or  2  per  cent,  of  dissecting-room  subjects  show  evidence  of 
the  parasite,  but  it  would  appear  from  the  investigations  of  H.  U. 
Williams  ^  that  this  estimate  is  much  too  low,  for  careful  examination 
of  505  cadavers  taken  at  random  showed  old  encapsulation  and  calcifi- 
cation in  no  less  than  27  instances,  or  5.34  per  cent.  The  birthplaces 
of  the  subjects  included  all  of  the  most  important  countries  of  Europe 
and  North  America,  but  the  number  of  cases  examined  was  too  small 
to  admit  of  accurate  conclusions  as  to  the  influence  of  nationality  upon 
the  frequency  of  the  disease.  It  is  evident  that  many  cases  of  trichinosis 
escape  detection,  and  that,  as  Williams  points  out,  estimates  have  been 
based  on  naked-eye  diagnosis. 

In  spite  of  the  danger  of  eating  trichinous  meat,  there  are  those  who 
are  not  deterred  by  fear  from  eating  it.  In  Germany,  for  instance,  it 
has  happened  a  number  of  times  that  hogs  which  have  been  condemned 
and  ordered  buried  by  the  sanitary  authorities  have  been  dug  up  sur- 
reptitiously and  eaten.^ 

Trichinosis  bears  certain  resemblances  to  typhoid  fever  and  to  acute  tu- 
berculosis, but  in  addition  is  accompanied  by  oedema  and  intense  pain. 
It  arises  from  eating  the  infested  meat  in  a  raw  or  not  well  cooked 
condition.  The  trichinse  are  killed  by  exposure  to  155°  F.,  if  they  are 
not  encapsulated  ;  otherwise  by  a  temperature  of  158°  to  160°.  They 
are  not  aifected  by  intense  cold,  putrefactive  processes,  nor  ordinary 
smoking,  but  are  killed  by  long  pickling. 

The  first  symptoms  appear  in  a  few  days  after  ingestion,  and  indi- 
cate irritation  of  the  alimentary  canal.  These  are  followed  by  febrile 
symptoms  and  intense  muscular  pains.  Death  may  occur  within  a 
few  weeks.  In  case  of  recovery,  the  parasites  become  encysted,  and 
then  are  incapable  of  producing  further  injury  to  their  host.  The 
manner  in  which  they  produce  their  effects  is  as  follows  :  When  the 
infested  meat  reaches  the  stomach,  the  digestive  juices  dissolve  the 
capsules,  and  the  parasites  thus  are  left  in  a  free  state.  In  the  intes- 
tine, they  find  conditions  favorable  to  growth,  and  in  a  few  days'  time 
they  grow  so  large  that  they  can  be  seen  with  the  naked  eye  and  appear 
like  fine  threads. 

The  female  parasites  when  fully  mature  begin  to  produce  young, 
each  to  the  extent  of  upward  of  500.  These  begin  at  once  a  migra- 
tion through  the  walls  of  the  intestine  and  find  their  way  to  all  parts 
of  the  body,  and  it  is  during  this  stage  that  the  fever  and  intense  pain 
are  caused. 

In  Plate  I.,  Fig.  2,  and  Plate  II.,  Fig.  1,  are  seen  thin  sections  of 
muscle  from  a  human   subject,  showing  the  worm  coiled  up  and  the 

^Philadelphia  Medical  Journal,  June  1,  1901. 
'■'Journal  of  Medical  Research,  July,  1901,  p.  64. 

^  For  an  account  of  such  a  case  consult  Zeitschrift  fiir  Fleisch-  und  Milchhj-giene, 
1897,  VII.,  p.  104. 


PLATE  II. 


Fig.   1. 


» 'StSy '» 


Triehinse   in   Human    Muscle,  showing  Tliiekened 
Capsule.     X  7S. 


Tr'ichin£B    in    Pig    Muscle.     X  7S. 


MEAT  AND  FISH  AND  PARASITIC  DISEASE.  41 

thickened  capsule  formed  about  it.  In  Plate  II.,  Fig.  2,  it  may  be 
seen  within  the  muscle  of  an  infested  pig. 

The  sheep  disease  which  is  known  as  rot,  which  term,  it  must  be 
said,  is  used  to  include  a  large  number  of  abnormal  conditions,  but 
which,  in  its  strict  application,  means  a  parasitic  disease  of  the  liver,  is 
believed  by  many  to  be  of  sufficient  importance  to  warrant  the  con- 
demnation of  the  flesh  of  the  animal,  but  the  scientific  evidence  on  this 
point  is  to  the  effect  that  no  possible  harm  can  come  to  the  consumer, 
even  though  the  liver  itself  be  eaten.  The  parasite  infests  not  alone 
sheep,  but  cattle  as  well,  and  is  known  as  the  "  fluke."  Of  the  many 
varieties  of  flukes,  there  are  but  two  known  in  the  United  States  ;  these 
are  the  common  liver  fluke  (leberwurm,  leberegel,  schafegel,  douve 
h^patique)  and  the  large  American  fluke.  The  former  infests  cattle 
and  sheep  ;  the  latter,  only  cattle. 

The  life  history  of  the  worm  is  exceedingly  complicated,  and  is  as 
follows  :  The  adult  or  hermaphroditic  worm  fertilizes  itself  in  the 
biliary  passages  of  the  liver,  and  produces  an  exceedingly  large  num- 
ber of  eggs,  which  pass  to  the  intestine  of  the  host  with  the  bile,  and 
are  expelled  in  the  feces.  Such  of  the  eggs  as  eventually  reach  water 
give  rise  after  a  longer  or  shorter  period,  according  to  temperature,  to 
a  ciliated  embryo,  which  on  its  escape  from  the  e.g'g  becomes  a  free 
swimming  ciliated  miracidium,  and  enters  the  body  of  certain  species 
of  snails,  where  it  comes  to  rest.  Here  the  organism  grows,  and,  after 
a  time,  certain  germ  cells  in  its  posterior  portion  develop  a  still  differ- 
ent form  of  life,  the  ridise.  These  wander  to  the  host's  liver  and  in- 
crease in  size,  and  in  turn  develop  from  their  germ  cells  the  next  gen- 
eration, which  are  called  cercarise.  These  leave  the  body  of  the  snail 
and  swim  about  in  the  water,  and  some  become  attached  to  blades  of 
grass,  where  they  form  enveloping  cysts  and  undergo  anatomical  changes. 
For  their  next  stage  it  is  necessary  that  they  be  received  into  the  stomach 
of  some  herbivorous  animal  by  being  swallowed  with  the  grass  to  which 
they  are  attached.  On  reaching  the  stomach,  the  cysts  are  destroyed  and 
the  parasites  migrate  to  the  liver  and  become  adult  hermaphrodites,  thus 
completing  the  cycle.  Occasionally  they  wander  to  the  lungs  and  other 
parts  of  the  body.  In  the  liver,  the  parasites  attach  themselves  to  the 
walls  of  the  bile  ducts,  which  may  become  completely  blocked,  and  they 
cause  the  breaking-down  of  the  surrounding  tissues  and  general  symptoms 
due  to  structural  changes.  The  parasite  cannot  be  transmitted  directly 
from  animal  to  man,  since  it  requires  an  intermediate  host,  and  in  the 
stage  preceding  its  final  development  it  is  not  attached  to  material  con- 
stituting human  food.  There  are,  to  be  sure,  some  instances  of  the  dis- 
ease in  man,  though  not  by  direct  transmission  from  meat.  The  con- 
dition caused  by  flukes  is  known  variously  as  rot,  liver  rot,  fluke  dis- 
ease, and  distomatosis. 


42  FOODS. 

TRANSMISSION   OF   DISEASE    BY    MEAT   AND    FISH. 

Living  pathogenic  bacteria  in  diseased  meat  and  fish  may  gain  access 
to  the  stomach  in  limited  numbers  and  beget  no  disease.  If  they  are 
not  destroyed  by  the  gastric  juice,  they  have  to  contend  with  myriads 
of  organisms  normal  to  the  intestines,  and  it  is  only  when  the  condi- 
tions are  such  as  to  favor  extensive  multiplication  that  they  are  likely 
to  produce  harmful  effects.  In  meat  that  is  cooked  thoroughly,  they 
are  killed  by  the  heat  to  which  they  are  subjected. 

It  is  well  known  that  the  stomach  has  great  protective  power  in 
its  natural  functions,  since  certain  violent  organic  poisons  may  be 
taken  into  that  organ  without  injury,  while  if  Ihe  same  are  intro- 
duced into  the  circulation,  the  results  are  fatal ;  thus  the  A'enom  of  poi- 
sonous serpents  is  digested  and  made  harmless  by  the  stomach  juices. 
An  instance  of  the  immunity  conferred  by  cooking  or  by  the  process 
of  digestion,  or  by  both  together,  and  of  the  fatal  result  of  the  admis- 
sion of  the  harmful  element  of  the  same  meat  to  the  system  through 
cuts  and  abrasions,  is  given  by  Lardier.^     The  case  is  as  follows  : 

A  cow  died  suddenly  of  anthrax  and  M^as  dressed  for  food.  The 
meat  was  eaten  by  a  large  number  of  people,  none  of  whom  suffered 
the  slightest  inconvenience  or  injury.  A  number  of  cats,  however, 
which  ate  some  of  the  waste  matters  and  licked  up  the  blood,  died  with 
some  suddenness.  A  woman  who  bought  the  head  and  wounded  her- 
self in  the  process  of  cutting  it  up  had  a  eharbon  at  the  place  of  injury 
and  died.  Two  men  who  holjied  skin  the  cow  had  eharbon,  but  re- 
covered. A  calf  belonging  to  one  of  these  two  died  of  anthrax,  and 
another  man,  removing  the  skin,  cut  himself  and  died.  The  skin  of 
the  original  animal  was  sold  and  the  purchaser  put  it  in  a  shed  on  his 
farm.  Some  time  later,  one  of  his  cows  died  suddenly,  and  the  man 
who  dressed  the  carcass  wounded  himself  during  the  process,  acquired 
a  eharbon,  and  died.  How  much  farther  this  series  of  fatalities  might 
have  extended  cannot  be  known,  since  the  authorities  took  steps  in  the 
matter  and  prevented  further  fatalities. 

Many  instances  are  known  in  which  the  flesh  of  cattle  dead  of  in- 
fectious disease  has  been  eaten  with  impunity.  During  the  siege 
of  Paris,  for  example,  when  the  food  supply  was  exceedingly  limited 
in  amount,  no  one  paid  the  slightest  attention  to  the  condition  of  meat 
in  respect  to  disease,  even  glandered  horses  finding  a  ready  market, 
and,  so  far  as  is  known,  no  ill  effects  resulted. 

Many  years  ago,  when  the  rinderpest  was  very  prevalent  in  Bohemia, 
the  diseased  cattle  were  killed  and  buried  by  order  of  the  government ; 
but  the  poorer  class  dug  up  the  carcasses  and  cooked  and  ate  them 
without  suffering  any  evil  consequences  whatsoever. 

During  the  prevalence  of  the  same  disease  in  England  in  the  early 
sixties,  the  meat  from  the  diseased  animals  in  all  stages  of  the  distem- 
per was  sent  in  enormous  quantities  to  market,  and  sold  and  eaten 
without  evil  effects.  A  similar  immunity  has  often  been  noticed  after 
1  Eevue  d'Hygiene,  1898,  No.  5,  p.  431. 


TRANSMISSION  OF  DISEASE  BY  MEAT  AND  FISH.  43 

the  consumption  of  the  carcasses  of  animals  dying  from  acute  pleuro- 
pneumonia. In  ordinary  cases  of  this  disease,  which  is  peculiar  to  beef 
cattle,  the  effects  are  localized  in  the  lungs.  Sometimes,  in  very  pi-o- 
nounced  cases,  the  flesh  is  altered  in  appearance,  l^ecoming  dark  and 
discolored,  and  it  is  also  moist  and  flabby.  It  is  believed  that  the  meat 
is  edible,  if  it  possesses  a  normal  appearance.  The  meat  in  rinderpest 
undergoes  no  marked  change  in  appearance,  excepting  in  advanced 
cases,  when  it  is  dark  in  color  and  flabby  and  of  disagreeable  odor. 

In  ordinary  cases  of  foot  and  mouth  disease,  it  appears  that  the  car- 
cass is  edible,  but  in  exceptional  cases,  when  the  animal  has  suffered  for 
a  long  time,  the  flesh  may  be  so  deteriorated  as  to  be  undesirable.  As 
a  rule,  although  the  disease  is  very  infectious,  its  course  is  mild  and 
interferes  only  slightly,  if  at  all,  with  the  condition  of  the  meat,  which 
generally  cannot  be  distinguished  from  that  of  healthy  animals. 

Although  many  instances  are  Ivnown  that  show  that  the  meat  of 
animals  suffering  with  anthrax  may  be  eaten  without  injury,  it  is  the 
unanimous  opinion  of  those  who  have  given  the  matter  attention,  that, 
no  matter  how  good  the  meat  may  appear,  it  should  be  condemned  and 
destroyed.  If  the  meat  is  well  cooked,  accidents  are  rare,  but  many 
cases  of  fatal  injury,  involving  a  large  nmnber  of  victims,  have  been 
traced  to  the  use  of  such  meat,  presmnal^ly  not  thoroughly  cooked. 
In  spite  of  the  protection  conferred  by  cooking,  there  is  such  an  ele- 
ment of  danger,  even  in  the  handling  of  the  meat,  that  its  use  should 
be  discouraged  and  forbidden.  In  Scotland,  it  is  a  common  practice 
with  farm  laborers  and  other  poor  to  eat  the  meat  of  sheep  which 
have  died  of  acute  inflammatory  diseases,  even  of  anthrax.  The  car- 
cass of  an  animal  dying  of  disease  is  the  perquisite  of  the  herdsman 
and  almost  invariably  is  eaten  after  being  salted.  Xo  precaution  is 
taken,  except  to  cut  away  the  darker  portions  of  the  meat  Avhich 
show  stagnation  of  the  blood.  Occasionally,  serious  consequences, 
due  either  to  imperfect  cooking  or  to  insufficient  salting,  result  from  its 
consumption. 

It  is  held  generally  that  the  flesh  of  animals  that  have  died  from 
•actinomycosis,  puerperal  fever,  '^  strangles,''  hog  cholera,  and  sheep  scab 
is  unfit  for  human  food. 

Tuberculosis. — The  cattle  disease  most  commonly  known  in  this 
country,  if  not  elsewhere,  is  tuberculosis,  and  concerning  the  advisability 
of  using  the  flesh  of  its  victims,  there  is  much  difference  of  opinion, 
here  and  abroad.  The  disease  is  more  common  in  cows,  especially  those 
kept  in  confinement,  than  in  steers  and  oxen.  It  is  almost  an  unknown 
disease  in  the  great  herds  roaming  the  western  plains.  In  Berlm,  in 
1892-93,  15.1  per  cent,  of  all  cattle,  1,55  per  cent,  of  swine,  0.11  per 
cent,  of  calves,  and  0.004  per  cent,  of  sheep  slaughtered  showed  some 
evidence  of  the  existence  of  the  disease.  In  Copenhagen,  in  the  years 
1890-93,  the  figures  were  somewhat  higher  tlian  those  of  Berlin,  ex- 
cepting in  the  case  of  sheep.  They  were  as  follows  :  17,7  per  cent,  of 
cattle,  15.3  per  cent,  of  swine,  0,2  per  cent,  of  calves,  and  only  one 
.sheep  out  of  337,014.     At  the  abattoirs  of  Leipzig,  in  1897,  nearly 


44  FOODS. 

half  of  the  cows  and  about  20  per  cent,  of  the  other  cattle  were  found 
to  be  tuberculous;  2.78  per  cent,  of  swme,  0.2  per  cent,  of  calves,  and 
8  sheep  out  of  49,559. 

Out  of  over  8,000  beeves  of  American  origin  landed,  slaughtered, 
and  exammed  at  Hamburg,  4  were  found  to  be  tuberculous,  while  of 
the  same  number  of  native  animals,  640,  or  160  times  as  many,  were 
found  to  be  afflicted  with  the  disease.  At  that  time  the  German  press 
had  been  carrying  on  one  of  its  periodical  agitations  against  the  impor- 
tation of  American  beef  cattle  on  account  of  the  dangers  to  which 
native  breeds  were  thereby  subjected. 

In  Great  Britain,  30  per  cent,  of  the  cows  are  estimated  by  Mac- 
Faydean  to  be  tuberculous.  In  Belgium,  of  20,850  animals  tested 
with  tuberculin  in  1896,  48.88  per  cent,  reacted.  In  Denmark,  of 
67,263  thus  tested,  32.80  per  cent,  reacted.  In  Mexico,  about  a  third 
of  the  beeves  slaughtered  are  tuberculous. 

In  this  country,  while  the  percentage  of  affected  animals  is  low,  it  is 
believed  to  be  on  the  increase,  both  with  cattle  and  swine.  In  the 
State  of  New  York,  it  is  said  by  veterinarians  that,  in  some  districts  in 
which  the  herds  are  mainly  of  the  hardy  grades  of  the  Ayrshire,  Hol- 
stein,  and  Short-horn  families,  about  1  per  cent,  of  the  cows,  and  in 
others  where  Jerseys  and  Guernseys  are  more  common,  about  2  to  3 
per  cent,  are  tuberculous.  In  Massachusetts,  those  in  a  position  to  be 
best  informed  state  that,  among  cows,  the  disease  is  much  more  frequent 
than  in  New  York,  but  that  it  is  rarely  to  be  found  in  calves,  steers^ 
and  oxen.  In  Pennsylvania,  the  State  veterinarian  believes  that  not 
over  2  per  cent,  of  all  cattle  are  tuberculous.  At  the  large  abattoirs  of 
this  country,  about  1  in  2,000  cattle  is  found  to  be  tuberculous.  Dur- 
ing the  two  years  ended  June  30, 1899,  8,831,927  cattle  were  inspected 
by  the  Federal  authorities,  and  7,015,  or  1  in  1,259,  were  condemned 
on  account  of  tuberculosis.  During  1900,  of  4,861,166  inspected,, 
5,279,  or  1  in  921,  were  condemned.  Of  23,336,884  hogs  mspected,. 
5,440,  or  1  in  4,290  were  sufficiently  affected  to  warrant  condemnation 
of  at  least  a  part  of  the  carcass. 

The  organs  involved  most  frequently  in  tuberculosis  of  animals  are 
the  liver,  lungs,  kidneys,  brain,  and  udder.  The  muscles  are  affected 
very  rarely,  although  the  bacilli  have  been  found  in  the  expressed  juice. 

At  what  stage  of  the  disease  meat  becomes  unfit  for  food,  is  a  ques- 
tion over  which  there  is  much  controversy.  Extremists  on  the  one 
side  believe  in  condemnmg  the  entire  carcass  on  the  slightest  evidence 
of  disease  in  any  part  thereof,  while  those  on  the  other  side  maintain, 
that  the  entire  animal  may  be  used  as  food  without  injury.  In  Eng- 
land, the  practice  is  to  condemn  any  carcass  in  which  the  disease 
has  made  such  extensive  progress  that  the  flesh  has  become  dete- 
riorated. The  Royal  Commission  on  Tuberculosis  ^  concluded  that 
meat  from  tuberculous  animals  may  be  consumed  with  impunity,  if 
sufficient  discrimination  and  care  are  exercised  in  slaughtering  and 
dressing.  Every  part  containing  tubercles  should  be  removed  and 
^  The  Veterinary  Journal  and  Annals  of  Comparative  Patholog.y,  June,  1895* 


TEAXSMISSION  OF  DISEASE  BY  MEAT  AND  FISH.  45 

destroyed,  and  the  whole  carcass  itself  in  advanced  or  general 
tuberculosis. 

The  French  law  excludes  carcasses  with  generalized  tuberculosis  and 
those  in  which  local  lesions  have  involved  the  greater  part  of  an  organ. 
The  same  is  true  in  Austria.  In  Prussia,  the  meat  is  held  to  be  unfit 
for  food  if  the  animal  has  begun  to  show  emaciation,  but  is  passed  as 
fit  for  human  consumption  if  the  disease  occurs  in  only  one  organ,  and 
in  general,  if  the  animal  is  well  nourished.  In  Belgium,  the  law  of 
September  30,  1895,  permits  the  sale  of  meat  of  tuberculous  animals 
after  sterilization. 

Meat  from  tuberculous  cattle  is  infective  to  other  animals  in  very 
variable  degrees.  As  a  rule,  the  more  advanced  the  disease,  the  more 
likely  is  the  meat  to  be  infective.  Experiment  has  demonstrated  that 
infection  depends  to  a  not  inconsiderable  extent  upon  contamination  of 
the  meat,  in  the  process  of  dressing,  by  the  hands,  knives,  or  cloths, 
which  have  been  in  contact  with  tuberculous  matter. 

Although  lesions  in  the  muscular  tissue  itself  are  not  at  all  common, 
positive  results  have  repeatedly  been  obtained  in  experiments  in  which 
the  expressed  juice  of  the  meat  has  been  injected  into  susceptible 
animals.  Thus,  Kastner  obtained  9  positive  results  in  1 1  injections  of 
the  juice  of  the  meat  of  7  tuberculous  animals,  andSteinheil  transmitted 
the  disease  to  guinea-pigs  by  means  of  juice  from  meat  apparently 
sound.  Arloing  inoculated  the  muscle  juice  of  10  tuberculous  cows  into 
guinea-pigs  and  demonstrated  that  that  from  2  of  the  animals  was  infec- 
tive. Nocard  produced  the  disease  with  the  muscle  juice  of  but  1  of 
21  tuberculous  cows  with  which  he  experimented.  All  of  these  cows 
had  been  condemned  at  the  abattoir  on  account  of  extensive  lesions. 
Woodhead,  Galtier,  Humbert,  and  others  have  met  with  varying  degrees 
of  success  in  similar  experiments. 

That  tuberculosis  can  be  transmitted  to  animals  by  feeding  them  on 
tuberculous  material  has  been  abundantly  proved,  but  the  lesions  pro- 
duced almost  never  involve  the  muscular  apparatus,  and  many  of  the 
subjects  escape  infection  altogether.  It  was  reported,  for  example,  by 
Thomassen,  at  the  Tuberculosis  Congress  at  Paris,  that  of  10  young 
pigs,  each  of  which  was  made  to  eat  4.5  kilos  of  meat  from  animals 
with  advanced  general  tuberculosis,  but  2  were  affected,  and  their  por- 
tions had  contained  a  quantity  of  splintered  bone.  Ravenel '  has  held 
for  a  long  time  that  food  tuberculosis  may  appear  first  in  the  lungs  and 
cervical  glands,  and  cites  the  case  of  2  cows  which,  fed  on  tuberculous 
material,  developed  extensive  disease  of  the  lungs  and  lesions  nowhere 
€lse.  As  stated  by  Dr.  D.  E.  Salmon,^  Woodhead,  St.  Clair  Thomp- 
son, and  Lord  Lister  have  shown  "  that  infection  through  the  medium 
of  the  food  may  not  necessarily  be  accompanied  by  disease  of  the  in- 
testines. The  organs  first  attacked  after  feeding  on  tubercular  material 
may  be  the  mesenteric  glands  and  liver,  or  even  the  bronchial  and 
mediastinal  glands  and  the  lungs." 

'  Philadelphia  Medical  .Journal,  August  14,  1901,  p.  284. 

^  Bulletin  No.  '.iy>,  Bureau  of  Animal  Indu.strj,  Washington,  1901, 


46  FOODS. 

The  question  of  the  identity  of  the  bacilli  of  human  and  bovine 
tuberculosis,  raised  in  1901  by  Koch's  assertion  of  the  impossibility 
of  transference  of  the  disease  from  man  to  cattle  and  from  cattle  to 
man,  has  led  to  much  experimentation  and  study,  and  although  there 
is  as  yet  no  general  agreement  in  the  interpretation  of  the  results  ob- 
tained, the  weight  of  evidence  appears  to  favor  the  contention  that  the 
two  diseases  are  one  and  the  same,  althongh  reciprocal  transmissibility 
is  opposed  by  systemic  differences.  The  respective  organisms  differ  in 
virulence,  morphology,  and  cultural  peculiarities,  but  so  do  different 
strains  of  the  same  variety.  Eavenel  ^  believes  that  the  bovine  bacillus 
shows  persistent  peculiarities  of  growth  and  morphology,  which  enable 
it  to  be  differentiated  from  the  human  variety,  and  that  it  is  much  more 
pathogenic,  not  only  for  nearly  all  of  the  species  of  experimental  ani- 
mals, but  for  man  also.  He  says,^  moreover,  that  human  bacilli  with. 
a  high  degree  of  virulence  for  experimental  animals  are  rarely  found, 
and  that  cultures  highly  pathogenic  for  cattle  are  still  more  rare.  That 
the  bovine  bacilli  are  more  dangerous  to  man  than  the  hnman  variety,, 
is  the  conclusion  drawn  also  by  Fibiger  ^  from  a  review  of  recent  work 
on  the  communicability  of  human  tuberculosis  to  cattle.  Experiments 
conducted  by  Nocard,  CipoUiua,  and  others  indicate  that  the  bovine 
bacillus  is  the  more  infective.  Nocard*  observed  that  monkeys  fed 
with  material  cf)ntainino'  bovine  bacilli  became  infected  much  sooner 
than  did  those  whose  food  contained  the  human  variety  ;  and  Cipol- 
lina^  produced  general  tuberculosis  in  a  healthy  ape  with  milk  contain- 
ing bovine  bacilli,  while  a  calf  resisted  infection  with  the  human 
variety.  In  Ravenel's  experiments,  guinea-pigs  infected  with  human 
bacilli  lived  more  than  twice  as  long  as  those  inoculated  with  the  bovine 
variety,  and  rabbits  were  much  less  extensively  infected  and,  indeed, 
gained  in  weight. 

That  human  bacilli  from  different  lesions  are  differently  virulent,  has 
been  observed  repeatedly.  Those  from  the  lungs  almost  invariably  fail 
to  infect  calves,  but  Fibiger  and  Jensen  ^  found  that  bacilli  from  3  cases 
of  chronic  intestinal  tuberculosis  were  exceedingly  virulent,  and  Wolff '^ 
produced  general  tuberculosis  in  a  calf  which  he  inoculated  with  mate- 
rial from  a  similar  source.  Ravenel  ^  also  has  found  two  cultures  from 
the  mesenteric  glands  of  milk-fed  children,  one  quite  as  virulent  as 
bovine  bacilli,  and  the  other  more  potent  than  the  usual  human  culture. 
Orth  ^  has  convinced  himself  by  experiment  and  observation  tliat 
human  and  bovine  tuberculosis  are  reciprocally  transmissible,  and  he 
believes  that  virulence  can  be  increased  materially  by  passage  through 

^  Journal  of  Comparative  Medicine  and  Veterinary  Archives,  1902,  pp.  65,  139. 

^  Journal  of  the  American  Medical  Association,  June  3, 1903. 

'^  Hospitalstidende,  XL VI.,  Nos.  9  and  10. 

*  .Journal  of  the  Sanitary  Institute,  January,  1903,  p.  571. 

^  Berliner  klinische  Wochenschrift,  February  23,  1903,  p.  163. 

6  Ibidem,  September  22,  1902. 

'  Ibidem,  November  17,  1902. 

^  Journal  of  the  American  Medical  Association,  June  3,  1903. 

'  Berliner  klinische  Wochenschrift,  July  20,  1903. 


TRANSMISSION   OF  DISEASE  BY  MEAT  AND   FISH.  47 

a  series  of  animals.  Behring  ^  increased  the  virulence  of  the  human 
bacillus  by  passage  through  rabbits  and  goats,  until  it  became  as  viru- 
lent for  cattle  as  any  strain  of  bovine  bacilli ;  and,  according  to  Sal- 
mon,^ Mohler  did  the  same  by  passage  through  five  cats.  Hamilton 
and  Young  ^  noted  an  enormous  increase  in  virulence  on  reinoculation 
from  one  calf  to  another  and  great  variation  in  morphological  character. 
Arloing  reports  positive  results  from  inoculation  of  cattle,  asses,  sheep, 
and  hogs  with  human  bacilli  from  five  sources,  and  Theobald  Smith 
has  found  a  human  culture  directly  virulent  for  cattle. 

Raw,^  who,  during  the  past  few  years  has  had  more  than  3000  cases. 
of  pulmonary  tuberculosis  under  observation,  inclines  to  the  belief 
that  man  is  subject  to  two  kinds  of  tuberculosis  :  the  pulmonary  form,, 
rare  in  children  under  12,  and  due  to  human  bacilli,  and  other  forms, 
as  tubercular  joints,  tubercular  meningitis,  and  abdominal  tuberculosis, 
rare  in  adults  and  due  to  bovine  bacilli.  In  a  period  of  12  years  he 
saw  nearly  300  cases  of  tabes  mesenterica,  and  not  one  of  the  subjects 
was  a  breast-fed  child.  Von  Hansemann^  gives  the  particulars  of  25 
cases  of  intestinal  tuberculosis  due  apparently  to  bovine  bacilli.  He 
believes  that  infection  can  take  place  through  the  healthy  mucous 
membrane,  and  von  Behring  ^  is  of  like  mind.  He  believes  that  the 
chief  source  of  tuberculosis  is  infected  milk,  and  that  infection  of 
infants  is  due  to  lack  of  continuity  of  the  epithelial  lining  of  the  ali- 
mentary tract,  which  permits  the  passage  of  bacteria. 

Evidence  that  infection  of  the  lungs  can  occur  through  food  without 
local  lesions  of  the  digestive  tract  is  oifered  by  several.  Thus,  Nicolas 
and  Descas ''  fed  fatty  broth  containing  large  numbers  of  tubercle  bacilli 
to  healthy  dogs,  some  of  which,  after  three  hours,  yielded  chyle  con- 
taining Ijacilli  in  such  abundance  that  they  could  be  demonstrated 
microscopically  ;  and  Ravenel  ^  introduced  a  quantity  of  bovine  bacilli 
in  melted  butter  into  the  stomachs  of  8  healthy  fasting  dogs,  and  found 
that  the  chyle  and  mesenteric  glands,  removed  about  4  hours  later,, 
were  infective  for  guinea-pigs,  and  that  not  the  slightest  evidence  of 
abnormality  of  the  intestinal  mucosa  could  be  seen.  MacFadyen* 
obtained  like  results  with  monkeys  fed  with  tuberculous  material  from 
cattle.  General  tuberculosis  was  produced,  but  no  lesions  of  the  intes- 
tines were  observed. 

The  German  Tuberculosis  Commission,  appointed  on  Koch's  sug- 
gestion, found  that  different  bovine  cultures  varied  much  in  virulence, 
some  failing  to  transmit  the  disease  to  other  cattle.  They  tested  39 
cultures  of  human  origin  and  found  4  that  caused  general  tuberculosis 

^  Beitrage  zur  Exper.  Therapie,  No.  2. 

^.Journal  of  the  American  Medical  Association,  March  12,  1904. 

» Public  Health,  September,  1903,  p.  689. 

*  British  Mcflifjil  .Journal,  October  8,  1904. 

M',er]in.-i-  klinischc  Wochenschrift,  1903,  No.  7,  p.  141,  and  No.  8,  p.  170. 

"Deutsche  medicinische  Wochenschrift,  1903,  No.  .39. 

'Centralblatt  fiir  IJakteriologie,  etc.,  1902,  XXXII.,  p.  306. 

".Journal  of  Medical  Research,  December,  1903,  p.  460. 

»The  Lancet,  September  12,  1903. 


48  FOODS. 

in  calves.  Thus,  both  kinds  dififer  in  virulence.  But  the  four  that 
proved  virulent  for  calves  were  derived  from  children,  and  KosseP 
concludes  that  the  children  must  have  been  infected  by  bovine  bacilli. 
His  experiments  show  that  bovines,  in  a  certain  small  proportion  of 
cases,  may  yield  to  human  bacilli,  and  in  endeavoring  to  explain  the 
fact,  he  admits  that  the  reverse  is  also  true.  Orth,^  having  succeeded 
in  producing  general  tuberculosis  in  2  out  of  5  calves  inoculated  with 
human  bacilli,  asks  Koch  to  reconcile  his  own  negative  results  with  the 
positive  results  of  others. 

Of  very  great  importance  is  the  interim  report  of  the  Royal  Com- 
mission, appointed  in  1901  to  inquire  into  the  relations  of  human  and 
animal  tuberculosis,  which  concludes  ^  that  the  two  are  identical,  both  in 
general  features  and  in  finer  histological  details.  More  than  20  strains 
of  human  tuberculous  material — from  lungs,  sputum,  glands,  and  joints 
— were  employed,  and  7  of  them  were  found  to  be  capable  of  causing 
acute  tuberculosis  in  cattle,  with  lesions  in  various  organs  (lungs,  spleen, 
liver,  lymphatic  glands,  etc.).  "  In  some  instances  the  disease  was  of 
remarkable  severity."  Several  of  the  less  virulent  strains  were  found 
to  gain  greatly  on  reinoculation  from  one  bovine  into  another  or  into  a 
guinea-pig. 

Concerning  the  possibility  of  direct  transmission  of  tuberculosis  from 
animal  to  man  by  inoculation,  considerable  evidence  is  oifered,  but  in 
most  cases  the  infection  is  local  and  is  due  to  wounds  received  in  mak- 
ing autopsies  on  diseased  cattle.  Pfeiifer  *  records  an  accident  of  this 
sort  whicli  was  followed  in  18  months  by  death  from  phthisis,  and  the 
originally  infected  joint  was  found  to  be  extensively  tubercular. 
Spronck  and  Hoefnagel  ^  record  a  similar  case.  A  man  aged  63 
years  cut  his  finger  while  skinning  a  very  tuberculous  cow,  and,  though 
the  wound  healed  quickly,  the  glands  at  the  elbow  became  enlarged 
and,  after  nine  months,  they  were  excised  and  found  to  be  infective 
for  guinea-pigs.  The  disease  was  conveyed  from  one  of  these  to  a 
healthy  heifer,  which  showed  general  infection  after  two  months.  The 
man  developed  a  catarrh  of  the  right  apex  20  months  later.  Lassar  ^ 
has  seen  in  ten  years  34  cases  of  undoubted  inoculation  tuberculosis, 
chiefly  in  veterinarians,  butchers,  and  others  who  handle  meats. 

The  fact  that  so  few  cases  of  infection  occur  among  the  army  of 
men  who  are  constantly  exposed  to  the  possibility  of  wounds  during 
slaughtering  leads  Flick  ^  to  conclude  that  bovine  tuberculosis  is  only 
slightly  virulent  for  man,  and  that  it  is  not  right  to  declare  meat  and 
milk  from  tuberculous  animals  dangerous  to  man. 

Concerning  the  possibility  of  transmission  of  tuberculosis  by  eating 
the  meat  of  diseased  animals,  there  is  practically  no  evidence  of  value, 

^  Berliner  klinische  Wochenschrift,  July  20,  1903. 

'^  Ibidem. 

^Interim  Report,  London,  1904. 

*  Zeitschrift  fiir  Hygiene,  III.,  p.  209. 

5  La  Semaine  Medicale,  October  15,  1902,  p.  341. 

®  Deutsche  niedicinische  Wochenschrift,  October  2,  1901. 

'Journal  of  Tuberculosis,  1902,  IL,  No.  4. 


TBANS3nSSI0N  OF  DISEASE  BY  MEAT  AND  FISH.  49 

hut  whatever  danger  there  is,  if  any  at  all,  is  disposed  of  by  thorough 
booking,  since  thereby  the  bacillus  is  quickly  killed.  Since  raw  meat 
is  frequently  used  as  food,  particularly  in  some  diseased  conditions,  it 
is  best,  in  order  to  be  on  the  safe  side,  to  see  that  meat  so  used  shall 
be  free  from  infective  properties. 

Typhoid  Fever  and  Cholera. — Foods  of  all  kind  may  be  made  the 
bearers  of  infection  to  man,  though  themselves  in  good  condition.  Par- 
ticularly is  this  noticeable  with  regard  to  oysters,  Avhich  have  many 
times  conveyed   the  specific  organisms  of  typhoid  fever  and  cholera. 

In  1880,  Sir  Charles  Cameron  ^  brought  to  the  attention  of  the  pro- 
fession, that  oysters,  transplanted  from  the  coast  of  the  County  of  Wex- 
ford to  the  northern  shore  of  Dublin  Bay,  had  for  some  years  been 
much  subject  to  disease  and  had  died  in  large  numbers.  Specimens 
which  were  examined  were  found  to  contain  sewage  matters,  and  inves- 
tigation showed  that  the  beds  "  were  literally  bathed  in  sewage."  He 
oifered  the  suggestion  that  raw  oysters,  taken  from  the  shore  close  to 
sewer  outlets,  were,  perhaps,  as  likely  to  act  as  the  vehicle  of  typhoid 
fever  and  other  diseases  as  contaminated  water  or  milk,  and  advised 
that  "  oyster  beds  should  not  be  laid  down  at  any  point  on  or  close 
to  the  mouth  of  a  sewer."  But  the  warning  appears  to  have  excited 
no  more  than  a  languid  interest  until  1893,  when  the  late  Sir  R. 
Thorne-Thorne,  in  a  report  to  the  Local  Government  Board,  stated 
his  belief  that  the  sporadic  cases  of  cholera  which  had  occurred  at 
various  inland  places  in  England  in  that  year  were  due  to  oysters  and 
other  shellfish  from  sewage-contaminated  water  at  Grimsby,  where  there 
had  been  a  small  outbreak  of  the  disease. 

In  the  following  year  occurred  the  well-known  outbreak  of  typhoid 
fever  at  Wesleyan  University,  which  was  so  ably  and  conclusively 
traced  by  Professor  Conn  ^  of  that  institution  to  polluted  oysters.  On 
October  20,  1894,  several  of  the  students  were  reported  as  slightly 
ill,  with  a  moderate  degree  of  fever.  The  number  of  cases  grew 
from  day  to  day,  and  shortly  included  several  of  undoubted  typhoid 
fever.  By  November  1st,  there  M^ere  20  cases  of  the  disease,  which 
number  was  shortly  further  increased  to  23.  All  of  the  victims  were 
m.en  ;  there  was  no  illness  among  the  58  women  students.  Investi- 
gation completely  absolved  the  water  supply,  the  general  and  par- 
ticular food  supplies  of  the  various  boarding  places,  and  the  local 
■conditions  of  the  dormitories  and  outside  lodgings  of  all  suspicion  of 
blame.  It  appeared  that  nearly  all  of  the  victims  were  members  of 
three  of  the  seven  college  fraternities.  The  combined  membership  of 
the  three  was  about  one  hundred.  On  October  1 2th,  eight  days  before 
the  development  of  the  first  symptoms,  all  seven  fraternities  had  had 
their  initiation  ceremonies  and  had  celebrated  in  the  usual  way  with  a 
supper.  Investigation  of  the  origin  of  the  components  of  the  suppers 
showed  that  there  was  but  one  dish  from  a  common  source,  and  that 
was  oysters.     The  three  afflicted  societies  and  one  other  had  obtained 

'  British  Medical  Journal,  September  18,  1880,  p.  471. 
2  Medical  Record,  Dec.  15,  1894,  p.  743. 


50  FOODS. 

their  oysters  from  a  local  dealer  ;  of  the  remaining  three,  two  had  had 
no  oysters,  and  the  third  had  had  some  from  a  dealer  in  Hartford.  Of 
the  four  supplied  by  the  local  dealer,  one  had  eaten  the  oysters  cooked, 
and  its  membership  was  not  invaded.  Thus  the  trouble  was  sifted 
down  to  the  raw  oysters  from  the  local  dealer.  But  there  Avas  one 
victim  who  was  a  non-society  man,  and,  clearly,  his  case  could  not  be 
traced  to  the  initiation  supper.  Investigation  of  his  dietetic  history 
established  the  guilt  of  the  local  oyster  supply  even  more  securely,  for 
it  was  shown  that  he  had  eaten  raw  oysters  from  the  same  lot  at  the 
shop  of  the  dealer.  It  was  learned,  too,  that  5  men  from  Yale  had 
attended  the  exercises  of  the  societies  in  which  the  outbreak  occurred,, 
and  inquiry  developed  the  information  that  2  of  the  5  were  seized  with 
typhoid  fever  some  weeks  after  their  return  to  New  Haven.  Further 
investigation  revealed  the  fact  that  the  incriminated  oysters  had  been 
brought  from  a  bed  in  Long  Island  Sound,  and,  on  October  10th,  two 
days  before  use,  had  been  stored  in  a  bed  at  tlie  mouth  of  the  Quin- 
nipiac  River,  a  short  distance  (300  feet)  from  the  outlet  of  a  private 
drain  from  a  dwelling,  in  wdiich  2  persons  lay  ill  with  typhoid  fever. 

Dr.  Arthur  Newsholrae,^  M.  O.  H.  for  Brighton,  England,  reported 
that  of  53  cases  of  typhoid  fever  occurring  within  his  district  during 
1894,  no  fewer  than  15  were  due  to  infected  oysters,  and  6  to  other 
contaminated  shellfish  (clams,  cockles,  and  mussels).  In  a  later  com- 
munication,^ after  a  thorough  examination  of  the  cases  that  had  occurred 
within  four  years,  he  reported  the  percentages  of  infection  due  to  oys- 
ters and  mussels  as  follows  :  In  1894,  38.2  ;  1895,  33.9  ;  1896,  31.^8  ; 
1897,  30.7. 

Dr.  J.  T.  C.  Nash,^  M.  O.  H.  for  Sou  then  d-on-Sea,  says  that  prior 
to  1900  attacks  of  typhoid  fever  within  his  district  were  ascribed  to 
the  commonly  accepted  causes  and  occasionally  to  shellfish.  In  1900, 
investigation  showed  that  in  a  majority  of  the  reported  cases  there  was 
a  history  of  consumption  of  shellfish  w'ithin  2  or  3  weeks  of  the  onset. 
In  a  majority  of  the  cases  reported  during  the  last  5  months  of  1901 
there  was  a  similar  history.  During  June  and  July,  1902,  in  a  major- 
ity of  the  39  cases  reported  there  was  a  history  of  eating,  within  a 
month  of  the  onset,  cockles  from  a  sewage-polluted  creek  in  another 
district,  where,  during  June,  9  cases  of  typhoid  fever  had  existed. 
Cockles  obtained  from  these  layings  were  examined  and  the  presence 
of  sewage  bacteria  was  demonstrated.  In  a  later  commanication  ^  he 
states  that  in  82  of  the  102  cases  of  typhoid  fever  reported  during^ 
1902  there  was  a  shellfish  history.  Diminished  consumption  of  shell- 
fish, the  adoption  of  better  methods  of  storage,  and  the  exercise  of 
greater  care  in  obtaining  supplies  from  clean  layings  were  followed  by 
a  very  decided  diminution  in  the  incidence  of  typhoid  fever.  By  care- 
ful inquiry  he  determined  that  somewhat  less  than  5  per  cent,  of  the 

1  British  Medical  Journal,  June  8,  1905,  p.  1285. 

2  Public  Health,  September,  1898. 

^Journal  of  the  Sanitary  Institute,  January,  1903,  p.  369. 
*  Journal  of  State  Medicine,  December,  1903,  p.  710. 


TRANSMISSION  OF  DISEASE  BY  MEAT  AND  FISH.  51 

entire  population  of  the  district  were  eaters  of  shellfish,  and  during 
1902  the  attack-rate  of  typhoid  fever  per  1000  among  this  section  was 
51.25  against  3.28  for  the  whole  population,  and  0.75  for  the  non- 
eaters  of  shellfish.  The  attack-rate  among  the  dealers  and  their  em- 
ployees was  no  less  than  160  per  1000. 

i)r.  J.  F.  Allen,^  M.  O.  H.  for  Westminster,  secured  specimens  of 
cockles  which  were  from  the  same  bed  as  some  which  were  supposed  to 
have  caused  a  number  of  cases  of  typhoid  fever,  and  had  them  ex- 
amined, at  the  Jenner  Institute,  for  sewage  bacteria.  The  results  were 
positive,  and  the  typhoid  bacillus  itself  was  found  to  be  present.  Hew^- 
lett  ^  records  that  cockles  purchased  at  the  fishmarket  of  Billingsgate 
and  examined  by  Klein  yielded  the  usual  sewage  bacteria  and  the 
typhoid  organisms  as  well.  Four  cases  of  typhoid  fever  attributed  to 
cockles  from  the  same  source  were  the  cause  of  the  inquiry.  Sewage 
contamination  was  demonstrated  by  the  same  authority  in  11  of  18 
lots  of  oysters  from  five  dilFerent  localities. 

Chantemesse  ^  relates  the  following  case  :  There  had  been  no  case 
of  typhoid  fever  in  the  village  of  I'Herault  Saint  Andre  de  San- 
gonis  for  about  a  year,  when,  on  February  15th,  a  shopkeeper  received 
a  consignment  of  oysters  from  Gette.  The  entire  lot  was  consumed  by 
14  persons,  all  of  whom  were  made  sick.  In  the  6  dwellings  in 
which  the  victims  lived,  no  other  inmates  were  sick  in  any  way.  Eight 
of  the  number  were  made  only  slightly  ill,  the  symptoms,  which  in- 
cluded abdominal  pain,  vomiting,  diarrhoea,  borborygmus,  anorexia, 
and  general  malaise,  lasting  but  2  or  3  days.  The  4  youngest,  who 
ate  but  a  few,  were  very  sick  for  a  much  longer  time  (15  to  25  days), 
but  recovered.  The  stools  were  very  offensive,  were  passed  with  pain, 
and  w^ere  dysenteric  in  appearance ;  there  was  tympanites  with  tender- 
ness and  gurgling.  All  4  were  greatly  prostrated.  The  remaining  2, 
a  woman  of  twenty  and  a  man  of  twenty-one,  developed  very  severe 
cases  of  typhoid  fever.      The  woman  died. 

Mosny,*  to  whom  the  French  authorities  referred  the  whole  subject 
of  mollusk  poisoning  for  investigation,  has  reported  that  5  members  of 
a  family  of  7,  living  in  a  village  in  a  suburb  of  Paris,  in  which  there 
had  been  no  case  of  typhoid  fever  in  4  years,  were  made  sick  after 
eating  oysters  sent  to  them  from  Cette.  Four  were  seized  in  the 
evening  of  the  following  day  with  gastro-intestinal  disturbance,  which 
lasted  24  hours.  On  the  eighteenth  day,  a  youth  of  17  years  devel- 
oped unmistakable  symptoms  of  typhoid  fever,  of  which,  9  days  later, 
he  died.  In  March,  1897,  Chatin^  reported  the  case  of  a  family,  of 
which  several  members  were  stricken  with  typhoid  fever  after  eating 
oysters  from  a  bed  which  was  contaminated  by  sewage. 

Klein  and  Boyce  have  shown  that  oysters  contaminated  by  typhoid 

'  .Journal  of  the  Sanitaiy  Institute,  January,  1903. 
'^  .Journtil  of  State  Medicine,  March,  1903,  p.  163. 
3  Bulletin  iU:  i'Acadeniie  de  Mcdecine,  1896,  35-36,  p.  588. 

*  Revue  d'lly^iene,  .January,  February,  and  March,  1900. 

*  La  Semaine  M^dicale,  1897,  p.  9. 


52  FOODS. 

bacilli  can  retain  their  infective  properties  for  2  or  3  weeks,  and  it  is 
shown  that  those  from  sewage-contaminated  beds  may  not  be  eaten 
with  entire  safety  until  they  have  lain  for  about  2  weeks  in  unpolluted 
water.  It  appears,  however,  that  in  cockles  the  typhoid  organism 
thrives,  and  that  this  kind  of  shellfish  is  not  freed  of  its  infective 
properties  by  storage  in  clean  water.  Although  cockles  are  not 
eaten  raw,  the  cooking  to  which  they  are  subjected  is  by  no  means 
thorough,  for  boiling  for  any  considerable  time  makes  them  tough  and 
uneatable. 

It  was  shown  by  Foote,^  after  the  outbreak  at  Wesleyan  University, 
that  typhoid  cultures,  introduced  within  the  cells  of  oysters  from  the 
bed  from  which  the  incriminated  oysters  were  derived,  were  virulent  at 
the  end  of  48  hours,  which  was  the  period  which  elapsed  between  the 
gathering  and  consumption  of  those  which  caused  the  outbreak.  Fur- 
thermore, it  was  demonstrated  that,  if  the  specimens  were  kept  at 
57°  F.,  the  organisms  were  active  as  long  as  a  month  later. 

The  influence  of  the  sewage  of  a  large  city  is  shown  by  C.  A.  Fuller,^ 
who  collected  samples  of  water  and  shellfish  from  various  places  in 
Narragansett  Bay,  into  which  about  14,000,000  gallons  of  sewage  from 
Providence,  Rhode  Island,  are  discharged  daily.  Water,  oysters,  clams, 
and  mussels,  taken  at  a  distance  of  a  quarter  of  a  mile  from  the  sewer 
outlet,  yielded  Bacilbis  coli  communis,  Bacillus  cloacce,  and  Bacterium 
lactis  aerogenes.  The  water  and  oysters  from  a  bed  two  miles  distant 
yielded  the  same  organisms.  Bacillus  coli  communis  was  found  in  30 
per  cent,  of  the  oysters,  and  in  60  per  cent,  of  the  samples  of  water 
from  a  bed  situated  in  the  line  of  a  strong  tidal  current,  five  miles 
away ;  and  in  40  per  cent,  of  the  oysters  and  70  per  cent,  of  the  water 
samples  from  another  in  sluggish  water  more  than  five  miles  away. 
One  bed  six  miles  distant  was  found  to  be  contaminated,  but  those 
farther  down  than  six  and  one-half  miles  were  unpolluted. 

These  findings  are  in  accord  with  the  statement  of  Dr.  E.  Klein,^ 
that  the  nearer  to  sewer  outlets  oysters  and  cockles  are  planted,  the 
greater  the  percentage  of  specimens  yielding  evidence  of  pollution. 
In  the  examination  of  oysters  he  holds  that  the  presence  of  Bacillus 
enteritidis  sporogenes  alone  is  not  sufficient  proof  of  recent  sewage  pol- 
lution, but  that  when  the  spores  of  this  organism  are  found  together 
with  streptococci  and  Bacillus  coli  communis  they  constitute  strong 
evidence  of  recent  contamination. 

Dr.  Hibbert  W.  Hill  ^  has  recorded  interesting  results  of  examination 
of  clams  from  flats  in  the  immediate  vicinity  of  the  sewer  outlets  of  a 
number  of  private  dwellings.  Attention  was  devoted  solely  to  the 
bodies  of  the  clams  and  not  to  the  water  contained  between  the  shells, 
which  was  practically  the  same  as  that  which  surrounded  them.  The 
technique  followed  was  such  as  to  insure  absolutely  against  contamiua- 

1  Medical  News,  March  23,  1895. 

2  Science,  1902,  No.  375,  p.  363. 

^  British  Medical  Journal,  Fehruarv  21,  1903. 

*  Eeport  of  the  Board  of  Health  of  Boston,  Massachusetts,  for  1901. 


TRANSMISSION  OF  DISEASE  BY  MEAT  AND  FISH.  53 

tion  by  bacteria  on  the  surface,  and  the  portion  of  the  body  selected  as 
most  likely  to  show  infection  was  the  intestines.  The  following  were 
isolated  and  identified  :  Bacillus  coli  communis,  Bacillus  enteritidis 
sporogenes,  and  Bacillus  aerogenes  capsulatus  (Welch),  all  three  of 
which  are  found  commonly  in  sewage.  The  tyjihoid  bacillus  was  not 
found  nor  was  it  expected,  since  there  was  but  1  case  in  the  neighbor- 
hood and  the  excreta  were  disinfected.  Dr.  Hill  adds  that  the  search 
for  typhoid  bacilli  in  sewage  known  to  contain  them  is,  in  most  cases, 
practically  hopeless,  since  even  in  severe  epidemics  the  number  of 
typhoid  patients  contributing  to  the  sewage  is  almost  always  small  in 
comparison  with  the  total  contributing  persons,  and  only  a  small  pro- 
portion of  the  bacteria  present  in  a  typhoid  stool  are  typhoid  bacilli ; 
and  to  hope  to  find,  by  examining  a  few  cubic  centimeters  from  a  large 
mass  of  water,  a  bacillus  which  is  present  in  the  proportion  of  one 
to  every  ten  or  hundred  gallons  of  water,  is  almost,  if  not  quite, 
useless. 

From  a  series  of  experiments  undertaken  to  determine  the  question 
of  viability  of  the  typhoid  organism  in  sea  water  and  within  the  oyster, 
Bordoni-Uffreduzzi  and  Zernoni  ^  concluded  that  it  will  live  over  2 
weeks  in  sea  water  and  from  3  to  4  days  in  oysters,  without 
lessening  of  virulence.  Oysters  from  Spezia,  Venice,  and  elsewhere, 
were  examined  to  determine  the  presence  of  the  typhoid  organism  in 
the  water  contained  between  the  shells  or  in  the  tissues.  The  results 
were  negative  on  this  point,  but  the  colon  bacillus  was  isolated  from 
oysters  from  3  different  sources.  Oysters  immersed  in  sterilized  sea 
water,  which  later  was  infected  with  cultures  of  the  typhoid  organism, 
yielded  virulent  bacilli  from  the  water  between  their  shells  up  to  the 
ninth  day  of  examination,  but  never  from  the  tissues  themselves. 

Other  observers  have  found  the  bacteria  of  cholera  and  typhoid  fever, 
B.  coli  communis,  B.  proteus  vulgaris,  and  other  organisms,  in  oysters 
contaminated  by  sewage,  and  all  unite  m  the  opinion  that  the  presence 
of  B.  coli  communis  should  arouse  suspicion  and  induce  improvements 
in  the  management  and  supervision  of  oyster  beds. 

In  the  investigation  of  outbreaks  of  typhoid  fever  supposedly  due  to 
oysters,  bacteriological  proof  of  specific  mfection  of  those  eaten  or  of 
others  from  the  same  lot  always  has  been  and  always  will  be  wanting, 
since,  long  before  the  appearance  of  the  first  symptoms  of  the  disease, 
the  material  is  no  longer  available  for  investigation.  But,  in  view  of 
the  fact  that  pathogenic  bacteria  have  been  found  in  the  water  between 
the  shells  of  oysters  from  polluted  beds  ;  that  they  have  been  known 
to  live  for  days  in  the  tissues  and  retained  water ;  and  that,  in  the 
eases  investigated,  the  beds  have  been  found  to  be  exposed  to  the  influ- 
ence of  sewage,  we  may,  therefore,  properly  conclude  that  a  causal  rela- 
tion is  very  possible. 

The  danger  of  infection  arises  wholly  from  the  presence  of  sewage 
in  the  water  where  the  oysters  are  planted  or  stored.  The  remedy  lies 
either  in  transferring  the  beds  to  cleaner  situations  or  in  storing  the  con- 
'  Giomale  della  Reale  Societa.  Italiana  d'igiene,  1899,  p  500. 


54  FOODS. 

taminated  oysters  in  clean  sea  water  until  the  bacteria  either  have  per- 
ished or  have  been  washed  away.  What  constitutes  a  sufficient  length 
of  time  to  insure  purification,  is  a  matter  of  some  disagreement.  Many 
believe  that  a  week  is  enough ;  others,  that  16  days  should  be  allowed. 
Ovsters  should  not  be  stored  where  sewage  matters  can  reach  them 
through  long  distances  by  currents  along  the  shore,  nor  where  prevailing 
winds  can  exert  a  harmful  influence  to  the  same  end. 

Poisoning  by  Meat  and  Fish. 

Animal  foods  are  the  frequent  cause  of  most  distressing  disorders 
which  not  rarely  have  a  fatal  termination.  Some  of  these  are  due  to 
poisonous  properties  inherent  in  the  living  animal,  some  to  bacterial 
j)oisons  formed  in  meats  showing  no  evidence  of  unwholesomeness, 
and  some  to  decomposition  products  developed  during  storage  or  putre- 
faction. 

1.  Poisoning  Due  to  Substances  Normally  Present  in  the  Living 
Organism. — As  has  been  stated,  certain  species  of  fish  are  always  poi- 
sonous and  others  only  at  times,  and  in  some  cases  only  individual 
members  are  so  constituted.  Certain  species  are  so  well  known  to  be 
23oisonous  m  perfectly  fresh  condition  that  they  never  are  eaten  by  the 
natives  of  the  places  where  they  are  found,  except  for  purposes  of  sui- 
cide. Some  have  poisonous  glands  connected  with  their  fins,  some  have 
poisonous  ovaries,  and  others  are  poisonous  throughout.  Some  are 
jjoisonous  only  in  the  raw  state,  and  others  whether  cooked  or  not. 
The  symptoms  produced  vary  widely,  sometimes  indicating  gastro- 
enteritis, sometimes  involvement  of  the  central  nervous  system. 

The  mussel  is  regarded  not  uncommonly  as  an  intrinsically  poisonous 
shellfish,  but  the  weight  of  evidence  indicates  that  mussel-poisoning  is 
due  to  conditions  of  disease  or  infection  arising  from  residence  in  pol- 
luted water.  Its  poisonous  properties  have  long  l)een  recognized,  and 
have  been  the  subject  of  a  number  of  dissertations  by  early  writers ; 
thus  Behrens,  De  affectionibus  a  comestis  mytulis,  Hannover,  1735,  and 
Moehring,  Mytidorum  quorundam  venenum  et  ab  eo  natas  papulas  cuti- 
culares  Epistola,  Nuremberg,  1744.  In  France,  where  great  quantities 
of  mussels  are  eaten,  cases  of  poisoning  thereform  are  rare,  owing 
doubtless  to  the  fact  that  those  taken  from  polluted  harbors  are  kept 
for  a  week  or  more  in  clean  water  elsewhere. 

2.  Poisoning  Due  to  Bacterial  Products  in  Meats  and  Fish. — 
What  is  loiown  commonly  as  meat-poisoning,  fish-poisoning,  and 
sausage-poisoning  is  due  to  the  products  of  a  number  of  micro-organisms 
having  no  connection  with  the  usual  diseases  of  man.  These  products, 
which  include  toxins  and  ptomains,  cause  an  extremely  wide  variety  of 
symptoms,  which,  as  may  be  observed  on  examination  of  the  collection 
of  reported  outbreaks  given  below,  indicate  the  possible  derangement 
of  function  of  practically  every  part  of  the  system.  There  are  two 
groups  of  symptoms,  however,  which  are  fairly  constant,  either  one  of 
which  may  predominate  over  all  the  rest.      These  are  (1)  the  manifes- 


POISONING  BY  MEAT  AND  FISH.  55 

tations  of  profound  disturbance  of  the  gastro-intestinal  canal,  and  (2) 
those  indicating  more  or  less  intense  poisoning  of  the  central  nervous 
system.  Prominent  among  these  latter  are  impaired  vision  (dilated 
pupils,  ptosis,  amphodiplopia,  etc.),  and  glosso-pharyngeal  paralysis ; 
and  when  those  are  present,  the  case  is  said  to  be  one  of  "  botulism." 
This  term,  which  came  into  existence  by  reason  of  the  fact  that  many 
of  the  earlier  observed  cases  of  food-poisoning  were  traced  to  sausages 
(botulus,  a  sausage),  is,  in  the  light  of  our  present  knowledge,  unfortu- 
nate and  misleading,  for  the  condition  may  be  caused  not  only  by 
sausage,  but  by  any  form  of  meat  and  fish  which  may  happen  to  be 
contaminated  by  the  micro-organisms  which  produce  the  peculiar  toxin 
(or  toxins)  by  which  the  manifestations  are  caused.  And  it  is  not  true, 
as  is  supposed  by  some,  that  botulism  is  caused  by  the  proteid  bacterial 
poisons  alone  (commonly  known  as  toxins),  but  by  certain  of  the  basic 
crystalline  products  of  decomposition,  known  as  ptomains,  as,  for 
example,  mytilotoxin,  a  ptomain  isolated  by  Salkowski  and  Brieger  from 
•contaminated  mussels. 

Not  uncommonly,  ptomains  are  regarded  as  necessarily  poisonous 
substances.  This,  however,  is  far  from  being  the  truth.  They  are 
products  of  decomposition  brought  about  by  micro-organisms  which 
break  up  the  complex  organic  matters  into  less  complex  compounds, 
which  in  turn  are  split  up  into  products  of  diminishing  complexity, 
until  the  final  products  are  water,  hydrogen,  carbonic  acid,  sulphur- 
etted hydrogen,  ammonia,  nitrogen,  and  salts.  During  this  process 
of  decomposition,  at  different  stages,  the  ptomains,  which  are  organic 
bases,  are  formed.  Some  are  poisonous,  but  the  great  majority  of 
those  thus  far  isolated  are  wholly  inert.  All  contain  nitrogen,  but 
not  all  contain  oxygen,  thus  resembling  the  vegetable  alkaloids.  The 
variety  of  ptomains  formed  depends  upon  the  kinds  of  micro-organisms 
at  work,  the  nature  of  the  substance  undergoing  decomposition,  and  the 
conditions  of  temperature,  access  of  air,  and  other  attendant  circum- 
stances. One  species  of  bacteria  may  produce  no  ptomains  from  one 
kind  of  material,  and  poisonous  or  inert  ones  from  another.  At  one 
stage  of  decomposition  no  ptomains  may  be  formed,  at  another  several 
may  be  present,  and  later  these  may  have  disappeared  completely, 
for  they  are  but  intermediate  products. 

Brieger  has  isolated  a  number  of  varieties  of  ptomains  from  decom- 
posing meats  and  fish,  including  neurine,  choline,  and  one  which  appears 
to  be  identical  with  muscarine  (all  three  of  these  are  antagonized  in  their 
])0!sonous  action  by  atropine),  and  neuridine,  putrescine,  cadaverine, 
another  which  produces  effects  similar  to  those  of  curare,  and  others. 
Vaugban  discovered  the  very  important  ptomain,  tyrotoxicon,  in  milk 
and  cheese. 

Many  of  the  poisrmous  compoiuids  formed  during  putrefaction  retain 
their  active  character  long  after  tlie  organisms  through  whose  agency 
they  have  been  produced  have  ])erished.  This  was  noted  as  early  as 
1856  by  Panum,  who  found  that  the  poison  of  certain  putrid  meat 
retained  its  activity  even  after  it  had  been  boiled  11  hours,  and  his 


56  FOODS. 

observation  has  repeatedly  been  confirmed  by  others.     Naturally,  no 
amount  of  cooking  will  suffice  to  render  such  meat  harmless. 

The  physiological  action  of  these  poisons  is  widely  different.  Some 
cause  intense  gastro-intestinal  irritation,  some  act  directly  on  the  heart,, 
some  on  the  central  nervous  system,  and  some  on  particular  centers. 
Very  different  effects  are  produced  in  different  people,  owing  perhaps  to 
varying  degrees  of  susceptibility  and  also  to  unequal  distribution  of  the 
poison  through  the  mass  of  meat. 

The  extent  to  which  the  putrefactive  process  has  advanced  is  by  no 
means  of  such  importance  in  the  determination  of  the  question  of  pos- 
sible ill  effects,  as  the  nature  of  the  engaged  bacteria  and  of  their 
products,  for  meat  may  be  extremely  puti^id  and  yet  not  be  poisonous,, 
and,  on  the  other  hand,  may  be  apparently  normal  and  yet  deadly  in 
its  effects.  Many  savage  peoples  prefer  putrid  fish  and  meat,  and  the 
more  rotten  it  is,  the  greater  their  enjoyment  in  its  consumption.  In 
less  degree,  the  same  is  true  of  many  of  the  most  enlightened  people, 
who  prefer  game  when  decomposition  is  fairly  well  advanced.  On  the 
other  hand,  the  severest  outbreaks  of  food-poisoning  have  followed  the 
eating  of  meat  apparently  not  undergoing  decomposition.  Indeed,  the 
majority  of  persons  will  reject  meat  which  has  the  slightest  taste  or 
odor  indicating  beginning  putrefaction,  since  even  this  makes  it  repug- 
nant to  the  senses.  In  many  cases,  the  poisonous  principles  appear  to 
be  developed  after  the  meat  has  been  eaten,  through  changes  occurrmg 
within  the  intestines. 

The  bacteria  which  have  thus  fiir  been  shown  to  have  been  the  cause 
of  outbreaks  of  meat-  and  fish-poisoning  include  certam  spore-bearing 
anaerobes  isolated  by  Van  Ermeugem  (i?.  botxdinus),  and  Klein  (^\ 
entetntidis  spot^ogenes),  a  number  of  derivatives  of  B.  eoli  isolated  by 
Gaertner  {B.  enter itid'is),  Basenau  (jB.  hovis  morbijicans),  Kaensche  (i)\ 
Morseelensis  and  B.  Breslaviensis),  Gaffky  and  Paak  (B.  Friedeber gen- 
sis),  Abel,  Giinther,  and  others,  besides  B.  proteus  vulgans,  B.  proteus 
mirabilis,  Stajjhylococcus  pyogenes  jiavus,  and  others.  The  first  men- 
tioned (^B.  botulinus)  produces  an  extraordinarily  virulent  toxin,  which 
has  been  the  subject  of  careful  investigation,  which  has  proved  that  it 
is  related  closely  to  the  toxins  of  diphtheria  and  tetanus. 

Study  of  a  bacillus  which  Trautmann  ^  isolated  as  the  cause  of  an 
outbreak  of  poisoning  at  Diisseldorf,  and  comparison  thereof  with  cul- 
tures of  B.  Friedebergensis,  B.  enteritidis,  B.  3Iorseelensis,  B.  boris 
morbijicans,  B.  Breslaviensis,  and  of  the  organisms  isolated  by  Fischer, 
Abel,  and  Giinther,  and  also  of  the  various  strains  of  paratyphoid 
bacilli,  led  hira  to  the  conclusion  that,  while  these  several  kinds  present 
slight  differences  in  morphology  and  cultural  peculiarities,  they  show 
no  fundamental  difference  and  are  merely  varieties  of  one  and  the  same 
organism.  Others  have  called  attention  to  the  similarity  of  symptoms 
in  meat-poisoning  (not  botulism)  and  paratyphoid,  and  the  belief  is 
growing  that  the  differences  in  the  nature  and  severity  of  symptoms 
and  in  the  order  of  their  appearance  are  dependent  upon  the  slight 
racial  differences  in  the  bacteria  and  upon  the  degree  of  virulence  and 
^Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XLV.,  p.  139,  and  XL VI.,  p.  68. 


POISONING  BY  MEAT  AND  FISH.  57 

individual  susceptibility.  Many  outbreaks  of  meat-poisoning  have 
been  indistinguishable  from  paratyphoid,  and  many  of  severe  form  have 
been  mistaken  for  true  typhoid,  Trautmann  believes  that  the  typical 
meat-poisoning  is  the  hyperacute,  and  paratyphoid  the  subacute,  mani- 
festation of  an  etiologically  similar  disturbance,  and  he  places  all  of 
the  exciting  causes  under  the  general  head  of  B.  paratyphosus. 

Onset  and  Course  of  Symptoms. — The  first  symptoms  in  cases  of 
poisoning  by  fish  and  meats  may  occur  within  an  hour  or  two  after  eat- 
ing or  may  be  delayed  a  number  of  days.  In  one  outbreak  cited  (see 
Poisoning  by  Herrings,  page  61),  in  which  5  persons  were  seized,  the 
initial  symptoms  appeared  in  2,  3,  5,  7,  and  9  days  respectively ; 
ordinarily  they  appear  Avithin  a  few  hours — 3,  6, 12,  When  numbers  of 
persons  are  affected  by  the  same  food,  the  onset  is  by  no  means  uni- 
form. In  the  Ellezelles  case  (see  page  69),  in  which  20  persons  were 
seized,  the  time  in  which  the  symptoms  first  were  manifested  ranged 
from  3  to  36  hours,  but  as  a  rule,  it  is  the  appearance  within  the  same 
day  of  similar  symptoms  in  a  number  of  persons  which  calls  attention 
to  the  food  supply  as  a  common  cause  of  the  trouble.  Poisoning  by 
ptomains  is  manifested  generally  within  a  few  hours. 

In  cases  of  rapid  onset,  the  progress  either  to  recovery  or  a  fatal 
termination  is  commonly  short,  but  may  be  sometimes  a  matter  of 
months,  and  in  these  exceptional  cases  eventual  recovery  is  probable. 
The  shortest  case  on  record  is  that  of  mussel-poisoning  at  Wilhelms- 
haven  (see  page  60),  in  which  1  victim  died  in  2,  another  in  3,  and 
2  others  in  5  hours  after  eating. 

A  peculiar  tendency  to  relapses  often  is  observed.  The  patient  begins 
to  improve,  when  suddenly  the  original  symptoms  reappear  with  equal, 
greater,  or  diminished  intensity.  Improvement  may  be  succeeded  again 
by  a  relapse,  and  the  alternation  may  obtain  for  many  months.  The 
toxins  secreted  by  the  original  invading  bacteria  are  antagonized  by 
antitoxins  produced  by  the  system  and  improvement  occurs  ;  then  dur- 
ing this  interval  the  spore-bearers  find  opportunity  to  develop  a  new 
crop  of  bacteria,  which,  again  producing  toxins,  cause  a  recurrence  of 
the  original  symptoms. 

Nature  of  Symptoms. — As  has  been  stated,  the  effects  produced  vary 
very  greatly,  but  the  symptoms  of  abdominal  disturbance  and  of  poi- 
soning of  the  central  nervous  system  are  the  most  constant  as  well  as 
most  predominant.  Fever  may  or  may  not  be  present ;  usually  it  is 
not,  but  in  some  outbreaks  temperatures  exceeding  104°  F.  have  been 
recorded.  In  some  cases,  the  temperature  is  subnormal.  Disturbance 
of  the  circulation  is  more  common  than  fever,  the  pulse  being  small 
and  rapid,  and  sometimes  dicrotic.  In  a  few  instances,  marked  embar- 
rassment of  respiration  has  been  noted.  In  most  of  the  recorded  cases, 
no  mention  is  made  of  involvement  of  the  kidneys,  but  in  some  in- 
stances evidence  of  acute  nephritis  has  been  observed.  Dysuria, 
anuria,  and  paralysis  of  the  bladder  are  not  uncommon.  In  most  eases, 
extreiiK;  muscular  weakness  is  a  prominent  symptom,  and  not  infre- 
quently muscular  pains  and  cramps.  While  diarrhoea,  long  continued, 
is  a  most  common  occurrence,  in  many  cases  most  obstinate  constipation. 


■58  FOODS. 

sometimes  following  .cliarrhcea  and  sometimes  present  from  the  first,  is 
noted.  In  some  cases  abdominal  symptoms  are  by  no  means  prominent, 
and  in  others  they  are  practically  the  only  ones  observed.  The  symp- 
toms of  involvement  of  the  nervous  system  include  those  mentioned 
above,  and  drowsiness  or  insomnia,  headache,  dizziness,  delirium,  dimin- 
ished co-ordination  of  movement,  numbness,  cramps,  convulsions,  and 
paralyses. 

Post-mortem  Appearances. — The  post-mortem  appearances  observed 
in  cases  of  poisoning  are  very  inconstant,  both  as  to  extent  and  kind, 
and  are  by  no  means  proportionate  to  the  severity  of  the  symptoms. 
Even  when  a  number  of  individuals  succumb  to  the  same  influences,  the 
appearances  may  show  but  little  in  common.  Thus,  in  the  AVelbeck 
<3ase  (page  66),  one  showed  nothing  more  than  a  few  bright  red  patches 
in  the  stomach  ;  a  second,  congestion  of  the  gastro-intestinal  mucous 
membrane ;  and  a  third,  severe  parenchymatous  inflammation  with  dis- 
tention and  plugging  of  the  arterioles  and  capillaries  of  the  Malpighian 
■corpuscles  by  emboli  of  bacteria.  The  most  extensive  changes  observed 
are  those  occurring  in  poisoning  by  mussels  and  oysters,  in  which  cases 
the  extremely  rapid  onset  and  the  very  short  course  to  a  fatal  termina- 
tion suggest  the  action  of  poisonous  ptomains.  Indeed,  animal  experi- 
mentation has  demonstrated  that  certain  of  these  compounds  produce 
these  very  changes,  which  include  great  enlargement  of  the  spleen,  punc- 
tiform  ecchymoses  and  hemorrhagic  infarctions,  and  fatty  degenera- 
tion of  the  heart,  liver,  and  kidneys.  In  cases  of  meat-poisoning,  the 
appearances  noted  range  from  a  few  red  patches  in  the  intestines  to 
severe  gastro-enteritis  with  destructive  changes  in  all  the  principal 
viscera. 

Character  of  Meats  which  Cause  Poisoning. — In  general,  outbreaks  of 
poisoning  are  caused  by  the  meat  of  animals  slaughtered  while  suffer- 
ing from  diseases  other  than  those  which  are  best  known  to  the  public 
because  of  the  great  destruction  wrought  when  raging  in  epidemic  form  ; 
but  they  may  also  be  traced  to  the  flesh  of  perfectly  healthy  animals 
which  has  become  contaminated,  both  in  the  raw  and  cooked  states,  by 
poison-producing  bacteria. 

The  most  dangerous  forms  of  meat-poisoning  are  those  due  to  the 
pysemias,  septicaemias,  and  pneumo-enteritis,  and  the  greatest  mtensity 
of  action  is  produced  by  preparations  made  from  the  entrails. 

In  a  majority  of  the  reported  outbreaks,  the  meat  has  been  consumed 
either  raw  or  only  imperfectly  cooked,  or  after  being  kept  a  day  or  two 
after  being  cooked.  The  meats  most  commonly  the  cause  are  pork  and 
its  preparations,  and  veal.  Both  yield  a  considerable  amount  of  gelatin, 
and  this  fact  has  been  suggested  as  having  an  important  bearing,  since 
this  material  is  a  medium  which  offers  favorable  opportunities  for  the 
growth  of  bacteria. 

Most  of  the  reported  outbreaks  have  occurred  in  the  countries  of 
Europe,  where  the  meat  supply,  in  consequence  of  being  very  restricted, 
is  utilized  to  its  fullest  extent.  Viscera  which  with  us  are  rejected  as 
refuse,  and  the  flesh  and  viscera  of  animals  slaughtered  in  consequence 


POISONING  BY  MEAT  AND  FISH.  59 

of  sickness,  with  the  consent  and  approval  of  official  veterinarians,  are 
sold  and  eaten.  Another  reason  for  the  frequency  of  the  outbreaks  is 
a  very  common  preference  for  scraped  or  minced  raw  meats  and  for 
sausages  of  domestic  manufacture  made  under  most  unsanitary  con- 
ditions. 

Veal. — According  to  Vallin,  in  a  communication  to  the  Academy 
of  Medicine  in  1895,  a  large  number  of  outbreaks  of  poisoning  in 
Germany,  Switzerland,  and  elsewhere  are  due  to  the  consumption  of 
veal  from  animals  either  sick  or  too  immature.  Darde  and  Drouineau ' 
relate  that  they  have  seen  nearly  the  whole  strength  of  a  military 
•company,  135  out  of  147,  poisoned  by  eating  roast  veal.  The  symp- 
toms appear  generally  in  from  6  to  24  hours,  and  include  vomiting, 
purging,  and  great  prostration.  Dilatation  of  the  pupil  is  common, 
but  not  constant.     Occasionally,  skin  eruptions  appear. 

By  Vallin,^  and  by  others  as  well,  it  is  deemed  probable  that  veal- 
poisoning  is  due  largely  to  the  existence  of  septic  pyaemia  and  septic 
pneumo-enteritis  in  calves,  and  Van  Ermengem  has  suggested  that  a 
number  of  septic  diseases  of  these  animals  are  grouped  commonly  under 
the  head  of  diarrhoea.  He  fed  the  fresh  meat  of  one  of  these  calves 
to  mice  and  guinea-pigs,  which  died  within  a  few  days  with  enteritis. 
From  the  bone  marrow  he  isolated  an  organism  which  appears  to  be  re- 
lated closely  to  Gaertner's  B.  enteritidis,  and  which  on  inoculation  into 
animals  produces  a  fatal  enteritis. 

Beef. — Beef-poisoning  has  been  noticed  with  considerable  frequency, 
following  the  use  of  meat  from  animals  slaughtered  while  sick,  and  it 
has  been  pointed  out  by  several  observers  that  certain  septic  diseases  of 
•cattle  are  especially  prone  to  render  meat  poisonous.  These  include  the 
septic  form  of  calf  paralysis,  hemorrhagic  enteritis  of  calves,  septic 
metritis  of  cows,  various  intestinal  disorders,  the  septico-pysemic  dis- 
eases, and  a  number  of  others.  Gaertner's  B.  enteritidis  was  discovered 
by  him  originally  in  the  flesh  of  a  cow  that  had  been  slaughtered  on 
account  of  a  severe  diarrhoea,  and  in  the  spleen  of  a  person  who  died  in 
consequence  of  eating  it.  He  showed  that  not  only  the  bacillus,  but 
also  its  boiled  bouillon  cultures,  are  highly  toxic. 

Many  deaths  have  been  recorded  as  a  consequence  of  eating  the  cooked 
meat  of  cows  slaughtered  on  account  of  puerperal  fever,  and  it  was  from 
such  an  animal  that  Basenau  isolated  B.  bovis  morbificans.  This  cow 
showed  such  lesions  of  the  viscera  that  the  director  of  the  Amsterdam 
abattoir  forbade  the  use  of  the  meat. 

Basenau  ^  lias  examined  the  flesh  of  beeves  which  had  succumbed  to 
a  variety  of  diseases,  and  he  has  isolated  a  number  of  species  of  l:)ac- 
teria  bearing  a  close  resemblance  to  B.  bovis  morbificans,  all  of  which 
are  fatal  to  mice.  Some  of  them  produce  poisonous'  matters  which 
withstand  boiling  without  impairment  of  their  pro])erties.  Ordinary 
inspection  being  useless  for  determining  whether  such  meat  is  infected, 

'  Archives  de  M^decine  et  dc  Pli;irni!icie  militaires,  1895. 
''  Revue  d'lTvtriene,  l«!t5,  XViJ.,  p.  47:^ 
»  Archiv  fur*  J lygiene,  XXXIl.,  p.  219. 


60  FOODS. 

he  recommends  that  bacteriological  and  feeding  experiments  should  be 
instituted  together  within  24  hours  after  slaughtering.  If  no  colonies 
are  observed  at  the  end  of  24  hours  and  no  bacteria  are  seen  in  the  tis- 
sues, the  meat  may  be  regarded  as  safe  to  eat.  If  colonies  are  yielded,, 
the  acceptance  or  rejection  of  the  meat  must  depend  upon  the  results  of 
the  feeding  experiments.  If  the  mice  fed  on  the  raw  meat  die  and  those 
fed  on  the  cooked  meat  survive,  it  may  be  concluded  that  the  meat  is. 
safe,  if  thoroughly  cooked.  If  both  die,  the  meat  should  unhesitatingly- 
be  condemned. 

Sausage. — Sausage  has  long  been  recognized  as  a  very  common 
cause  of  j)oisouing,  and  has  a  much  larger  record  of  accidents  than  any 
other  meat  or  meat  compound.  This  is  due  in  large  part  to  a  very 
common  practice  of  making  use  of  all  manner  of  uninviting  fragments 
and  scraps  of  meat,  oifal,  and  the  flesh  of  sick  and  ill-conditioned 
animals  in  preparing  sausage  meat,  and  perhaps  to  a  greater  extent  to 
the  extremely  unsanitary  methods  of  manufacture  which  obtain  in  those 
districts  where  this  form  of  poisoning  is  most  prevalent.  In  many 
instances,  the  symptoms  caused  are  due  to  the  presence  of  j)tomains,  and 
in  many  to  the  contained  bacteria  and  their  toxins. 

In  most  instances,  it  is  impossible  to  fix  the  blame  upon  any  in- 
dividual constituent,  nor  aside  from  its  scientific  interest  is  this  of 
special  importance.  The  symptoms  present  as  wide  variations  in  char- 
acter as  are  observed  in  any  other  form  of  food-poisoning 

The  process  of  smoking,  to  which  certain  varieties  of  sausages  are 
subjected,  while  not  destructive  to  the  bacteria  of  putrefaction,  is  often 
successful  in  masking  any  unpleasant  smell  or  taste  due  to  change. 

Cases  Illustrative  of  Poisoning'  by  Fish  and  Meat. 

Poisoning-  by  Mussels.  Case  I. — At  Wilhelmshaven,  in  1885, 
several  longshoremen  and  their  families,  19  persons  in  all,  were  stricken 
with  ver)"  severe  symptoms  shortly  after  eating  a  meal  of  mussels. 
The  symptoms  were  m  general  the  same  in  all,  regardless  of  the  amount 
eaten,  and  included  nausea  and  vomiting  without  abdominal  pain  or 
purging,  trembling,  constriction  of  the  throat,  dizziness,  and  diminished 
coordination  of  movement  similar  to  that  due  to  alcoholic  intoxication. 
There  was  no  fever.  Speech  was  difficult  and  thick,  and  in  a  short 
time  the  legs  were  unable  to  support  the  body.  The  pupils  were  dilated 
and  imresponsive  to  reaction  tests.  The  extremities  were  cold  and 
numb.  Four  deaths  occurred,  one  within  two  hours,  one  in  three  and 
a-half,  and  the  others  within  five  hours  from  the  time  of  ingestion.  The 
autopsy  in  the  only  case  examined  revealed  enteritis,  enormous  enlarge- 
ment of  the  spleen,  numerous  hremorrhagic  infarctions,  and  fatty  degen- 
eration of  the  heart,  liver,  and  kidneys. 

In  this  case,  the  sudden  onset  and  rapidly  fatal  termination  indicate 
a  true  poisoning  rather  than  an  invasion  of  the  system  by  bacteria,  and, 
indeed,  the  poison  was  proved  by  Salkowski  and  Brieger  to  be  a  ptomain, 
to  which  they  gave  the  name  mytilotoxin. 


CASES  ILLUSTRATIVE  OF  POISONING  BY  FISH  AND  MEAT.      61 

Case  II. — Dr.  James  S.  Combe/  of  Edinburgh,  reported,  in  1828, 
an  outbreak  which  involved  a  large  number  of  persons  of  the  lower 
class  ranging  in  age  from  2  to  70  years.  The  first  case  seen  was  a 
man  of  60,  who  complained  of  thirst,  heat  in  the  mouth,  difficulty  in 
swallowing,  tension  about  the  jaws  and  throat.  The  pulse  was  small 
and  weak,  the  respiration  normal,  the  surface  cool.  The  hands  were 
numb  and  the  legs  unable  to  support  the  body.  Recovery  followed 
purgative  treatment.  He  had  supped  the  evening  before  with  a  friend, 
who  died  during  the  night.  They  had  eaten  mussels  boiled  with  salt, 
but  had  noticed  no  peculiarity  of  taste.  The  next  case  seen  was  that 
of  a  man  of  30  who,  on  the  previous  evening,  had  picked  a  few  mussels, 
not  over  five  or  six,  and  had  eaten  them  raw.  No  effects  were  noticed 
until  morning,  excepting  slight  burning  of  the  lips  and  tongue.  On 
attempting  to  get  up  he  found  that  he  could  not  stand,  although  he, 
like  the  first,  could  move  his  legs  about  in  bed. 

Although  hundreds  of  cases,  with  many  deaths,  were  said  to  have 
occurred,  in  consequence  of  which  the  magistrates  issued  a  warning 
against  the  use  of  mussels.  Dr.  Combe  found  but  thirty  cases  with  two 
deaths.  In  all,  the  symptoms  presented  a  striking  uniformity,  though 
they  varied  much  in  severity.  Most  of  the  victims  had  eaten  the 
mussels  boiled  with  salt  and  pepper,  and  none  had  noticed  any  unusual 
taste.     In  general  the  symptoms  appeared  in  an  hour  or  two. 

The  man  who  died  had  vomited  a  few  hours  after  eating.  He  lay 
down,  had  occasional  general  trembling,  was  rational  to  thg  last,  and 
died  as  if  by  increasing  weakness.  On  section  a  few  dark-red  patches 
were  found  in  the  ileum.  The  stomach  was  empty  and  presented  no 
abnormal  appearance.  The  other  fatal  case  was  that  of  a  woman  who 
died  in  three  hours  after  eating.  The  autopsy  revealed  a  full  stomach 
containing  mussels  and  potatoes,  and  beyond  a  few  red  patches  in  the 
intestine  the  viscera  were  quite  normal. 

In  his  report.  Dr.  Combe  referred  to  a  case  related  by  Captain  Van- 
couver,^ a  number  of  whose  men  ate  a  breakfast  of  roasted  mussels. 
Soon,  several  were  seized  with  numbness  about  the  face  and  extremities, 
followed  by  involvement  of  the  whole  body.  One  man,  who  died  in 
five  and  a  half  hours  after  eating,  was  unable  to  swallow,  and  though 
he  could  row  in  the  boat  while  sick,  he  was  unable  to  stand  on  leaving  it. 

Poisoning"  by  Herrings. — A  case  mvolving  five  persons,  reported 
by  R.  David,'^  is  remarkable  for  the  variety  of  manifestations,  the  length 
of  time  that  elapsed  before  the  appearance  of  the  symptoms,  and,  in 
two  of  them,  the  severity  and  duration  of  the  illness.  The  afflicted 
persons,  adult  members  of  one  family,  ate  on  March  19,  1898,  some 
raw  red  herrings,  which  gave  off  odor  indicative  of  commencing  putre- 
faction. Each  ate  the  same  amount,  a  whole  fish,  but  whether  each 
fish  was  equally  advanced  in  decomposition  cannot,  of  course,  be  deter- 
mined, and  the  differing  degrees  of  severity  of  effects  maybe  explained 

'  IC(linbiirj<h  Medical  and  Surgical  .Journal,  1828,  XXIX.   p.  86. 

^  Voviif^i!  of  Discovery,  Vol.  I  V.,  )).  45. 

■'•  Deutsche  iiiediciiiisc'lK;  Woclienschrift,  1899,  No.  8. 


62  FOODS. 

by  unequal  susceptibility.  The  father  and  mother  aged,  respectively,. 
65  and  67  years,  suffered  least;  the  son,  aged  31,  was  affected  more 
seriously ;  the  two  daughters  presented  unusually  severe  and  compli- 
cated symptoms. 

The  first  effects  were  manifested  by  the  son,  who,  on  the  second  day, 
was  seized  with  loss  of  appetite,  disagreeable  eructations,  vomiting, 
diarrhoea,  dryness  of  the  throat,  and  general  weakness.  On  the  fol- 
lowing day,  he  was  better,  but  soon  became  worse.  Diarrhcea  was 
followed  by  obstinate  constipation,  which  finally  yielded  to  cathartics. 
Five  days  later,  he  had  dminess  of  sight,  which  was  followed  after  a 
week  by  double  vision  and  difficult  deglutition.  The  symptoms  gradu- 
ally abated,  and  on  May  27th  there  was  distinct  improvement  of  sight. 
On  June  2d  glasses  were  hardly  needed. 

The  mother  first  showed  symptoms  on  the  fifth  day,  when  nausea, 
constipation,  and  dryness  of  the  throat  appeared.  Several  days  later 
she  had  double  vision  and  difficult  deglutition. 

The  father's  case  began  on  the  ninth  day  and  presented  similar  symp- 
toms, which  disappeared  in  six  weeks. 

One  of  the  daughters  was  seized  on  the  third  day  with  bad  taste  in 
the  mouth,  constipation,  and  dryness  of  the  throat,  followed  in  six  days 
by  dimness  of  near  vision,  then  by  doable  vision,  paralysis  of  accom- 
modation, and  difficult  swallowing.  As  was  the  case  with  the  others, 
the  temperature,  circulation,  and  urine  remained  normal.  On  May  2d, 
there  was  complete  mability  to  swallow  and  it  was  necessary  to  intro- 
duce food  by  means  of  a  stomach-tube.  There  was  slight  ptosis 
of  the  right  eye,  then  of  both ;  the  voice  was  nasal ;  the  gait  M^as 
affected  and  the  pulse  became  very  small,  though  not  very  rapid.  On 
May  9th,  bladder  symptoms,  which  had  been  gradually  appearing,  cul- 
minated in  paralysis  of  that  organ,  and  after  the  13th,  a  variety  of 
bladder  and  abdominal  symptoms  appeared.  In  the  first  part  of 
July,  she  felt  completely  well,  but  a  month  later  she  suffered  a  slight 
relapse,  with  reappearance  of  constipation,  difficult  deglutition,  and 
disturbance  of  vision,  which  persisted  Avith  varying  intensity  into  Sep- 
tember. Complete  recovery  did  not  occur  until  October,  almost  seven 
months  after  the  initial  symptoms. 

The  other  daughter  first  showed  symptoms  after  the  lapse  of  a 
week.  These  were  in  the  main  like  those  of  her  sister,  but  were  more 
severe  and  extensive.  She  began  to  improve  in  May,  and  then  ensued 
alternate  improvement  and  loss  of  ground,  better  one  day  and  worse 
the  next.  On  the  15th,  there  was  pain  in  the  left  hypochondrium  ;  on 
the  1 7th,  an  eruption  like  that  of  scarlet  fever  over  the  whole  body, 
with  albuminuria,  but  no  casts.  On  the  19th,  severe  pain  in  the  left 
hypochondrium,  less  in  the  right,  and  tenderness  in  the  region  of  the 
kidneys,  with  epistaxis,  disappearance  of  the  rash,  slight  desquamation, 
and  improved  vision.  At  the  end  of  May,  the  albuminuria  and  pain 
in  the  region  of  the  kidneys  had  nearly  disappeared,  and  deglutition 
was  perfect.  On  June  2d,  heart  complications  appeared,  which 
persisted    into    November,   when    hypertrophy   was    established.     In 


CASES  ILLUSTRATIVE  OF  POISONING  BY  FISH  AND  MEAT.      63- 

August,  after  a  general  improvement,  there  was  a  relapse  like  that 
which  occurred  in  the  case  of  her  sister.  Improvement  was  well 
established  in  October,  and  in  November  she  had  almost  wholly 
recovered. 

Unfortunately,  it  was  impossible  to  make  a  bacteriological  and  chem- 
ical examination  of  the  fish,  because  no  material  was  obtainable. 

Poisoning  by  Salmon. — Professor  Vaughan^  reports  the  following 
case  :  "  K.,  a  very  vigorous  man  of  34  years,  ate  freely  of  canned 
salmon.  Others  at  the  table  with  him  remarked  that  the  taste  of  the 
salmon  was  peculiar,  and  refrained  from  eating  it.  Twelve  hours  later, 
K.  began  to  suffer  from  uausea,  vomiting,  and  a  griping  pain  in  the 
abdomen.  Eighteen  hours  after  he  had  eaten  the  fish,  the  writer  saw 
him.  He  was  vomiting  small  quantities  of  mucus,  colored  with  bile,, 
at  frequent  intervals.  The  bowels  had  not  moved  and  the  griping 
pain  continued.  He  was  covered  with  a  scarlatinous  rash  from  head  to 
foot.  His  pulse  was  140,  temperature  102°  F.,  and  respiration  shal- 
low and  irregular."  After  appropriate  treatment  he  began  to  improve. 
"The  next  day  the  rash  disappeared,  but  the  temperature  remained 
above  the  normal  for  four  or  five  days,  and  it  was  not  until  a  week 
later  that  the  man  was  able  to  leave  his  house."  Vanghan  examined 
the  salmon  and  found  a  micrococcus  present  in  great  numbers.  This 
organism,  grown  for  twenty  days  in  a  sterilized  egg,  produced  a  most 
potent  poison.  The  white  became  thin,  watery,  and  markedly  alkaline,, 
and  ten  drops  sufficed  to  kill  white  rats. 

Poisoning  by  Oysters. — Case  I. — The  following  case,  which  ended 
fatally,  is  reported  by  Brosch.^  An  officer  ate  a  number  of  oysters^ 
toward  midnight,  and  within  6  hours  was  seized  with  headache,  pain 
in  the  side,  nausea,  dimness  of  sight,  difficult  deglutition,  retention  of 
urine,  and  salivation.  Toward  noon,  right  facial  paralysis,  dilatation 
of  the  right  pupil,  and  thickness  of  speech  appeared,  followed  shortly 
by  cyanosis,  ptosis  of  the  right  eyelid,  great  muscular  relaxation,  and 
paralysis  of  respiration.  Autopsy  revealed  punctiform  ecchymoses  in 
various  parts,  enlargement  of  the  spleen,  and  fatty  degeneration  of  the 
liver  and  kidneys. 

Case  II. — Another  fatal  case  is  recorded  by  Casey  :^  "H.  P.,  about 
32  years  of  age,  ate  8  oysters  for  supper,  remarking  at  the  time  that 
one  of  them  was  bad.  Others  of  the  same  lot  appeared  to  be  quite 
fresh  and  were  eaten  by  other  persons  with  impunity.  Symptoms  of 
poisoning  began  about  12-14  hours  later,  with  pain  in  the  back,  soon 
fi)llowed  by  violent  pains  in  the  stomach,  frequent  vomiting,  and  intense 
thirst.  The  bowels  did  not  act.  These  symptoms  continued  until  the 
following  morning,  when  the  pulse,  which  had  been  small  and  quick, 
l>ecarae  almost  imperceptible,  the  fingers  shrunken,  the  nails  blue.  The 
t')ngue  was  at  that  time  dark  and  swollen,  and  swallowing  difficult. 
There  were   occasional  spasms   of  the  arms.     A  little  later,  the  jaw 

^  Ptomains,  Leucomains,  Toxins,  and  Antitoxins,  1896,  p.  56. 
2  Wiener  klinisclie  Wochens(tiirift,  ISDfi,  No.  Kl 
^  I'.ritisli  Medifiil  .Joiirnal,  Mareii  'A,  1894,  p.  463. 


64  FOODS. 

became  set,  and  soon,  after  a  sudden  struggle  for  breath,  he  died,  41 
hours  after  eating  the  oysters.  At  the  post-mortem  examination,  the 
beart  was  found  to  be  very  soft  and  relaxed  and  contained  fluid  blood. 
The  kidneys  and  spleen  were  also  very  soft  and  congested  ;  the  stomach 
<?mpty  and  darkly  congested  ;  the  peritoneum  was  thickly  studded  with 
ilecks  of  lymph." 

Poisoning  by  Veal. — Boyer '  reports  the  following  case  of  sextuple 
])oisoning  by  veal.  The  persons  affected  were  members  of  one 
household,  and  ranged  widely  in  point  of  age,  the  youngest  being 
•children  of  3  and  6  years.  The  symptoms  appeared  in  the  night, 
about  6  hours  after  the  food  was  taken,  and  began  with  vomiting  and 
violent  colic.  In  the  morning,  all  had  intense  gastric  irritability,  coated 
t^jngue,  pain  on  pressure,  especially  in  the  right  iliac  fossa,  rumbling, 
.'flight  tympanites,  and  scanty  urine.  The  cook  had  markedly  dilated 
])iipils,  a  sensation  of  suffocation,  constriction  and  dryness  of  the 
throat,  and  intense  suffusion  of  the  face.  The  child  of  6  had  dilated 
pupils  and  disturbance  of  vision,  and  finally  pain  and  stiffness  of  the 
muscles  of  the  neck.  The  younger  of  the  two  children  and  the  mother 
were  affected  less  than  the  others,  and  made  a  more  rapid  recovery. 
The  chambermaid  had  at  first  a  certain  degree  of  aggravation  of  symp- 
toms, with  a  tendency  to  syncope  and  great  muscular  weakness,  which 
latter  effects  were  marked  also  in  the  case  of  the  cook,  who  continued 
for  some  time  to  be  troubled  by  dilatation  of  the  pu])ils  and  disturbed 
vision.  At  the  end  of  nine  days,  there  was  no  evidence  of  danger,  and 
the  two  most  severely  affected  \Aere  well  on  the  way  to  recovery. 

Unfortunately,  no  bacteriological  examination  was  made  either  of  the 
meat  or  the  discharges,  but  the  nature  of  the  symptoms  leaves  no  room 
for  doubt  as  to  their  cause. 

Case  II. — Drs.  AVilkinson,^  Ashton,  and  Durham  have  recorded  an 
•extensive  outbreak  of  poisoning  due  to  imperfectly  cooked  veal  pies. 
All  the  cases,  over  fifty  in  number,  presented  very  similar  symp- 
toms, the  chief  of  which  were  severe  and  uncontrollable  vomiting  and 
diarrhoea,  accompanied  at  first  by  shivering,  and  followed  by  collapse. 
In  some  there  were  violent  abdominal  pains,  and  in  several  the  abdo- 
men was  swollen  and  tender.  Many  had  severe  pains  in  the  back.  The 
symptoms  began  in  from  5  to  14  hours  after  eating,  and,  as  a  rule, 
were  severe  from  the  start.  The  motions  were  first  grass-green,  then 
dark  green,  and  highly  offensive.  The  severity  of  the  diarrhoea  in- 
creased on  the  second  day  ;  one  patient  was  purged  40  or  more  times 
in  a  single  day.  In  very  few  cases,  the  dejecta  contained  a  little 
blood. 

In  the  worst  cases,  the  patients  became  semi-comatose,  restless,  and 
delirious  in  the  course  of  a  few  hours.  Occasionally,  there  were  dis- 
turbances of  vision,  which  lasted  until  the  temperature,  which  ranged 
from  100°  in  the  mildest  to  104.5°  F.  in  the  severest  cases,  became  nor- 
mal.    The  pulse  was  very  rapid,  weak,  and  dicrotic.     Many  of  the  pa- 

'  Lvon  medical,  May  14,  1899. 

2  Public  Health,  January,  1899,  and  British  Medical  Journal,  December  17,  1898. 


CASES  ILLUSTRATIVE  OF   POISONING  BY  FISH  AND  MEAT.      65 

tients  were  markedly  cyanotic  and  had  more  or  less  difficulty  in  breath- 
ing. Some  had  cramps,  and  nearly  all  had  muscular  pain  and  stiffness. 
In  very  many  cases,  herpes  appeared  about  the  lips  on  the  third  to 
the  sixth  day,  and  some  had  a  rash  followed  by  desquamation.  Con- 
valescence in  the  severe  cases  was  prolonged ;  some  were  still  weak 
after  three  and  a  half  months.  Four  cases  terminated  fatally,  and  in 
two  of  these,  autopsies  were  secured.  The  brain  surface  showed  slight 
congestion ;  the  small  intestines  showed  congested  patches,  which  be- 
came larger  and  more  numerous  lower  down,  and  did  not  correspond 
with  Peyer's  patches.  The  whole  lower  third  was  highly  congested, 
and  contained  yellow  diarrhoeic  fluid.  Otherwise  the  organs  of  the 
body  were  in  a  fairly  healthy  condition. 

Investigation  of  the  cause  of  the  outbreak  yielded  the  following 
facts :  On  July  26th,  an  apparently  healthy  calf  was  slaughtered, 
and  two  days  later  the  fore  quarter  and  breast  were  delivered  to  a 
baker,  who  made  the  meat  into  the  pies  which  were  shown  to  have  been 
the  cause  of  the  outbreak.  Other  portions  of  the  animal  were  sold  to 
others,  who  made  pies  which  caused  no  trouble.  A  portion  of  a  knuckle 
end,  which  was  in  the  possession  of  the  butcher  when  the  investigation 
was  begun,  was  to  all  appearances  perfectly  good. 

The  baker  to  whom  the  trouble  was  traced  made,  on  the  day  he 
received  the  meat,  160  veal  pies  and  108  pork  pies.  The  pastry  was 
the  same  for  the  entire  lot,  and  both  kinds  were  treated  to  the  same 
lot  of  jelly,  which  was  made  by  boiling  the  veal  bones  with  two  pigs'- 
feet  in  4  quarts  of  water.  Inasmuch  as  the  pork  pies  caused  no 
disturbance  of  any  kind,  no  responsibility  could  be  attached  to  the 
pastry  or  to  the  jelly.  The  veal  pies  were  baked  in  not  less  than  3 
nor  more  than  5  batches,  hence  the  batches  would  have  included  about 
32,  42,  or  53  pies.  The  time  occupied  in  baking  each  batch  was  said 
to  have  been  about  20  minutes.  The  number  of  persons  affected  was 
over  50  and  as  in  some  cases  single  pies  were  shared  by  2,  3,  and  4 
persons,  it  is  obvious  that  less  than  50  pies  caused  all  the  trouble. 
Since  no  other  parts  of  the  animal  caused  any  sickness,  there  can  be 
no  doubt  that  the  contamination  of  the  meat  occurred  after  the  sale  and 
deliv^ery. 

According  to  the  findings  of  Dr.  Durham,  based  on  a  study  of  the 
blood  of  a  number  of  the  patients  as  to  the  behavior  of  the  serum 
when  tested  for  clumping  jjroperties  with  various  micro-organisms, 
with  controls  of  serum  from  normal  persons,  the  outbreak  was  due  to 
B.  enteritidis.  This  limitation  of  the  inquiry  was  necessitated  by  the 
fact  that  it  was  impossible  to  secure  either  one  of  the  pies,  or  part 
of  one,  or  any  of  the  first  vomitings.  The  conclusion  arrived  at, 
strengthened  by  the  fact  that  all  4  fatal  cases  were  from  pies  which 
wfTf!  2  or  more  days  old  when  eaten,  which  period  allowed  enormous 
multiplication,  makes  most  probable  the  further  conclusion  that  one 
whole  batch  was  cooked  so  insiifficiontly  as  to  preclude  the  killing  of 
the  organisms,  which,  according  to  I>asenau,  cannot  survive  exposure 
f|)i'  1   iiiiniitc  to  a  tcnipci'uture  of  70°  C. 


66  FOODS. 

Poisoning-  by  Pork. — Case  I. — Meredith  Young  ^  records  a  case 
of  pork-poisoning  in  which  5  persons  were  affected.  The  offending 
meat  was  three-quarters  of  a  pound  of  "  pig's  cheek,"  which  was 
eaten  at  half-past  four  in  the  afternoon,  between  which  time  and  the 
onset  of  symptoms  nothmg  else  was  eaten.  On  the  following  morning, 
Mr.  A.  was  seized  suddenly  with  vomiting,  purging,  and  severe 
abdominal  pain,  and  shortly  afterward  became  very  feverish  and  weak, 
and  suffered  from  severe  frontal  headache.  His  wife  had  severe 
abdominal  pain,  and  toward  noon  was  strongly  purged.  She  suffered 
nausea,  retched,  but  could  not  vomit,  had  fever  and  severe  headache, 
and  was  much  more  prostrated  and  took  more  time  to  recover  than 
her  husband.  She  was  miable  to  ingest  food  for  3  days.  The  daughter 
w^as  taken  sick  at  the  same  time  and  with  the  same  symptoms,  though 
less  severely.  Her  chief  symptom  was  an  overpowering  tendency  to 
sleep.  A  fourth  person,  who  ate  but  little  as  compared  with  the  amounts 
ingested  by  the  others,  was  purged  slightly,  but  suffering  nothing  more. 
The  remaining  member  showed  no  effects  until  during  the  second  night. 
On  the  following  morning,  she  was  feverish,  had  severe  headache  and 
abdominal  pain,  and  retched  unsuccessfully.  Purging  did  not  occur 
until  the  afternoon.  As  was  the  case  with  the  daughter,  the  most 
prominent  symptom  after  the  onset  was  somnolence.  Recovery  fol- 
lowed in  every  case.  Investigation  showed  that  the  cheeks  had  been 
cooked  2  days  before,  and  had  been  placed  together  to  cool  and  "  set." 
It  was  estimated  that  between  50  and  60  persons  had  purchased  of 
them,  but  all  but  a  small  proportion  were  unknown  to  the  seller,  and 
so  no  systematic  inquiry  could  be  made.  Only  4  could  be  followed 
up,  and  2  of  these  rej)orted  no  trouble  ;  a  third  was  made  severely 
sick  and  lost  2  days'  work,  and  the  fourth,  after  eating,  drank  so 
much  beer  that  he  was  made  sick  and  lost  it  all  by  vomiting,  and  yet 
was  affected  like  the  others,  but  not  so  actively.  It  was  impossible  to 
procure  any  of  the  meat  or  vomited  matter  or  dejections  for  bacterio- 
logical examination. 

Case  II. — At  the  Seventh  International  Medical  Congress,  held  in 
London,  in  1881,  Ballard^  read  before  the  section  on  State  Medi- 
cine an  account  of  a  very  serious  outbreak,  now  generally  known  as 
the  "  Welbeck  case."  This  involved  72  persons,  who  attended  a  sale 
of  timber  and  machinery  on  the  estate  of  the  Duke  of  Portland  at  Wel- 
beck, which  lasted  from  Tuesday,  June  15,  1880,  through  the  week. 
Refreshments  were  served  by  the  keeper  of  a  public  house,  and  among 
the  articles  furnished  were  seven  hams,  to  which  the  entire  trouble 
was  traced.  While  many  complaints  were  made  that  the  ham  was  not 
sufficiently  cooked,  that  the  fat  was  yellowish  or  greenish,  that  it  was 
too  salt,  that  it  "  tasted  queer,"  and  that  it  had  no  true  flavor  of  ham, 
many  made  no  complaint,  and  no  one  said  that  it  was  tainted.  Of  the  72 
persons  seized,  4  died.     The  history  of  3  of  these  follows  : 

1.  W.  AY.,    aged    64,    ate   ham   on  Wednesday   and    Friday,  and 

1  Public  Health,  .June,  1899. 

^  Supplement  to  lOth  Annual  Eeport  of  the  Local  Government  Board,  1881,  p.  36. 


CASES  ILLUSTRATIVE   OF  POISONING  BY  FISH  AND  MEAT.      67 

was  seized  on  Friday  night,  when  he  comphuued  of  feeling  cokl.  On 
Satnrday  morning,  he  ate  but  little  and  said  he  ached  all  over.  In  the 
course  of  the  day,  he  suffered  from  vomiting  and  diarrhoea,  with  severe 
pain  and  cramps  in  the  legs.  The  evacuations  were  exceedingly  offen- 
sive and  were  passed  involuntarily.  The  pulse  was  128  ;  temperature 
not  taken.  On  Monday,  he  began  to  collapse,  and  on  Friday,  he  died. 
The  post-mortem  examination  revealed  little  that  was  noteworthy,  but 
microscopic  examination  of  the  kidneys  showed  parenchymatous  inflam- 
mation, and  distention  and  plugging  of  the  aflPerent  arterioles  and  capil- 
laries of  the  Malpighian  corpuscles  by  emboli  of  bacilli. 

2.  Mrs.  L.,  aged  62,  ate  some  scraps  of  the  ham  on  Wednes- 
day, and  was  seized  on  Friday  with  faintness,  diarrhoea,  vomiting,  and 
abdominal  pain.  On  the  following  day  she  fell  into  a  state  of  collapse, 
and  on  the  following  Tuesday  she  died.  The  mucous  membrane  of  the 
stomach  and  intestines  was  highly  congested ;  otherwise  the  autopsy 
revealed  nothing  abnormal. 

3.  Mr.  S.,  aged  37,  ate  four  sandwiches  on  Thursday.  In  the- 
evening  he  vomited,  and  diarrhoea  began.  In  the  morning  of  the 
following  day,  he  complained  of  burning  pain  in  the  lower  part  of  the 
abdomen.  The  vomiting  and  purging  continued.  Though  cold  and 
clammy  to  the  touch,  he  complained  that  he  was  "  all  on  fire."  He  had 
cramps  in  the  legs  and  was  very  restless.  His  mind  was  clear  to  the 
last.  The  discharges  were,  at  first,  watery  and  offensive,  and  later  were 
dark  green  in  color.  He  was  very  thirsty  and  drank  freely  of  water. 
He  died  on  the  following  Friday.  Only  a  partial  autopsy  was  made. 
This  revealed  bright-red  patches  on  the  mucosa  of  the  stomach. 

The  period  of  incubation  was  accurately  determined  in  51  cases ;  in 
5  it  was  12  hours  or  less,  in  34  it  was  between  36  and  48,  and  in  4 
it  exceeded  48  hours.  In  njany  cases  the  onset  was  sudden,  and  in 
others  it  was  preceded  by  greater  or  less  indisposition.  The  most  con- 
stant symptom  was  diarrhoea.  "  In  about  a  third  of  the  cases  the  first 
definite  symptom  was  a  sense  of  chilliness,  usually  with  rigors  or  tremb- 
ling, in  one  case  accompanied  by  dyspnoea ;  in  a  few  cases  it  was  gid- 
diness with  faintness,  sometimes  accompanied  by  a  cold  sweat  and 
tottering ;  in  others  the  first  symptom  was  headache  or  pain  somewhere 
in  the  trunk  of  the  body,  e.  g.,  in  the  chest,  back,  between  the  shoulders, 
or  in  the  abdomen,  to  which  part  the  pain,  wherever  it  might  have  com- 
menced, subsequently  extended. 

"  In  one  case  the  first  symptom  noticed  was  a  difficulty  in  swallow- 
ing. In  two  cases  it  was  intense  thirst.  But,  however  the  attack  may 
have  commenced,  it  was  usually  not  long  before  pain  in  the  abdomen, 
diarrhfea,  and  vomiting  came  on,  diarrhoea  being  of  more  certain  occur- 
rence than  vomiting.  The  pain  in  several  cases  commenced  in  the  chest 
or  between  the  shoulders,  and  extended  first  to  the  upper  and  then  to 
the  lower  part  of  the  abdomen.  It  was  usually  very  severe  indeed, 
'inickly  producing  prostration  or  faintness  with  cold  sweats.  It  was 
variously  described  as  '  cranipy,'  '  l)iirning,'  'tearing/  etc. 

"  'I'lif!  diarrlireal  discharges  were  in  some  cases  quite  unrestrainable, 


68  FOODS. 

and  (where  a  description  of  them  could  be  obtained)  were  said  to  have 
been  exceedingly  offensive,  and  usually  of  a  dark  color.  Muscular 
weakness  was  an  early  and  very  remarkable  symptom  in  nearly  all 
cases,  and  in  many  it  was  so  great  that  the  patient  could  only  stand  by 
holding  on  to  something.  Headache,  sometimes  severe,  was  a  common 
and  early  symptom ;  in  most  cases  there  was  thirst,  often  intense  and 
most  distressing.  The  tongue,  when  observed,  was  described  usually  as 
thickly  coated  with  a  brown  velvety  fur,  but  red  at  the  tip  and  edges. 

"  In  the  early  stage,  the  skin  was  often  cold  to  the  touch,  but  after- 
ward some  fever  set  in,  the  temperature  arising  in  some  cases  to  101°, 
103°,  and  104°  F.  In  a  few  severe  cases  where  the  skin  was  actually 
cold,  the  patient  complained  of  heat,  insisted  on  throwing  off  the  bed- 
clothes, and  was  very  restless.  The  pulse  in  the  height  of  the  illness 
became  quick,  countmg  in  some  cases  100  to   128. 

"  The  above  were  the  symptoms  most  frequently  noted.  Other 
symptoms  occurred,  however,  some  in  a  few  cases,  and  some  in  only 
solitary  cases.  These  I  now  proceed  to  enumerate.  Excessive  sweat- 
ing, cramps  in  the  legs,  or  in  both  legs  and  arms ;  convulsive  flexion  of 
the  hands ;  aching  pain  in  the  shoulders,  joints,  or  extremities  ;  a  sense 
of  stiffness  of  the  joints  ;  prickling  or  tingling  or  numbness  of  the  hands, 
lasting  far  into  convalescence  in  some  cases ;  a  sense  of  general  com- 
pression of  the  skin,  drowsiness,  hallucinations,  imperfection  of  vision, 
and  intolerance  of  light. 

"  In  three  cases  (one  that  of  a  medical  man)  there  was  observed 
yellowness  of  the  skin,  either  general  or  confined  to  the  face  and  eyes. 
In  one  case,  at  a  late  stage  of  the  illness,  there  was  some  ]iulmonary 
congestion,  and  an  attack  of  what  was  regarded  as  gout.  In  the  fatal 
cases  death  was  preceded  by  collapse  like  that  of  cholera,  coldness  of 
the  surface,  pinched  features  and  blueness  of  the  fingers  and  toes,  and 
around  the  sunken  eyes.  The  del)ility  of  convalescence  was  in  nearly 
all  cases  protracted  to  several  weeks. 

"  The  mildest  cases  were  characterized  usually  by  little  remarkable 
beyond  the  following  symptoms,  viz.,  abdominal  pains,  vomiting,  diar- 
hcea,  thirst,  headache,  and  muscular  weakness,  any  one  or  two  of  which 
might  be  absent." 

Investigation  of  the  hams  showed  absence  of  trichinae  and  the  pres- 
ence of  a  bacillus,  which  on  inoculation  into  animals  was  found  in  most 
cases  to  produce  a  pneumonia. 

The  period  of  incubation  indicates  that  in  these  cases  there  was  a 
true  bacterial  infection. 

Case  III. — Another  epidemic  investigated  by  Ballard^  involved 
a  far  greater  number  of  persons  and  had  an  unusual  attendant 
mortality,  nearly  500  persons  out  of  a  population  of  about  100,000 
(Middlesbrough)  dying  during  the  year  of  a  peculiar  form  of  pleuro- 
pneumonia. 

The  cause  of  this  remarkable  epidemic  was  proved  to  be  the  con- 
sumption of  what  was  known  as  ^'American  bacon,"  a  food  product 
'Supplement  to  18th  Annual  Eeport  of  the  Local  Government  Board,  1889,  p.  163. 


CASES   ILLUSTRATIVE  OF  POISONING  BY  FISH  AND  MEAT.      69 

prepared  from  imported  salt  pork  at  a  number  of  local  establishments 
conducted  under  most  unsanitary  conditions.  Twenty  samples  of 
bacon,  some  obtained  at  shops  and  some  at  the  homes  of  victims, 
were  examined,  and  fourteen  were  found  to  be  distinctly  poisonous  to 
animals.  The  lesions  discovered  in  the  dead  animals  were  of  the  same 
nature  and  extent  of  those  in  the  organs  of  the  persons  who  had  died. 
These  included  destructive  changes  in  all  the  principal  viscera,  and 
more  particularly  in  the  lungs.  Dr.  Klein  discovered  in  the  lung  a 
short  bacillus  which  had  never  before  been  described.  Inoculation 
experiments  on  animals  produced  results  identical  with  those  following 
feeding  experiments  with  the  so-called  bacon. 

Case  IV. — A  remarkable  outbreak  due  to  raw  pickled  ham  has 
been  recorded  by  Van  Ermengem^  and  carefully  investigated  by  him- 
self and  others.  More  than  twenty  members  of  a  musical  society  at 
Ellezelles,  in  Belgium,  were  seized  with  serious  illness  after  eating  the 
greater  part  of  a  raw  pickled  ham  ;  three  died  within  a  Aveek,  and  ten 
lay  in  a  critical  condition.  Other  parts  of  the  animal  from  the  same 
pickling  tub  were  eaten  in  a  raw  state  without  ill  eifects,  and  pieces  of 
the  particular  ham  had  been  consumed  a  short  time  before,  also  without 
ill  eifects.  Only  those  persons  who  ate  of  the  ham  were  seized  with  the 
very  peculiar  train  of  symptoms  recorded.  Most  of  them  were  seized 
in  from  20  to  24  hours,  3  in  less  than  that  time,  and  a  few  as  late  as 
36  hours  after  eating. 

The  first  symptoms  were  gastric  pain,  nausea,  and  vomiting  of  un- 
digested food  and  gelatinous  blackish  matters.  Instead  of  diarrhoea, 
which  one  would  expect,  there  was  obstinate  constipation  in  all  but 
2  cases,  and  the  first  dejections,  with  or  without  cathartics,  were  black 
and  viscid.  In  every  case,  in  from  36  to  48  hours,  there  were  pro- 
found disturbances  of  vision — amphodiplopia,  marked  dilatation  of  the 
pupils,  with  absence  of  reaction  to  light,  ptosis  of  both  lids,  and  a 
peculiar  fixed  stare.  There  was  burning  thirst  with  a  strangling  sensa- 
tion in  the  throat.  Swallowing,  even  of  liquids,  was  difficult  or  impos- 
sible, and  every  attempt  was  accompanied  by  choking. 

In  some  instances,  the  saliva  was  suppressed  and  the  mucous  mem- 
brane dry  and  glossy.  The  voice  was  weak,  and  with  some  there  was 
total  aphonia.  Dysuria  and  anuria  were  common.  There  was  but 
little  disturbance  of  respiration  and  circulation  ;  the  pulse  never  reached 
over  90,  respiration  was  quiet,  temperature  normal.  Consciousness  and 
general  sensibility  remained  unimpaired  throi\ghout,  except  in  the  fatal 
cases,  in  which  alone,  several  hours  before  death,  there  occurred  collapse, 
dyspncea,  small  irregular  pulse,  light  delirium,  and  coma. 

There  was  obstinate  insomnia  in  many,  during  the  first  period.  The 
extremities  and  trunk  muscles  showed  neither  complete  paralysis  nor 
atrophy,  but  there  was  great  general  muscular  weakness,  and  slight 
movements  caused  extreme  fatigue.  After  two  or  three  weeks,  the  eye 
symptoms  began  t^)  improve.  The  dilated  pupils  contracted,  the  cloudi- 
ness disappeared,  and  the  half-paralyzed  eyelids  regained  their  power, 

'  Zeitsclirifl  fur  Hygiene  und  IiifeclioiiskriinUlieiten,  XXVi.,  p.  1. 


70  FOODS. 

Diplopia  disappeared  only  when  both  eyes  were  fixed  laterally.  Par- 
alysis of  accommodation  lasted  a  long  time  after  the  disappearance  of  all 
the  other  symptoms,  and  normal  vision  did  not  return  until  after  six 
to  eight  months. 

Autopsy  in  two  cases  showed  no  characteristic  changes  in  the  organs, 
only  extensive  hypersemia  of  the  kidneys,  liver,  and  meninges,  and 
softening  and  unusual  friability  of  the  stomach  walls.  In  one,  the  liver 
showed  marked  degeneration,  and  the  brain  punctiform  hemorrhages. 
!Neither  the  liver  nor  Iddneys  showed  anything  unusual  on  bacteriologi- 
cal examination,  but  the  spleen  yielded  an  anaerobic  bacillus,  which 
proved  later  to  be  capable  of  causing  botulism. 

The  pig  from  which  the  ham  came  was  killed  some  months  pre- 
viously, and  what  was  not  eaten  at  once  was  pickled  in  the  usual  way. 
During  the  time  that  elapsed  between  the  pickling  and  the  supper, 
the  greater  part  of  the  animal  had  been  consumed  without  causing  any 
sickness,  but  the  ham  whicli  was  nearly  intact  was  the  last  to  be  eaten, 
lay  on  the  bottom  of  the  tub,  and  was  the  only  part  that  was  immersed 
completely  in  the  weak  brine.  What  was  left  of  it  gave  no  odor  of 
putridity,  but  had  a  distinct  odor  like  that  of  rancid  butter.  That  the 
ham  had  a  bad  taste,  was  agreed  by  nearly  all  who  ate  of  it.  It  appeared 
normal  to  the  eye,  but  was  pale,  like  any  meat  that  has  been  soaked 
some  time  in  water.  There  was  no  evidence  of  decomposition,  and 
no  ptomains  were  detected. 

Bacteriological  examination  proved  in  diiferent  parts  the  presence  of 
a  hitherto  unknown  spore-bearing  bacillus  in  great  abundance,  the 
.same  organism  as  that  isolated  from  the  spleen  of  one  of  the  victims. 
It  produced  an  extraordinarily  virulent  toxin,  which  was  isolated  by 
Brieger  from  cultures  supplied  by  the  discoverer,  by  whom  the  organ- 
ism was  named  Bacillus  bohdhms.  The  toxin  is  rendered  inert  })y  a 
temperature  of  60°  to  70°  C,  therein  agreeing  with  other  bacterial 
toxins  thus  far  isolated. 

Attempts  to  discover  the  organism  in  the  feces  of  various  animals 
and  in  filth  of  various  kinds,  and  in  specimens  from  where  the  pig  was 
raised  were  negative  in  results. 

Feeding-experiments,  conducted  on  various  kinds  of  animals  with  the 
meat  itself  and  with  aqueous  triturations  of  it  added  to  other  foods,  ])ro- 
duced,  as  a  rule,  fatal  results  with  the  same  train  of  symptoms  as  above 
mentioned.  Subcutaneous  injections  of  the  watery  extract  produced  the 
same  results  as  feeding-ex^)eriments.  The  aqueous  extract  kept  in  the 
dark  in  a  sealed  tube  retained  its  properties  unimpaired  for  10  months, 
and  small  pieces  of  the  meat  kept  in  cotton-stoppered  tubes  without 
special  precautions  retained  their  virulence  even  longer.  The  ]ioison 
resists  the  effects  of  putrefaction,  and  proved  to  be  equally  poisonous 
after  4  days'  standing  in  a  mixture  with  feces,  decomposing  blood  and 
urine,  and  filtration  through  porcelain.  A  fresh  filtrate,  to  which  were 
added  B.  prodigiosus,  B.  proteus  liquefaciens,  B.  fluorescens  indrides, 
and  B.  coli,  was  found  at  the  end  of  a  week  to  be  as  active  as  ever. 

Poisoning  by  Beef. — Case  I. — In  December,  1841,  more  than  40 


CASES  ILLUSTRATIVE   OF  POISONINO  BY  FISH  AND  MEAT.      71 

cases  of  poisoning  occurred  in  New  York  City  from  eating  smoked 
beef.  As  a  rule  the  symptoms  began  several  hours  after  eating,  with 
pain  and  discomfort  in  the  epigastrium,  extending  to  the  back  and  loins. 
Vomiting  and  purging  were  followed  by  great  thirst  and  burning  pain 
at  the  pit  of  the  stomach,  which  became  so  irritable  that  it  could  tolerate 
neither  food  nor  drugs.  Extreme  prostration  followed,  the  functions 
of  the  nervous  and  muscular  system  being  greatly  affected.  One  victim 
died,  and  with  the  others  convalescence  was  extremely  slow.  Autopsy 
revealed  nothing  beyond  inflammation  of  the  ileum. 

Case  II. — In  May,  1888,  at  Frankenhausen,  58  persons  were  made 
sick  by  eating  the  meat  of  a  cow  killed  while  ill  with  diarrhoea  and 
passed  as  edible  by  a  veterinary.  The  symptoms  were,  in  general, 
nausea,  vomiting,  diarrhoea,  fever,  drowsiness,  dizziness,  and  great  de- 
pression. Those  who  ate  the  meat  in  the  raw  state  were  seized  without 
exception,  and  the  severity  of  the  seizure  was  directly  proportionate 
to  the  amount  eaten.  One  victim  who  ate  a  pound  and  a  half  died 
within  35  hours,  while  those  who  ate  least  suffered  least.  Those  who 
ate  the  cooked  meat  fared  differently.  Not  all  were  attacked,  nor  did 
the  severity  of  the  symptoms  bear  any  relation  to  the  amount  taken. 
Thus,  some  who  ate  freely  suffered  but  little,  while  very  severe  effects 
were  caused  by  slight  amounts  of  the  meat,  and  even  by  small  por- 
tions of  the  broth.  Thirty-six  who  ate  the  cooked  meat  escaped 
altogether.  From  a  portion  of  the  meat,  and  from  the  spleen  of  the 
person  who  died,  Gaertner'  isolated  B.  enteriticUs,  which,  since  then, 
has  been  shown  to  have  been  the  cause  of  numerous  other  outbreaks. 

Case  III. — In  June,  1889,  137  persons,  including  50  children,  in 
and  about  Cotta,  in  Saxony,^  were  made  ill  by  eating  the  meat  of  a 
cow  slaughtered  on  June  17th,  because  of  an  inflammatory  condition 
of  the  udder.  On  the  11th,  she  had  suddenly  stopped  giving  milk 
and  had  refused  food  and  drink.  The  meat  appeared  to  be  normal  in 
every  way  and  was  sold  on  the  day  after  slaughter.  The  first  cases 
appeared  during  the  night  of  the  day  of  sale.  The  majority  of  the 
victims  had  eaten  the  minced  meat  in  the  raw  state,  others  only  after 
it  had  been  cooked,  and  some  had  eaten  only  broth.  The  butcher  who 
sold  the  meat  tasted  as  much  as  would  cover  a  knife-blade,  and  suffered 
from  diarrhoea,  headache,  and  abdominal  pain  for  three  days.  His  as- 
sistant did  the  same,  and  fared  even  worse.  In  one  case,  the  symptoms 
began  with  a  chill ;  in  another,  with  difficult  deglutition,  double  vision, 
and  anxiety;  in  the  rest,  with  nausea,  vomiting,  diarrhoea,  headache, 
abdominal  pain,  dizziness,  great  lassitude,  restlessness,  lethargy,  and 
unquenchable  thirst.  In  many  cases,  the  eyes  were  glassy,  and  the 
pui)i]s  much  dilated.  The  tongue  was  commonly  dry  and  coated.  The 
cliildren  affected  were  extraordinarily  weak,  and  some  had  fever  as  high 
as  104.7°  F.  A  l)aei]lus  isolated  from  the  meat  by  Johne  was  found 
by  Cxaertner  to  differ  in  some  respects  from  B.  enteritidis. 

'  Corresponflenz-Bliitter  des  allgeineinen  iirztlichen  Vereins  von  Thiiringen, 
]S\i.  9. 

''  XXI.  .JahresV)ericIit  ueber  das  Medicinalwesen  im  Konigreich  Sachsen,  p.  104. 


72  FOODS. 

Case  IV. — Poisoning  by  canned  corned  beef  at  Sheffield,  reported 
by  W.  IN".  Parker.^  On  October  11,  1899,  a  six-pound  tin  of  corned 
beef  was  opened,  and  about  two-thirds  were  sold,  chiefly  in  quar- 
ter pounds.  Beyond  the  fact  that  the  meat  seemed  less  solid  than 
usual  and  the  jelly  rather  oily,  nothing  unusual  was  noticed.  It  had 
no  odor,  its  taste  was  normal,  though  quite  salt,  and  but  one  customer 
found  its  flavor  disagreeable.  So  far  as  is  known,  none  who  ate  escaped  ; 
24  persons  ranging  in  age  from  2  to  89  years  were  affected.  The  fol- 
lowing serves  as  an  example,  though  each  case  presented  one  or  more 
symptoms  peculiar  to  itself. 

A  woman  of  35  ate  2  ounces  of  the  meat  at  12.30,  and  in  2 
hours  was  seized  with  faintness,  dizziness,  and  drowsiness,  followed 
by  nausea,  and  great  muscular  weakness,  especially  of  the  legs.  Per- 
sistent vomiting  with  frequent  retching  soon  occurred,  accompanied 
by  intense  frontal  headache,  and  followed  by  colic  which  was  not  re- 
lieved by  purging.  One  hour  after  seizure,  she  was  taken  to  the  hos- 
pital, where  she  lay  on  a  couch  in  a  state  of  collapse  with  her  knees 
drawn  up.  Her  face  was  pale,  with  livid  patches  around  the  eyes,  and 
bathed  in  perspiration.  The  skin  was  cold  and  clammy,  the  pulse 
small  and  rapid,  the  respiration  shallow,  the  temperature  subnormal, 
and  the  pupils  dilated.  Her  stomach  was  washed  out,  and  in  a  short 
time  the  pain  and  retching  ceased,  the  character  of  the  pulse  improved, 
drowsiness  was  diminished,  and  only  the  lieadache  and  purging 
remained.  Within  an  hour,  the  condition  of  collapse  and  other 
symptoms  reappeared,  but  with  less  severity.  The  stomach  was  again 
washed  out,  and  this  time  the  good  effects  were  permanent.  On 
the  following  morning,  all  that  was  complained  of  was  slight  frontal 
headache. 

The  approximate  latent  period  varied  between  one  and  three  and  a 
half  hours,  but  in  only  2  cases  was  it  more  than  two  and  a  half  hours. 
Frontal  headache  was  present  in  all  but  4,  vomiting  in  all  but  1,  pain 
in  only  12,  marked  collapse  in  12,  profuse  discharges  in  all  but  6. 
The  initial  symptoms  were  the  same  in  all;  that  is,  drowsiness  or 
giddiness,  or  both. 

Only  one  case  resulted  fatally,  that  of  a  boy  7  years  old,  who  ate 
2  ounces.  His  symptoms  were  especially  severe ;  collapse  was  very 
marked  and  he  required  constant  stimulation.  About  10  hours 
after  the  onset,  he  had  a  series  of  clonic  contractions  of  the  flexor 
muscles  of  the  neck,  arms,  and  legs.  The  movements  were  violent, 
rapid,  and  almost  rhythmical,  commencing  first  in  the  neck  and  arms, 
but  soon  affecting  the  legs.  The  eyes  were  fixed  and  staring,  and  the 
pupils  widely  dilated.  After  lasting  an  hour  and  a  half,  the  convul- 
sions ceased.  They  reappeared  in  half  an  hour,  affecting  first  the 
right  arm  and  right  side  of  the  face,  but  soon  became  general. 
The  collapse  gradually  deepened,  and  the  boy  died  15  hours  after 
seizure.  Autopsy  showed  nothing  more  than  a  general  hyperjeraia 
of  the  stomach  and  intestines,  with  a  few  hemorrhagic  erosions  in  the 
1  British  Medical  Journal,  November  11,  1899. 


CASES  ILLUSTRATIVE  OF  POISONING  BY  FISH  AND  MEAT.      73 

gastric  mucous  membrane.  A  microscopic  examination  of  the 
kidney  showed  cloudy  swelling  of  the  cortex,  with  a  few  scattered 
hemorrhages. 

All  the  other  victims  convalesced  rapidly  and  were  discharged  from 
the  hospital  within  48  hours.  Stimulants,  chiefly  in  the  form  of  strych- 
nine and  brandy,  were  administered  freely.  The  meat  was  examined 
baeteriologically  about  11  hours  after  the  tin  was  said  to  have  been 
opened.  In  the  outer  parts  of  the  meat,  many  species  of  organisms 
were  found.  The  only  organism  present  both  in  cultures  from  the 
centre  of  the  meat  and  in  those  from  the  surface  was  the  bacillus  of 
Gaertner. 

Case  V. — An  outbreak  at  Mansfield,  in  which  65  persons  became 
ill  after  eating  the  flesh  of  a  cow  slaughtered  in  consequence  of  trau- 
matic pericarditis,  has  been  reported  by  Weseuberg.^  Oiily  those 
who  ate  of  the  minced  meat  in  a  raw  state  or  of  the  partly  cooked 
liver  were  aifected ;  those  who  ate  of  the  well-cooked  meat  escaped 
without  exception.  The  symptoms  were  vomiting  and  diarrhoea, 
violent  headache  and  abdominal  pain,  general  muscular  weakness, 
dizziness  and  lassitude.  The  discharges  were  sometimes  greenish, 
sometimes  brownish,  and  always  extremely  offensive.  With  few  excep- 
tions, the  symptoms  abated  in  from  3  to  5  days,  and  all  recovered 
except  one,  and  that  a  doubtful  case  of  a  child  who  was  not  known 
with  certainty  to  have  partaken,  and  whose  symptoms  might  have 
been  due  to  other  causes. 

The  unconsumed  meat  when  received  for  examination  was  already 
fairly  well  advanced  in  decomposition  and  partly  maggoty.  All  except 
one  piece,  which  was  faintly  acid  to  litmus  papers,  was  alkaline  in 
reaction.  Cultures  on  agar  and  in  bouillon  were  made  from  a  piece 
taken  from  a  part  which  was  apparently  not  yet  in  process  of  decom- 
position. Inoculation  of  the  bouillon  cultures  and  of  small  bits  of  the 
meat  into  white  mice  produced  fatal  results,  in  some  cases  within  from 
18  to  28  hours  and  in  others  within  3  days.  A  guinea-pig  which 
received  a  subcutaneous  injection  of  the  bouillon  culture  of  the 
crushed  meat  died  in  48  hours,  having  shown  marked  lassitude  and 
profuse  diarrhoea.  In  all  cases,  section  showed  enlargement  of  the 
spleen,  which  was  bluish-red  in  color,  strong  injection  of  the  small 
intestine,  and  marked  redness  of  the  medullary  substance  of  the 
kidneys.  Cover-glass  preparations  from  the  spleen  showed  fairly  long 
and  broad  bacilli,  and  the  same  were  developed  on  agar  from  the  meat 
itself. 

Poisoning  by  Horse  Meat. — Gaffky  and  Paak^  investigated  an 
outbreak  in  the  district  of  Ijowenberg,  which  was  known  to  involve  at 
least  30  and  probably  more  individuals.  The  offending  materials 
were  horse  meat,  horse  liver,  and  horse  sausage.  The  patients  com- 
plained very  soon  after  eating,  in  one  case  within  a  half  hour,  of 
nausea,  headache,  abdominal  pain,  borborygmus,  diarrhoea,  dizziness^ 

'  Zeitschrift  fiir  Ilyj^iene  iind  Infeetiotiskriuikheiten,  XXVIII.,  p.  484. 
'^  Arbeiten  aus  deiii  kaisci'liclien  Gesiiii(llioitsnmte,  VI.,  p.  159. 


74  FOODS. 

trembling,  and  great  thirst.  The  temperature  rose  to  104°  F.  One 
case  terminated  fatally.  Bacteriological  examination  revealed  a  bacil- 
lus which  diflfered  in  some  respects  from  that  of  Gaertner. 

Poisoning  by  Sausages. — Case  I. — Tripe  ^  reported  in  IS^ovem- 
ber,  1879,  an  outbreak  which  included  64  out  of  66  persons  who  had 
eaten  of  a  single  batch  of  sausages.  The  onset  was  characterized  by 
vomiting,  purging,  and  dizziness,  which  came  on  after  intervals  of 
varying  length.  There  was  extreme  weakness,  and  many  had  severe 
cramps  in  the  legs  and  pains  in  the  abdomen.  In  the  majority  of 
cases  the  vomiting  and  purging  lasted  from  36  to  48  hours.  The 
discharges  were  very  offensive,  and  looked  like  dirty  wash-water. 
There  was  marked  cerebral  disturbance,  and  a  sensation  of  acridity 
in  the  throat  was  common.  One  of  the  victims  died,  but  the  autopsy 
Tevealed  nothing  unusual  beyond  a  number  of  red  patches  in  the 
intestine.  The  remaining  sausages  were  found  to  have  a  tainted  and 
putrid  odor. 

Case  II. — The  "  Limmetshausen  case."  The  liver  of  a  healthy 
pig  was  made  into  sausages,  which  were  then  smoked  for  a  number  of 
days  and  hung  up.  On  the  eighth  day,  they  were  eaten  by  a  family 
and  a  number  of  invited  guests,  one  of  whom,  objecting  to  their  peculiar 
taste,  refrained  from  eating  and  escaped  the  trouble  that  came  to  all  the 
rest.  The  symptoms,  which  appeared  within  a  short  time,  were  the 
same  in  kind  in  all,  but  differed  in  severity.  They  included  abdominal 
pain,  vomiting,  dizziness,  dryness  of  the  mouth  and  throat,  and  diffi- 
cult deglutition.  The  pupils  became  dilated,  and  vision  was  much  im- 
paired and  finally  lost.  The  muscular  and  nervous  systems  were  very 
much  affected;  the  pulse  was  rapid  and  weak;  respiration  became  em- 
barrassed, swallowing  and  speaking  impossible.  Death  ensued  in  3 
cases,  preceded  by  great  lividity  of  the  face  and  spasms  of  the 
■extremities. 

Case  III. — Van  Ermengem^  relates  an  instance  in  which  the  remain- 
ing sausages  of  a  lot  which  had  caused  illness  in  several  persons  were 
apparently  so  wholesome  and  looked  so  inviting  that  the  exjx'rt  and 
his  assistants  to  whom  they  were  sent  ate  them  and  themselves  became 
ill.  The  expert  died  on  the  sixth  day,  and  autopsy  showed  gastro- 
enteritis, acute  nephritis,  and  fatty  degeneration  of  the  liver.  Gaert- 
ner's  B.  ententidis  was  found  both  in  the  organs  and  in  the  sausages. 
The  latter  were  made  of  horse  meat. 

Case  IV. — Carl  Giinther^  reports  that,  in  several  places  in  Poseu,  a 
large  number  of  persons  were  made  sick  after  eating  pork  sausages  and 
blood,  all  of  which  had  been  supplied  by  one  butcher.  The  most  im- 
portant symptoms  were  abdominal  pain,  vomiting,  purging,  great 
weakness,  and  lassitude.  One  man  of  47  years  died  after  hardly  a 
day's  sickness.  Gtinther  examined  portions  of  the  deceased  and  also 
samples  of  meat  and  blood  found  in  the  house,  and  sausage  and  meat 

^Medical  Times  and  Gazette,  Nov.  29,  1879. 

'^Kevue  d'Hy^iene,  1896,  p.  761. 

^  Archiv  fiir  Hygiene,  XXVIII.,  p.  146. 


CASES  ILLUSTRATIVE  OF  POISONING  BY  FISH  AND  MEAT.      75 

from  the  shop  of  the  butcher.  From  the  victim's  spleen  and  liv^er  he 
isolated  B.  enteritidis,  but  while  a  number  of  species  were  found  in  the 
foods,  this  bacterium  was  not  detected,  perhaps  having  perished 
through  the  influence  of  the  other  species  present. 

Case  V. — This  interesting  case  of  poisoning  by  sausage  composed 
of  pork  and  beef  is  related  by  Silberschmidt/  and  serves  as  an 
illustration  of  the  methods  commonly  employed  in  the  manufacture  of 
sausages.  Nearly  fifty  people  were  poisoned  by  eating  a  kind  of  sau- 
sage known  in  Switzerland  as  "Landjager."  It  is  made  of  beef,  often, 
also,  horse  meat  with  pig  fat.  The  materials  are  chopped  rather 
<3oarsely,  spiced,  put  into  casings,  pressed  flat  for  a  day,  smoked  two 
•days,  dried  in  the  air  several  days  more  and  then  eaten  in  the  raw 
state.  The  sausages  in  this  instance  were  made  of  cow  beef  from  ani- 
mals that  had  been  certified  as  sound  by  a  veterinarian,  and  pork  that 
had  been  bought  about  two  weeks  previously  and  kept  with  preserva- 
tive salt,  and  had  appeared  fresh  and  unchanged  when  used.  In 
the  morning  of  the  first  day  that  the  sausages  were  on  sale,  a  man  and 
iiis  wife  ate  one  of  them  together,  and  both  were  made  so  sick  toward 
-evening  and  during  the  night  that  a  physician  was  called.  In  the 
afternoon  of  the  same  day,  19  fishermen  ate  of  them,  and  on  the  fol- 
lowing day  it  was  reported  that  all  of  them  had  been  made  sick.  In 
the  evening,  another  man  ate  one,  and  it  pleased  him  so  much  that  he 
took  one  home  to  his  wife  and  children.  On  the  next  day,  he  had 
abdominal  pains,  headache,  vomiting,  diarrhoea,  thirst,  and  a  chill. 
In  the  afternoon,  his  wife  and  two  children  who  had  eaten  were  simi- 
larly seized.  A  boatman  who  ate  two  whole  sausages  suffered  no 
inconvenience  beyond  a  little  pain  on  the  following  day.  Another, 
who  was  sick  eighteen  days  and  then  returned  to  his  work,  was  seized 
-again  ten  days  later  with  the  same  train  of  symptoms.  One  man, 
aged  eighteen  years,  entered  the  hospital  in  the  morning  of  the  second 
day,  and  died  during  the  night,  two  days  and  a  half  after  ingestion 
of  the  sausage.  At  the  time  of  entrance,  the  abdomen  was  sensitive 
and  he  was  passing  grayish  watery  stools;  in  the  afternoon,  he  was 
<ielirious,  and  his  pulse  was  very  small,  irregular,  and  rapid.  Dur- 
ing the  night  he  collapsed  and  died.  Section  after  twelve  hours 
showed  a  spleen  of  normal  size,  swollen  mesenteric  glands,  and  hyper- 
emia of  the  stomach  and  intestines.  The  follicles  were  much  swollen, 
and  in  the  ileum  were  several  areas  from  4  to  6  cm.  in  length  by  1  cm. 
in  breadth,  where  the  mucous  membrane  was  discolored  and  eroded. 
Other  organs  were  normal.  Six  others  of  those  afl^ected  were  discharged 
from  the  hospital  after  from  seven  to  fifteen  days'  treatment.  In  an 
adjoining  town,  where  sausages  of  the  same  lot  were  sold,  there  were  16 
other  cases,  all  with  the  same  symptoms.  Taking  all  the  cases  to- 
gether, the  symptoms  of  prominence  were  as  follows:  Very  severe, 
partially  crampy,  abdominal  pains;  very  profuse  diarrhoea,  the  stools 
numb(!ring  from  eight  to  twelve  ])er  day,  and  in  color  varying  between 
gray,  greenish,  and  yellow;  usually  vomiting,  the  rejected  mutters  being 
'  Zeitschrift  fiir  Hygiene  unci  Infectionskrankheiten,  XXX.,  p.  328. 


76  FOODS. 

watery  and  brownish ;  sunken  eyes,  high  fever,  great  lassitude,  tender- 
ness over  abdomen,  cramps  in  the  calves,  great  thirst,  and,  occasionally^ 
meteorism.  In  most  of  the  cases,  the  symptoms  appeared  on  the  day 
after  eating.  The  duration  of  the  illness  ranged  between  one  and 
thirty  days,  the  greater  number  recovering  in  two  weeks,  and  becoming 
fit  for  work  in  three. 

As  is  commonly  the  case  in  these  outbreaks,  the  attention  of  the 
authorities  was  not  drawn  to  the  matter  in  either  town  until  some  days 
had  elapsed.  Chemical  analyses  of  unused  sausages  were  made  at  both 
places.  One  analyst  reported  negative  results  ;  the  other  reported  the 
presence  of  ptomains,  but  did  not  further  particularize.  Bacteriological 
investigation  revealed  the  presence  of  a  variety  of  organisms,  as  was 
to  have  been  anticipated,  and  among  them,  especially  marked,  Proteus 
vulgaris. 

Poisoning-  by  Kid  Meat. — Hensgen  ^  has  reported  the  case  of  a 
whole  family  stricken  after  eating  the  meat  of  a  kid  which  was  killed 
when  but  a  few  days  old.  A  twelve  year  old  girl  M^as  seized  in  eleven 
hours  with  a  chill,  followed  by  fever,  dizziness,  vomiting,  and  violent 
diarrhoea.  The  temperature  rose  to  103.6°  F.  She  was  confined  to 
her  bed  for  five  days.  The  father,  forty-nine  years  old,  was  seized 
with  the  same  symptoms  in  twelve  to  thirteen  hours,  and  had  also 
headache,  pain  in  the  joints,  thirst,  and  inability  to  walk.  The  tongue 
was  dry,  the  pulse  rapid  and  small,  and  the  pupils  reacted  slowly.  He 
was  sick  eight  days.  The  mother,  who  ate  but  little,  was  seized  sud- 
denly in  the  night  with  vomiting,  and  such  great  dizziness  that  she  was 
unable  to  walk  without  holding  on  to  the  furniture.  A  boy,  under  two 
years  of  age,  was  seized  in  the  night  ^^■ith  vomiting  and  violent  diar- 
rhoea, which  soon  became  bloody.  The  stools  were  unusually  offensive, 
and  persisted  so  for  several  days.  He  was  sick  nine  days.  Three 
other  children,  who  ate  but  very  little,  were  sick  two  days  with  slight 
abdominal  pain  and  diarrhoea.  No  material  was  obtainable  for  exami- 
nation. The  butcher  said  that  the  kid  was  apparently  healthy,  but  the 
mother  declared  that  the  meat  around  the  joints  of  the  hind  legs  was 
very  soft  and  watery,  and  the  joints  themselves  enlarged  (septic  poly- 
arthritis ?). 

Meat  Inspection  and  Slaughtering. 

The  value  and  advisability  of  thorough  inspection  of  meats  before 
they  are  placed  on  sale  are  universally  conceded.  In  this  country, 
under  the  inspection  law  of  March  3,  1891,  all  meat  intended  for  ex- 
port is  required  to  pass  a  very  strict  system  of  inspection.  The  ani- 
mals are  inspected  before  being  slaughtered,  and  their  carcasses  are 
examined  microscopically  by  officials  of  the  Bureau  of  Animal  Indus- 
try before  being  packed.  The  inspection  of  meat  for  local  consump- 
tion is  wholly  a  matter  of  local  authority  ;  some  States  have  inspection 
laws  and  others  hav^e  none ;  many  cities  have  special  regulations  which 
are  enforced  by  officials  who  may  or  may  not  be  competent  through 
'  Zeitschrift  fiir  Fleisch-  und  Milchhygiene,  VIII.,  p.  181. 


MEAT  INSPECTION  AND  SLAUGHTERING.  77 

proper  training.  In  Germany,  the  system  of  inspection  is  very  rigid, 
particularly  in  the  case  of  meats  from  foreign  countries.  This  is  due 
very  largely  to  the  activity  of  the  agricultural  interests  in  jn-otecting 
themselves  from  outside  competition  ;  and  luider  the  benevolent  ])lea 
of  protecting  the  health  of  meat  consumers,  much  care  and  attention 
are  given  to  hunting  for  excuses  for  excluding  American  meats  which 
have  already  been  inspected. 

The  Federal  meat  inspection  service  is,  according  to  Salmon,^ 
a  sanitary  rather  than  a  commercial  inspection,  applied  not  alone  to 
meats  for  export,  but  also  to  those  intended  for  inter-state  commerce. 
Curiously,  however,  the  very  important  inspection  for  trichinae  is  pri- 
marily a  commercial  matter,  being  applied  only  to  pork  intended  for 
shipment  to  certain  foreign  countries  which  require  it. 

The  United  States  inspectors  are  instructed  to  condemn  all  female 
animals  in  an  advanced  stage  of  gestation,  and  to  prevent  their  slaughter 
for  food,  Salmon  ruling  that,  though  "  the  animal  is,  strictly  speaking, 
in  a  physiologic  condition,  it  is  not  m  its  usual  physiologic  condition, 
nor  is  the  change  one  which  is  calculated  to  improve  the  quality  of  the 
meat."  Females  in  which  parturition  has  recently  occurred  are  like- 
wise condemned  as  unfit  for  food.  Many  animals  are  condemned  on 
account  of  bruises  and  injuries  received  on  their  way  to  market ;  during 
1900,  there  were  condemned  for  this  cause,  in  round  numbers,  carcasses 
or  parts  of  carcasses  of  4500  cattle,  1,000  sheep,  and  12,300  hogs. 
In  some  of  these,  the  injuries  were  extensive,  sometimes  complicated 
with  abscesses,  septic  infection,  and  gangrene. 

The  cattle  diseases  most  prominent  as  causes  of  condemnation  are 
tuberculosis,  actinomycosis,  and  ansemia ;  next  in  order  are  septicaemia, 
pneumonia,  peritonitis,  pyaemia,  icterus,  abscesses,  and  Texas  fever.  In 
swine,  the  most  common  diseases  are  hog  cholera,  swine  plague,  tubercu- 
losis, icterus,  pyaemia,  abscesses,  pneumonia,  inflammations  of  the 
abdominal  cavity,  septicaemia,  and  tumors.  The  most  common  causes 
of  condernnation  of  sheep  are  anaemia  and  emaciation,  bruises  and 
injuries,  tuberculosis,  abscesses,  pneumonia,  uraemia,  septicaemia,  icterus, 
and  pyaemia. 

In  by  no  means  every  case  is  the  entire  carcass  of  an  animal  afflicted 
with  tuberculosis  or  actinomycosis  condemned,  since,  in  the  early  stages, 
both  diseases  usually  are  localized,  and  the  carcass  as  a  whole  not 
affected.  A  tuberculous  animal  is  condemned  wholly  when  there  is 
emaciation  or  generalization  of  the  lesions,  and  "  when  the  lesions  in 
any  organ  or  organs  are  of  such  number  and  size  as  to  indicate  that, 
the  system  at  large  may  have  been  affected,  either  by  inflammation,  by 
the  mixed  infection,  by  the  secretion  and  absorjition  of  pus  or  toxic 
principles,  or  by  interference  with  the  general  nutrition  of  the  body" 
(Salmon).  In  nine  years  of  Federal  meat  inspection,  the  condemna- 
tions per  10,000  animals,  were,  according  to  Salmon,^  as  follows  :  cattle, 
0.48;  sheep,  8.1  ;  swine,  87. 

^  .Toumal  of  tlif  Aincriftnn  Mt-dicid  Association,  Dec.  2H,  1901,  p.  1715. 
■''  Il)i(lcm,  March  :'.(»,  I'JDI. 


78  FOODS. 

In  inspecting  meats,  special  attention  should  be  paid  to  the  connective 
tissue  and  glandular  organs.  The  odor  of  a  carcass  should  be  sweet, 
and  the  meat  should  communicate  no  unpleasant  smell  to  a  wooden 
skewer  thrust  into  it  and  withdrawn.  The  muscle  should  be  firm  and 
elastic,  but  not  tough.  Any  variation  from  the  natural  color  should  be 
regarded  with  suspicion,  very  dark  color  suggesting  febrile  condition, 
or  that  the  animal  was  not  slaughtered,  or  was  slaughtered  in  a  dying 
condition.  Such  meat  undergoes  decomposition  much  more  rapidly 
than  normal  meat.  Animals  that  have  been  drowned  or  have  been 
killed  by  accident  without  being  bled  yield  a  dark  and  discolored  meat 
that  is  likely  to  decompose  more  rapidly  than  that  of  animals  that  have 
regularly  been  slaughtered,  but  an  animal  that  has  been  injured,  but 
not  killed,  may  be  slaughtered,  properly  bled  and  dressed,  and  its  meat 
is  then  perfectly  good. 

Animals  should  be  kept  without  food  for  at  least  twelve  hours  before 
slaughter,  and  the  carcasses  should  be  hung  for  a  number  of  hours  to 
cool.  Many  diseases  are  indicated  more  clearly  after  the  body  has 
cooled. 

The  Jewish  method  of  slaughtering  is  regarded  by  many  as  far 
superior  to  any  other.  According  to  Dembo,^  it  is  the  most  rational 
;from  a  hygienic  standpoint,  since  the  animal  is  bled  rapidly  and  com- 
pletely, and  the  convulsive  movements  cause  the  meat  to  be  more 
tender  and  of  more  attractive  appearance.  Lactic  acid  is  developed, 
and  through  its  chemical  action  on  potassium  phosphate,  potassium 
lactate  and  acid  phosphate  of  potassium  are  formed.  The  latter 
hinders  the  development  of  micro-organisms,  delays  the  formation 
of  ptomains  and  other  poisonous  matters,  and  improves  the  taste. 
Rigor  mortis  comes  on  more  quickly,  and  the  meat  is,  therefore,  more 
quickly  available  for  use,  and  also  will  keep  several  days  longer  than 
ordinarily. 

A  process  of  slaughtering  originating  in  Denmark  appears  to 
have  borne  the  test  of  a  hard  three-months'  trial  in  a  very  satisfactory 
manner,  and  recommends  itself  for  adoption  in  the  tropics,  where 
meats  decompose  with  exceeding  rapidity.  The  animal  is  shot  in 
the  forehead  and  killed  or  stunned,  and  as  it  falls,  an  incision  is  made 
over  the  lieart  and  the  ventricle  is  opened  for  two  purposes  :  to  allow 
the  blood  to  escape,  and  to  admit  of  the  injection  of  a  solution  .of  salt 
through  the  bloodvessels  by  the  aid  of  a  powerful  syringe.  The  process 
requires  but  a  few  minutes,  and  the  carcass  may  be  cut  up  at  once. 

EGGS. 

Eggs  form  a  valuable  substitute  for  meats,  being  fairly  rich  in  fats 
and  proteids,  and  are  well  adapted  to  the  stomach  of  the  invalid  and 
convalescent  when  meats  cannot  be  borne.  The  nutritive  part  of  the 
white  is  practically  limited  to  proteids,  which  amount  to  about  12  per 
cent.  ;  the  yolk  is  richer  in  proteids,  and  contains  in  addition  about  33 
'Deutsche  Vierteljahrschrift  fiir  offentliche  Gesundheitspflege,  XXVI.,  p.  688. 


EGGS. 


79 


per  cent,  of  fat.  The  albumin  of  the  white  is  in  a  condition  of  solu- 
tion in  cells  with  very  thin  walls.  The  fatty  matters  of  the  yolk  are 
in  a  condition  of  emulsion,  being  held  in  suspension  by  the  vitellin. 
The  entire  yolk  is  held  together  by  an  enveloping  membrane  and  is  sus- 
pended in  the  white,  being  held  in  position  by  an  albuminous  band  at 
either  end  : 

The  following  table  by  Langworthy  ^  shows  the  average  composition 
of  eggs  of  diiferent  sorts  : 


Refuse. 

Water. 

Protein. 

Fat. 

Ash. 

Fuel 

value  per 

pound. 

Hen: 

Whole  egg  as  purchased    .... 
Whole  egg,  edible  portion    .   .   . 
White 

Per  cent. 
11.2 

Per  cent. 
65.5 
73.7 
86.2 
49.5 
73.3 
65.6 
64.8 

60.8 
70.5 
87.0 
45.8 

59.7 
69.5 
86.3 
44.1 

63.5 
73.7 
86.7 
48.3 

'60.5 
72.8 
86.6 
49.7 

67.3 
74.4 
6.4 

Per  cent. 
11.9 
13.4 
12.3 
15.7 
13.2 
11.8 
11.9 

12.1 
13.3 
11.1 

16.8 

12.9 
13.8 
11.6 
17.3 

12.2 
13.4 
11.5 
17.4 

11.9 
13.5 
11.6 
16.7 

9.7 
10.7 
46.9 

Per  cent. 
9.3 
10.5 
.2 
33.3 
12.0     • 
10.8 
11.2 

12.5 
14.5 

.03 
36.2 

12.3 
14.4 
.02 
36.2 

9.7 
11.2 
.03 
32.9 

9.9 
12.0 

.03 
31.8 

10.6 
11.7 
36.0 

Per  cent. 
0.9 
1.0 

.6 
1.1 

.8 

.6 

.7 

.8 
1.0 

.8 
1.2 

.9 
1.0 

.8 
1.3 

.8 

.9 

.8 

1.2 

.8 

.9 

.8 

1.2 

.9 
1.0 
3.6 

Calm-les. 
635 

720 
250 

Yolk 

16.7 
10.9 

13.7 

1,705 

Whole  egg  boiled,  edible  portion 
White-shelled  eggs  as  purchased 
Brown-shelled  eggs  as  purchased 
Duck: 

Whole  egg  as  purchased    .... 
Whole  egg,  edible  portion    .   .   . 

White 

Yolk 

765 
675 
695 

750 
860 
210 

1,840- 

Goose : 

Whole  egg  as  purchased    .... 
Whole  egg,  edible  portion    .  .  . 
White 

14.2 

760- 
865. 
215 

Yoik 

1,850- 

Turkey : 

Whole  egg  as  purchased    .... 
Whole  egg,  edible  portion    .  .   . 
White 

13.8 

635 
720 
215 

Yolk 

1,710 

Guinea  fowl : 

Whole  egg  as  purchased    .... 
Whole  egg,  edible  portion    .  .  . 
White 

16.9 

640 
755 
215 

Yolk                           

9.6 

1,655 

625 

695 

2525 

Plover: 

Whole  egg  as  purchased    .... 

Whole  egg,  edible  portion    .  .   . 
Evaporated  hens'  eggs 

The  proteids  of  eggs  have  been  studied  by  Osborne  and  Campbell,^ 
who  found  that  the  yolk  contains  a  large  amount  of  protein  which 
resembles  a  globulin,  but  is  believed  to  be  a  mixture  of  compounds  of 
protein  matter  with  lecithin.  The  proteids  of  the  white  were  found  to 
include  ovalbumin,  ovomucin,  ovomucoid,  and  conalbumin. 

Eggs  contain  a  certain  amount  of  sulphur,  to  which  the  staining  of 
silver  spoons  and  the  odor  of  rotten  eggs  (hydrogen  sulphide)  are  due. 
The  rotting  of  eggs  is  supposed  to  be  due  to  the  admission  of  fermenta- 
tive micro-organisms  through  the  pores  of  the  shell,  or  to  those  already 
present  before  the  shell  is  formed. 

It  is  a  commonly  accepted  idea  in  some  parts  of  the  country  that 
eggs  with  brown  shells  are  of  greater  richness  than  others,  and  that  the 
degree  of  richness  is  directly  proportionate  to  the  depth  of  color.  In 
some  markets,  on  the  other  hand,  the  white  egg  is  held  in  higher  esteem. 

'  U.  S.  Department  of  Afjriciilture,  Farmei-s'  Bulletin,  No.  128  (1901). 
^  Report  of  Connecticut  Experiment  Station,  1899,  p.  339. 


80 


FOODS. 


According  to  the  results  of  an  extensive  study  of  the  chemical  composi- 
tion of  eggs  carried  on  at  the  California  Experiment  Station  mainly  for 
the  purpose  of  determining  what  differences,  if  any,  exist  between  them, 
there  is  no  basis  of  fact  for  the  popular  belief.  In  fact,  the  very  slight 
differences  noted  were  in  favor  of  the  white  eggs,  but  the  average  dif- 
ferences between  the  two  kinds  were  less  than  the  fluctuations  between 
individual  specimens  of  the  same  group.  The  figures  obtained  are 
})resented  in  the  following  table  taken  from  Farmers'  Bulletin  No.  87  :^ 


ANALYSIS  OF  BKOWN-SHELLED  AND  WHITE-SHELLED  EGGS. 


Brown-shelled  eggs: 

Yolk 

White 

Entire  egg 

White-shelled  eggs: 

Yolk 

White 

Entire  egg 


Water. 

Protein. 

Fat. 

Ash. 

Shell. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

Per  ct. 

49.59 

15.58 

.33.52 

1.04 

86.60 

11.99 

.21 

.54 

65.57 

11.84 

10.77 

.64 

10.70 

49.81 

15.49 

33.34 

1.05 

86.37 

12.14 

.35 

.56 

64.79 

11.92 

11.22 

.67 

10.92 

Total. 


Per  ct. 
99.73 
99.34 
99.52 

99.69 
99.42 
99.52 


The  question  of  influence  of  breed  on  composition  has  been  investi- 
gated at  the  Michigan  Experiment  Station.  The  results  showed  that 
the  variations  in  composition  are  too  slight  to  be  of  practical  value, 
and,  as  with  the  brown  and  the  white  eggs,  so  slight  as  to  be  less  than 
the  variations  between  individual  specimens  from  the  same  Ijreed.  The 
influence  of  the  nature  of  the  feed  was  investigated  also,  and  was  found 
to  be  of  little  or  no  importance. 

The  flavor  of  eggs  varies  according  to  age,  those  which  are  per- 
fectly fresh  having  the  finest  flavor.  It  is  dependent  also,  to  some 
extent,  upon  the  nature  of  the  food  consumed  by  the  fowl,  the  best 
coming  from  a  purely  grain  feed.  A  very  nitrogenous  feed  causes  a 
more  or  less  disagreeable  flavor  and  odor.  The  influence  of  highly 
flavored  feed  has  been  studied  by  Emery,^  who  fed  hens  with  a  ration 
containing  wild  onion  tops  and  bulbs.  After  fifteen  days,  the  eggs 
having  no  unusual  taste,  each  hen  received  daily  one  ounce  of  this 
addition  instead  of  a  half  ounce  as  before,  and  in  three  days  the  eggs 
were  flavored  so  strongly  as  to  be  repugnant  to  the  taste. 

The  iron  content  of  the  yolk  of  eggs  is  said  by  Schmidt  ^  to  be  in- 
creased materially  by  feeding  saccharate  of  iron  to  hens.  He  asserts, 
also,  that  the  iron  so  incorporated  is  more  assimilable  than  most  iron 
preparations  given  in  the  anasmic  condition.  Aufsberg  *  asserts  that 
by  feeding  certain  iron  compounds,  the  iron  content  can  be  increased 
eight  times. 

The  digestibility  of  eggs  has  been  studied  at  the  Minnesota  Experi- 

1  Government  Printing  Office,  Washington,  1899,  p.  24. 
^  Bulletin  167,  North  Carolina  Experiment  Station. 
'  Zeitychrift  fiir  angewandte  Chemie,  1900,  p.  705. 
*  Pharmaceutische  Zeitung,  1900,  p.  366. 


LARD.  81 

ment  Station.^  It  was  shown  that,  while  the  method  of  cooking  has 
some  effect  on  the  rate  of  digestion,  the  total  digestibility  is  not  aifected. 
Eggs  boiled  three,  five,  and  twenty  minutes,  and  digested  for  five  hours 
with  pepsm  solution,  showed  at  the  expiration  of  that  time  respectively 
8.3,  3.9,  and  4.1  per  cent,  of  undigested  proteids.  Cooked  for  five  and 
ten  minutes  in  water  at  180°  F.  and  similarly  treated,  they  left  no  un- 
digested residuum. 

LARD. 

Lard  is  the  semi-solid  fat  of  the  slaughtered  hog,  separated  from  the 
tissues  by  the  aid  of  heat.  According  to  the  parts  from  which  it  is  de- 
rived, it  is  classified  as  follows  :  (1)  Neutral  lard.  This  is  derived 
from  the  fresh  leaf,  which  is  reduced  to  a  pulp  after  being  cooled,  and 
then  rendered  in  the  kettle.  A  part  of  the  fat  is  separated  at  from 
105°  to  120°  F.,  and  the  residue  is  sent  to  the  rendering  tanks  for 
further  treatment.  The  lard  obtained  is  washed,  while  hot,  with  water 
containing  a  trace  of  sodium  carbonate,  common  salt,  or  dilute  acid. 
(2)  Leaf  lard.  This  is  obtamed  from  the  residue  above  mentioned, 
which  is  subjected  to  steam  heat  under  pressure.  (3)  Choice  kettle 
rendered  lard.  This  is  obtained  from  the  remaining  portions  of  the 
leaf  together  with  the  fat  from  the  backs.  Both  tlie  leaf  and  back  fat 
are  passed  first  through  a  pulping  machine.  (4)  Prime  steam  lard. 
This  is  made  from  the  head,  the  fat  of  the  small  intestine,  trunmings, 
and  other  fatty  parts. 

The  spleen,  pancreas,  trachea,  and  all  other  refuse  parts  and  trim- 
mings, with  the  exception  of  the  small  intestine,  the  liver,  lungs,  and 
part  of  the  heart,  go  into  the  rendering-kettle  for  what  fat  there  may 
be  in  them,  and  the  product  is  variously,  but  not  graphically,  desig- 
nated. 

"  Refined  lard  "  is  a  term  used  to  designate  a  lard  composed  chiefly 
of  cotton  oil  and  stearin.  It  is  known  more  often  as  "lard  com- 
pound." 

Physical  and  Chemical  Properties  of  Lard. — At  40°  F.,  the 
specific  gravity  is  0.890 ;  at  100°,  about  0.860 ;  it  differs  not  very 
materially  from  that  of  the  substances  used  as  adulterants,  excepting 
cotton-seed  oil,  which  is  notably  heavier.  The  melting-point  ranges 
from  39.1°  to  44.9°  C.  (102.4°  to  112.8°  F.),  according  to  the  part 
of  the  carcass  from  which  the  fat  is  derived,  and  hence  it  cannot  be 
taken  as  a  safe  guide  in  the  determination  of  purity. 

Pure  lard,  melted,  and  mixed  with  strong  sulphuric  or  nitric  acid, 
will  give  only  a  slight  color,  which  may  be  yellowish,  pinkish,  or 
inclined  to  light  l)rownish.  Cotton-seed  oil  and  other  seed  oils,  and 
mixtures  containing  them,  similarly  treated,  yield  any  color  between 
yellowish  brown  and  very  brownish  black  or  even  black.  The  re- 
fractive index  of  pure  lard  is  materially  lower  than  that  of  cotton- 
seed CiW. 

Pure  lard  contains  only  tnices  of  volatile  fatty  acids,  5  grams  yield- 

'  Farmei's'  Bulletin  No.  87,  Gov(.-rnni<Mit  Printing  Office,  Wnsliin.t,4f)n,  ]8!)9,  p.  20. 


82  FOODS. 

ing  an  amount  which  is  neutralized  by  ^  or  f  of  a  cc.  of  decinormal 
sodium  hydrate  sokition.  The  non-volatile  fatty  acids  are  present  to 
the  extent  of  about  95  per  cent.  The  iodine  absorption  number  varies 
according  to  the  part  of  the  carcass  from  which  the  fat  is  derived,  but 
averages  about  60.  The  iodine  number  of  cotton-seed  oil  is  about  109, 
and  that  of  stearin  is  approximately  20.  Thus,  these  substances  used 
as  adulterants  may  be  mixed  in  such  proportion  as  to  yield  the  normal 
iodine  number  of  lard. 

With  nitrate  of  silver  solution,  pure  lard  causes  no  more  than  the 
very  slightest  amount  of  reduction,  and  generally  none  at  all ;  but  cotton- 
seed oil  causes  a  very  marked  reduction  of  the  salt  to  the  metallic  state, 
with  the  result  that  the  mixture  has  a  brownish  or  black  appearance 
from  the  minute  black  particles  formed. 

A  small  amount  of  lard,  dissolved  in  a  mixture  of  equal  parts  of 
alcohol  and  strong  ether  in  a  test-tube  and  allowed  to  stand  in  a  cool 
place,  will,  when  the  solvent  in  large  part  is  evaporated,  show  masses 
of  crystals,  which,  on  examination  under  the  microscope,  are  seen  to  be 
rhombic  and  extremely  variable  in  size.  Beef  stearin,  similarly  treated, 
shows  fan-shaped  and  dumbbell-shaped  clusters  of  needle  crystals. 
Mixtures  of  pure  lard  and  beef  stearin  will  show  both  forms  of  crys- 
tals. Sometimes,  when  crj^staUization  proceeds  rapidly,  the  crystals 
from  pure  lard  are  extremely  small,  and  are  clustered  in  such  a  way  as 
to  be  distinguished  from  beef  stearin  crystals  only  with  great  difficulty. 
It  is  essential  that  the  crystallizing  process  shall  proceed  slowly,  and 
that  the  amount  of  lard  dissolved  in  half  a  test-tube  of  the  solvent 
shall  be  quite  small — not  larger  than  a  large  pea.  The  mouth  of  the 
test-tube  should  be  stopped  with  cotton. 


Section  3.     MILK   AND   MILK   PRODUCTS. 

.     MILK. 

Milk  is  a  solution  of  sugar,  mineral  matter,  and  proteids,  with  other 
proteids  and  fat  in  suspension.  Its  composition  is  very  variable,  not 
alone  as  between  different  species  of  mammalia  by  which  it  is  produced, 
but  as  between  different  individuals  of  the  same  species.  Of  the 
domestic  animals,  the  ass  and  mare  produce  milk  which  most  closely 
approximates  that  of  woman  in  composition,  but  our  chief  interest  in 
milk  as  an  article  of  food  in  general  use  lies  in  that  produced  by  cows 
and,  to  a  certam  extent,  in  that  of  goats,  which  is  very  similar  in  com- 
position. While  the  composition  of  milk  of  other  animals  than  those 
already  mentioned  can  have  for  most  of  us  merely  a  scientific  interest, 
it  may  be  of  some  practical  utility  in  the  management  of  breast-milk 
to  bear  in  mmd  that  the  milk  of  animals  whose  diet  is  largely  or  chiefly 
meat  is  richest  in  those  elements,  the  proteids,  that  are  most  commonly 
at  the  bottom  of  digestive  disturbances  in  breast-fed  children. 

Composition  of  Cows'  Milk. — The  composition  of  milk  of  average 
good  quality  may  be  expressed  fairly  in  round  numbers  as  follows  : 


iMILK.  83 

Fat 4.00 

Sugar 5.00 

Proteids 3.30 

Mineral  matter 0.70 

Total  solids 13.00 

Water 87.00 

100.00 

According  to  Vieth,  the  average  coraposition  of  more  than  120,000 
samples  analyzed  in  England  was  : 

Fat 4.10 

Solids  not  fat ■. 8.80 

Total  solids 12.90 

Water 87.10 

100.00 

The  average  of  a  large  number  of  analyses  made  in  this  country 
showed  :  ^ 

Fat 4.00 

■      Sugar 4.95 

Proteids 3.30 

Minei'al  matter 0.75 

Total  solids • 13.00 

Water 87.00 

100.00 

The  milk  yielded  by  426  cows  from  private  farms  in  Massachusetts^ 
and  by  1  75  more  belonging  to  public  institutions,  was  analyzed  by  the 
author  and  his  associates,  and  found  to  give  the  following  results  :  ^ 

426  cows  from  private  farms,  total  solids 13.36 

175  cows  from  public  institutions,  total  solids 13.00 

601  cows  (both  classes),  total  solids 13.26 

Fat. — The  fat  of  milk  exists  in  very  minute  globules  which  vary 
widely  in  size,  the  largest  being  between  six  and  seven  times  larger 
than  the  smallest,  but  the  latter  are  most  abundant.  Whether  or  not 
they  have  an  albuminous  envelope,  is  a  matter  of  doubt,  the  evidence 
for  and  against  being  about  equal,  and  of  no  great  importance. 

It  consists  of  glycerides  of  ten  different  fatty  acids,  five  of  which 
belong  to  the  non-volatile  and  five  to  the  volatile  class.  The  glycerides 
of  the  former  group  constitute  by  far  the  greater  part.  They  are 
stearin,  palmitin,  olein,  myristin,  and  butin  ;  the  two  last  are  present 
in  very  minute  amounts.  Those  of  the  latter  group  give  the  character- 
istic butter  flavor.  They  are  butyrin,  caproin,  caprylin,  caprin,  and 
laurin  ;  the  two  first  are  the  important  ones,  and  together  amount  to 
over  7  |)er  cent,  of  the  whole  fat ;  the  three  others  are  present  in  but 
insignificant  traces. 

'  American  Experiment  Station  Record,  V.,  No.  10. 

''  The  detailed  analyses,  with  data  as  to  breed,  nature,  and  amount  of  feed,  etc.,  can 
be  found  in  the  pamphl(;t  issued  by  the  State  Board  of  Health  :  Results  of  Inquiries 
Relative  to  the  Quality  of  Milk  as  Produced  in  Massachusetts.   R(jston  :  February,  1887. 


84  FOODS. 

The  fat,  being  the  lightest  part  of  milk,  tends  to  rise  to  the  surface 
when  the  milk  is  allowed  to  stand,  and  then  forms  a  layer  which  we 
know  as  cream.  This  contains  not  fat  alone,  but  all  of  the  constituents 
of  the  milk,  and  is,  therefore,  simply  milk  containing  an  excessive 
amount  of  fat. 

It  is  a  common  error  to  regard  the  depth  of  the  cream  layer  which 
forms  on  standing  a  given  length  of  time  as  an  infallible  measure  of 
the  richness  of  the  milk  by  which  it  is  yielded ;  but  cream  does  not 
always  rise  well  in  rich  milk,  even  after  standing  more  than  twenty- 
four  hours.  The  author  repeatedly  has  found  the  percentage  of  cream 
thrown  up  by  a  specimen  of  milk  in  a  100  cc.  graduate  in  twenty-four 
hours,  as  measured  by  the  lines  of  graduation,  to  be  less  than  the  actual 
percentage  of  fat  as  shown  by  analysis.  The  rapidity  with  which  the  fat 
iinds  its  way  to  the  surface  depends  largely  upon  the  size  of  the  fat 
globules.  The  largest  rise  first,  and  the  very  smallest  may  not  rise  at 
all.  Again,  a  watered  milk  throws  up  its  fat  more  quickly  than  a 
normal  specimen,  although  it  does  not  contain  as  much.  It  appears, 
therefore,  that  a  milk  of  inferior  grade  may  under  some  circumstances 
show  a  deeper  cream  layer  than  a  milk  of  unusual  richness.  Generally 
speaking,  however,  a  rich  milk  will  usually  show  its  quality  on  standing. 

The  first  part  of  a  milking  is  always  poor  in  fat,  the  middle  portion 
contains  about  the  average  amount  of  the  whole,  and  the  last  portion  is 
always  the  richest.  The  first  portion  is  known  as  "  fore-milk,"  the  last 
as  "  strippings."  A  specimen  of  "  strippings,"  analyzed  by  the  author, 
gave  the  following  results  : 

Fat 9.82 

Sugar 4.00 

Proteids 4.21 

Ash 0.79 

Total  solids 18.82 

Water 81.18 

100.00 

Milk-sugar. — Lactose  or  sugar  of  milk,  is  peculiar  to  milk.  It  is 
much  less  soluble  in  Avater  than  dextrose  and  sucrose.  Heated  to 
100°-131°  C,  it  becomes  changed  in  color  to  brownish,  and  at  higher 
temperatures  loses  water  of  crystallization  and  undergoes  further  change. 
At  175°  C,  lactocaramel  is  formed.  When  heated  in  solution,  in  milk 
itself,  for  example,  it  begins  to  undergo  decomposition  changes  at  70° 
C  and  above.  Through  the  action  of  the  lactic  ferments,  it  gives  rise 
to  lactic  acid.     In  the  polariscope,  it  is  dextrorotary. 

Proteids. — The  greater  part  of  the  proteids  of  milk,  about  80  per 
cent.,  is  casein,  or,  as  it  is  called  sometimes,  caseiuogeu.  It  contains 
both  sulphur  and  phosphorus,  and  is  in  intimate  combination  with  cal- 
cium phosphate.  It  is  not  coagulated  by  heat,  but  is  precipitated  by 
acids,  by  M'hich  the  combination  is  l:)roken  up.  In  the  presence  of 
lactic  acid  in  small  amounts,  due  to  the  breaking  up  of  lactose,  coagu- 
lation is  hastened  by  the  application  of  gentle  heat.     This  phenomenon 


MILK.  85 

is  observed  very  commonly  in  the  case  of  milk  which  to  the  taste  is 
apparently  sweet,  but  which  is  ''just  on  the  turn," 

The  chief  part  of  the  remainder  of  the  proteids  is  lactalbumin.  This 
is  coagulated  by  heating  to  65°-73°  C,  but  not  by  dilute  acids.  It 
contains  sulphur,  but  no  phosphorus.  In  amount  it  ranges  from  0.2 
to  0.8  per  cent.  It  is  much  more  abundant  in  colostrum.  The  re- 
maining proteids  are  lactoglobulin,  which  is  coagulated  by  heat ;  lacto- 
protein,  coagulable  by  neither  heat  nor  dilute  acids,  and  fibrin.  Each 
exists  in  but  very  small  amounts. 

Mineral  Matter. — The  mineral  matter  contained  in  milk  consists  of 
phosphates  and  chlorides  of  potassium,  sodium,  calcium,  and  magnesium, 
and  extremely  minute  traces  of  iron.  Of  the  bases,  potassium  is  the 
most  abundant,  with  calcium,  sodium,  and  magnesium  in  the  order- 
given.  The  phosphates  predominate  over  the  chlorides.  Part  of  the- 
calcium  exists  in  combination  as  phosphate  with  the  casein,  and  the- 
rest,  according  to  Danilewsky,^  as  mono-  and  tricalcium  phosphate  and 
in  combination  with  citric  acid.  Part  of  the  magnesium,  also,  exists  in 
combination  with  citric  and  other  organic  acids.  In  very  small 
amounts,  these  are  normal  constituents  of  milk  of  various  animals.  In: 
human  milk,  citric  acid  is  present  to  the  extent  of  about  0.05  per  cent.,, 
and  in  cows'  milk,  it  is  about  three  times  as  abundant. 

Specific  Gravity. — The  specific  gravity  of  cows'  milk  of  normal  com- 
position ranges  from  1.029  to  1.034.  It  increases  very  slightly  for 
about  five  hours  after  the  milk  is  drawn,  and  then  becomes  stationary. 
The  increase  is  believed  to  be  due  to  molecular  modification  of  the 
casein,  and  not  to  the  escape  of  gases.  It  is  lowered  by  fat  and  water, 
and  by  the  presence  of  bubbles  of  air,  and  is  raised  by  removal  of  cream. 

Reaction. — When  freshly  drawn,  milk  shows  the  so-called  amphoteric 
reaction ;  that  is,  it  is  acid  to  litmus  and  alkaline  to  turmeric.  The 
alkaline  reaction  is  intensified  on  warming,  but  the  acid  reaction  is  not 
influenced  thereby.  On  standing,  the  alkaline  reaction  is  overcome 
by  the  lactic  acid  which  is  formed  gradually  from  the  sugar,  and  the 
acid  reaction  is  increased  in  consequence  of  the  same.  The  original 
acid  reaction  is  due  to  the  presence  of  phosphates,  the  alkaline  to  alka- 
line carbonates.  Human  milk  is  normally  alkaline,  and  that  of  car- 
nivora  is  acid. 

Appearance. — The  appearance  of  normal  milk  is  too  familiar  to  need 
description  ;  but  under  certain  rare  abnormal  conditions,  milk  may 
assume  different  colors,  including  blue,  yellow,  violet,  and  red.  These 
changes  of  color  are  due  to  the  action  of  certain  bacteria,  and  are  always 
evidence  of  unsanitary  conditions  to  which  the  milk  is  exposed  at  the 
dairy  or  during  distribution  and  storage. 

Blu(j  milk  is  due  to  the  action  of  B.  cyanogenes,  which  produces  a 
blue  color  in  no  other  food  material.  For  its  development  it  requires 
the  presence  of  lactic  ferments,  and,  therefore,  has  no  effect  on  milk 
that  is  sterile.  Another  organism  capable  of  producing  the  same  effect 
is  Jj.  cyaneofluoreaoanH. 

'  Wratsch,  VM)\,  p.  549. 


S6  FOODS. 

A  red  color  may  be  caused  by  B.  prodigiosus  or  B.  lactis  erythro- 
^enes,  sometimes  by  blood,  and,  it  is  said,  by  madder  and  other  red 
coloring-matter  in  the  feed.  Yellow  is  caused  by  B.  synxanthus,  and 
Adolet  by  B.  violaceus. 

All  of  these  abnormal  milks  are,  aside  from  their  uninviting  appear- 
ance, unfit  for  food,  since  they  are  likely  to  cause  gastro-intestinal  irri- 
tation. Thus  Eichert  ^  records  a  case  of  severe  diarrhoea,  with  very 
offensive  stools,  in  a  child  of  nine  months,  which  was  due  to  red  milk 
caused  by  a  bacillus  (probably  B.  lactis  erythrogenes)  present  in  the  milk 
^ucts  at  the  time  of  milking. 

Another  abnormal  condition  caused  by  a  large  variety  of  organisms 
is  characterized  by  alteration  of  the  natural  consistence  to  one  of 
sliminess,  which  appears  only  some  hours  after  the  milk  is  drawn. 
Slimy  or  "ropy"  milk  throws  up  no  cream,  and  cannot  be  churned, 
but  altliough  it  is  most  repugnant  to  the  senses,  it  causes  no  digestive 
<listurbances  if  ingested.  In  three  specimens  of  ropy  milk  from  as 
many  different  creameries  in  the  State  of  New  York,  Ward"  found  the 
change  due  to  B.  lactis  viscosus  (Adametz). 

Taste. — The  flavor  of  milk  is  modified  very  sensibly  by  the  char- 
acter of  the  feed  and  by  the  absorption  of  gases  and  volatile  matters  of 
all  kinds.  It  is  affected  very  readily  by  turnips,  garlic,  wild  onion, 
mouldy  hay  and  grain,  distillery  swill,  and  damaged,  rotten  ensilage. 

Bitterness  of  taste  may  be  due  either  to  some  constituent  of  the  feed 
or  to  bacteria.  AYhen  due  to  feed,  the  taste  is  bitter  from  the  very 
ffrst,  but  Avhen  caused  by  bacterial  agency  it  develops  some  time  after 
milking,  when  the  organisms  which  produce  it  have  had  the  opportu- 
nitv  to  act  upon  the  proteids  or  whatever  constituent  may  be  concerned. 
It  'mav  be  due  also  to  inflammatory  conditions  of  the  udder,  in  which 
case  it  mav  or  may  not  be  noticeable  when  the  milk  is  freshly  drawn. 
The  bacteria  concerned  in  producing  bitterness  may  exist  in  the  ducts 
of  the  teats,  or  may  come  from  stable  filth.  Damman^  mentions  a 
case  in  which  the  persistently  bitter  taste  disappeared  after  the  floor 
of  the  stable  was  cleaned  and  disinfected,  and  the  ducts  of  the  teats 
syringed  out  with  disinfectant  solution.  Strong-smelling  disinfectants 
may  not  be  used  in  dairies  because  of  the  readiness  with  which  milk 
absorbs  odors.  This  absorptive  capacity  is  so  well  recognized  that  milk 
is  stored  commonly  in  separate  compartments  of  refrigerators,  away 
from  foods  which  evolve  distinct  odors. 

Presence  of  Alcohol. — Distilleiy  swill  not  only  causes  a  decidedly 
had  flavor,  but  may,  in  addition,  and  contrary  to  a  generally  accepted 
idea,  cause  an  alcoholic  milk.  Thus,  according  to  H.  W.  Weller,*  a 
sample  of  milk  derived  from  cows  fed  on  distillery  refuse  containing 
5.90  per  cent  of  alcohol  yielded  in  addition  to  a  high  proportion  of 
milk  solids,  0.96  per  cent,  by  weight  of  alcohol.     The  milk  was  com- 

'  Zeitschrift  fiir  Fleisch-  und  Milchhjgiene  VIII.,  No.  5. 

»  Science,  1901,  No.  322,  p.  .324. 

'  Deutsche  thieriirztliche  Wochenschrift,  1897,  No.  1. 

*  Foi-schungsberichte  iiber  Lebensmittel,  etc.,  1897,  p.  206. 


MILK.  87 

plained  of  on  account  of  an  unpleasant  after-taste.  Teichert^  records 
a  case  in  which  calves  and  lambs  failed  to  thrive,  and  many  died  from 
a  form  of  diarrhoea.  The  mothers  were  fed  on  distillery  waste,  and 
yielded  milk  containing  alcohol.  That  alcohol  or  something  connected 
therewith  may  be  eliminated  in  milk,  is  shown  by  numerous  cases, 
among  which  are  the  following:  Vallin^  records  that  a  nursing  infant 
Avas  seized  with  convulsions  with  great  regularity  on  Mondays  and 
Thursdays,  but  was  quite  well  on  other  days.  Investigation  showed 
that  the  wet-nurse  on  Sundays  and  AYednesdays,  her  "days  out,"  was 
in  the  habit  of  drinking  freely  of  alcoholics.  The  curtailment  of  the 
privilege  was  followed  by  disapjjearance  of  the  difficulty.  Farez^  cites 
2  cases  which  show  the  bad  influence  of  alcohol  on  nursmg  children. 
In  one,  the  wet-nurse  drank  wine  at  meals,  and  especially  in  the  even- 
ing, and  the  child  never  ceased  fretting,  crjang,  and  screaming  from  9 
o'clock  until  11.  The  nurse  complained  bitterly  of  the  naughtiness  of 
the  child,  and  was  grieved  at  the  suggestion  that  she  was  herself  at 
fault  through  drinking  too  much,  but  she  was  induced  to  abstaui  from 
alcohol  entirely,  and  from  that  time  there  was  no  further  trouble.  In 
the  other  case,  the  mother  drank  tea  at  noon  and  wine  at  dinner,  and 
the  child  was  quiet  during  the  afternoon,  but  screamed  and  fretted  all 
the  evening;  and  until  midnig-ht.  A  change  to  wine  at  noon  and  tea 
at  dinner  produced  a  corresponding  change  in  the  behavior  of  the 
child,  the  turbulent  period  occurring  in  the  afternoon.  AVhen  the 
mother  eliminated  wine  from  her  dietary  entirely,  the  trouble  ceased. 

Colostrum. — The  milk  secreted  before  and  in  the  early  stage  of 
lactation  is  known  as  colostrum.  It  is  a  yellow,  somewhat  viscid  fluid 
of  strong  odor  and  acid  reaction.  In  composition,  it  diifers  very  ma- 
terially from  milk,  particularly  in  its  percentage  of  proteids.  It  con- 
tains, sometimes,  so  large  a  percentage  of  lactalbumin  and  lactoglobulin 
that  it  is  coagulated  by  boiling.  Its  content  of  casein  is  al:)out  normal, 
but  it  is  not  coagulated  by  rennet,  or  at  most  imperfectly.  In  the  early 
stages,  its  sugar  is  dextrose  and  not  lactose.  According  to  Tiemann,* 
it  ranges  in  specific  gravity  from  1.0299  to  1.0594,  in  fat  from  0.56 
to  9.28,  in  proteids  from  4.66  to  21.78,  in  ash  from  0.82  to  1.25,  and 
in  total  solids  from  12.93  to  32.93.  Under  the  microscope,  it  shows 
large  corpuscles,  known  as  colostrum  corpuscles,  which  disappear  within 
two  weeks  at  most  after  the  time  of  calving. 

Changes  Produced  in  Milk  by  Boiling. — Boiling  causes  greater 
coalescence  of  the  fat  glol^ules,  changes  in  the  character  of  the  sugar, 
coagulation  of  lactalbumin,  and  destruction  of  micro-organisms  and 
ferments.  Boiled  milk,  therefore,  will  keep  better  than  raw  milk.  The 
scum  which  forms  on  the  surface  is  largely  fat,  casein,  and  lactalbu- 
min, and  occurs  in  consequence  of  rapid  evaporation  at  that  point. 
Boiled  milk  is  digested  slightly  less  readily  than  raw  milk,  and  sour 

1  Milcli  Zeitiin^r  1901,  p.  148. 

'•'Revue  (ITIyKiene,  181)(i,  p.  '.153. 

^  Tribune  inedicule,  .June  20,  1900,  )).  488. 

*ZeitHclirift  fur  pliysiologisclie  Cheniie,  1898,  p.  363. 


88  FOODS. 

milk  is  digested  more  readily  than  either  ;  but  boiled  milk,  as  will  be 
noted  later  (see  page  92),  is  not  always  a  desirable  food  for  young 
infants,  on  account  of  its  changed  character.  The  question  whether  or 
not  a  given  milk  has  been  boiled  may  readily  be  determined  by  the 
application  of  simple  tests  (see  Analysis  of  Milk). 

Changes  Due  to  Bacterial  Action. — At  ordinary  temperatures, 
milk  soon  begins  to  midergo  changes  initiated  and  carried  along  by 
various  species  of  micro-organisms  which  exist  in  the  ducts  of  the  teats 
or  fall  into  the  pail  from  the  external  surface  of  the  udder  or  surround- 
ing parts,  or  from  the  air,  or  from  the  hands  and  clothes  of  the  milker, 
or  which  are  already  present  in  the  pail  or  other  vessel  into  which  the 
milk  is  received.  The  most  common  change  is  brought  about  by  the 
lactic  ferments,  of  which  more  than  a  hundred  species  have  already 
been  identified.  They  attack  the  milk-sugar  aud  cause  the  formation 
of  lactic  acid,  which,  on  accumulating  in  sufficient  amount,  causes  the 
milk  to  curdle.  Their  multiplication  proceeds  most  rapidly  at  tem- 
peratures ranging  from  25°  to  30°  C.  Therefore,  in  order  to  inhibit 
their  action  as  far  as  possible,  milk  should  be  cooled  without  delay  and 
kept  in  storage  at  low  temperature.  In  addition  to  the  lactic  ferments, 
there  are  others  which  are  known  as  casein  ferments.  These  produce 
a  substance  much  like  rennet  in  its  action.  They  may  act  in  the  ab- 
sence of  the  lactic  ferments,  and  then  their  action  is  accompanied  by 
the  development  of  alkalinity. 

Under  certain  conditions,  in  addition  to  changes  in  taste,  color,  and 
consistency  already  noted,  intensely  poisonous  benzene  derivatives  are 
formed,  the  most  important  of  which,  diazobenzene,  called  by  its  dis- 
coverer. Professor  V.  C  Vaughan,  tyrotoxicon,  is  the  exciting  cause 
of  the  train  of  symptoms  commonly  known  as  milk  poisoning,  cheese 
poisoning,  and  ice-cream  poisoning. 

A  number  of  other  organisms  constitute  the  group  of  so-called  butyric 
ferments,  many  of  which  are  of  the  class  of  casein  ferments.  They 
cause  the  production  of  butyric  acid  in  the  decomposition  of  proteids. 

In  consequence  of  the  action  of  the  various  species  of  organisms,  it 
is  important  that  bacteria  in  general  should  be  excluded  as  completely 
as  possible  from  milk  by  the  observance  of  the  utmost  cleanliness  in 
milking,  handling,  and  storing.  The  milk  of  cows  stalled  in  badly 
ventilated,  imclean  stables,  and  of  cows  with  unclean  udders,  M'ill  decora- 
pose  much  more  rapidly  than  that  of  cows  kept  under  better  sanitary 
conditions.  Even  when  the  cow  and  her  surroundings  are  kept  in  a 
cleanly  state,  the  very  first  part  of  a  milking  should  be  rejected,  on 
account  of  the  very  large  munbers  of  bacteria  present  in  the  ducts  of 
the  teats.  Under  even  the  best  of  conditions,  many  bacteria  are  present 
in  freshly  drawn  milk,  and  these  increase  rapidly  in  number  unless 
killed  by  the  action  of  heat  or  other  germicides.  Indeed,  it  has  been 
found  impossible  in  the  majority  of  experiments  to  obtain  sterile  milk 
even  when  the  greatest  precautions  have  been  observed  to  exclude 
extraneous  organisms. 

The  first  part  of  a  milking  is  richest  in  bacteria,  because  those  which 


MILK.  89 

have  multiplied  within  the  ducts  of  the  teats  since  the  previous  milking 
are  expelled  mostly  with  the  fore-milk,  but  even  the  very  last  portions 
of  the  strippings  may  contain  as  many  as  500  bacteria  per  cc.  Thus, 
Schultz^  found  in  the  first  portions  of  cows'  milk  97,240  per  cc,  in 
the  strippings  500,  and  in  goats'  milk  78,718  and  665.  For  the  attain- 
ment of  the  best  results  as  to  keeping  qualities,  all  dirt  should  be 
brushed  from  the  cow  before  milking,  and  the  udder  and  flank  should 
be  dampened,  in  order  that  dust,  fine  dirt,  and  bacteria  may  be  retained 
m  situ,  and  not  fall  into  the  milk-pail,  which  should  always  be  perfectly 
clean  before  use. 

The  difference  in  the  number  of  bacteria  which  fall  into  milk  when 
proper  precautions  are  observed  and  when  they  are  neglected  is  very 
considerable.  Thus,  Soxhlet  found  that  the  milk  of  a  cow  with  a  dirty 
udder,  stalled  in  a  dirty  stable,  kept  sweet  50  hours  at  ordinary  tem- 
perature, and  that,  when  her  udder  was  washed  and  she  was  milked  in 
the  open  air,  it  remained  sweet  a  day  and  a  half  longer.  Still  more 
instructive  are  the  results  obtained  by  Freeman,^  who  exposed  plates, 
3.5  inches  in  diameter,  for  two  minutes  as  follows  :  one  in  the  open 
air,  one  inside  a  barn,  and  a  third  in  front  of  the  milk  pail  under  a 
cow  in  the  same  barn  while  being  milked.  The  first  plate  showed  6, 
the  second  111,  and  the  third  1,800  colonies.  Such  a  number  of  bac- 
teria, falling  upon  so  small  a  surface  within  so  short  a  time,  is  an 
index  of  the  enormous  number  which  may  fall  into  a  pail  during 
the  time  required  for  a  complete  milking. 

The  enormous  number  of  bacteria  which  may  be  commonly  present 
in  ordinary  market  milk,  the  great  influence  thereon  of  non-observance 
of  the  strictest  cleanliness,  and  the  extreme  rapidity  of  multiplication 
under  favoring  conditions,  are  shown  in  most  striking  manner  by 
W.  H.  Park,'^  who  exposes  the  inexcusable  lack  of  cleanliness  in  the 
methods  of  procuring  milk,  and  of  care  in  cooling,  and  in  keeping  it 
during  transportation  to  the  city.  Milk  from  individual  cows,  where 
every  reasonable  means  was  taken  to  insure  cleanliness,  yielded  an  aver- 
age of  6,000  bacteria  per  cc.  when  5  hours  old,  and  kept  at  45°  F.,  to 
which  temperature  it  was  cooled  soon  after  it  was  drawn.  After  24 
hours,  the  average  number  fell  to  1,933 ;  after  48,  it  increased  to  17,816. 
Milk  taken  in  winter  in  well-ventilated,  fairly  clean,  but  dusty,  barns, 
and  cooled  within  2  hours  to  45°  F.,  the  visible  dirt  having  been 
cleaned  off  the  hair  about  the  udder,  the  milkers'  hands  wiped  off,  but 
not  washed,  the  pails  and  cans  clean,  but  the  straining  cloths  dusty, 
yielded  the  following  average  figures:  At  time  of  milking,  15,500; 
after  24  hours,  21,666;  after  48  hours,  76,000.  Milk  taken  from 
cows  kept  in  ordinary  barns,  the  conditions  as  to  cleanliness  of  sur- 
roundings and  method  of  milking  being  about  what  obtain  on  the  aver- 
age farm,  yielded  the  following  average  figures : 

'  Arfhiv  fiir  HvKiene,  XIV.,  p.  2fi0. 
2  Medical  KecoVd,  March  8,  18%. 
^Journal  of  Hygiene,  July,  1901,  p.  391. 


90  FOODS. 

Winter.  Summer. 

Shortly  after  milking 16,650  30,366 

After  24  hours 31,000  48,000 

After  48  hours 210,000  680,000 

Twenty  samples  of  average  milk  taken  immediately  on  arrival  in 
the  city,  much  of  it  having  been  transported  more  than  200  miles, 
yieldecl  from  52,000  to  35,200,000  bacteria  per  cc.  (average,  5,669,- 
850).  The  average  temperature  of  the  samples  when  taken  from  the 
cans  w^as  45°  F.  Milk  as  sold  in  the  shops  dnring  the  morning  hours 
yielded  the  following  averages : 

From  tenement  districts,  mid-winter  (13  samples)  ....     1,977,692 
From  well-to-do         "  "  (10        "       j.    .    .    .       327,500 

From  tenement         "         September  (5        "       )  .    .    .    .  15,163,600 
From  well-to-do         "  "  (  5        "       )  .    .    .    .    1,061,400 

Concerning  the  influence  of  temperature  upon  the  rapidity  of  bacte- 
rial multiplication  in  milk,  it  is  noted  that  milk  which  is  rapidly  and 
sufficiently  cooled  keeps  almost  unaltered  for  36  hours,  w^hile  if  insuffi- 
ciently cooled,  it  deteriorates  rapidly.  The  majority  of  milk  bacteria 
grow  best  at  temperatures  above  70°  F.,  but  two-thirds  of  the  species 
isolated  will  develop  good  groAvth  at  39°  F,  at  the  end  of  7  days. 
They  increase  slowly  after  the  germicidal  properties  of  the  milk  have 
disappeared,  and  when  the  organisms  have  become  accustomed  to  the 
low  temperatures. 

The  influence  of  different  temperatures  on  the  rapidity  of  bacterial 
multiplication  is  well  shoA\'n  by  the  results  obtained  on  allowing  por- 
tions of  the  same  specimen  to  stand  under  otherwise  similar  conditions. 
At  temperatures  below  50°  F.,  there  was  at  the  end  of  24  hours  no  in- 
crease— in  fact,  a  decrease — in  the  number  of  bacteria  ;  but  at  higher 
temperatures,  the  multiplication  was  enormous.  The  original  number 
per  cc.  was  3000,  and  the  growi:hs  at  the  several  temperatures  above 
55°  F.  Avere  as  follows  at  the  end  of  24  and  48  hours: 


Temperature. 

24  hours. 

48  hours. 

60°  F., 

180,000 

28,000,000 

68° 

450,000 

25,000,000,000 

86° 

1,400,000,000 

94° 

25,000,000,000 

Milk  of  fair  quality  from  a  shop  was  kept  at  90°  F.  for  8  hours, 
during  which  time  its  contained  bacteria  increased  from  92,000  to 
6,800,000  per  cc. ;  another,  of  poor  quality,  under  the  same  conditions, 
showed  an  increase  from  2,600,000  to  124,000,000. 

Such  growths  of  bacteria  in  milk  intended  for  human  use  can  in  no 
way  improve  the  milk,  but  must  seriously  affect  its  wholesomeness. 
To  avoid  them,  the  means  are  simple :  cleanliness  everywhere  and  Ioav 
temperatures ;  cleanliness  of  the  cows'  exterior,  of  the  stable,  of  the 
milkers  and  their  clothing,  of  all  vessels  employed — milk  pails,  pans, 
bottles,  etc. — and  of  the  places  where  the  milk  is  stored. 


MILK.  01 

Preservation  of  Milk. — The  keeping  quality  of  milk  is  influenced 
by  cold,  which  retards  the  growth  and  multiplication  of  bacteria  which 
bring  about  decomposition  ;  by  heat,  which  destroys  them  ;  and  by  pre- 
servatives, which  either  kill  them  or  retard  their  growth.  Preservation 
by  cold  is  in  many  respects  preferable  to  either  of  the  other  methods. 
The  constituents  are  in  no  way  altered  in  character,  there  is  no  change 
in  digestibility,  and  no  element  is  introduced  into  the  system  with  the 
milk  to  exert  any  harmful  influence  upon  the  digestive  processes.  In 
places  where  ice  is  expensive  or  not  obtainable,  this  method  is  not 
available,  but  where  it  is  cheap  and  plentiful,  it  is  the  one  in  most  com- 
mon use.  In  some  parts  of  Europe,  milk  is  frozen  into  solid  blocks  by 
the  ammonia  process,  and  shipped  in  that  form  to  market.  A  large 
part  of  the  milk  supply  of  Copenhagen  is  received  from  a  distance  in 
large  air-tight  cans,  into  each  of  which  a  block  of  frozen  milk,  weighing 
about  25  pounds,  is  placed,  to  keep  the  milk  in  which  it  floats  at  a  low 
temperature. 

Preservation  by  heat  includes  pasteurization  and  sterilization.  In 
pasteurization,  the  whole  bulk  of  the  milk  is  heated  to  not  over 
158°  F.,  maintained  at  that  temperature  for  10  or  15  minutes,  and 
then  cooled  rapidly  in  order  to  preserve  the  fresh  flavor  and  prevent  the 
multiplication  of  such  of  the  bacteria  as  survive.  The  length  of  time 
required  for  the  destruction  of  bacteria  varies  with  the  temperature 
employed.  Thus,  about  70  per  cent,  of  saprophytic  bacteria  are  killed 
in  an  hour  at  140°  F.,  in  15  minutes  at  150°,  in  10  minutes  at  158°, 
in  5  minutes  at  176°,  in  2  minutes  at  194°,  and  in  1  minute  at  203°. 
It  is  essential  that  all  apparatus  and  vessels  used  in  cooling  and  storing 
shall  be  clean  and  sterile.  This  process  is  quite  sufficient  for  all  prac- 
tical purposes  and  hygienic  requirements,  unless  the  milk  is  to  be  kept 
for  a  longer  time  than  usual,  in  which  case  it  should  be  repeated  at 
the  end  of  24  hours.  Temperatures  higher  than  158°  F.  cause  the 
milk  to  acquire  a  cooked  flavor,  which  to  many  persons  is  disagree- 
able. 

According  to  H.  Bitter,^  all  pathogenic  bacteria  in  milk  are  killed 
with  absolute  certainty  by  exposure  to  154.4°  F.  for  a  half  hour,  and 
the  milk  is  altered  thereby  in  neither  appearance  nor  taste.  Under 
ordinary  circumstances  20  minutes'  exposure  is  quite  sufficient.  Some 
authorities  assert  that  temperatures  of  140°  to  147°  F.  are  sufficiently 
high  for  the  purpose,  but  Professor  Theobald  Smith  ^  has  shown  that, 
while  tubercle  bacilli  are  destroyed  within  20  minutes  at  140°  F.,  the 
formation  of  a  surface  pellicle  into  which  they  are  carried  by  fat 
globules  shields  them  from  the  heat,  so  that  they  may  survive  an 
exposure  of  over  an  hour  to  149°  F.  It  is  asserted  by  Morgenroth  ^ 
that  at  least  30  minutes'  exposure  to  158°  F.  is  necessary  to  kill  all 
of  the  bacilli,  but  that  the  same  result  can  be  attained  at  a  much  lower 
temperature  (131°  F.)  in  3  hours'  heating  in  a  thermojjhore.      It  has 

1  Zeitschiift  fiir  Hygiene,  VIIL,  p.  240. 

^  .Joiirriiil  of  Kx|KTirriental  Medicine,  ]S99,  p.  217. 

•*  Ilygieni.sche  Rundschau,  Sept.  15,  1900,  p.  865. 


92  FOODS. 

been  asserted  also  by  M.  Beck  •  that  158°  F.,  and  even  176°  F.,  are 
not  sufficiently  bigh,  even  when  maintained  30  minutes,  for  the  destruc- 
tion of  all  the  tubercle  bacilli  in  milk  intentionally  infected.  He 
heated  such  milk  for  30  minutes  at  both  of  the  above  temperatures^ 
and  then  injected  it  into  15  guinea-pigs,  all  of  which  became  tubercu- 
lous after  5  to  8  weeks.  But  Levy  and  Bruns,^  after  experimenting 
with  milk  enclosed  in  flasks  placed  in  a  water-bath,  found  that,  so  far 
as  the  tubercle  bacillus  is  concerned,  milk  is  sterilized  after  15  to  25 
minutes'  exposure  to  149°-158°  F.  It  seems  probable,  on  the  whole, 
that  the  widely  divergent  results  of  various  experimenters  have  been 
due  to  diiFerences  in  manipulation  and  in  physical  conditions. 

All  the  lactic  ferments  are  destroyed  very  easily,  but  some  of  the 
casein  ferments  are  very  resistant,  and  their  spores  still  more  so,  and 
are  not  killed  by  boiling  for  a  number  of  hours  ;  and  it  is  to  the  pres- 
ence of  these  hardy  varieties  that  the  difficulty  of  complete  sterilization 
is  due. 

Sterilization  requires  continuous  heating  under  pressure  for  about 
two  hours  at  248°  F.,  at  which  temperature  not  alone  the  bacteria  and 
their  spores  are  destroyed,  but  the  normal  appearance  and  taste  of  the 
milk  as  well.  Part  of  the  sugar  is  converted  to  caramel,  part  of  the 
casein  is  precipitated,  and  the  milk  will  no  longer  form  a  cohesive 
caagulum  with  rennet. 

In  the  opinion  of  many  practitioners,  neither  pasteurization  nor 
sterilization  is  free  from  objection  in  infant  feeding,  since  even  a  temper- 
ature of  155°  F.  influences  the  nutritive  value  injuriously.  Many 
cases  of  scorbutus  and  dyspepsia  in  infants  have  been  attributed  to  the 
use  of  sterilized  milk,  and  it  seems  probable  that  the  trouble  is  con- 
nected with  the  destruction  of  the  zymases  normally  present.  These 
ferments,  the  presence  of  which  was  announced  in  1900  by  Escherich^ 
have  been  studied  by  Spolverini,^  who  isolated  no  less  than  seven,  two 
of  which,  pepsinic  and  trypsinic,  are  present  always  in  both  human  and 
cows'  milk;  the  others,  araylolytic,  lipasic,  glycolytic,  etc.,  are  not 
constant.  All  are  soluble,  and  none  can  withstand  the  sterilizing 
temperature. 

To  avoid  the  untoward  results  of  the  use  of  sterilized  milk,  Free- 
man* proposes  that  the  cream  be  allowed  to  rise,  and  then  be  removed 
and  subjected  alone  to  sterilization,  after  which  it  may  be  mixed  in 
proper  proportion  with  the  skimmed  milk,  which  contains  only  a  very 
small  number  of  bacteria,  since  about  99  per  cent,  of  them  are  carried 
into  the  cream  layer  by  the  fat  globules. 

Preservation  of  milk  by  the  addition  of  antiseptics  is  unnecessary^ 
unjustifiable,  and  possibly  injurious.  If  milk  is  drawn  properly  from 
decently  clean  animals  into  clean  vessels  by  clean  milkers,  and  stored 
in  clean  places,  it  will  keep  sweet  quite  as  long,  under  ordinary  circum- 

^  Dentsche  Vierteljahrsschrift  fiir  offentliche  Gesundheitspflege,  XXXII.  p.  430. 
'^  Hygienische  Rundschau,  July  15,  1901,  p.  669. 
"Archives  de  Medecine  des  Enfants,  Dec,  1901. 
*  Archives  of  Pediatrics,  August,  1899. 


MILK.  93 

stances  and  under  the  usual  conditions  of  frequent  delivery,  as  is  desired 
by  the  consumer.  The  addition  of  antiseptics,  which  only  retard 
growth  of  bacteria  without  destroying  them,  enables  the  vendor  to 
supply  stale  milk  instead  of  fresh,  and  to  dispense  with  part  of  the 
sanitary  precautions  otherwise  necessary.  The  substances  used  are  by 
no  means  wholly  innocent  in  their  action  on  the  human  system,  even 
in  very  small  quantities  and,  moreover,  it  is  impossible  to  control  the 
amount  added  by  a  single  individual  or  to  be  sure  that  successive 
handlers  have  not  contributed  additional  doses.  The  substances  used 
as  milk  preservatives  are  boric  acid,  borax,  salicylic  acid,  formaldehyde, 
carbonate  of  sodium,  and  chromates. 

Boric  acid  and  borax  are  used  generally  in  combination  with  each 
other,  experience  having  shown  that  the  mixture  is  more  efficient  than 
either  alone.  The  minimum  efficient  quantity  of  the  mixture  is  about 
10  grains  to  the  quart,  an  amount  which  even  for  an  adult  may  well  be 
regarded  as  a  fairly  large  medicinal  dose.  In  addition  to  its  action  on 
the  general  system,  it  exerts  a  varying  effisct  on  the  digestion  according 
to  the  amount-  present.  According  to  Professor  R.  H.  Chittenden, 
borax  retards  the  amylolytic  action  of  saliva,  boric  acid  in  amounts  less 
than  1  per  cent,  favors  it,  and  both  increase  gastric  digestion  in  small 
amounts  and  retard  it  in  large. 

The  use  of  salicylic  acid  in  milk  is  not  extensive.  It  is  a  fairly 
efficient  preservative.  Formaldehyde  has  come  into  use  within  a  few 
years.  It  is  a  most  efficient  preservative,  and  not  alone  inhibits  growth 
but  also  kills  the  bacteria.  According  to  tests  made  by  Dr.  C.  P. 
Worcester,^  1  part  of  commercial  formalin  in  100,000  of  milk  will 
postpone  the  curdling-point  6  hours;  1  in  50,000,  24  hours;  1  in  20,- 
000,  48  hours;  1  in  10,000,  138  hours;  1  in  5,000,  156  hours.  Al- 
though nothing  is  known  as  to  the  action  of  small  amounts  of  for- 
maldehyde on  the  general  system,  it  is  not  correct  to  assume  that,  in 
the  absence  of  evidence  to  the  contrary,  it  is  necessarily  harmless  or 
beneficial.  While  the  occasional  ingestion  of  a  small  amount  of  for- 
maldehyde may  produce  no  effect,  we  cannot  reason  that  its  daily  use 
over  a  long  period  will  be  equally  non-productive.  An  occasional 
drink  of  water  containing  lead  will  do  no  injury,  while  its  daily  use 
may  cause  lead  paralysis,  and  in  the  same  way  formaldehyde  may  be 
the  cause  of  serious  disturbances  attributed  to  something  else.  But 
whether  harmful  or  not,  the  use  of  this  agent  and  of  others  is  unnec- 
essary and  unjustifiable.  Aside  from  its  possibly  poisonous  action, 
there  is  the  objection  that  it  alters  the  character  of  the  milk  proteids ; 
the  casein  })ecomes  uncoagulable  by  rennet,  except  in  thick  clots,  and 
much  less  digestible,  or  wholly  indigestible,  by  the  proteolytic  ferments. 
Certain  it  is  that  anything  that  imposes  additional  burdens  on  the 
digestive  function  of  infants  and  invalids  can  hardly  be  regarded  as  a 
proper  substance  for  use  in  fi>od.     Annet,^  after  a  study  of  formalde- 

>  Twenty-nintl]  AhiiikiI  li^iH^rt  of  tlie  Stale  Board  of  Health  of  Massachu.setts,  1897, 
p.  559. 

^Tlie  Lancet,  Nov.  ]],  ■].S99. 


94  FOODS. 

hjde  and  boric  acid  as  milk  preservatives,  (3oncludes  tlaat  they  are  in- 
jurious, especially  to  young  infants,  and  suggests  the  possibility  of  a 
causal  relation  between  their  use  and  the  great  infant  mortality  during 
the  hot  months. 

Carbonate  of  sodium  is  a  weak  agent,  and  does  not  postpone  decom- 
position to  an  extent  sufficient  to  encourage  its  wide  adoption.  So  far 
as  is  known,  there  can  be  no  objection  to  its  use  on  the  score  of  injury, 
except  in  so  far  as  the  assertion  tliat  sodium  lactate,  formed  by  its 
decomposition  by  the  free  lactic  acid,  acts  as  a  mild  cathartic,  is  worthy 
of  credence. 

The  chromates  are  not  extensively  employed,  but  have  been  found 
present  in  preservative  powders  used  in  France.  Deniges  ^  foimd  the 
normal  chromate  of  potassium  in  two  of  these  preparations,  and  the 
dichromate  and  chromate  together  in  a  third.  The  latter  was  recom- 
mended in  the  proportion  of  2  grams  to  50  liters  of  milk.  According 
to  Froidevaux,^  such  an  amount  of  potassium  dichromate  is  insuffi- 
cient to  retard  coagulation  and  imparts  an  abnormal  intense  yellow 
color  to  the  milk. 

The  further  discussion  of  the  subject  of  milk  preservatives  may 
be  looked  for  below,  under  the  general  subject  of  Food  Preserva- 
tives. 

Adulteration  of  Milk. — This  most  important  article  of  food  is 
more  subject  to  adulteration  than  any  other,  since  it  lends  itself  so 
readilv  to  fraudulent  manipulation.  The  principal  adulterations  are 
the  addition  of  w^ater  and  the  abstraction  of  cream.  The  former 
diminishes  the  nutritive  value,  and,  if  the  water  used  is  from  an 
tmclean  sotirce,  increases  the  possibility  of  disseminating  disease  ;  the 
latter  robs  the  milk  of  one  of  its  most  valuable  constituents.  The 
detection  of  these  adulterations  by  analysis  is  not  always  possible,  since 
a  rich  milk  may  be  slightly  watered  or  only  partially  skimmed  and  still 
show  average  quality.  Again,  even  though  the  watering  be  fairly 
extensive,  it  cannot  always  be  proved  that  the  milk  was  not  of  low 
grade  from  natural  causes,  since  some  cows  give  milk  which  on  analysis 
is  far  below  average  good  milk  and  bears  every  resemblance  to  watered 
milk.  Further,  a  milk  containing  very  little  fat  may  be  naturally 
poor  in  that  constituent  or  may  be  the  first  part  of  a  milking. 

In  consequence  of  the  difficulty  of  proving  the  addition  of  water  or 
abstraction  of  cream,  and  because  of  the  enormous  importance  of  secur- 
ing a  public  supply  of  at  least  average  good  quality,  most  States  have 
fixed  legal  standards,  to  which  milk  intended  for  sale  must  conform. 
The  standard  for  total  solids  is  commonly  13,  12.5,  or  12  per  cent.  ; 
and  for  fat,  3,  3.5,  3.7,  and  4  per  cent.  By  the  adoption  of  a  legal 
standard,  all  milk  of  low  grade,  whether  so  by  reason  of  fraudulent 
practices  or  be  use  of  poor  feed  or  individual  peculiarity  of  the  cow, 
must  be  treated  alike.  By  prohibiting  the  sale  of  all  milk  not  of  a 
Certain  grade,  it  becomes  unnecessary  to  prove  fraud  or  criminal  knowl- 

1  Kevue  International  des  Falsifications,  IX.,  p.  36. 
^  Journal  de  Pharmacie  et  de  Cheiuie,  1896,  p.  155. 


3IILK.  95 

edge,  the  allegation  of  inferior  quality  being  sustained  by  the  results 
of  the  analysis. 

Other  forms  of  adulteration  include  the  addition  of  coloring  matters 
for  the  purpose  of  concealing  watering  or  skimming,  or  to  give  a  creamy 
tint  to  a  very  white  milk,  and  the  addition  of  preservatives,  and,  occa- 
sionally, of  other  foreign  substances.  The  coloring  matters  commonly 
used  are,  annatto,  caramel,  and  combinations  of  aniline  dyes.  Their 
detection  is  by  no  means  difficult  (see  Analysis  of  Milk). 

It  is  a  common  belief,  even  among  people  of  more  than  average 
intelligence,  that  milk  as  found  in  the  market  is  very  largely  a  mixture 
of  chalk  and  water.  Upon  what  this  absurd  tradition  is  based,  it  is 
difficult  to  surmise,  since  even  though  a  person  were  led  to  practise  such 
a  miserable  fraud,  he  would  discover  that  chalk  and  water  will  need 
constant  stirring  to  maintain  even  the  outward  semblance  of  milk,  and 
that  a  few  minutes'  standing  is  sufficient  for  complete  separation  into  a 
deposit  of  chalk  and  a  fairly  clear  supernatant  liquid.  A  less  common, 
but  equally  absurd,  notion  that  calves'  brains  are  a  common  adulterant 
of  milk,  arose  about  half  a  century  ago  from  the  report  of  a  microscopi- 
cal examination  of  a  milk  sediment  in  which  certain  particles  were 
detected  which  bore  a  resemblance  to  nerve  tissue.  Calves'  brains  do 
not  lend  themselves  readily  to  the  making  of  emulsions,  the  supply  is 
limited,  and  they  find  a  fairly  good  market  in  their  true  character. 

Cane  sugar  is  said  to  have  been  found  at  rare  intervals,  and  gelatin 
is  used  occasionally  as  a  thickening  for  cream.  Starch  is  believed  by 
many  to  be  a  common  adulterant,  but  it  is  used  very  rarely.  In  the 
course  of  many  years'  supervision  of  a  large  public  milk  supply,  during 
which  several  hundred  thousand  samples  of  milk  were  examined  for 
adulterants  of  all  sorts,  but  one  instance  of  the  use  of  starch  fell  under 
the  author's  notice.  This  was  due  to  a  shortage  in  the  normal  supply, 
which  led  a  dealer  to  dispense  a  mixture  of  water  and  condensed  milk, 
which  latter  component  had  been  thickened  with  starch. 

CONDENSED   MILK. 

Condensed  milk  is  prepared  by  evaporating  milk  to  about  a  third  or 
a  fourth  of  its  volume  in  vacuum  pans.  It  is  sold  in  bulk  for  immedi- 
ate use,  and  in  hermetically  sealed  tin  cans  for  use  as  occasion  demands. 
Most  of  that  sold  in  tins  is  made  from  skimmed  milk,  and  is,  therefore, 
very  deficient  in  fat ;  and  much  of  it  contains  a  large  proportion  of  cane 
sugar,  which  is  added  to  increase  its  keeping  qualities.  Condensed 
milk  is  in  many  respects  and  under  certain  conditions  a  valuable  food 
])reparation,  but  its  use  in  infant  feeding  when  other  milk  is  obtainable 
is  not  a  wise  one,  since  it  is  deficient  in  one  of  the  most  important  ele- 
ments, and  contains  another  which  is  not  a  normal  constituent. 

KOUMISS   AND   KEFIR. 

These  are  fermented  preparations  containing  lactic  and  carbonic  acids 
and  a  small  amount  of  alcohol.     They  are  produced  through  the  action 


96  FOODS. 

of  micro-orgauisms  v/hich  induce  fermentative  changes  and  bring  about 
a  partial  conversion  of  the  proteids  to  albumoses  and  peptones.  Both 
had  their  origin  in  Russia,  where  they  have  been  in  use  for  many 
years.  Koumiss  is  made  generally  from  the  milk  of  mares,  but  may  be 
made  from  that  of  cows  with  the  assistance  of  added  sugar.  Kefir  is 
made  more  commonly  from  the  milk  of  cows.  Both  are  effervescent 
liquids  having  somewhat  the  taste  of  butter-milk,  and  are  valuable  in 
the  feeding  of  the  sick  and  of  those  with  impaired  digestive  function. 
The  "  kefir  grains "  are  small,  hard,  granular  particles  which  contain 
the  requisite  organisms.  They  are  added  to  the  milk  after  being  soaked 
until  soft,  and  their  action  is  completed  in  two  or  three  days. 

CREAM. 

Cream,  as  already  stated,  may  be  defined  as  milk  containing  a  large 
excess  of  fat,  and  correspondingly  lacking  in  water.  The  degree  of  rich- 
ness is  dependent  upon  the  method  employed  in  its  separation  from  the 
original  volume  of  milk.  That  obtained  by  the  common  method  of 
skimming  contains  ordinarily  about  16  to  24  per  cent,  of  fat,  while  that 
se])arated  by  the  centrifugal  machine  contains  from  20  to  upward  of  50 
per  cent.,  according  as  the  machine  is  regulated  for  "  light "  or  "  heavy  " 
cream.  The  latter  is  so  thick  as  to  give  rise  to  a  common  notion  that 
corn  starch  is  used  as  an  adulterant.  This  substance,  however,  is  used 
rarely  if  ever  in  this  way.  Gelatin  is  employed  as  an  adulterant  to  a 
limited  extent.  A  preparation  largely  advertised  to  the  trade  at  one 
time  as  a  "  cream  thickener "  was  analyzed  by  the  author,  and  found 
to  be  a  mixture  of  gelatin,  borax,  and  boric  acid.  The  common  adul- 
terants of  cream  are  preservatives  and  coloring  agents.  The  former 
are  used  mostly  during  the  hot  months  ;  the  latter  during  the  winter, 
when,  on  account  of  the  difference  in  feed,  the  cream  has  not  the  char- 
acteristic yellow  tint  so  highly  prized. 

Milk  as  a  Factor  in  the  Spread  of  Disease. 

Milk  may  act  as  a  carrier  of  disease  or  cause  of  functional  disturb- 
ance through  infectious  or  poisonous  matters  originally  present,  or  re- 
ceived or  evolved  during  handling  and  distribution.  Thus,  milk  may 
be  poisonous  by  reason  of  matters  derived  from  the  feed  or  of  sub- 
stances formed  after  it  is  drawn  ;  it  may  contain  organisms  of  various 
kinds  connected  with  bovine  diseases ;  it  may  become  contaminated  in 
various  ways  with  matter  containing  the  exciting  cause  of  various 
human  diseases. 

Poisonous  Milk. — Cei-tain  plants  eaten  by  cows  may  cause  milk  to 
become  unfit  for  drinking  because  of  toxic  properties.  Poison  ivy 
(Mhus  toxicodendro7i),  for  example,  causes  in  cows  a  condition  known 
as  "trembles,"  during  the  continuance  of  which  their  milk  is  said  to 
cause  severe  gastric  symptoms  with  great  weakness.  The  most  promi- 
nent symptoms  are  pain,  nausea,  vomiting,  constipation,  and  subnormal 
temperature.      If  the  milk  be  boiled,  the  poisonous  properties  are  de- 


MILK  AS  A   FACTOR  IN  THE  SPREAD   OF  DISEASE.  97 

stroyecl.  Accordiiig  to  Dr.  D.  D.  Grout/  whatever  the  nature  of  the 
poison  in  milk  from  cows  afflicted  with  "  trembles,"  it  attacks  the  cen- 
tral nervous  system  and  produces  characteristic  trembling  and  profound 
loss  of  muscular  power.  He  believes  that  a  peculiar  microzyme  exists 
in  the  blood,  and  has  pathogenic  properties,  which  may  be  reproduced 
indefinitely  through  the  milk  and  through  butter  and  cheese  made 
therefrom. 

The  leaves  of  the  common  artichoke  are  said  '^  to  cause  abdominal 
pain,  vomiting,  and  diarrhoea. 

As  stated  on  a  preceding  page,  milk  may  undergo  a  peculiar  form 
of  decomposition  resulting  in  the  production  of  an  intensely  violent 
poison,  a  benzene  derivative,  known  as  tyrotoxicon.  Fortunately,  this 
is  an  uncommon  change,  but  it  betrays  to  the  consumer  no  sign  of  its 
occurrence  at  the  time  of  drinking.  The  effects  produced  are  various, 
and  are  well  illustrated  by  the  following  cases  : 

Case  I. — Reported  by  Dr.  W.  K.  JSiewton  and  Mr.  S.  Wallace.^ 
On  August  7,  1886,  24  guests  of  one  hotel  at  Long  Branch,  and  19 
of  another  hotel  at  the  same  place,  were  taken  sick  soon  after  supper 
with  the  same  train  of  symptoms,  which  were  nausea,  vomiting,  cramps, 
and  collapse,  dryness  of  the  throat,  and  burning  sensation  in  the  oesoph- 
agus ;  in  many  cases  there  was  absence  of  diarrhoea,  and  in  several 
there  was  active  diarrhoea  without  vomiting.  Many  had  violent  vom- 
iting followed  by  collapse.  As  a  rule,  the  nausea  and  vomiting  were 
persistent  and  obstinate,  and  accompanied  by  a  tendency  to  exhaustion 
and  collapse.  A  w^eek  later,  30  guests  of  still  another  hotel  were 
seized  in  precisely  the  same  manner.  The  onset  occurred  in  from 
one  to  four  hours  after  eating,  but  in  one  instance  the  symptoms 
appeared  almost  immediately  after  drinking  about  a  quart  of  milk. 
Investigation  showed  that  the  trouble  was  due  wholly  to  milk,  for  only 
the  milk-drinkers  were  seized,  and  those  who  had  had  no  other  food 
were  the  worst  sufferers.  The  three  hotels  were  served  by  one  dealer, 
who  made  two  deliveries  daily.  The  milk  of  the  second  delivery  was 
the  cause  of  the  mischief  in  each  outbreak.  It  was  drawn  at  noon,  and, 
without  being  cooled  at  all,  Avas  carted  eight  miles  in  the  heat  of  the 
day.  The  cows  were  healthy  and  well  fed.  In  a  portion  of  the  milk 
that  caused  the  third  group  of  cases,  the  presence  of  tyrotoxicon  was 
demonstrated. 

Case  II. — This  was  a  most  extraordinary  outbreak,  limited  to  a 
flimily  consisting  of  father,  mother,  son,  and  daughter,  of  whom  all 
but  the  first  mentioned  died.  The  family  physician  called  Professor 
V.  C.  Vaughan  in  consultation  after  the  fourth  member  of  the  family 
was  seized,  and  from  his  report  of  the  case  the  following  facts  are 
taken.  The  first  one  seized  was  the  father,  a  man  of  fifty  years.  When 
first  seen,  he  was  vomiting  severely,  his  fiice  was  flushed,  and  his  tem- 
perature was  suljnormal  (96°  F.).    There  was  marked  throbbing  of  the 

'  Qiintwl  ill  American  Medicine,  Aug.  31,  11)01. 

2  Miifiizeitnng,  1891,  j).  40. 

•■'  Medical  NewH,  .September  25,  1886,  p.  343. 


98  FOODS. 

abdominal  aorta,  the  tongue  was  heavily  coated,  and  the  breathing  wa* 
very  labored.  The  pupils  were  dilated,  and  much  of  the  body  was  cov- 
ered with  a  rash.  The  vomiting  continued  some  hours,  the  vomitus  being- 
colored  with  bile.  The  bowels  had  not  moved,  but  under  the  influence 
of  a  cathartic,  a  stool  occurred  on  the  following  day.  Retching  and 
vomiting  continued  during  that  day  and  night,  and  there  was  persistent 
stupor.  During  the  following  three  days,  there  was  but  little  change. 
Then  improvement  began,  but  recovery  required  a  month.  The  son,  a 
strong  youth  of  eighteen,  was  the  next  to  be  seized,  four  days  after  the 
beginning  of  his  father's  sickness.  The  symptoms  were  similar,  but 
were  more  violent,  and  there  was  no  rash.  On  the  following  evening, 
the  mother,  about  forty-five,  was  seized  in  the  same  way,  and  on  the 
succeeding  evening,  the  daughter  also.  On  the  day  following  the  last 
seizure,  none  of  the  cases  showed  improvement.  The  temperatures 
were  subnormal,  94°  and  95°  F.  All  complained  of  a  burning  con- 
striction in  the  throat  and  difficult  swallowing,  and  called  frequently 
for  ice.  Two  days  later,  the  mother  and  son  died ;  the  daughter  grew 
worse,  became  unconscious,  remained  so  three  days,  and  then  died. 

Post-mortem  examination  in  the  case  of  the  daughter  revealed  no 
characteristic  lesions  to  account  for  death.  The  outbreak  was  most 
carefully  and  thoroughly  investigated  from  every  standpoint,  and  the 
conclusion  reached  was  that  tyrotoxicon  was  the  cause.  The  milk 
had  been  kept  in  a  buttery  which  was  in  a  most  unsanitary  condition. 
During  three  years,  the  family  had  suffered  frequent  attacks  of  like 
character,  but  they  were  much  less  severe.  Fresh  milk,  placed  in  the 
butteiy  over  night,  and  then  examined  for  tyrotoxicon,  gave  unmis- 
takable chemical  and  physiological  evidence  of  that  poison.  Fresh 
milk  inoculated  with  dirt  from  the  buttery  floor  also  developed  it,  as 
did  also  other  portions  treated  with  vomitus,  stomach  contents,  and 
aqueous  extract  of  the  intestines,  while  a  fifth  specimen  untreated 
remained  free  from  it.  All  the  evidence  in  this  case  pointed  to  the 
more  or  less  constant  presence  of  poison  in  the  milk,  and  the  wide 
variation  in  the  time  of  seizure  in  the  final  outbreak  indicates  that 
all  w^ere  not  affected  by  the  same  day's  supply. 

Milk  from  Diseased  Cows. — The  milk  of  cows  suffering  from  the 
prominent  cattle  plagues  is  more  or  less  altered  in  composition,  and 
there  appears  to  be  evidence  that  it  may  be  actually  dangerous. 

In  rinderpest,  the  proteids  are  much  increased — in  fact,  more  than 
doubled  ;  the  mineral  constituents  are  considerably  increased,  and  the  fat 
and  sugar  are  diminished. 

In  foot  and  mouth _  disease,  the  total  solids  are  increased  considerably, 
or  diminished  at  different  stages,  and  the  milk  will  sometimes  coagulate 
on  boiling,  by  reason  of  the  excessive  amount  of  coagulable  ])roteids. 
There  is  reason  to  believe  that  this  disease  may  be  communicated  to 
other  animals  through  the  milk,  and  there  is  evidence  that  the  use  of 
the  milk  by  man  will  produce  local  lesions  in  the  mouth  and  throat. 
Thus,  Notter  and  Firth  ^  mention  an  epidemic  of  sore  throat  at  Dover,, 
1  The  Theory  and  Practice  of  Hygiene :  London,  1896,  p.  305. 


MILK  AS  A   FACTOR  IN  THE  SPREAD   OF  DISEASE.  99 

in  1884,  in  which  there  were  205  cases  of  vesicular  eruption  in  the 
throat  or  on  the  lips,  enlarged  tonsils,  and  in  most  cases  enlarged  glands 
of  the  neck,  all  occurring  within  a  week  in  persons  supplied  by  a  single 
dairy  where  the  disease  existed.  It  is  asserted  by  Pott^  that  such  milk 
in  the  raw  state  may  induce  a  similar  affection  in  man,  and  especially 
in  children. 

In  anthrax,  the  milk  has  an  abnormal  appearance  and  decomposes 
rapidly.  The  specific  organism  has  been  isolated  in  active  condition  by 
Boschetti  ^  from  milk  as  late  as  fourteen  days  after  it  had  been  drawn. 

In  actinomycods,  particularly  if  the  udder  is  involved,  the  milk 
should  be  avoided,  although  there  appears  to  be  little  direct  evidence 
bearing  upon  transmission  of  the  disease  to  man  by  this  means.  It 
is  certain,  however,  that  the  disease  does  occur  sometimes  in  man,  and 
though  in  the  matter  of  transmission  of  disease  from  animals  to  man 
nothing  should  be  taken  for  granted,  it  is  commendable  in  such  cases 
of  lack  of  positive  knowledge  to  err  on  the  side  of  safety,  and  to  avoid 
and  prohibit  the  use  of  such  milk. 

The  milk  of  cows  afflicted  with  garget,  an  inflammatory  condition 
of  the  milk  ducts,  is  believed  to  have  caused  epidemics  of  gastro-intes- 
tinal  irritation,  and  there  is  reason  to  believe  that  it  may  be  a  common 
cause  of  cholera  infantum.  In  an  investigation  instituted  to  deter- 
mine the  cause  of  diarrhoea  among  the  consumers  of  milk  of  a  certain 
dairy,  Lameris  and  Van  Harrevelt  ^  discovered  the  presence  of  strepto- 
cocci in  great  numbers  in  the  udder  of  a  cow  which  recently  had  recov- 
ered from  an  attack  of  garget.  AVhether  in  this  particular  instance 
these  micro-organisms  were  the  cause  of  the  disturbance  among  the 
consumers,  cannot  definitely  be  asserted,  but  according  to  the  researches 
of  Escherich,  Adametz,  and  others,  the  severe  diarrhoeas  of  infancy  are 
due  largely  to  the  presence  of  Streptococcus  pyogenes.  This  and  other 
pathogenic  organisms  appear  to  be  exceedingly  common  in  ordinary 
market  milk,  and  in  the  milk  of  cows  with  no  apparent  local  disease. 
Thus,  Eastes*  discovered  streptococci  in  106  of  186  samples  examined ; 
Beck,^  in  35  of  56  samples  of  the  Berlin  supply  ;  Bergey,®  in  20  of  40 
samples  of  market  milk,  and  in  3  of  59  samples  from  first-class  dairies. 
Reed  and  Ward''  have  recorded  the  case  of  a  cow,  one  of  the  Cornell 
University  herd,  apparently  healthy,  whose  milk  yielded  streptococci 
at  intervals  extending  over  two  years  and  a  half.  When  the  animal 
was  killed,  the  udder  was  examined,  and  showed  an  abundance  of  the 
organisms.  From  the  secretions  of  certain  diseased  udders,  Klein  * 
isolated  two  varieties  of  pyogenic  bacteria — £.  diphtheroides  and  Strep- 
tococcus radlatus  {'pyogenes). 

Other  pathogenic  organisms  commonly  present  in  milk  include  mi- 

'  Miinchener  medicinisflie  Wochenschrift,  July  25,  1899. 

^  Giornale  di  Medicina  Veterinaria,  1891. 

'*  Zeitschrift  fur  Flcisc-h-  und  Milchhvffiene,  1900,  p.  114. 

*  British  Medical  .Jouniiil,  Nov.  11,  1899. 

^  I>eutsche  Vici-tclj;ilirssclnin  fiir  (iflentliclie  Gesundheitspflege,  1900,  p.  430. 

"  Amerifan  Mcrlifinc,  April  liO,  190],  p.  122. 

'  CentrMlhlalt  fiir  HiiktcrioioKic,  1901,  XXIX.,  p.  496. 

•*  -Journal  of  Hygiene,  January,  1901,  p.  78. 


100  FOODS. 

crococci,  found  by  Bergey  in  36  of  40  samples  of  market  milk,  and  in 
16  of  59  samples  from  lirst-class  dairies  ;  Staphylococcus  'pyogenes  aureus, 
found  by  the  same  investigator  in  3  of  8  samples  from  individual  cows 
of  first-class  dairies;  by  Leblanc/  in  the  ducts  of  10  of  the  24  teats 
of  6  dairy  cows  examined  ;  and  Staphylococcus  aureus  and  albus,  found 
by  Leblanc,  v.  Hellens,  and  others.  B.  coll  communis  is  present  almost 
invariably  in  milk  from  all  sources,  and  Proteus  vulgaris  is  found  fre- 
quently. 

The  presence  of  the  various  pyogenic  bacteria  in  milk,  whether  due 
to  their  existence  within  the  milk  ducts  or  to  even  slight  lesions  on  the 
hands  of  the  milkers,  is  a  matter  of  grave  concern  as  a  common  cause 
of  serious  gastro-intestinal  disorders,  especially  in  children  in  their 
first  years. 

It  would  appear  from  a  report  made  by  GaflPky,^  that  the  milk  of 
cows  suffering  from  specific  enteritis  may  l)e  a  cause  of  sickness.  Three 
persons  connected  with  the  Institute  of  Hygiene  at  Giessen  were  seized, 
after  drinking  milk  from  a  cow  suffering  from  such  a  disease,  with 
nausea,  vomiting,  diarrhoea,  and  mental  confusion.  One  recovered  in 
a  few  days,  the  others  in  about  four  Aveeks.  The  milk  was  drunk  in 
the  raw  state. 

Concerning  the  agency  of  milk  of  tuberculous  cows  in  spreading 
tuberculosis,  there  is,  as  in  the  case  of  tuberculous  meat,  a  wide  diver- 
gence of  opinion.  There  can  be  no  doubt  that  the  milk  of  such  cows 
may  convey  the  infection  to  other  animals,  but  Avhether  to  man  cannot 
be  definitely  stated,  because  of  the  impossibility  of  experimentation,  and 
since,  in  any  case  of  supposed  transmission,  very  many  other  possible 
agencies  must  be  eliminated.  As  stated  on  a  preceding  page,  local  in- 
fection by  meat  through  wounds  incurred  at  autopsies  of  tuberculous 
animals  is  not  impossible,  but  cases  of  similar  infection  through  milk 
are  exceedingly  rare.  Salmon  ^  cites  but  3  cases  in  all ;  one,  from  the 
application  of  cream  to  a  leg  sujjposedly  poisoned  by  ivy  ;  a  second, 
from  milking  with  a  wound  in  one  finger ;  and  a  third,  from  attempted 
removal  of  tattoo-marks  by  the  introduction  of  milk  through  needle- 
punctures. 

There  can  be  no  doubt  that  the  tubercle  bacillus  finds  its  way  into 
milk,  particularly  if  the  udder  is  involved,  but  even  wdien  not.  This 
was  asserted  so  long  ago  as  1889  by  Professor  H.  C.  Ernst,*  who,  after 
a  very  extended  inquiry,  proved  that  the  milk  of  cows  M'ith  tubercu- 
losis in  any  part  of  the  body,  and  with  no  local  lesion  of  the  udder 
whatever,  may  contain  the  bacillus.  This  finding  has  been  confirmed 
by  a  number  of  more  recent  observations.  Especially  noteworthy  is  the 
investigation  pursued  by  Drs.  Rabinowitsch  and  Kempner,'^  who  obtained 
positive  results  from  inoculation  experiments  on  guinea-pigs  with  the 
milk  of  10  out  of  15  cows  that  had  reacted  to  tuberculin.     Of  these 

'  Lyon  medical,  1900,  p.  561. 

■■^  Deutsche  niedicinische  Wochenschrift,  1892,  No.  14. 

'*  Bulletin  33,  Bureau  of  Animal  Industry,  1901. 

■*  American  Journal  of  Medical  Sciences,  November,  1889. 

^  Zeitschrift  fiir  Hygeine  und  Infectionskrankheiten,  XXXI.,  p.  137. 


MILK  AS  A   FACTOR  IN  THE  SPREAD    OF  DISEASE.         101 

10  animals,  only  1  showed  clinical  evidence  of  involvement  of  the 
ndder,  and  only  1  other  showed  any  sign  of  it  on  microscopical  exami- 
nation. Others  who  have  obtained  positive  results  from  animals  with 
normal  udders  include  Bollinger,  Delepine,  Bang,  and  Adami. 

Similarly,  the  milk  of  a  tuberculous  mother  may  be  infective,  even 
though  no  mammary  lesions  exist.  Such  an  instance  is  reported  by 
Roger  and  Gamier :  ^  The  woman  died,  seventeen  days  after  confine- 
ment, with  pulmonary  tuberculosis.  On  the  fourth  day  after  delivery, 
2  guinea-pigs  were  inoculated  with  her  milk,  one  of  them  with  positive 
results.  The  child  lost  weight  from  birth,  and  died  at  six  months  with 
tubercular  lesions  of  the  mesenteric  glands,  liver,  kidneys,  and  spleen. 

But  the  question  of  excretion  of  bacteria  by  active  mammary  glands 
with  no  apparent  lesions  has  not  been  studied  exhaustively.  According 
to  Basenau,^  only  those  bacteria  which  are  capable  of  actmg  on  the 
walls  of  the  blood-vessels  so  as  to  cause  hemorrhages  are  able  to  pass 
from  the  blood  into  the  milk,  and  in  those  cases  in  which  B.  tuberculosis 
has  been  detected  in  the  absence  of  evidence  of  mammary  lesions,  the 
chances  are  that  more  or  less  alteration  of  the  vessel  walls  has  occurred 
in  consequence  of  disturbed  nutrition.  The  experiments  of  Basch  and 
Weleminsky^  lead  one  to  the  conclusion  that  Basenau's  position  is 
correct.  They  infected  animals  with  different  species  of  pathogenic 
organisms,  and  found  that,  even  when  the  blood  teemed  with  anthrax 
bacilli,  the  milk  showed  no  evidence  of  their  presence  unless  there  were 
local  conditions  especially  favorable,  such  as  vascular  lesions,  which 
may  be  caused  by  the  hemorrhage-producing  bacteria.  It  has  l:»een 
demonstrated  by  Ostertag*  that  the  milk  of  cows  which  show  no  evi- 
dence of  tuberculosis  beyond  reacting  to  tuberculin  contains  no  bacilli, 
and  that  calves  and  pigs  fed  thereon  for  months  do  not  become  tuber- 
culous. 

It  is  asserted  commonly  that  the  use  of  milk  from  tuberculous  cows 
is  a  positive  danger  to  public  health,  and  attention  is  directed  to  the 
persistently  high  rate  of  mortality  from  tuberculosis  in  all  its  forms 
among  very  young  children,  and  to  improvement  in  the  death-rates 
from  other  causes.  It  is  asserted  that  this  condition  can  be  explained 
in  only  one  way ;  that  is,  that  a  very  large  proportion  of  market  milk 
is  derived  from  tuberculous  cows,  and  thus  bottle-fed  children,  if  at 
all  susceptible,  become  infected. 

As  to  the  probable  proportion  of  infected  market  milk,  owing  to  the 
wide  differences  in  results  obtained  by  various  investigators,  no  definite 
statement  can  be  given.  E,abinowitsch,  for  example,  found  it  to  be  28 
per  cent.;  Massone'^  by  inoculation  experiments  ]3laced  it  at  9  ;  Ott^  at 
11.6.     Sladen''  found  that  more  than  half  of  the  samples  taken  from 

'  Comptes  rendiisde  la  Soci(?t^  de  Biologie,  March  2,  1900. 

•''  Arfhiv  fijr  Hygiene,  XXITI.  (1895),  p.  44. 

■'  Ihiflem,  XXXV.  (1899),  p.  205. 

*  Zeitsfhiift  fur  Hygiene  iind   Infeetionskrankheiten,  XXXVIII.  (1901),  p.  415. 

■•  Annali  d'lgiene  Sperimentale,  1897,  p.  939. 

"  Zcitsehrift  Air  Milcli-  iind  Flei.schhygiene,  1898,  No.  8. 

'  The  Lancet,  Jan naiy  14,  1899. 


102   ^  FOODS. 

the  supply  of  the  colleges  at  Cambridge  (England)  conveyed  tubercu- 
losis to  guinea-pigs  on  inoculation;  but  Eastes^  found  the  bacillus  in 
but  11  out  of  186  samples  of  milk  which  he  examined.  Others  have 
obtained  results  anywhere  within  the  range  of  6  to  50  per  cent.  Doubt- 
less the  differences  are  due  to  variations  in  local  conditions,  to  diifer- 
■ences  in  technic,  and  to  accidents  always  attending  hap-hazard  securing 
of  any  article  of  food  in  open  market. 

Taking  the  mean  of  the  figures  given,  and  accepting  that  as  a  fair 
approximation  of  the  extent  to  which  public  supplies  are-  infected,  it 
must  be  agreed  that,  if  infection  through  milk  is  possible,  the  amount 
of  disease  so  caused  is  quite  small  in  proportion  to  the  number  of  the 
population  who  are  exposed  daily  to  the  danger.  There  are  but  few 
reported  cases  in  which  the  influence  of  other  possible  couditions  can  be 
excluded  so  thoroughly  as  to  leave  no  reasonable  doubt  of  the  causal 
relation  of  milk.  Single  instances  are  necessarily  of  less  value  than 
groups  of  cases,  and  the  latter  are  much  less  common  than  generally 
is  sup[)osed.  From  the  number  available  the  following  are  selected  as 
illustrations : 

BrouardeP  records  the  death  of  7  children  with  no  hereditary  taint, 
inmates  of  a  convent,  from  tuberculosis  supposedly  induced  by  the  use 
of  milk  from  a  cow  with  tuberculosis  of  the  udder.  Another  case 
reported  by  him,  and  quoted  by  Freudenreich,-^  is  one  in  which  5  of  14 
girls  in  a  boarding-school  became  infected  and  died.  The  milk  M'hich 
they  had  used  daily  came  from  a  tuberculous  cow. 

Demme*  re])orted  as  the  only  instance  in  his  experience  in  which  all 
other  causes  could  satisfactorily  be  excluded,  a  group  of  4  infants  of 
liealthy  parentage  fed  upon  uncooked  milk  of  tuberculous  cows.  They 
all  died  of  tuberculosis  of  the  intestine,  and  the  diagnosis  was  confirmed 
by  autopsy.  Later,  he  reported-^  still  another  death  from  the  same 
cause  at  four  months.  In  this  case  also  there  was  alisolutely  no  family 
history  of  tuberculosis.  After  the  confirmation  of  the  diagnosis  by 
autopsy,  the  coav  was  slaughtered  and  found  to  be  tuberculous. 

A  more  extensive  outbreak  among  older  children  was  reported  by 
Ollivier  to  the  Academy  of  Medicine,  Paris,  on  February  24,  1891.  A 
^voman  of  twenty-one  years,  of  good  family  history,  who  had  always 
enjoyed  good  health,  died  of  tubercular  meningitis  shortly  after  taking 
up  her  residence  in  a  boarding-  house  in  which  within  a  short  time 
previously  11  school  girls  had  been  seized  with  tulDcrculosis.  It  was 
learned  that  the  milk  supply  was  derived  from  a  single  animal  which 
was  extensively  tuberculous.  Shortly  afterward,  still  another  girl  died 
of  phthisis  pulmonalis  in  the  same  house. 

Some  of  these  cases,  if  not  all,  may  be  accepted  as  very  strong  evi- 
<lence  that  tuberculosis  may  be  spread  through  the  agency  of  milk. 

^  British  Medical  Journal,  INoveniber  11,  1S99. 
^  Annales  d'Hvgiene  publiqne,  XXIY.,  p.  65. 
^  Les  Microbes  et  leur  des  Kole  dans  la  Laiterie,  Paris,  1894,  \).  45. 
*  Jahresbericht  liber  die  Thiitigkeit  des  Jennei-'schen  Kinderspitals  in  Bern,  1882, 
p.  48. 

5  Ibidem,  1886,  p.  20. 


MILK  AS  A   FACTOR  IN  THE  SPREAD   OF  DISEASE.         103 

But  if  it  is  true  that  so  large  a  proportion  of  the  milk  supply  is  from 
diseased  cows,  and  that  the  disease  is  communicable  in  this  way,  it 
follows  that  with  the  vast  majority  of  drinkers  of  raw  milk  the  bacilli 
perish  or  are  discharged  without  gaining  entrance  to  the  tissues. 

Granting  that  much  of  the  public  milk  supply  is  derived  from  tuber- 
culous cows,  and  that  it  is  consumed  very  largely  in  unsterilized  condi- 
tion by  very  young  children,  one  would  naturally  expect,  if  the  bovine 
bacillus  is  markedly  infective  to  man,  to  find  a  very  high  death-rate 
from  abdominal  tuberculosis  among  the  very  young.  It  is  asserted  that 
this  is  the  case,  and  elaborate  arguments  in  favor  of  the  statement  that 
tuberculous  milk  is  responsible  for  a  great  part  of  the  constantly  high 
infantile  death-rate  have  been  based  on  figures  given  by  the  late  Sir  K. 
Thorne-Thorne,  in  his  Harben  lectures,  in  November,  1898,  showing  that, 
whereas  in  England  and  Wales  the  returns  for  1891-1895,  compared 
with  those  for  1851-1860,  indicate  a  reduction  in  mortality  from 
phthisis  at  all  ages  of  45.4  per  cent.,  and  from  all  forms  of  tuberculosis 
of  39.1  per  cent.,  the  decrease  in  tabes  mesenterica  was  for  all  ages  only 
8.5,  and  for  children  under  five  only  3  per  cent. ;  and  that,  moreover, 
for  children  under  one  year  there  was  not  only  no  reduction,  but  an 
actual  increase  of  27.7  per  cent.  Such  figures,  emanating  from  so  high 
an  authority,  would  seem  to  admit  of  but  one  explanation,  namely, 
that  infected  milk  is  a  danger  hardly  to  be  overrated.  But  these  figures 
are  directly  opposed  to  clinical  experience  elsewhere  and,  as  will  appear, 
are  incorrect.  Dr.  D.  Bovaird  ^  points  out  that  it  is  only  in  England 
that  reports  indicate  any  considerable  number  of  cases  of  primary  intes- 
tinal tuberculosis,  and  asserts  that  it  is  very  rare  in  and  about  New 
York  City,  and  that  the  evidence  connecting  tuberculosis  in  children 
with  infected  milk  is  very  meagre.  Koch  has  called  attention  to  the 
great  infrequency  of  primary  tuberculosis  of  the  intestine  among  children 
in  institutions  in  Berlin  ;  and  Biedert,^  too,  asserts  that  the  amount  of 
tubercular  infection  through  the  alimentary  canal  is  very  small.  Adami  ^ 
is  of  the  opinion  that  tuberculosis  of  young  children,  and  especially  peri- 
toneal and  intestinal  tuberculosis,  is  remarkably  rare  in  the  great  cities 
of  North  America  ;  but  Jacobi,*  while  admitting  that  primary  tubercu- 
lar ulcerations  of  the  intestine  and  primary  tuberculosis  of  the  mesen- 
teric glands  are  rare,  holds  that  peritoneal  tuberculosis  is  very  common. 
Adami  cites  the  mortality  returns  for  Montreal  for  the  year  ended 
June,  1 900,  showing  that  of  935  deaths  from  tuberculosis,  but  4  were 
of  children  under  fourteen,  and  3  of  these  were  from  abdominal  tuber- 
culosis in  children  under  five  years.  Crookshank  ^  dissents  from  the 
opinion  that  abdominal  tuberculosis  of  children  is  connected  with  in- 
fected milk,  but  believes  that  not  sufficient  consideration  is  given  to  the 
possibility  of  infection  from  human  sources. 

The  fallacy  of  Thorne-Thorne's  figures  has  been  pointed  out  by  Carr, 

'  Arcliivcs  f)f  T^.-diiitrics,  Doc,  1901. 

'^  Bcrliiici-  klinisi'lic  Wocficiisclirit't,  Novenibev  25,  1901. 

2PliilM(l(l|)hi;i  Mcdicnl  Journal,  I'Y-hrniiry  22,  1902. 

*  New  York  Medifal  .Joiiniiil,  .January  25,  1902. 

5  Tlie  Lancet,  Novembei'  2,  1901. 


104  FOODS. 

Guthrie,  Donkin,  and  others,  and  all  arguments  based  thereon  must  fall 
to  the  ground.  In  December,  1898,  Carr^  showed  that  the  vast  ma- 
jority of  cases  returned  as  tabes  mesenterica  were  probably  of  maras- 
mus, due  to  gastro-intestinal  catarrh.  Guthrie"  concluded  from  the 
results  of  77  autopsies  performed  by  him  on  tuberculous  children  that 
the  disease  begins  far  more  commonly  in  the  chest  than  in  the  abdomen, 
and  that  tabes  mesenterica  as  a  cause  of  death  in  young  children  is 
practically  unknown  or  extremely  rare.  Donkin,  who  contends  that 
the  original  significance  of  the  terra  "tabes  mesenterica"  no  longer 
holds,  says  :  ^  "  We  all  know  that  all  kinds  of  intestinal  and  other  dis- 
orders are  constantly  styled  '  tabes  mesenterica  ^  by  those  who  fail  to 
cure  them." 

Notwithstanding  the  paucity  of  cases  which  oifer  strong  evidence  of 
a  causal  relation  between  infected  milk  and  the  occurrence  of  tubercu- 
losis, and  in  spite  of  the  now  recognized  differences  between  the  bovine 
and  human  bacilli,  the  possibility  of  danger  in  individual  cases  cannot 
lightly  be  brushed  aside.  According  to  Theobald  Smith,*  it  is  quite 
possible  that  something  interferes  with  the  absorption  of  bovine  bacilli, 
while  allowing  the  human  bacilli  to  pass  ;  and  while  racial  differences 
probably  prevent  the  absorption  of  bovine  bacilli  under  ordinary  circum- 
stances, and  a  few  bacilli  are  harmless,  there  is  danger  if  the  digestive 
tract  is  flooded  with  bacilli  from  tuberculous  udders.  Ostertag  ^  advo- 
cates the  culling  out  of  all  cows  showing  clinical  evidence  of  tubercu- 
losis (beyond  reacting),  and  especially  of  all  with  lesions  within  the 
udder. 

Leblanc^  is  of  the  opinion  that  the  milk  of  tuberculous  cows  is 
dangerous,  not  on  account  of  the  bacilli,  but  ou  account  of  the  toxins 
that  it  contains,  for  it  has  been  proved  to  have  toxic  properties. 
Michellazzi  has  shown  that  such  milk  injected  into  tuberculous  ani- 
mals causes  a  reaction,  and  that  the  milk  of  a  tuberculous  mother  will 
in  time  prove  toxic  to  her  child. 

Milk  Contaminated  from  without  with  Organisms  Related 
to  Human  Diseases. — Milk  may  become  contaminated  with  infec- 
tive matter  in  various  ways.  It  may  receive  it  from  the  hands,  per- 
son, and  clothing  of  the  milkers  and  others  by  whom  it  is  handled, 
whether  they  are  themselves  sick  or  convalescent,  or  acting  in  the 
capacity  of  nurse  or  attendant  for  others ;  it  may  acquire  it  from 
unclean  vessels  rinsed  in  polluted  water,  or  from  water  with  which  it 
has  fraudulently  been  mixed.  Outbreaks  traced  to  milk  generally 
involve  a  considerable  number  of  persons,  and  appear  with  some  sud- 
denness. In  fact,  it  is  the  simultaneous  appearance  of  a  large  number 
of  cases  that  draws  attention  to  the  water  supply  or  milk  as  a  common 
cause.     Sporadic  cases  are  rarely  traceable  to  milk. 

On  account  of  the  danger  of  specific  contamination  of  milk,  no  per- 

1  The  Lancet,  1898,  II.,  p.  1662. 

'  Ibidem,  1899,  I.,  p.  286. 

^  British  Medical  Journal,  Octoher  14,  1899,  p.  1046. 

*  Medical  News,  Febriiarv  22,  1902.  ^  Loco  citato. 

«  Lyon  medical,  April  14,"  1901,  p.  561. 


MILK  AS  A   FACTOR  IN  THE  SPREAD   OF  DISEASE.  105 

son  sick  with  or  convalescent  from  infectious  disease,  and  no  person 
having  to  do  with  the  care  of  the  sick,  or  with  the  disposal  of  their 
excreta,  or  with  the  washing  of  their  linen,  should  be  allowed  to  handle 
milk  intended  for  the  use  of  others.  Public  authorities  are  rapidly 
becoming  awakened  to  the  importance  of  restrictive  measures  in  this 
regard,  and  in  many  communities  it  has  been  made  a  criminal  offence 
to  fail  to  give  notice  of  the  presence  of  cases  of  infectious  disease  at 
the  place  of  production  of  milk  or  among  those  engaged  in  its  distribu- 
tion and  sale. 

Diphtheria. — A  large  number  of  epidemics  have  been  reported  in 
which  a  positive  connection  with  the  milk  supply  appears  to  have  been 
fairly  well  made  out ;  but  so  far  as  is  known,  there  is  no  connection 
between  any  disease  of  the  cow  and  that  which  we  know  as  diphtheria, 
although  a  number  of  outbreaks  of  diphtheria  have  been  reported  as 
traced  to  garget.  The  specific  organism  of  diphtheria  may  be  intro- 
duced into  milk  from  the  discharges  of  persons  employed  in  the  hand- 
ling and  distribution  of  milk  before  they  have  recovered  thoroughly 
from  the  disease.  Dr.  J.  W.  H.  Eyre  ^  found  the  bacillus  of  diphtheria 
in  samples  of  milk  supplied  to  a  large  school  where  a  number  of  cases 
of  the  disease  had  occurred.  The  organisms  gave  the  usual  character- 
istics, and  no  reason  appears  for  doubting  their  identity. 

Schottelius  ^  proved  that  the  bacillus  of  diphtheria  can  grow  very 
rapidly  in  raw  milk,  less  so  in  sterilized  milk  at  ordinary  temperature, 
but  very  much  better  at  37°  C  Inasmuch  as  the  organism  may  per- 
sist for  long  periods  after  the  disease  apparently  has  disappeared,  and 
may  be  present  in  the  throats  of  persons  in  apparent  health,  it  need  not 
excite  wonder  when  it  is  reported  present  in  milk. 

Cholera. — Undisputed  evidence  of  the  connection  between  milk  and 
Asiatic  cholera  is  not  very  common.  There  is  some  disagreement  as  to 
the  viability  of  the  cholera  organisms  in  milk;  thus,  Hesse ^^  found  that 
fresh,  raw  milk  exerts  a  destructive  influence  on  them ;  that,  in  fact, 
they  begin  to  die  as  soon  as  they  are  mixed  with  it.  He  found  that 
they  die  at  ordinary  room  temperature  within  12  hours,  and  at  incu- 
bator temperature  in  from  6  to  8  hours.  The  age  of  cultures,  the 
nature  of  the  culture  media,  and  the  addition  of  the  latter  to  the  milk 
with  the  bacteria,  appear  not  to  affect  the  result.  Sterilized  milk  was 
found  to  be  a  better  culture  medium.  Basenau  *  disagrees  with  Hesse. 
He  found  that  uncooked  milk  does  not  kill  the  organisms  in  10  hours, 
that  they  are  active  after  38  hours,  and  that  up  to  the  point  of  coagu- 
lation of  the  milk  they  increase  considerably  in  number.  He  found 
that  in  polluted  milk  they  remain  active  at  least  32  hours  at  different 
temperatures  (room  temperature,  24°  and  37°  C),  and  that  they 
remain  active  even  after  the  milk  has  coagulated. 

Weigraann  and  Zirn  ^  found  that  the  length  of  time  cholera  bacteria 

'  BritiKli  Medical  .Toui-na],  Septernbcii-  2,  1889. 

''  rentTHlhlatt  fiir  BakterioloKic,  AMli.  J.,  XX.,  No.  25. 

''  Zf'itsclirift  fill-  Ify^-ienc  iind  Iiifectionskrankheiten,  XVII.,  p.  238. 

^  Arcliiv  fiir  IIy«iiTic,  XXIII.,  )).  170. 

*  Cenlralhlall  fiir  JJakteiiologie,  etc.,  1894,  No.  8. 


106  FOODS. 

remain  active  depends  upon  the  ratio  they  bear  to  the  number  of  other 
organisms  present,  and  that  in  order  to  survive  for  many  hours  they 
woidd  have  to  be  added  to  milk  in  exceedingly  large  numbers. 

The  evidence  that  cholera  can  be  disseminated  through  the  agency 
of  milk  is  exceedingly  limited,  and  about  the  only  case  free  from  doubt 
is  that  recorded  by  Simpson,^  who  relates  that  9  cases  of  cholera 
occurred  suddenly  on  a  ship  in  the  harbor  of  Calcutta,  10  men  of  whose 
crew  had  obtained  milk  from  a  native.  One  drank  but  little  and 
escaped,  4  died  of  undoubted  cholera,  and  5  M^ere  very  sick  with  diar- 
rhoea. Eight  others  who  used  condensed  milk  only,  and  those  who 
used  no  milk  whatever,  were  unaifected.  It  was  learned  that  the 
vendor  had  diluted  the  milk  about  one-fourth  with  water  from  a  tank 
to  Avhich  dejections  from  cholera  patients  had  gained  access  and  in  which 
the  clothes  of  the  patients  were  washed. 

Scarlet  Fever. — In  December,  1885,  occurred  what  has  become  com- 
monly known  as  the  Hendon  outbreak  of  scarlet  fever,  due  to  a  disease 
of  cows,  and  since  that  time  a  number  of  other  epidemics  have  been 
traced  apparently  to  a  common  milk  supply.  In  the  Hendon  case,  a 
number  of  cows  were  or  had  been  sick  with  an  infectious  eruption  of 
the  udders,  and  there  can  be  no  doubt  that  the  disease  under  considera- 
tion was  spread  through  the  agency  of  milk  coming  from  this  dairy ; 
but  other  cows  having  the  same  disease  caused  no  trouble,  and  the  pos- 
sibility of  contamination  from  human  sources  could  not  be  excluded 
absolutely.  A  number  of  other  outbreaks  of  the  disease  have  some- 
what doubtfully  been  ascribed  to  similar  teat  eruptions,  but  in  no  case 
is  the  evidence  conclusive.  On  the  other  hand,  there  is  undoubted 
evidence  that  the  disease  has  many  times  been  spread  by  milk  from 
farms  where  children  and  others  were  sick  with  it. 

In  tracing  epidemics  of  this  and  other  diseases  to  a  common  cause, 
there  is  always  danger  of  lending  too  much  importance  to  coincidence, 
and  of  coming  thereby  to  unwarranted  conclusions.  As  an  illustration, 
the  following  case  may  be  cited  :  In  1897,  in  one  of  the  outlying 
wards  of  Boston,  a  large  number  of  cases  of  scarlet  fever  occurred 
with  some  suddenness  among  children  chiefly  of  the  well-to-do  class. 
Naturally  there  was  much  disturbance  of  the  public  mind,  and  an  in- 
vestigation was  undertaken  immediately.  It  was  ascertained  that 
nearly  all  of  the  families  concerned  were  supplied  by  one  milkman, 
Avho  "raised"  all  the  milk  which  he  handled,  and  the  responsibility  for 
the  outbreak  was  at  once  laid  at  his  door.  His  premises  were  ex- 
amined by  the  health  authorities  and  found  to  be  in  excellent  condition. 
No  case  of  disease  or  indis]iosition  had  occurred  in  his  family  or  among 
his  help  within  a  number  of  months,  nor  had  he  or  anybody  on  the 
place,  so  far  as  could  be  ascertained,  been  in  contact  with  any  case  of 
scarlet  fever  or  of  any  other  infectious  disease.  His  cows  were  examined 
by  a  thoroughly  competent  veterinarian  and  pronounced  in  every  respect 
healthy.  Nevertheless,  public  excitement  ran  so  high  that  his  business 
fell  away  very  considerably.  Had  a  single  cow  shown  the  slightest 
1  Indian  Medical  Gazette,  May,  1887. 


MILK  AS  A  FACTOR  IN  THE  SPREAD   OF  DISEASE.         107 

evidence  of  an  eruptive  disease  of  the  teats,  the  epidemic  might  have 
been  hailed  as  another  Hendon  outbreak,  and  been  quoted  in  sanitary 
history  as  a  noteworthy  example.  The  fact  that  the  great  majority  of 
cases  occurred  among  his  patrons  was  easily  explainable,  for  he  was 
known  to  be  a  careful,  cleanly,  honest  dealer,  and  was,  therefore,  the 
very  sort  of  man  to  attract  the  particular  class  whose  homes  M'ere 
invaded.  The  children  affected  belonged  to  closely  affiliated  groups  of 
playmates.  Further  investigation  revealed  the  fact  that  the  first  case 
was  of  a  lad  whose  family  was  not  a  customer  of  the  suspected  dealer, 
and  that,  immediately  before  taking  to  his  bed,  he  had  been  playing 
with  a  number  of  those  who  were  among  the  next  to  be  seized.  These 
in  their  turn  had  been  associated  with  others,  and  so  the  infection  had 
spread.  Thus,  what  might  have  served  as  a  most  useful  example  of  a 
milk-borne  epidemic  of  scarlet  fever  fell  to  the  ground,  and  the  unfor- 
tunate dealer  was  absolved  from  responsibility. 

Typhoid  Fever, — There  can  be  no  doubt  that,  in  the  spread  of  typhoid 
fever,  milk  plays  a  part  only  second  in  importance  to  that  of  drinking- 
water.  A  very  great  number  of  epidemics  have  been  traced  beyond 
a  possibility  of  dispute  to  milk  coming  from  farms  where  cases  of  the 
disease  have  occurred.  The  contamination  is  brought  about  by  the 
hands  of  the  milkers  or  other  handlers,  who,  in  addition,  assist  in 
nursing,  or  by  the  addition  of  infected  water,  or  through  washing  j)ails, 
cans,  and  other  vessels  in  such  water. 

From  time  to  time,  tabulated  analyses  of  outbreaks  supposed  to  be 
due  to  contaminated  milk  have  been  published,  but  a  very  large  pro- 
portion of  the  cases  included  are  based  on  very  insufficient  evidence, 
sometimes  exceedingly  slight,  such  as  that  a  cow  had  drunk  from  water 
into  which  drainage  from  the  barnyard  had  had  access.  But  within 
recent  years,  a  number  of  extensive  epidemics  in  this  country  and  else- 
where have  been  traced  with  as  much  definiteness  to  the  milk  supply, 
as  have  others  to  the  water  supply,  and  with  the  same  and  only  clefect 
that  the  bacteriological  proof  has  been  lacking.  As  is  the  case  when 
outbreaks  occur  from  polluted  water,  when  attention  is  drawn  to  the 
possible  cause,  the  bacteriological  evidence  is  no  longer  obtainable,  the 
conditions  having  changed  during  the  period  of  incubation. 

The  State  Board  of  Health  of  Massachusetts  has  traced  a  number 
of  extensive  epidemics  to  the  use  of  polluted  milk,  but  in  no  instance 
has  the  organism  been  found  in  the  milk.  In  the  city  of  Boston  also, 
where  the  local  authorities  keep  a  constant  eye  on  the  reports  of  typhoid 
fever  cases  with  particular  reference  to  the  possibility  of  dissemination 
tln'ongh  milk,  a  number  of  small  outbreaks  have  been  traced  definitely 
to  milk  supplies  derived  from  small  farms  where  persons  sick  with  the 
diswisc  were  nursed  by  those  who  had  milked  the  cows  and  handled  the 
milk,  and  in  these  instances  also  the  bacteriological  evidence  is  lacking. 

That  the  organism  can  retain  its  vitality  in  milk,  and  even  in  sour 
milk,  has  definitely  been  settled.  Hein  found  tlie  organism  in  sour 
milk  at  ].'}°-l  H°  V;.  after  thirty-five  days,  ))ut  not  after  fi)rty-("ight. 
Hesse  has  found  it  in  sterilizer!  milk  after  four  months.     Drs.  Fraenkel 


108  FOODS. 

and  Kister/  having  reason  to  believe  that  the  unusual  amount  of  ty- 
phoid fever  at  Hamburg  during  the  summer  of  1897  was  due  in  part 
to  infected  buttermilk,  undertook  the  study  of  the  question  whether  B^ 
typhosus  can  exist  in  that  fluid,  concerning  which  point  there  had  been 
more  or  less  of  conflicting  testimony.  Obtaining  some  samples,  they 
first  investigated  the  number  and  identity  of  the  contained  bacteria, 
and  learned  that,  while  the  number  varied  widely,  the  species  were 
always  about  the  same.  Finding  no  pathogenic  organisms,  they  steril- 
ized specimens  in  test-tubes  a  half  hour  a  day  for  three  days,  then 
planted  the  typhoid  bacillus  in  them  and  kept  them  at  diiferent  tem- 
peratures ;  on  ice  and  at  22°  and  37°  C.  Loops  were  taken  from  each 
from  time  to  time  and  planted,  and  each  yielded  positive  results.  The 
specimen  kept  at  room  temperature  was  under  observation  nine  days  ; 
the  others  were  not  examined  after  the  third.  The  specimens  of  fresh, 
buttermilk  containing  all  its  bacteria  were  planted  and  kept  under  the 
same  conditions,  and  from  them  the  same  results  were  obtained.  Yet 
there  M^as  this  difference,  that  there  was  always  a  diminution  in  the 
number  of  the  pathogenic  organisms,  and  this  was  the  more  marked^ 
and  sometimes  very  rapid,  with  increasing  temperatures. 

Cholera  Infantum. — In  eveiy  large  community,  it  has  become  cus- 
tomary to  expect  as  a  normal  condition  a  large  death-rate  among  chil- 
dren with  the  advent  of  hot  weather.  This  increased  death-rate  is 
limited  very  largely  to  the  very  early  age  periods  and  to  children  fed 
on  cows'  milk,  and  while  children  of  the  poor  are  the  ones  most  com- 
monly attacked,  those  of  the  well-to-do  are  by  no  means  free.  During 
the  siege  of  Paris,  the  infant  mortality  was  reduced  to  a  half  of  its 
yearly  average,  although  the  general  death-rate  had  doubled.  This 
unusual  condition  was  attributed,  no  doubt  correctly,  to  the  fact  that 
mothers  were  obliged  to  nurse  their  infants  when  they  could,  on  account 
of  the  great  scarcitv  of  cows'  milk  and  other  foods. 

The  common  milk  bacteria  are  ordinarily  harmless,  but  it  appears 
that  some  sj^ecies  under  certain  conditions  produce  toxins  in  sufficient 
amounts  to  cause  gastric  and  intestinal  disturbances.  According  to 
Baginsky,-  a  large  part  of  the  annual  amount  of  cholera  infantum  is 
due  to  these  products  (see  under  Garget,  p.  99). 

Dr.  E.  AV.  Hope^  investigated  over  a  thousand  cases  of  autumnal 
diarrhoea,  and  found  that,  of  233  deaths  of  infants  under  three  months^ 
only  16  had  not  received  other  than  their  natural  food.  That  is  to  say, 
the  deaths  among  artificially  fed  children  under  three  months  of  age 
were  fifteen  times  as  numerous  as  among  those  nursed.  In  no  less  than 
22  per  cent,  of  the  whole  number  of  fatal  cases,  other  members  of  the 
household  had  suffered  from  diarrhoea.  The  most  striking  instance  of 
the  communicability  of  the  disturbance  was  that  at  an  infants'  home  in 
which  Avere  10  cliildren  under  the  age  of  five  months,  all  in  perfect 
health.    An  infant  of  two  months  was  admitted  in  July  with  vomiting 

^  Miinchener  medicinische  Wochenschrift,  Febnifiiy  18,  1898. 
-  Berliner  klinische  "Wochenschrift,  1894,  Nos.  43  and  44. 
^  Public  Health,  July,  1899. 


MILK  AS  A   FACTOR  IN  THE  SPREAD   OF  DISEASE.         109 

and  diarrhoea,  and  within  a  few  days  6  of  the  other  infants  and  the 
nurses  were  sick  in  the  same  way.  The  4  other  children  were  taken 
away  at  once.  The  admitted  chikl  and  the  6  that  became  infected  all 
died.     The  4  that  were  taken  away  were  saved. 

Bacteriological  examination  of  milk  has  shown  the  presence  of  ex- 
tremely active  organisms,  including  B.  enteritidis  sporogenes  of  Klein,' 
which  has  been  found  by  its  discoverer  in  the  ileum  contents  of  chil- 
dren and  adults  with  diarrhoeal  conditions,  but  not  in  a  condition  of 
health.  It  has  been  found  by  Audrewes  in  the  discharges  of  cases  of 
sporadic  diarrhoea  of  adults,  and  by  Klein  in  three  different  outbreaks 
among  the  inmates  of  a  single  hospital.  It  is  a  common  saprophyte 
found  in  sewage,  in  polluted  rivers,  and  in  manured  garden  soil,  and  is 
very  commonly  detected  in  milk,  the  use  of  which  has  not  been  fol- 
lowed by  untoward  results.  Under  certain  unlmown  conditions,  it 
becomes  highly  pathogenic,  and  recent  milk  cultures  are  intensely 
virulent  when  inoculated  subcutaneously  in  guinea-pigs. 

It  is  probable  that  to  this  organism  was  due  an  outbreak  of  milk- 
poisoning  in  Malta,  described  and  investigated  by  J.  Zammit."  In  one 
village,  5  families  comprismg  12  persons  were  seized  with  vomiting, 
■diarrhoea,  and  cramps,  and  2  children  succumbed.  Post-mortem  exam- 
ination revealed  nothing  except  congestion  of  some  of  the  viscera.  Sub- 
sequently, in  another  village,  1 7  persons  in  5  houses  were  attacked  with 
severe  gastro-enteritis  and  collapse.  The  symptoms,  which  came  on  in 
all  cases  about  three  hours  after  drinking  milk,  included  vomiting, 
■diarrhoea,  acute  pain  in  the  stomach  and  bowels,  cramps  in  the  extrem- 
ities, weak  and  irregular  pulse,  and  cold  and  clammy  skin.  The  per- 
sons concerned  in  both  outbreaks  obtained  their  milk  from  the  same 
dealer,  whose  cans,  which  had  a  sour  smell,  yielded  on  bacteriological 
examination  a  bacillus  having  all  the  characteristics  of  the  one  men- 
tioned. Families  which  were  supplied  by  the  same  dealer,  but  directly 
from  the  goats,  showed  no  symptoms,  and  the  goats  themselves  were 
free  from  disease. 

Andrewes  ^  has  described  3  much  more  extensive  outbreaks,  referred 
to  above,  due  to  the  same  organism,  in  one  of  which  the  offending  food 
was  found  to  be  rice  pudding  made  with  milk.  The  first  and  second 
outbreaks,  in  which  no  one  article  of  food  could  be  incriminated,  in- 
volved respectively  59  and  146  patients ;  the  third  involved  86.  In 
all  3  outbreaks,  the  great  majority  of  the  attacks  were  mild,  but  in  some 
of  the  more  severe  cases,  the  discharges  contained  mucus  and  blood. 
In  all  3,  the  organism  was  found  in  the  stools,  and  in  the  second,  it  was 
fotmd  in  the  milk  given  out  on  the  previous  day.  In  the  third,  it  was 
impossible  to  ol)tain  any  of  the  milk,  but  the  pudding  made  with  it 
yielded  the  organisms,  in  s])ite  of  the  heat  to  which  the  compound  had 
been  subjected  during  its  preparation.      It  was  found  by  direct  experi- 

1  Centralblatt  fiir  Bacterioloffie,  etc.,  XXII.,  Ahtli.  L,  Nos.  20  and  21;  XXIII., 
Abth.  L,  No.  ]?,. 

'  British  Mwlical  .Journiil,  Miiy  12,  ]'.)00,  p.  ll-jl. 
'  The  Lancet,  January  7,  IHW. 


110 


FOODS. 


Fig.  1. 


WATER         FAT 

C.C.12a 65^ 


~iH 


-3H 


Feser's  lactoscope. 


ment  that  the  interior  of  such  a  pudding  did  not  attain  a  temperature 
above  98°  C.  during  cooking,  a  temperature  below  that  necessary  for 
the  destruction  of  the  spores,  which  are  among  the  most  resistant 
known. 

Analysis  of  Milk. 

For  ordinary  purposes  of  determining  the  quahty  of  milk,  the  pres- 
ence or  absence  of  added  water,  and  whether  it  has  been  robbed  of  its 
cream,  a  complete  chemical  analysis  is  by  no  means  always  necessary, 

since  much  may  be  learned  from 
Fig.  2.  simple  inspection  by  means  of  the 
lactodensimeter  and  the  lactoscope. 
The  lactodensimeter  (Fig.  2),  or 
lactometer,  is  merely  a  large  hy- 
drometer with  a  stem  graduated  to 
show  specific  gravities  ranging  from 
1.015  to  1.040.  The  lactoscope, 
invented  by  Professor  Feser,  is  an 
instrument  designed  to  mdicate  the 
approximate  fat  content  of  milk. 
It  consists  of  1.  glass  cylinder,  into 
the  base  of  which  a  smaller  cylinder 
of  white  glass,  closed  at  the  top 
and  mounted  on  a  metallic  base,  is 
fitted.  The  larger  cylinder  is  grad- 
uated along  the  side ;  the  smaller 
one  bears  a  number  of  black  hori- 
zontal lines.  The  instrument  is 
shown  in  Fig.  1. 

The  principle  of  the  instrument 
is  based  upon  the  fact  that  the 
opacity  of  milk  is  due  mainly  to 
the  fat  globules  in  suspension,  and 
that,  therefore,  the  richer  a  milk 
is  in  fat,  the  greater  is  its  opacity, 
and  the  more  it  must  be  diluted 
to  reduce  the  opacity  to  such  an 
extent  as  to  permit  the  passage  of 
light. 

The  method  of  use  is  as  follows  : 
Four  cc.  of  the  specimen  are  de- 
livered from  a  pipette  into  the  cylinder  through  the  opening  in  its  upper 
end,  and  then  water  is  added  in  small  portions  and  thoroughly  mixed 
by  inversion  of  the  instrument,  the  orifice  being  kept  closed  by  the  tip 
of  the  forefinger.  As  soon  as  the  successive  additions  of  water  have 
reduced  tlie  opacity  of  the  mixture  to  such  an  extent  that  the  black 
lines  on  the  white  cylinder  can  be  discerned  so  distinctly  that  they  may 
be  counted,  the  height  of  the  liquid  on  the  scale  is  noted  and  the  per- 


ANALYSIS  OF  HULK.  Ill 

centage  of  fat  indicated  is  read.  Four  ec.  of  skimmed  milk  will  re- 
quire so  little  water  that,  when  the  lines  can  be  seen,  the  level  of  the 
mixture  will  be  very  low  on  the  scale,  while  with  rich  milk  it  will  be 
correspondingly  high,  and  with  cream  the  whole  cylinder  will  be  filled, 
and  even  then  the  lines  cannot  be  made  out. 

Control  analyses  show  that  the  instrument  gives  very  fairly  accurate 
results.  Neither  of  these  instruments  alone  can  be  depended  upon 
to  indicate  the  true  quality  of  milk,  excepting  in  the  case  of  samples 
which  are  either  very  good  or  very  bad.  The  specific  gravity  alone  is 
especially  fallacious  as  a  guide  for  the  following  reasons  :  The  specific 
gravity  of  normal  milk  at  59°  F.  ranges  between  1.029  and  1.034. 
The  removal  of  cream  causes  it  to  rise ;  the  addition  of  water  causes  it 
to  fall.  A  normal  milk  when  robbed  of  its  cream  may  show  a  specific 
gravity  of  1.036,  and  then  if  a  small  amount  of  water  is  added,  the 
gravity  is  brought  down  to  1.032  ;  that  is  to  say,  within  normal  limits. 
Thus,  a  milk  after  being  doubly  treated  so  as  to  reduce  its  nutritive 
value,  may  show  a  normal  specific  gravity,  and,  on  this  test  alone,  be 
classed  as  pure.  Nor  is  this  the  only  objection  to  a  system  of  inspec- 
tion of  this  most  important  food  based  upon  the  use  of  the  lactometer, 
since  milks  exceptionally  rich  in  fat  have  a  specific  gravity  below  the 
normal,  and  thus  may  be  condemned  as  watered. 

The  lactoscope  alone  is  also  not  to  be  depended  upon  in  all  cases, 
since  a  milk  which  shows  a  normal  content  of  fat  may  be  one  of  con- 
siderable richness  in  that  constituent  and  extensively  watered.  Thus, 
a  specimen  containing  originally  4.50  per  cent,  of  fat  may  be  watered 
very  considerably,  and  yet  show  3.75  per  cent,  by  the  lactoscope. 

By  combining  the  use  of  both  instruments,  however,  the  fallacies  of 
either  are  exposed.  A  normal  specific  gravity  shown  by  the  one  and  a 
normal  fat  content  revealed  by  the  other  will  indicate  that,  even  if  the 
milk  has  been  tampered  with,  it  yet  possesses  average  richness.  A 
normal  specific  gravity  with  a  low  percentage  of  fat  will  indicate  skim- 
ming and  watering  ;  low  specific  gravity  with  normal  or  low  fat,  water- 
ing ;  and  high  specific  gravity  with  low  fat,  skimming.  Low  specific 
gravity  with  very  high  fat  will  indicate  unusual  richness  ;  thus,  cream 
has  a  very  low  specific  gravity,  due  to  its  preponderance  of  fat.  As  a 
test  of  the  accuracy  of  this  process  of  examination,  the  author  ^  caused 
to  be  analyzed  under  his  supervision  1,714  specimens  which  appeared 
by  those  tests  to  be  of  good  quality,  and  of  this  number  but  8  were 
found  to  have  deviated  materially  from  the  statute  requirement  of  13 
per  cent,  of  total  solids. 

Determination  of  Specific  Gravity. — In  taking  the  specific  gravity 
by  means  of  the  lactodensimeter,  the  milk  is  mixed  thoroughly,  in 
order  to  insure  homogeneity,  by  pouring  from  one  vessel  into  another  ; 
a  cylinder  of  sufficient  depth  to  allow  the  instrument  to  float  freely  is 
filled  with  the  milk,  and  the  instrument  is  carefully  inserted,  not 
dropped,  down  to  the  bottom,  and  then  released.  When  it  comes  to 
rest,  the  reading  of  the  stem  at  the  level  of  the  surface  of  the  liquid  is 
'  Thirty-first  Annua!  Keport  of  the  Inspector  of  Mill<,  Boston,  1889,  p.  11. 


112 


FOODS. 


Fig.  3. 


noted.  It  should  be  borne  in  mind  that  air  bubbles  are  retained  rather 
tenaciously  by  the  milk,  and  tend  to  lower  the  density,  and,  therefore, 
in  mixing  the  milk,  too  violent  action  must  be  avoided,  and  a  short 
time  should  be  allowed  for  the  bubbles  present  to  rise  to  the  surface 
and  escape. 

Inasmuch  as  the  gravity  varies  with  the  temperature,  and  the  instru- 
ment is  graduated  for  59°  F.,  either  the  milk  should  be  brought  to 
that  temperature,  or  a  correction  should  be  made  accord- 
ing to  the  deviation  above  or  below  that  point.  If  the 
milk  is  colder,  the  reading  will  be  too  high,  and,  if 
warmer,  too  low.  It  is  more  convenient  to  make  a  cor- 
rection for  temperature  than  to  heat  or  cool  the  speci- 
men to  the  normal  point.  The  deduction  of  a  half  de- 
gree of  gravity  for  each  five  degrees  of  temperature  below 
59°,  or  the  addition  of  the  same  amount  for  each  four 
degrees  above  59°,  will  be  found  to  be  approximately 
accurate  corrections. 

Determination  of  Fat. — For  the  accurate  determina- 
tion of  fat,  several  methods  are  in  use,  including  the 
following : 

I.  The  Paper-coil  Extraction  Method. — This  process 
requires  strips  of  thick  filter-paper,  free  from  substances 
soluble  in  ether  and  alcohol,  about  G.25  by  62.5  cm.,  and 
a  Soxhlet  extraction  apparatus.  The  most  approved  form 
of  the  latter  consists  of  three  separate  pieces  which  fit 
together  by  ground-glass  joints  (see  Fig.  3).  The  top 
and  bottom  pieces  are,  respectively,  an  upright  Liebig 
condenser  and  a  flask.  The  middle  piece,  which  is  the 
part  in  which  the  extraction  process  occurs,  consists  of  a 
glass  cylinder,  closed  at  the  bottom,  from  which  a  nar- 
rower cylinder  with  open  end  projects  downward.  The 
two  cylmders  are  connected  by  a  side  tube  which  opens 
into  the  upper  portion  of  each,  and  also  by  a  siphon 
which  opens  from  the  side  of  the  bottom  of  the  large 
cylinder,  extends  upAvard,  then  turns  upon  itself,  pierces 
the  middle  part  of  the  wall  of  the  lower  cylinder,  and 
terminates  within  and  just  beloAV  its  lower  end. 

"When  in  use,  the  substance  to  be  extracted  is  placed 
within  the  upper  cylinder,  upon  the  bottom  of  which  is 
placed  a  wad  of  absorbent  cotton,  which  prevents  the 
entrance  of  solid  particles  to  the  siphon  tube,  or  it  is  con- 
fined M'ithin  a  cartridge  of  thick  filter-paper  which  fits 
loosely  within  the  cylinder.  AYhen  the  cartridge  is  used, 
it  is  best  to  plug  its  open  end  with  absorbent  cotton,  in  order  to  pre- 
vent the  escape  of  fine  particles  of  the  contained  substance. 

The  three  separate  parts  are  joined  together  and  then  mounted  on  a 
water-bath.  The  ether  or  other  extracting  medium  is  contained  in  the 
flask,  the  exact  weight  of  which  has  been  determined.    The  heat  of  the 


Soxhlet  extrac 
tion  apparatus. 


ANALYSIS  OF  MILK.  113 

water-bath  causes  the  ether  to  volatilize,  and  the  vapor  passes  upAvard 
through  the  side  tube  into  the  extractor  and  thence  to  the  condenser, 
Avhere,  coming  in  contact  with  the  cold  surface  of  the  inner  tube  thereof, 
it  condenses  and  falls  upon  the  substance  to  be  extracted.  As  the  proc- 
ess continues,  the  condensed  liquid  accumulates  and  gradually  rises  until 
it  reaches  the  bend  of  the  siphon,  which,  when  full,  begins  to  act  and 
discharges  downward  into  the  flask  until  the  entire  liquid  is  returned  to 
its  starting-point.  During  its  accumulation,  it  acts  upon  the  substance 
within  the  cylinder,  and  extracts  more  or  less  of  the  fat  or  other  sub- 
stance, as  the  case  may  be,  which  is  carried  in  solution  into  the  flask. 
The  volatilization  continues,  and  the  process  is  repeated  again  and  again 
as  long  as  is  necessary,  and  in  this  way  the  whole  of  the  extracted 
matter  is  finally  within  the  flask,  since,  being  itself  non-volatile,  it 
remains  behind,  Avhile  the  liquid  by  whi^h  it  is  extracted  is  sent  con- 
tinually on  its  errand.  On  the  completion  of  the  process,  the  ether 
is  sent  up  again  into  the  cylinder,  and  before  it  reaches  the  level  of  the 
siphon  the  flask  is  disjointed.  The  remaining  ether  is  expelled  cau- 
tiously, and  the  flask  with  its  contents  is  placed  in  an  air-bath,  main- 
tained at  100°  C,  and  dried  until  its  weight  is  constant.  The  increase 
in  the  weight  of  the  flask  represents  the  amount  of  matter  extracted. 

In  determining  the  fat  of  milk  by  this  process  the  method  is  as  fol- 
lows :  To  one  of  the  strips  of  filter-paper,  made  into  a  coil,  a  definite 
weight  of  milk,  about  5  grams,  is  applied  in  either  of  two  ways.  A 
small  beaker  containing  about  the  required  amount  is  weighed  and  then 
the  coil  is  thrust  into  it,  kept  there  until  nearly  the  whole  has  been 
absorbed,  and  then  carefully  withdrawn  and  placed  dry  edge  downward 
upon  a  sheet  of  glass.  The  beaker  is  then  weighed  again,  and  the  loss 
in  weight,  which  represents  the  amount  of  milk  absorbed,  is  noted ;  or 
the  beaker  containing  the  milk  and  a  small  pipette  is  weighed,  and  then 
the  necessary  amount  of  milk  is  transferred  to  the  coil  from  the  pipette, 
after  which  operation  the  weight  of  the  beaker,  pipette,  and  the  remain- 
ing milk  is  noted,  and  the  difference  set  down  as  the  weight  of  the 
milk  absorbed.  The  coil  is  then  dried  in  an  air-bath  at  100°  C.  for  an 
hour  or  more,  at  the  expiration  of  which  time  it  is  ready  for  insertion 
into  the  extractor. 

After  it  has  been  acted  upon  by  the  ether  about  a  dozen  times,  the 
flask  is  detached  and  treated  as  above  mentioned.  After  being  allowed 
to  cool,  the  weight  is  noted  and  the  percentage  of  fat  calculated  arith- 
metically. 

Example. — The  amount  of  milk  absorbed  by  the  coil  was  4.950 
grams.  The  increase  in  the  weight  of  the  flask  was  0.173  gram.  Then 
the  amount  of  fat  present  in  the  sample  is  obtained  by  the  equation, 
4.95  :  0.1  73  :  :  100  :  x,  Avherein  .'^  =  3.49. 

2.  The  Werner- Schmidt  Method. — In  this  ]3rocess,  equal  volumes  of 
milk  and  hydrodiloric  acid,  about  100  cc.  of  each,  are  mixed  in  a  test- 
tube  and  boiled  for  about  a  minute  and  a  half,  or  heated  on  a  water- 
bath  or  steam-l)ath  until  tlic  uiixture  is  dark  brown  iu  color.  It  is 
then  cooled,  and  the  mixture  shaken  with  30  cc.  of  ether.     When  the 

8 


114  FOODS. 

two  liquids  have  separated,  the  supernatant  ether  is  withdrawn  by 
means  of  a  pipette  or  blown  out  with  the  assistance  of  a  double  tube 
such  as  is  used  in  wash-bottles,  the  delivery  tube  extending  into  the 
ether  layer  very  nearly  as  far  as  the  line  of  demarcation  between  the 
ether  and  the  acid  mixture.  The  operation  is  repeated  with  several 
fresh  smaller  portions  of  ether,  and  the  whole  of  the  ether  used  is 
collected  in  a  weighed  flask.  Then  the  ether  is  distilled  oif,  and  the 
flask  Avith  its  residuum  of  fat  is  heated  to  constant  weight  in  an  air- 
bath,  cooled,  and  weighed.  The  process  may  be  shortened  considerably 
by  treating  the  milk  in  a  graduated  tube  and,  after  thorough  shaking 
with  ether,  removing  an  aliquot  part  of  the  latter  by  means  of  a  pipette 
and  evaporating  to  dryness.  From  the  weight  of  this  residue,  the 
amoimt  of  fat  in  the  whole  volume  of  ether  can  readily  be  determined. 
Since  the  milk  taken  is  measured,  and  not  weighed,  a  correction  must 
be  made  for  gravity. 

Example. — Amount  of  milk  used  =  10  cc.  Specific  gravity  of 
specimen  =  1.032.  Weight  of  milk  used  =  1.032  X  10  =  10.32 
grams.  Amount  of  fat  found  =  0.397  gram.  Percentage  of  fat  in  the 
original  milk  ^  x  in  the  equation,  10.32  :  0.397  :  :  100  :  x ;  x  =  3.84. 

3.  The  Babcock  Centrifugal  Method. — In  this  process,  equal  volumes 
of  milk  and  sulphuric  acid  are  mixed  in  flasks  of  special  design  with 
narrow,  graduated  necks,  and  then  whirled  in  a  centrifugal  machine  for 
a  definite  length  of  time.  On  the  completion  of  the  process,  the  details 
of  which  are  given  below,  the  fat  in  a  pure  condition  is  within  the 
graduated  neck,  and  the  percentage  is  read  directly  off. 

The  kind  of  flask  used  is  shown  in  Plate  III.  It  has  a  capacity  of 
about  40  cc.  The  graduated  portion  of  the  neck  has  a  capacity  of  2  ce. 
The  details  are  as  follows  :  17.6  cc.  of  the  milk  are  measured  by  means 
of  a  pipette  and  introduced  into  the  flask.  Then  an  equal  volume  of 
sulphuric  acid,  specific  gravity  1.800,  is  added,  and  the  two  liquids  are 
mixed  thoroughly  by  gentle  rotaiy  motion.  Then  the  flask  is  placed 
in  a  centrifugal  machine  made  especially  for  the  purpose,  and  whirled 
for  five  minutes,  at  the  expiration  of  which  time  hot  water  is  added  up 
to  the  beginning  of  the  neck.  The  flask  is  whirled  again  for  two 
minutes,  and  more  hot  water  is  added  so  as  to  bring  the  fat  layer  well 
up  into  the  neck.  After  further  whirling  for  one  minute,  the  depth  of 
the  fat  layer  is  determined  by  reference  to  the  scale. 

This  process  gives  sufficiently  accurate  results  for  all  practical  pur- 
poses, and  is  in  common  use  at  experiment  stations  in  this  country.  It 
is  much  used  at  creameries  for  determining  the  butter  value  of  milk 
sent  in  from  the  surrounding  country; 

The  employment  of  sulphuric  acid  having  a  higher  specific  gravity 
than  that  given,  say  1.820,  is  objectionable  in  that  it  frequently  happens 
that  it  is  impossible  to  obtain  a  clear  fat  layer.  The  fat  itself  may  be 
turned  a  very  dark  color,  and  the  sugar  of  the  milk  may  be  attacked 
to  such  an  extent  that  charred  portions  of  it  will  separate  and  accumu- 
late within  and  beneath  the  column  of  fat,  and  so  prevent  a  satisfactory 
reading.     If  the  acid  used  is  weaker  than  1.800,  all  the  casein  may  not 


PLATE  III. 


-^9 
§-7 


Babcoek   Flask,  shov/ing   Fat  in   Neck. 


ANALYSIS  OF  MILK.  115 

be  held  in  solution,  and  portions  of  it  may  mingle  with  the  fat  and 
destroy  the  accuracy  of  the  test. 

In  Plate  III.  is  shown  the  fat  layer  in  the  stem  as  it  should  be,  free 
from  alteration  of  color  and  from  charred  sugar  and  particles  of  casein. 
It  will  be  observed  that  the  line  of  demarcation  between  the  water  and 
the  fat  in  the  stem  is  very  sharp.  For  cream,  a  flask  with  a  much 
broader  neck  is  employed. 

4.  The  Babcock  Asbestos  Method. — In  this  method,  the  dried  total 
solids  obtained  by  the  method  described  below  (No.  2)  are  extracted  in 
a  Soxhlet  extraction  apparatus. 

Determination  of  Total  Solids. — 1.  Weigh  into  a  flat-bottomed 
platinum  dish  of  about  2  inches  (5  cm.)  diameter,  5  grams  of  milk. 
Place  on  a  water-bath  for  an  hour  and  a  half.  Remove  to  a  hot-air 
bath,  maintained  at  100°  C,  until  its  weight  is  constant.  Cool  in  a 
desiccator  and  weigh.  The  difference  between  this  weight  and  that  of 
the  dish  alone  represents  the  total  solids  of  the  amount  of  milk  taken, 
and,  multiplied  by  20,  expresses  the  percentage  of  total  solids  in  the 
sample.  If  for  any  reason  it  is  desired  to  use  the  total  solids  for  ex- 
traction in  the  Soxhlet  apparatus,  the  dish  may  be  partly  filled  before 
weighing  with  fine,  clean,  dry  sand,  or  with  freshly  ignited  woolly 
asbestos.  One  objection  to  the  use  of  the  total  solids  in  this  way  is 
that  it  is  extremely  difficult  to  remove  the  whole  amount  from  the  dish, 
to  the  sides  and  bottom  of  which  a  portion  will  adhere  with  great  ten- 
acity, and  can  be  removed  only  by  burning.  To  obviate  this  diffi- 
culty. Dr.  C.  L.  Spaulding  has  suggested  lining  the  platinum  dish  with 
very  thin  tinfoil,  which,  after  the  weight  of  the  total  solids  has  beem 
noted,  is  withdrawn  with  the  sand  or  asbestos,  and  with  it  inserted  into 
the  extraction  apparatus. 

Formerly,  the  residue  of  the  milk  dried  in  the  dish  alone  without 
sand  or  asbestos  was  used  for  the  determination  of  fat  by  the  Wanklyn 
process,  which  consists  in  filling  the  dish  with  freshly  distilled  naphtha 
or  with  ether,  and  allowing  it  to  act  upon  the  residue  and  dissolve  out 
the  fat,  several  portions  being  used,  after  which  the  dish  is  dried  again 
and  weighed,  and  the  loss  in  weight  taken  as  the  measure  of  the  fat 
contained.  Inasmuch  as  the  solvent  cannot  penetrate  the  horny  layer 
which  forms  on  the  bottom  of  the  dish,  not  all  the  fat  can  thus  be  ex- 
tracted, and  the  figures  obtained  are  ordinarily  about  0.5  too  low. 

2.  The  Babcock  Asbestos  Method. — In  this  process,  the  milk  is 
weighed  into  a  cylinder  of  perforated  metal  or  into  a  filter-paper  cart- 
ridge filled  loosely  with  freshly  ignited  woolly  asbestos,  subjected  to  a 
temperature  of  100°  C.  until  the  weight  is  constant,  and  then  cooled 
and  weighed.  The  gain  in  weight  represents  the  total  solids  of  the 
amount  of  milk  taken.  The  cylinder  may  then  be  slipped  into  the 
extraction  apparatus  and  used  for  the  determination  of  fat. 

3.  Determination  of  Total  Solids  by  Formula. — Knowing  the  correct 
specific  gravity  and  the  amount  of  fat,  it  is  )K)Ssible  to  determine  lairly 
accurately  the  amount  of  total  solids  by  the  use  of  the  formula  of 
Ilchner  and   Richmond.      This   formula  is  as  follows:  F=r.O.Hr>d  T 


11-6  FOODS. 

—  0.2186  G,in  which  F  represents  fat,  T  the  total  solids,  and  G  the 
figures  of  the  specific  gravity  beyond  the  first  decimal  place. 

Example. — The  specific  gravity  of  a  specimen  of  milk  is  found  to 
be  1.030,  and  its  fat  content  3.95.  Then  applying  the  formula,  we 
have 

3.95        =0.859  T—  (0.2186  X  30),  or 

3.95        =  0.859  T  —  6.558,  or 

0.859  T  =  6.558  +  .3.95  =  10.508,  and  T  =  12.23. 

In  other  words,  multiply  0.2186  by  the  figures  expressing  specific 
gravity,  add  the  percentage  of  fat  to  the  product,  and  divide  the  result 
by  0.859. 

The  formula  may  also  be  used  to  determine  the  jiercentage  of  fat, 
the  specific  gravity  and  total  solids  being  known. 

Determination  of  Milk  Sugar. — The  amount  of  lactose  may  be 
determined  either  chemically  or  by  means  of  the  polariscope. 

1.  Method  by  Fehling  Solution, — Reagents  required  :  Solution  A. 
Dissolve  34.639  grams  of  pure  sulphate  of  copper  in  distilled  water 
and  dilute  to  a  liter.  Solution  B.  Dissolve  173  grams  of  potassium 
sodium  tartrate  (Rochelle  salt)  in  distilled  water,  add  100  cc.  of  sodium 
hydrate  solution  of  1.393  specific  gravity,  and  dilute  the  mixture  Avith 
distilled  Avater  to  a  liter. 

In  making  a  determination,  10  cc.  of  each  solution  are  mixed  in  a 
boiling  flask  of  about  300  cc.  capacity.  The  amount  of  copper  con- 
tained in  10  cc.  of  solution  A  requires  for  its  reduction  0.050  gram 
of  dextrose,  or  0.0667  gram  of  lactose. 

PPvOCESS. — Into  a  porcelain  evaporating  dish  of  suitable  size,  dis- 
charge from  a  pipette  25  cc.  of  milk.  Add  three  or  four  times  as  much 
Avater  and  heat  to  40°  C.  Add  acetic  acid,  a  drop  at  a  time,  with  con- 
stant stirring,  until  the  mixture  separates  into  curds  and  a  fairly  clear 
whey.  Transfer  the  whole  to  a  graduated  500  cc.  flask,  and  dilute  with 
water  to  the  500  mark.  Filter  a  portion  through  a  dry  filter,  and  use 
the  filtrate  for  titration.  Dilute  the  mixed  reagents  in  the  boiling  flask 
with  water  and  boil  over  a  Bunsen  flame.  From  a  burette  graduated  in 
tenths,  add  the  filtrate  fi'om  the  curds  a  little  at  a  time,  and  continue  the 
boiling  after  each  addition.  As  the  blue  color  begins  to  appear  faint, 
the  addition  should  be  made  cautiously,  in  order  not  to  overstep  the 
end  reaction.  As  soon  as  the  blue  color  is  discharged  completely,  note 
the  reading  of  the  burette. 

The  calculation  is  exceedingly  simple.  Since  0.0667  gram  of  lactose 
is  required  to  reduce  the  copper  in  the  reagent,  it  follows  that  that 
amount  of  the  substance  is  contained  in  the  number  of  cc.  of  the  whey 
used,  and  the  percentage  is  obtained  by  the  application  of  the  rule  of 
three. 

Example. — The  color  is  discharged  by  24.3  cc.  of  the  diluted  -whey. 
Then  in  the  whole  amount  of  milk  taken  the  amount  of  sugar  will  be 
cc  in  the  equation  24.3  :  0.0667  :  :  500  :  .r.  x  =  1.372.  The  amount 
of  milk  taken  was  25  cc,  hence  in  100  cc.  the  amount  would  be  5.49, 


ANALYSIS   OF  MILK.  117 

and  this  amount  divided  by  the  specific  gravity  gives  the  percentage  by 
weight.  Supposing  the  specific  gravity  to  be  1.030,  for  example,  the 
100  cc.  of  milk  weigh  103  grams,  and  the  percentage  of  sugar  will  be 
X  in  the  equation  103  :  100  :  :  5.49  :  x.  x  =  5.33.  Inasmuch  as  the 
means  of  the  first  equation  are  constants,  the  reckoning  resolves  itself 
into  dividing  four  times  their  product,  33.35,  or  133.4  by  the  number 
of  cc.  used,  and  dividing  this  result  by  the  specific  gravity  of  the 
specimen. 

2.  Method  of  Polariscopy. — The  determination  of  lactose  and  other 
sugars  by  means  of  the  polariscope  couibines  the  advantages  of  accu- 
racy and  of  rapidity.  The  instruments  in  common  use  are  of  two 
kinds  :  those  of  which  the  normal  sucrose  weight,  that  is  to  say,  the: 
amount  of  sucrose  which,  dissolved  in  water  and  made  up  to  100  cc.,. 
will  show  100  degrees  on  the  scale  when  observed  through  a  200  mm^ 
tube,  is  26.048  grams,  and  those  in  which  it  is  16.19  grams.  Of  the- 
former,  the  Ventzke-Scheibler  and  the  Schmidt  and  Haensch  modifica- 
tion, and  of  the  latter  the  Laurent  instrument,  may  be  regarded  as 
types.  The  Schmidt  and  Haensch  triple  field,  half-shadow  instrument 
possesses  the  advantage  of  doing  away  with  the  matching  of  colors, 
and  hence  may  be  used  by  those  who  are  color-blind,  and  even  with 
those  not  so  afilicted  gives,  on  the  whole,  the  most  satisfactory  results. 

Process. — Into  a  flask  graduated  on  the  neck  at  102.6  cc.  if  the  in- 
strument used  is  one  of  which  the  sucrose  normal  weight  is  26.048 
grams,  weigh  65.95  grams  of  milk,  or  into  one  graduated  at  101.6  cc, 
if  it  is  one  of  the  other  class,  weigh  40.99  grams,  add  1  cc.  of  solu- 
tion of  mercuric  nitrate  of  pharmacopoeial  strength,  shake  well,  and 
dilute  with  water  up  to  the  mark.  Filter  through  a  dry  filter-paper, 
fill  the  200  mm.  observation  tube,  and  note  the  reading  of  the  scale 
when  the  field  of  observation  is  uniform.  The  reading  divided  by  2 
equals  the  percentage  by  weight  of  lactose. 

The  weights  65.95  and  40.99  re j) resent  twice  the  normal  lactose 
weights  of  the  respective  types  of  instruments.  The  graduations  102.6 
and  101.6  are  adopted  instead  of  100  cc,  since  the  dried  precipitated 
curds  from  the  respective  amounts  of  milk  of  average  specific  gravity 
have  a  bulk  equal  to  the  excess  over  100  cc. 

Determination  of  Ash. — The  ash  may  be  determined  by  igniting 
the  residue  obtained  in  the  determination  of  total  solids,  provided  no 
other  substance  has  been  introduced  into  the  dish  with  the  milk.  The 
ignition  should  be  conducted  at  a  low  red  heat  until  the  ash  is  perfectly 
white.  Then  the  dish  is  cooled  in  a  desiccator  and  again  weighed.  The 
difference  between  this  final  weight  and  the  original  weight  of  the  empty 
dish  represents  the  amf)unt  of  mineral  matter  in  the  amount  of  milk 
taken.  Or  a  larger  amount  of  milk,  say  20  grams,  may  be  evaporated 
with  a  few  cc.  of  nitric  acid  and  the  residue  ignited  as  above. 

Determination  of  Proteids. — Having  determined  the  total  solids, 
fat,  >Mgai',  and  ash,  th(!  proteids  may  be  reckoned  by  difFerence — that 
is,  by  subtraf'ting  the  sum  of  the  fat,  sugar,  and  ash  from  the  total 
solids,  or  they   may  be  determined  directly  by  the  Kjeldahl  process. 


118  FOODS. 

which  depends  upon  the  conversion  of  the  nitrogenous  matter  into 
ammonium  sulphate,  which  then  is  decomposed  by  an  excess  of  strong 
alkali,  ammonia  being  set  free.  This  is  expelled  by  heat,  condensed 
with  the  accompanying  steam,  and  received  in  acid  of  known  strength. 

The  process  is  as  follows  :  Into  a  Kjeldahl  digestive  flask  introduce 
a  definite  weight,  say  5  grams  of  milk,  about  0.7  gram  of  mercuric 
oxide,  and  20  cc.  of  sulphuric  acid  of  1.840  specific  gravity,  free  from 
nitrates  and  ammonium  sulphate.  Place  the  flask  in  an  inclined  posi- 
tion and  heat  below  the  boiling-point  of  the  acid  for  from  five  to  fifteen 
minutes,  or  until  frothing  ceases.  Then  raise  the  heat  until  the  mixture 
comes  to  boiling,  and  continue  the  process  imtil  the  liquid  is  clear  and 
has  a  very  pale  straw  color.  This  will  require  ordinarily  less  than  an 
hour.  Withdraw  the  lamp,  and  drop  in,  in  small  quantities  at  a  time, 
permanganate  of  potassium,  until,  after  shaking,  the  liquid  acquires  a 
permanent  green  or  purple  color.  This  addition  is  not  always  or  even 
usually  necessary  to  secure  complete  oxidation,  but  since  it  is  sometimes 
required,  it  is  best  to  make  it  a  part  of  the  routine.  Allow  the  contents 
to  cool,  and  then  transfer  them  with  about  200  cc.  of  distilled  water, 
plus  sufficient  for  thorough  rinsing,  to  a  distilling  flask  of  about  5e50  cc. 
capacity,  fitted  with  a  rubber  stopper  and  a  bulb  tube  connected  with  a 
very  long  Liebig  condenser,  the  delivery  end  of  which  is  fitted  with  a 
glass  tube  bent  at  right  angles,  so  that  it  may  dip  beneath  the  surface 
of  the  acid  into  which  the  distillate  is  to  be  received.  Add  a  few  pieces 
of  pumice  or  granulated  zinc,  or  about  0.5  gram  of  zinc  dust,  to  pre- 
vent bumping,  and  25  cc.  of  a  4  per  cent,  aqueous  solution  of  sulphide 
of  potassium,  to  prevent  the  formation  of  compounds  of  ammonium 
and  mercury,  which  are  not  w^holly  decomposable  by  alkalies.  Shake, 
and  then  add  of  a  saturated  solution  of  sodium  hydrate,  free  from 
nitrates,  sufficient  to  make  the  reaction  strongly  alkaline,  pouring  it 
clown  the  side  of  the  flask  so  as  not  to  mix  at  once  with  the  acid  con- 
tents. Next  connect  the  flask  with  the  condenser,  mix  the  contents  by 
gently  rotating,  and  apply  the  flame.  Distil,  and  receive  the  disttllate 
in  a  vessel  containing  50  cc.  of  decinormal  sulphuric  acid.  When  about 
175  cc.  have  passed  over,  it  may  be  assumed  that  all  ammonia  has  been 
expelled,  and  then  the  distillate  is  titrated  with  decinormal  alkali,  using 
cochineal  or  methyl-orange  as  an  indicator.  From  the  difl^erence  in 
strength  of  the  decinormal  acid,  the  amount  of  ammonia  is  calculated, 
and  from  this  the  amount  of  nitrogen ;  and  this  multiplied  by  6.25 
gives  the  total  proteids. 

Detection  of  Added  Coloring-  Matters. — Annatto. — To  about  100 
cc.  of  milk  in  a  cylinder  about  1.5  inches  in  diameter,  add  a  few  cc.  of 
sodium  carbonate  solution,  to  insure  a  strongly  alkaline  reaction  during 
the  examination,  and  then  introduce  a  strip  of  heavy  white  filter-paper 
about  0.5  by  5.5  inches,  and  set  the  whole  away  in  a  dark  place  over 
night.  If  any  annatto  color  is  present,  it  will,  through  selective 
affinity,  pass  from  the  milk  to  the  fibre  of  the  paper,  which  thereby 
acquires  a  salmon  tint,  the  depth  of  which  is  dependent  naturally  upon 
the  amount  of  the  substance  present.    The  strip  is  withdrawn  from  the 


PLATE  IV. 


A.  Strip  of    Filter    Paper   Dyed    by  rmmerslon    in   Milk   Colored  with  Annatto, 

B.  Same   after  Treatment   witli   Solution   of   Protoohloride  of  Tin, 


PLATE  V. 


Fig.  1. 


^■0 


'->-L  , 


;>* 


.  vl 


-Js-pX 


Fig.  2. 


Residues   obtained   in  testing    Milk   for   Caramel. 

Fig.    1.    From  unoolored  milk. 

Fig.  2.    From  milk  containing  oaramel. 


ANALYSIS  OF  MILK.  119 

milk,  washed  gently  in  running  water,  and  laid  upon  a  piece  of  paper 
of  the  same  kind  as  itself.  If  so  much  as  1  part  of  the  annatto  solu- 
tion in  100,000  is  present,  the  strip  will  show  a  distinct  salmon  tint. 
On  dipping  the  strip  into  stannous  chloride  solution  the  color  is 
changed  to  pink. 

Another  method,  by  means  of  which  all  the  color  in  the  amount  of 
milk  operated  upon  may  be  concentrated  in  a  form  best  adapted  for 
preservation  and  for  exhibits  in  court,  is  as  follows :  Coagulate  from 
100  to  150  cc.  of  the  specimen  by  the  application  of  heat  and  acetic 
acid,  and  separate  the  coagulum  by  straining  through  a  piece  of  cheese- 
cloth. The  coloring  matter,  being  insoluble  in  acid  media,  is  precipi- 
tated with  the  curd,  which,  however,  will  show  to  the  eye  scarcely  any 
indication  of  its  presence.  The  curd  is  placed  in  a  mortar  and  tritu- 
rated with  50-75  cc.  of  ether,  which  next  is  transferred  to  a  stoppered 
separating  funnel  and  shaken  with  10  cc.  of  a  1  per  cent,  solution  of 
caustic  soda.  When  the  two  liquids  become  separated,  the  latter, 
which  now  contains  the  annatto  color,  is  drawn  off  into  two  porcelain 
or  glass  dishes  about  an  inch  in  diameter,  in  each  of  which  a  disk 
of  filter-paper  is  placed.  They  are  then  set  aside  in  the  dark  and 
left  over  night.  The  disks  are  then  removed  and  washed  in  fresh 
water.  If  annatto  is  present,  they  will  have  acquired  a  color  vaiying  in 
depth  according  to  the  amount  of  the  dye  in  the  sample.  One  disk  is 
immersed  in  stannous  chloride  solution,  the  other  in  weak  sodium  car- 
bonate, and  then  dried  and  mounted  on  a  white  card.  The  colors 
yielded  by  a  specimen  of  milk  to  which  no  unusual  amount  of  the 
adulterant  has  been  added  are  shown  in  Plate  IV. 

Caramel. — Pour  125  to  250  cc.  of  the  suspected  sample  into  an  equal 
volume  of  95  per  cent,  alcohol,  and  filter.  The  filtrate,  if  not  perfectly 
clear,  should  be  returned  and  passed  through  until  it  is  quite  free  from 
turbidity.  Any  caramel  present  will  be  in  solution  in  the  alcoholic 
filtrate,  and  may  modify  considerably  its  color,  which  normally  is 
yellowish  or  greenish  according  to  season,  the  latter  obtaining  in  spring 
and  summer.  To  100  cc.  of  the  filtrate  add  2  cc.  of  solution  of  basic 
acetate  of  lead,  which  will  precipitate  the  caramel  together  with  any 
remaining  proteids,  the  precipitate  showing  a  slight  brownish  color 
if  caramel  has  been  used  in  sufficient  amount  to  bring  about  the 
improved  appearance  which  is  the  object  of  its  employment.  Filter, 
wash  with  distilled  water,  and  dry  in  an  air-bath.  According  as  the 
amount  of  caramel  present  is  large  or  small,  the  horny  residue  on  the 
filter-paper  will  have  a  more  or  less  deep  chocolate  tinge.  The  residue 
yielded  by  a  pure  milk  will  be  either  almost  colorless,  or  yellow,  or 
slightly  inclined  to  brownish,  l)ut  not  to  chocolate  color.  The  appear- 
ance of  the  two  kinds  of  residue  is  shown  in  Plate  V. 

Caramel  may  ylso  be  shown  if  we  proceed  accf)rding  to  the  second 
metliod  described  for  the  detection  of  annatto.  The  curd,  after  being 
freed  from  the  whey  and  triturated  with  ether,  gives  uj)  to  this  solvent 
only  fiit  and  annntto.  If  caramel  or  anilins  an;  j)resent,  the  curd  will 
appear  brownish  in  tlie  one  case  and  more  or  less  intensely  yellow  in 


120  FOODS. 

the  other.  If  the  curd  is  now  shaken  with  hydrochloric  acid,  one 
of  the  following  changes  will  be  observed :  If  anilin-orauge  is  present, 
the  color  becomes  bright  pink  almost  immediately  ;  with  caramel  it 
becomes  gradually  brownish  blue ;  if  neither  is  present,  the  change  is 
to  blue. 

Anilin-orange. — See  preceding  paragraph.  A  more  direct  method  is 
proposed  by  Lythgoe.^  Place  15  cc.  of  milk  in  a  porcelain  dish  and 
add  about  the  same  volume  of  hydrochloric  acid  (specific  gravity  1.200). 
Agitate  gently,  to  bring  about  thorough  mixing  and  to  break  up  the 
resulting  curd  into  rather  coarse  lumps.  If  anilin-orange  is  present, 
the  curd  will  be  colored  pink ;  if  none  is  present,  it  will  be  white  or 
yellowish. 

Detection  of  Preservatives. — Borax  and  Boric  Acid. — These  sub- 
stances are  detected  easily  either  in  the  milk  itself  or  in  the  ash  after 
ignition  of  the  residue.  In  the  latter  case,  moisten  the  ash  Avith  a 
drop  or  two  of  strong  sulphuric  acid,  and  after  a  few  minutes  add  3  or 
4  cc.  of  strong  alcohol.  Dip  a  strip  of  turmeric  paper  into  the  mixt- 
ure and  allow  it  to  dry  without  the  aid  of  heat.  In  the  presence  of 
either  of  the  substances  sought  for,  the  paper  will  have,  when  dry,  the 
characteristic  red  color  due  to  boric  acid,  instead  of  the  yellow  color 
which  will  be  maintained  in  its  absence.  While  the  paper  is  drying, 
place  the  dish  in  a  dark  place  and  ignite  the  contained  alcohol.  If 
boric  acid  or  its  sodium  compound  is  present,  the  flame  will  show  at 
its  outer  edge  a  characteristic  greenish  coloration.  This  is  shown  most 
strongly  directly  after  the  alcohol  is  ignited. 

In  the  original  milk,  the  test  may  be  made  in  the  following  manner : 
Mix  a  few  drops  of  the  milk  and  an  equal  amount  of  fresh  tincture 
of  turmeric  in  a  small  porcelain  dish  and  evaporate  on  a  water-bath  to 
dryness.  Moisten  the  surface  of  the  residue  with  dilute  hydrochloric 
acid,  and  dry  again.  If  either  of  the  substances  is  present,  the  residue 
will  be  light  pink  to  dark  red  in  color,  and  the  addition  of  a  drop  of 
ammonia-water  will  change  this  to  a  green  or  greenish  blue,  according 
to  the  amount  of  the  preservative  present. 

Salicylic  Acid. — 1.  Coagulate  about  75  to  100  cc.  of  milk  with 
mercuric  nitrate  solution  or  hydrochloric  acid,  and  separate  the  whey 
by  filtration.  Shake  the  whey  with  ether,  decant  the  ether  into  a 
watch-glass,  and  allow  it  to  evaporate.  To  the  residue  on  the  watch- 
glass,  apply  a  drop  of  neutral  ferric  chloride.  If  salicylic  acid  is  pres- 
ent, the  characteristic  purple  coloration  is  produced.  2.  Mix  the  milk 
Avith  phosphoric  acid  and  strain  through  cloth.  Place  the  liquid  in  a 
flask,  connect  with  a  condenser,  and  distil.  Test  the  distillate  with 
ferric  chloride  from  time  to  time.  Any  salicylic  acid  present  will  go 
over  with  the  steam,  most  of  it  toward  the  end  of  the  operation. 

Formaldehyde. — Many  processes  for  the  detection  of  this  substance 
in  milk  have  been  devised,  some  exceedingly  simple  and  others  quite 
complicated.  Those  which  give  the  best  results  and  the  greatest  satis- 
faction are,  on  the  whole,  those  which  are  the  simplest  in  application 
1  Eeport  of  Massachusetts  State  Board  of  Health  for  1900,  p.  647. 


ANALYSIS  OF  MILK.  121 

and  require  the  least  expenditure  of  time.  The  test  should  be  applied 
within  a  few  days  after  the  addition  of  the  preservative,  since  after  a 
time  it  cannot  be  detected. 

1.  Method  by  Decolorized  Fuchsine. — Through  a  solution  of 
fuchsine  1  :  500  pass  a  current  of  sulphurous  acid  gas,  obtained  l^y 
heating  copper  wire  or  foil  with  sulphuric  acid,  until  the  color  is  dis- 
charged. Preserve  in  a  glass-stoppered  bottle.  To  10  cc.  of  milk,  add 
1  cc.  of  the  reagent  and  let  stand  ten  minutes.  Add  2  cc.  of  strong 
hydrochloric  acid  and  shake  or  stir  briskly.  The  color  which  appears 
in  the  first  instance  is  discharged  completely  by  the  acid  if  no  formal- 
dehyde is  present;  otherwise,  a  violet-blue  tinge  remains.  If  the  amount 
present  is  large,  the  end  color  will  be  correspondingly  intense.  This 
method  will  detect  the  admixture  of  1  part  of  formalin  in  50,000  of 
milk.  If  the  milk  be  distilled  first,  and  the  first  part  of  the  distillate 
treated  with  fuchsine  solution,  the  test  is  delicate  to  the  extent  of  re- 
vealing 1  part  in  500,000. 

2.  Method  by  Phloroglucin. — Add  to  10  cc.  of  milk  in  a  test- 
tube  2  or  3  cc.  of  a  0.10  per  cent,  solution  of  phloroglucin  and  5  to 
10  drops  of  a  10  per  cent,  solution  of  sodium  hydrate,  and  shake.  In  the 
presence  of  formaldehyde  a  gradual  red  coloration  appears ;  otherwise,  no 
such  change  is  observed.  This  test  is  said  to  reveal  1  part  in  50,000, 
but  such  a  claim  appears,  according  to  the  experience  of  the  author  and 
others,  not  to  be  justified. 

3.  Method  by  Ferric  Chloride. — Mix  in  a  porcelain  dish  10 
cc.  each  of  milk  and  hydrochloric  acid  (specific  gravity  1.200)  and  1  drop 
of  ferric  chloride  solution.  Heat  and  stir  vigorously.  If  formaldehyde 
has  been  added,  a  violet  color  will  appear  before  the  boiling-point  is 
reached,  varying  in  intensity  according  to  the  amount  present.  This 
process  is  exceedingly  delicate,  and  will  detect  1  part  in  500,000  in 
the  fresh  condition. 

4.  Method  by  Commercial  Sulphuric  Acid. — This  test  is  ex- 
ceedingly delicate  and  very  easily  applied.  It  cannot  be  performed 
with  pure  sulphuric  acid,  since  the  presence  of  a  trace  of  iron  is  neces- 
sary. If  one  desires  to  use  a  pure  acid  rather  than  the  ordinary  com- 
mercial grade,  the  addition  of  a  very  small  amount  of  ferric  chloride 
will  be  sufficient. 

Take  about  15  to  20  cc.  of  milk  in  a  test-tube  and  pour  about  5  cc. 
of  the  acid  gently  down  the  side  so  that  it  shall  pass  under,  rather  than 
mix  with,  the  milk.  Let  stand  a  few  minutes,  and  then  note  the  color 
at  the  junction  of  the  two  liquids.  If  formalin  is  present,  even  in  the 
slightest  traces,  a  violet  coloration  appears  at  the  line  of  junction.  In- 
asmuch as  jmre  milk  will  show  a  somewhat  purplish  color  when  in 
contact  with  strong  sidphuric  acid,  a  color  which  may  readily  be  mis- 
taken at  first  for  that  due  to  formaldehyde,  and  since  also  the  charring 
that  occurs  at  the  line  of  junction  will  often  obscure  the  reaction,  the 
process  as  originally  recommended  is  somewhat  faulty.  The  objecitions 
arc  removed,  howev(!r,  by  diluting  tin;  strong  acid  with  water  so  that 
its  specific  gravity  is  reduced  from  1.84r)  to  1.700.     The  action  of  the 


122  FOODS. 

stronger  acid  on  pnre  milk  is  shown  in  Plate  VI.,  Fig.  1,  which  shows 
the  dark  color  due  to  charring  and  the  purplish  color,  above  spoken  of, 
due  to  the  same  cause. 

In  Plate  VI.,  Fig.  2,  is  shown  the  appearance  of  the  line  of  junction 
of  pure  milk  and  the  diluted  acid.  It  will  be  observed  that  the  color 
j)roduced  is  but  a  faint  yellow.  In  Plate  VI.,  Figs.  3  and  4,  are 
shown  the  zones  produced  in  milk  containing  formaldehyde  in  the  pro- 
portions of  1  part  to  25,000  and  1  to  50,000  by  the  use  of  the  diluted 
acid.  As  may  be  inferred,  the  reaction  is  produced  rather  more  slowly 
with  the  weaker  acid.  It  is  best  to  allow  the  contact  to  continue  at 
least  an  hour  before  noting  a  negative  result. 

5.  Luebeet's^  Method  by  Potassium  Sulphate. — Place  5  grams 
of  coarsely  powdered  potassium  sulphate  in  a  100  cc.  flask  and  dis- 
tribute over  it  5  cc.  of  milk  by  means  of  a  pipette.  Then  pour  care- 
fully down  the  side  of  the  flask  10  cc.  of  sulphuric  acid  (specific  gravity 
1.840),  and  allow  the  whole  to  stand  quietly.  If  formaldehyde  is 
present,  a  violet  coloration  of  the  potassium  sulphate  occurs  within 
a  few  minutes,  and  gradually  diifuses  through  the  entire  liquid. 
If  none  is  present,  the  mixture  will  at  once  assume  a  brown  color, 
which  rapidly  changes  to  black.  This  test  is  sensitive  to  1  part  in 
250,000. 

Chromates. — Froidevaux^  recommends  dissolving  the  ash  of  about 
10  cc.  of  milk  in  a  few  drops  of  water  acidulated  with  nitric  acid  and, 
after  neutralizing  w'ith  magnesium  carbonate,  adding  a  few  drops  of  test- 
solution  of  nitrate  of  silver,  whereby  a  red  precipitate,  chromate  of 
silver,  is  formed.  As  a  control  test,  he  recommends  taking  up  another 
portion  of  ash  with  water  acidulated  wdth  sulphuric  acid,  and  adding 
little  by  little  tincture  of  guaiacum.  In  the  presence  of  chromates, 
an  intense  blue  color  is  produced,  which  disappears  very  quickly.  This 
process  will  detect  1  part  in  50,000.  Guerin  ^  claims  greater  delicacy 
for  the  following  method  :  To  5  or  10  cc.  of  milk  add  2  drops  of  a  1 
per  cent,  solution  of  sulphate  of  copper  and  2  or  3  drops  of  freshly 
prepared  tincture  of  guaiacum.  Pure  milk  gives  a  greenish  color,  while 
milk  containing  1  part  in  100,000  will  give  an  intense  blue,  which 
reaches  its  maximum  in  a  few  minutes. 

Methods  of  Distinguishing  between  Raw  and  Cooked  Milk. — To 
determine  w^hether  or  not  milk  has  been  cooked,  Saul  *  recommends  the 
addition  of  1  cc.  of  a  1  per  cent,  solution  (fresh)  of  ortol  (Orthometh- 
ylaminophenol  sulphate)  to  10  cc.  of  milk,  and  then  1  drop  of  com- 
mercial hydrogen  peroxide  solution.  Raw  milk  develops  a  red  color 
almost  immediately,  but  milk  heated  beyond  75°  C.  remains  unchanged. 

Dupouy  ^  gives  the  following  tests  : 

1.  Guaiacol.  Equal  volumes  of  milk  and  a  1  per  cent,  solution  of 
guaiacol  in  water  are  mixed  and  then  treated  with  hydrogen  peroxide. 

^  Journal  of  the  American  Chemical  Society,  September,  1901,  p.  682. 
^  Journal  de  Phamiacie  et  de  Chemie,  1896,  p.  155. 
3  Chemiker  Zeitung,  1897,  p.  174. 

*  British  Medical  Journal,  March  24,  1903. 

*  Journal  de  Pharmacie  et  de  Chemie,  1897,  p.  397. 


PLATE  VI. 


Fig.  1. 


Fig.  2. 


Fig.  8. 


Fig.  4. 


Fig.  1.  Coloration  Produced  by  Concentrated  Sulphuric  Acid,  Sp.  Gr.  1.840,  in 
Contact   -with    Pure    Milk. 

Fig.  2.  Coloration  Produced  by  Sulphuric  Acid  of  Sp.  Gr.  1.700  in  Contact 
with     Pure     Milk. 

Fig.  S.  Coloration  Produced  by  Sulphuric  Acid  of  Sp.  Gr.  1.700  in  Contact 
with     Milk    Containing     1     Part    of    Formaldehyde    in    25,000. 

Fig.  4.  Coloration  Produced  by  Sulphuric  Acid  of  Sp,  Gr.  J. 700  in  Contact 
with     Milk    Containing    1     Part    of    Formaldehyde    in    50,000. 


ANALYSIS  OF  MILK.  123 

The  immediate  production  of  a  yellow  color  indicates  that  the  specimen 
has  not  been  boiled. 

2.  Hydroquinone.  Three  cc.  of  milk  are  mixed  with  1  cc.  of  a 
fresh  10  per  cent,  aqueous  solution  of  hydroquinone  and  15  drops  of 
hydrogen  peroxide.  If  the  milk  has  not  been  boiled,  a  rose  color  im- 
mediately appears,  and  in  a  few  minutes  green  crystals  are  deposited. 

3.  Pyrocatechin.  Equal  volumes  of  raw  milk  and  an  aqueous  10 
per  cent,  solution  of  pyrocatechin  are  brought  together  and  treated 
with  hydrogen  peroxide.  With  raw  milk  a  yellowish-brown  color  is 
produced ;  with  boiled  milk  no  color  appears. 

4.  a-Naphthol.  Raw  milk  gives  with  an  aqueous  solution  of 
«-naphthol  and  hydrogen  peroxide  a  violet-blue  color.  Boiled  milk 
gives  none. 

Storch's  method^  is  as  follows  :  To  10  cc.  of  milk,  add  1  drop  of  a 
0.2  per  cent,  solution  of  hydrogen  peroxide  and  2  drops  of  a  2  per 
cent,  solution  of  p-phenylenediamin  and  shake  violently.  If  the  milk 
has  not  been  heated  to  78°  C.  (172.4°  F.),  an  immediate  blue  color 
will  appear;  if  it  has  been  heated  to  80°  C.  (178°  F.),  the  blue  color 
appears  in  about  a  half  minute ;  and  if  it  has  been  heated  higher  than 
this,  the  blue  will  not  appear  at  all.  Sour  milk  should  be  neutralized 
with  lime-water.  Formaldehyde  prevents  the  change  to  blue,  but 
permits  the  occurrence  of  a  faint  red.  The  p-phenylenediamin  solution 
keeps,  in  dark  glass,  about  two  months. 

Bernstein^  proposes  the  following:  To  50  cc.  of  milk,  add  4.5  cc. 
of  normal  acetic  acid,  shake  gently  until  coagulation  occurs,  and  filter. 
Heat  the  filtrate.  If  the  milk  has  not  been  pasteurized,  a  heavy  pre- 
cipitate of  lactalbumin  will  form.  The  higher  the  milk  has  been 
heated,  up  to  90°  C.  (194°  F.),  the  smaller  will  be  the  precipitate; 
and  if  it  has  been  heated  beyond  this,  no  precipitate  at  all  will 
form. 

Detection  of  Gelatin  in  Cream. — For  the  detection  of  gelatin  in 
cream,  to  which  it  sometimes  is  added  to  give  it  body,  Stokes^  recom- 
mends the  following  procedure  :  Dissolve  a  quantity  of  mercnrv  in 
twice  its  weight  of  strong  nitric  acid  (specific  gravity  1.420) ;  dilute 
with  water  to  25  times  its  bulk.  To  about  10  cc.  of  this  solution  add 
a  like  quantity  of  the  cream  and  about  20  cc.  of  cold  water.  Shake 
the  mixture  vigorously,  let  stand  for  five  minutes,  then  filter.  If 
much  gelatin  be  present,  it  will  be  impossible  to  get  a  clear  filtrate. 
To  the  filtrate,  or  to  a  portion  of  it,  add  an  equal  bulk  of  a  saturated 
aqueous  solution  of  picric  acid.  If  gelatin  be  present,  a  yellow  pre- 
cipitate will  immediately  be  produced.  The  whole  operation  is  performed 
in  the  cold,  and  if  the  mercury  solution  is  ready,  the  test  Mali  not  take 
more  tlian  ten  minutes.  Picric  acid  will  show  the  presence  of  1  part 
of  gelatin  in  1 0,000  parts  of  water. 

'  Zeitschrift  fiir  TJntersuchunc;  der  Nalinings-  unci  G-enussmittel,  1901,  p.  898. 
''Zeitschrift  fiir  Fleis(;li-  und  Milcliliygieiie,  1900,  p.  80. 
'  The  Analyst,  December,  1897. 


124  FOODS. 


BUTTER. 


This  valuable  milk  product  is  the  result  of  violent  agitation  of  cream 
until  its  fat  coalesces  into  granular  particles,  which  are  then  separated 
from  the  residual  buttermilk,  "  worked  "  to  expel  as  much  of  the  latter 
as  possible,  and,  with  or  without  the  addition  of  salt  and  coloring  mat- 
ter, formed  into  "  prints  "  or  "  pats,"  or  packed  in  bulk  in  boxes  and 
firkins.  Its  natural  color  varies  with  the  season,  the  so-called  June 
butter,  made  when  the  cows  from  whose  milk  it  is  produced  are  feeding 
on  grass,  being  bright  yellow,  while  that  made  when  they  are  stalled, 
and  fed  on  hay  and  other  winter  feed,  being  almost  white.  The  popu- 
lar demand  being  for  a  yellow  article  the  year  round,  it  is  customary 
to  secure  this  color  out  of  season  by  the  addition  of  annatto  and  other 
harmless  vegetable  coloring  agents,  the  use  of  which  has  almost  uni- 
versally the  sanction  of  laW' . 

The  flavor  is  influenced  much  by  the  character  of  the  feed,  by  the 
care  exercised  in  manufacture,  by  the  amount  of  added  salt,  by  age, 
and  by  the  conditions  of  storage.  Like  milk,  it  absorbs  odors  very 
readily,  both  those  which  improve  and  those  which  impair  its  flavor. 
Taking  advantage  of  this  fact,  it  is  the  custom  in  the  valley  of  the  A'^ar 
and  in  some  other  localities  to  place  the  freshly  made  product  in  prox- 
imity to  jasmine,  violets,  tuberoses,  and  other  flowering  plants,  in  order 
that  their  fragrance  may  be  absorbed.  This  practice  is  known  as 
"  enfleurage."  The  most  delicately  flavored  butter  under  natural  con- 
ditions is  that  to  which  no  salt  has  been  added,  but  it  has  the  disad- 
vantage that  within  a  short  time  it  acquires  a  "  cheesy  "  flavor,  due  to 
decom])osition  processes.  Owing  to  its  lack  of  keeping  qualities  and 
to  the  very  general  preference  for  a  more  pronounced  taste,  the  addi- 
tion of  salt  in  varying  amounts  is  the  rule.  Butter  of  good  quality 
has  but  slight  odor,  but  that  which  has  undergone  the  common  changes 
due  to  bacterial  action  has  the  characteristic  odor  and  taste  of  raucidity. 
This  is  due  to  decomposition  of  the  small  amount  of  curd  which  is  en- 
tangled in  the  making,  and  which  cannot  Avholly  be  excluded.  The  fat 
itself,  when  separated  from  the  curd  by  melting,  keeps  unchanged  for 
long  periods.  In  rancid  butter,  butyric  and  other  acids  are  liberated, 
and  others,  as  formic,  are  formed  by  absorption  of  oxygen.  Under 
some  unusual  conditions  not  wholly  understood,  butter,  without  becom- 
ing rancid  in  the  usual  sense,  undergoes  a  change  to  a  perfectly  white 
substance  with  a  marked  talloAvy  odor. 

Butter  varies  considerably  in  composition,  but  a  fair  average  may  be 
stated  as  foUows : 

Fat 84.00 

Water 12.00  . 

Curd 1.00 

Salts 2.50 

Lactose 0.50 

It  may  be  made  to  contain  a  much  higher  percentage  of  water,  with 
correspondingly  less  fat. 


BUTTER.  125 

The  fat  is  composed  of  glycerides  of  two  groaj)s  of  fatty  acids,  which 
have  been  mentioned  in  the  description  of  milk.  Those  of  the  in- 
sokible  non-volatile  acids,  oleic,  stearic,  and  palmitic,  constitute  about 
92.25  per  cent,  of  the  whole ;  and  those  of  the  soluble  volatile  acids, 
butyric,  caproic,  caprylic,  and  capric,  make  up  the  remainder.  It  is 
to  the  second  group  that  butter  owes  its  distinctive  flavor. 

The  amount  of  water  depends  largely  upon  the  thoroughness  with 
which  the  buttermilk  is  worked  out.  In  order  that  more  water  may 
be  held,  and  thus  a  greater  profit  realized,  some  makers  employ  gelatin 
as  an  adulterant.  One  gram  of  this  substance  will  take  up  about  10 
grams  of  water,  and,  when  mixed  with  butter  in  the  right  propor- 
tion, will  hold  water  in  the  above  ratio  without  affecting  the  consistence 
injuriously.  Others  employ  glucose  both  for  this  purpose  and  as  a 
preservative. 

The  salts  include  those  natural  to  milk  and  those  added  for  the  pre- 
vention of  rapid  decomposition.  The  usual  addition  is  common  salt, 
but  the  use  of  boric  acid  and  borax  is  extending  gradually. 

Apart  from  the  use  of  preservatives  and  of  agents  to  assist  in  retain- 
ing water,  butter  is  not  much  subject  to  adulteration,  excepting  in  the 
sense  that  substitution  of  an  article  of  less  value  when  butter  is  called 
for  is  a  form  of  adulteration.  This  substitute  is  known  variously  as 
artificial  butter,  butterine,  oleomargarine,  and  margarine.  Under  the 
United  States  statutes,  all  butter  or  substitutes  therefor  made  to 
resemble  it,  containing  fats  other  than  cream,  shall  be  known  as  oleo- 
margarine. 

Following  the  original  process,  oleomargarine  is  made  from  fresh 
beef  suet,  which,  after  being  cooled,  washed,  and  cut  into  very  fine 
pieces  by  machinery,  is  subjected  to  a  temperature  of  about  110°  F. 
for  several  hours,  in  order  to  separate  the  fat  from  the  tissue.  It  is 
then  drawn  off  and  kept  for  a  time  at  80°  to  90°  F.,  at  which  tem- 
perature the  stearin  solidifies,  and  then  is  separated  by  pressure  from 
the  "oleo-oil."  The  latter  is  churned  with  milk  or  with  milk  and  gen- 
uine butter,  colored  with  annatto,  and  otherwise  treated  like  butter. 
At  the  present  time,  oleomargarine  is  made  not  alone  from  beef  suet, 
but  to  a  much  greater  extent  from  "  neutral  lard,"  a  product  of  leaf 
lard.  Cotton-seed  oil  is  used  to  some  extent,  but  naturally  it  is  not  so 
well  adapted  to  the  purpose  as  the  solid  fats. 

Oleomargarine  has  been  misrepresented  to  the  public  to  a  greater 
extent  probably  than  any  other  article  of  food.  From  the  time  of  its 
first  appearance  in  the  market  as  a  competitor  of  butter,  there  has  been 
a  constant  attempt  to  create  and  foster  a  prejudice  against  it  as  an 
unwhf)lesome  article  made  from  unclean  refuse  of  various  kinds,  a 
vehicle  for  disease  germs,  and  a  disseminator  of  tapeworms  and  other 
unwelcome  parasites.  It  has  been  said  to  be  made  from  soaji  grease, 
from  the  carcasses  of  animals  dead  of  disease,  from  grease  extracted 
from  sewer  sludge,  and  from  a  \-ariety  of  other  articles  equally  unudajitcd 
to  its  manufacture.  The  ])ubH('ation  of  a  great  mass  of  untruth  cannot 
fail  tf)  have  at  least  a  j)art  of  its  desired  effect,  not  solely  on  the  minds 


126  FOODS. 

of  the  ignortiDt,  but  even  on  those  of  persons  of  more  than  average 
intelligence.  So  a  prejudice  was  created  against  this  valuable  food 
product,  but  it  is  becoming  gradually  less  pronounced. 

The  truth  concerning  oleomargarine  is  that  it  is  made  only  from  the 
cleanest  materials  in  the  cleanest  possible  manner ;  that  it  is  equally  as 
wholesome  as  butter ;  and  that  when  sold  for  what  it  is  and  at  its 
proper  price  it  brings  into  the  dietary  of  those  who  cannot  afford  the 
better  grades  of  butter  an  important  fat  food  much  superior  in  flavor 
and  keeping  property  to  the  chexiper  grades  of  butter,  which  bring  a 
higher  price.  Oleomargarme  cannot  be  made  from  rancid  fat,  and  in  its 
manufacture  great  care  must  be  exercised  to  exclude  any  material  how- 
ever slightly  tainted. 

Oleomargarine  is  not  and  cannot  be  made  from  fats  having  a  marked 
or  distinctive  taste,  and  its  flavor  is  derived  wholly  from  the  milk  or 
genuine  butter  employed  in  its  manufacture.  It  contains,  as  a  rule, 
less  water  than  does  genuine  butter,  and  consequently  any  difference  in 
food  value  is  in  its  favor.  It  undergoes  decomposition  much  more 
slowly,  and,  indeed,  may  be  kept  many  months  without  becoming  rancid. 
Much  has  been  said  concerning  its  digestibility,  and  alarmists  have  gone 
so  far  as  to  claim  that  it  is  very  indigestible,  and  likely  to  prove  a  pro- 
lific cause  of  dyspepsia,  quite  forgetting  that  the  materials  from  which 
it  is  made  have  held  a  place  in  the  dietaries  of  all  civilized  peoples  since 
long  before  butter  was  promoted  from  its  position  as  an  ointment  to  that 
of  an  article  of  food,  INIany  comparative  studies  have  been  made  on  this 
point,  and  the  results  in  general  have  shown  that  there  is  little  if  any 
difference.  H.  Liihrig  ^  has  proved  by  careful  experiment  that  the 
two  are  to  all  intents  and  pui-j^oses  exactly  alike  in  point  of  digesti- 
bility. 

Oleomargarine  has  been  the  subject  of  a  vast  amount  of  restrictive 
legislation  wherever  it  is  made  or  sold.  This  has  been  passed  in  the 
interest  of  dairymen  and  because  of  the  ease  with  which  it  may  be 
sold  fraudulently  as  butter  at  butter  prices.  To  the  practice  of  fraud 
in  its  retail  sale,  is  due  very  largely  the  passage  of  prohibitive  laws, 
many  of  which,  however,  have  been  declared  imconstitutional.  In 
Massachusetts,  for  example,  it  had  at  one  time  a  very  large  sale,  and  in 
the  city  of  Boston  alone  were  nearly  200  licensed  dealers.  But  the 
amount  of  fraudulent  dealing  was  so  great  that  the  Legislature  passed 
an  act  prohibiting  its  sale  if  it  contained  any  ingredient  causing  it  to 
look  like  butter ;  in  other  words,  no  annatto  or  other  substance  which 
would  cause  it  to  be  yellow  could  be  used  in  its  manufacture.  Since  its 
natural  color  is  almost  white,  and  since  white  butter  does  not  appeal  to 
the  eye,  the  result  was  practically  the  withdrawal  of  the  article  from 
Dpen  sale. 

In  Germany,  on  account  of  fraudulent  practices  in  the  adulteration 
of  butter  with  oleomargarine,  the  government  passed,  in  1897,  a  statute 
requiring  the  latter  to  contain  10  per  cent,  of  oil  of  sesame,  so  that  any 
subsequent  admixture  with  butter  may  readily  be  detected  by  Bau- 

1  Zeitschrift  fiir  Untersuchung  der  Nahrungs-  und  Genussmittel,  June,  1899,  p.  484. 


BUTTER.  127 

douin's  reaction.  This  is  a  red  coloration  brouglit  about  when  oil  of 
sesame,  furfurol,  and  hydrochloric  acid  are  brought  together ;  and  it  is 
sufficiently  delicate  to  show  the  adulteration  of  butter  with  2.5  per 
cent,  of  oleomargarine  containing  the  oil  in  the  proportion  stated. 
Experiment  has  shown  that  butter  made  from  the  milk  of  cows  fed  on 
sesame  does  not  yield  the  reaction,  but  the  fat  of  the  milk  of  goats  fed 
partly  on  sesame  has  been  found  to  give  it. 

The  principal  chemical  difference  between  butter  and  oleomargarine 
lies  in  the  relative  amounts  of  glycerides  of  the  soluble  and  insoluble 
fatty  acids.  Genuine  butter-fat  contains  nearly  8  per  cent,  of  butyrin, 
caproin,  caprin,  and  caprylin,  while  the  artificial  product  contains  these 
glycerides  only  as  they  are  introduced  in  the  amount  of  milk  or  butter 
with  which  it  is  churned,  for  they  are  not  present  in  suet,  lard,  and 
other  animal  fats. 

Of  late  years,  high-grade  butter  has  found  another  formidable  com- 
petitor in  what  is  known  variously  as  renovated  butter,  process  butter, 
and  hash  butter.  The  material  from  which  this  is  made  is  gathered 
from  dairies  scattered  over  a  wide  expanse  of  country,  and  differs 
widely  in  color,  texture,  age,  and  flavor.  It  is  melted,  purified  of  its 
rancidity  by  washing,  given  the  desired  yellow  color,  and  rechurned. 

Butter  as  a  Carrier  of  Disease. — Since  milk  is  known  to  be  a  car- 
rier of  the  germs  of  certain  diseases  under  some  conditions,  the  possi- 
bility that  butter  may  act  in  the  same  way  suggests  itself,  and  the  more 
strongly  since,  in  ordinary  creaming  of  milk,  all  but  a  very  small  pro- 
portion of  the  bacteria  rise  with  the  cream.  Ordinary  butter  contains 
millions  of  bacteria  to  the  gram,  but  whether  the  pathogenic  forms  can 
long  survive  has  not  been  investigated  very  extensively,  except  in  the 
case  of  the  bacillus  of  tuberculosis.  The  bacteria  of  cholera  and 
typhoid  fever  have  been  known  to  survive  several  days  after  being 
planted  in  butter,  but  beyond  this  we  have  little  knowledge. 

Brusaferro,  in  1891,  produced  tuberculosis  in  a  rabbit  through  the 
injection  of  butter  made  from  the  milk  of  a  cow  with  a  tuberculous 
udder.  Roth,  in  1894,  got  similar  results,  and  found,  moreover,  that 
2  out  of  20  market  samples  of  butter  used  by  him  yielded  positive  re- 
sults. Schuchardt  got  negative  results  from  42  samples,  while  Ober- 
miiller  found  the  bacillus  in  every  sample  of  Berlin  butter  used  in  his 
first  series  of  experiments.  Dr.  Lydia  Rabinowitsch  ^  examined  80 
samples  obtained  partly  in  Berlin  and  partly  in  Philadelphia,  and  found 
genuine  tubercle  bacilli  in  not  a  single  instance.  She  did,  however, 
find  a  spurious  organism,  which  produced  in  guinea-pigs  changes  which 
required  very  careful  examination  for  the  determination  of  its  non- 
tuberculous  character.  It  was  present  in  28.7  per  cent,  of  the 
samples.  Petri  ^  found  it  in  37.2  per  cent.,  the  genuine  bacillus  in 
32.4  per  cent.,  and  neither  the  one  nor  the  other  in  30.4  per  cent. 
Obermiiller,''  using  salted  butter  in  a  second  series,  determined  that  the 

'  Zeitsfhrift  fiir  Hygiene  unci  Infectionskranklieiten,  XXVI.,  p.  90. 
'^  Arbeiten  aiis  detn  kaiserlichen  MesuiidheiLsaiiite,  1898,  p.  27. 
•'  Hy^neniscJie  Kundschau,  1899,  No.  2. 


128  FOODS. 

injection  of  the  butter-fat  itself  introduced  a  cause  of  irritation,  and 
used,  therefore,  in  his  next  set  the  watery  fluid  separated  from  the 
butter  by  heat  and  centrifugation.  Four  samples  out  of  10  from  the 
vSame  source  as  his  first  lot  gave  undoubted  evidence  of  the  presence  of 
genuine  tubercle  bacilli.  Otto  Korn  ^  found  them  in  23.5  per  cent,  of 
samples  purchased  in  Freiburg,  and  Dr.  C.  Coggi^  in  only  2  out  of  100 
samples  purchased  in  Milan,  though  in  a  number  of  them  the  spurious 
organism  was  present.  Morgenroth^  has  subjected  oleomargarine  to  a 
similar  investigation,  since  milk  is  used  in  its  manufacture,  and  has  re- 
ported positive  results  from  9  out  of  20  samples.  Anuett*  examined 
28  samples  of  oleomargarine  (15  from  Berlin  and  13  from  Liverpool), 
and  found  virulent  tubercle  bacilli  in  only  1. 

We  have  as  yet  no  evidence  whatever  that  tuberculosis  has  ever  been 
spread  through  the  agency  of  butter,  but  the  subject  deserves  most 
thouo-htful  consideration. 

Analysis  of  Butter. — Ordinarily,  the  examination  of  butter  is  lim- 
ited to  the  determination  of  whether  or  not  it  is  mixed  with  or  replaced 
by  oleomargarine,  but  for  the  determination  of  its  food  value  it  is 
necessary  to  ascertain  the  proportions  of  fat  and  water.  It  is  some- 
times of  interest  also  to  determine  the  amount  of  salt  and  the  presence 
of  other  preservatives. 

Determination  of  Water. — AVeigh  a  gram  or  two  of  the  sample  into  a 
platinum  dish,  such  as  is  used  ui  the  analysis  of  milk,  and  dry  to  con- 
stant weight  on  a  water-bath. 

Determination  of  Fat. — Extract  the  residue  from  the  preceding  de- 
termination with  ether  or  freshly  distilled  naphtha,  being  careful  not  to 
remove  any  of  the  particles  of  curd  or  salt.  The  process  of  extraction 
is  very  sim])le,  consisting  in  filling  the  dish  about  half  full  of  the  sol- 
vent and  after  a  short  time  decanting  it  carefully  into  another  vessel, 
and  repeating  the  operation  until  nothing  is  extracted.  The  solvent, 
or  an  aliquot  part  thereof,  may  be  evaporated  in  a  weighed  beaker,  or 
the  dish  may  again  be  heated  to  a  constant  weight  and  the  fat  deter- 
mined by  difference.  The  residue  now  represents  the  curd,  lactose,  and 
mineral  matters. 

Determination  of  Salt,  etc. — Ignite  this  residue  at  as  low  a  tempera- 
ture as  possible,  and  thus  burn  off  the  casein  and  laclose.  Their  com- 
bined weight  is  ascertained  by  weighing  the  dish  anew.  What  now 
remains  in  the  dish  is  mineral  matter,  comprising  the  salts  natural  to 
milk  and  those  added.  Common  salt  may  be  determined  by  treating 
the  final  residue  with  w\ater  acidulated  Avith  nitric  acid,  and  titrating  in 
the  usual  way  with  standard  solution  of  silver  nitrate,  using  potassium 
chromate  as  an  indicator. 

Another  method  of  determining  salt  is  as  follows  :  Shake  a  known 
Aveight,  5-10  grams,  of  the  sample  with  hot  Avater  in  a  stoppered  sep- 

1  Archiv  fiir  Hygiene,  XXXVL,  p.  57. 

^  Giornale  della  E.  Societa  italiana  d'igiene,  July,  1899,  p.  289. 

■'  Hygienisclie  Rundschau,  1899,  No.  21. 

*  The  Lancet,  January  20,  1900. 


BUTTER.  129 

arating  funnel  until  it  is  melted  completely,  let  stand  until  the  fat 
gathers  on  the  surface  of  the  water,  and  then  draw  off  the  latter  through 
the  stopcock.  Repeat  the  operation  with  successive  portions  of  about 
20—25  cc.  of  hot  water  until  a  few  drops  of  the  washings,  tested  with 
silver  nitrate,  fail  to  show  a  cloudiness,  due  to  silver  chloride.  Allow 
the  combined  washings  to  cool,  and  then,  in  an  aliquot  portion,  deter- 
mine the  chlorine  by  standard  silver  nitrate  solution  in  the  usual  way. 

Determination  of  the  Nature  of  the  Fat. — To  determine  whether  or 
not  a  specimen  is  or  contains  oleomargarine,  an  examination  of  the 
nature  of  the  fat  is  necessary.  As  has  been  pointed  out,  genuine  butter 
contains  a  considerable  amount  of  volatile  fatty  acids,  while  the  artifi- 
cial product  contains  very  little ;  but,  on  the  other  hand,  the  genuine 
article  is  correspondingly  poorer  in  the  insoluble  non-volatile  fatty 
acids.  It  is  upon  these  differences  in  the  two  kinds  of  fat  that  the 
determination  of  the  question  of  genuineness  depends.  The  usual 
examination  is  limited  to  the  determination  of  the  volatile  fatty  acids 
in  a  given  weight  of  the  melted  fat  freed  from  water,  curd,  and  salt. 
The  fat  is  saponified,  the  resulting  soap  is  dissolved  in  water  and  then 
decomposed  by  means  of  sulphuric  acid,  and  the  volatile  fatty  acids, 
thus  freed  from  combination,  are  then  distilled  over,  and  their  amount 
estimated  by  means  of  decinormal  sodium  hydrate.  Five  grams  of 
genuine  butter-fat  will  yield  an  amount  which  will  require  at  least  24 
cc.  of  the  alkali  for  complete  neutralization,  while  an  equal  weight  of 
oleomargarine  yields  so  small  an  amount  that,  as  a  rule,  less  than  1  cc. 
is  required.  Mixtures  give  results  between  these  limits,  and  from  them 
one  can  estimate  approximately  the  proportion  of  butter  present. 

Process. — Heat  a  small  piece  of  the  sample  on  a  water-bath  in  a 
suitable  beaker  until  it  is  melted  completely,  and  the  contained  water, 
salt,  and  curd  have  collected  at  the  bottom.  Decant  a  sufficient  amount 
of  the  supernatant  fat  into  a  dry  filter  and  allow  it  to  pass  into  a  shal- 
low beaker.  When  about  10  grams  have  been  collected,  place  the 
beaker  in  a  basin  containing  water  and  ice,  and  allow  the  fat  to  become 
hard.  Place  a  small  filter  paper  on  one  of  the  pans  of  the  balance  and 
counterbalance  it  exactly  with  weights  on  the  other.  Then  weigh  out 
as  rapidly  as  possible  2.5  grams  of  the  fat,  transferring  it  to  the  paper 
by  means  of  a  spatula.  Place  the  paper  and  fat  in  a  300  cc.  Erlen- 
meyer  flask,  add  10  cc.  of  a  20  per  cent,  solution  of  caustic  potash  in 
70  per  cent,  alcohol,  and  then  place  the  flask  on  a  water-bath.  In  a 
short  time,  especially  with  gentle  rotation  of  the  flask,  the  fat  becomes 
completely  saponified.  Continue  the  heat  until  the  alcohol  is  expelled, 
and  remove  the  last  traces  of  the  vapor  by  blowing  into  the  flask  with 
a  bellows  or  by  swinging  it  in  the  air.  Add  50  cc.  of  hot  water,  and 
when  the  soap  is  brought  completely  into  solution,  add  25  cc.  of  10 
per  c(;nt.  sulphuric  acid.  The  latter  breaks  up  the  soap,  setting  free 
both  tlu;  soluble  and  insoluble  fatty  acids,  the  latter  in  the  form  of 
curds.  Connect  the  flask  with  a  Liebig  condenser,  after  introducing 
several  pieces  of  pumice  stone  to  prevent  bumping,  and  then,  with  the 
flask  supported  on  a  square  of  wire  netting  over  a  Bunscn  lamp,  distil 

9 


130  FOODS. 

slowly  until  50  cc.  have  been  collected.  Titrate  the  distillate  with 
decinormal  sodium  hydrate,  using  phenolphthalein  as  an  indicator. 
With  the  amount  of  fat  taken,  at  least  12  cc.  of  the  alkali  will  be 
required  for  neutralization,  if  the  specimen  is  genuine  butter. 

Many  analysts  prefer  to  employ  5  grams  of  fat  and  correspondingly 
larger  volumes  of  water,  and  to  distill  110  cc,  whereof  100  is  titrated. 
Some  prefer  also  to  carry  on  the  process  of  saponification  in  a  round- 
bottomed  flask  under  pressure.  Some  measure  the  fluid  fat  directly  into 
a  weighed  flask  from  a  pipette,  and  ascertain  the  amount  taken  by  re- 
weighing  after  the  fat  has  cooled  and  solidified.  The  saponifying  agent 
is  applied  in  cliflPerent  forms,  and  many  other  variations  in  detail  are 
recommended,  but  the  end  result  is  practically  the  same.  The  process 
described  has  been  found  in  the  experience  of  the  author  to  be  most 
satisfactory. 

The  LeflPmanu-Beam  process  has  much  to  recommend  it,  particularly 
in  the  saving  of  time.  The  saponifying  agent  is  prepared  by  mixing 
20  cc.  of  50  per  cent,  caustic  soda  solution  and  180  cc.  of  pure  concen- 
trated glyceria.  To  5  grains  of  fat  in  an  Erlenmeyer  flask  add  20  cc. 
of  this  solution,  and  then  heat  over  a  Bunsen  flame  until  saponification 
is  complete.  This  requires  but  a  few  minutes ;  the  completion  of  the 
process  is  shown  by  the  clear  condition  of  the  mixture.  The  soap  is 
diluted  with  135  cc.  of  boiled  water,  added  at  first  in  very  small  amounts 
to  prevent  foaming.  Then  5  cc.  of  dilute  sulphuric  acid  (200  cc.  in 
1000)  are  added,  and  the  preparation  is  ready  for  immediate  distilla- 
tion. Distil  110  cc,  mix  thoroughly,  and  pass  through  a  dry  filter^ 
titrate  100  cc,  and  to  the  result  add  yL  for  the  remaining  10  cc. 

If  one  wishes  to  determine  the  amount  of  insoluble  fatty  acids,  it  may 
be  done  in  the  following  manner,  but  it  should  be  said  that  the  process 
requires  much  more  time,  and  that  the  results  are  not  always  satisfac- 
tory, since  the  upper  limit  in  the  case  of  butter  is  so  near  the  lower 
limit  in  that  of  olemargarine  that  samples  yielding  results  close  to  the 
dividing  line  may  need  further  analysis  before  an  unqualified  opinion 
of  the  nature  of  the  specimen  can  be  given.  A  mixture  of  genuine 
butter  and  oleomargarine  may  give  results  well  within  the  normal  limits 
of  butter. 

Peocess. — Into  a  weighed  beaker  decant  a  few  grams  of  the  fat,  and, 
when  the  latter  has  cooled,  ascertain  the  amount  taken  by  reweighing. 
Saponify  as  above  described,  evaporate  the  alcohol,  dissolve  the  soap 
in  water,  and  decompose  it  by  the  addition  of  an  excess  of  acid.  Heat 
until  the  precipitated  insoluble  acids  are  melted,  then  allow  the  whole 
to  cool.  When  the  fatty  layer  has  assumed  the  character  of  a  solid 
crust,  break  a  small  hole  through  it  at  a  point  on  its  circumference  and 
another  on  the  opposite  side.  Weigh  a  funnel  and  a  dried  filter  of 
suitable  size,  place  the  latter  within  the  former,  wet  it  thoroughly,  and 
then  filter  the  liquid  from  beneath  the  crust.  Break  up  the  crust,  add 
boiling  water,  and  transfer  the  whole  to  the  filter.  Wash  repeatedly 
with  boiling  water  until  the  washings  have  no  longer  an  acid  reaction ^ 
then  let  drain  until  no  more  water  is  discharged.     The  filter-paper 


BUTTER. 


131 


being  wet,  the  melted  fatty  acids  do  not  pass  througli  with  the  wash- 
ino-s.  Place  the  funnel  and  its  contents  in  the  beaker  and  dry  in  an 
air-bath  at  100°  C.  to  constant  weight.  The  increase  in  the  combined 
weights  of  the  beaker,  funnel,  and  paper  represents  the  amount  of  in- 
soluble fatty  acids  in  the  amount  of  fat  taken. 

'Examination  of  Fat  by  Means  of  the  Butyro-refractometer. — A  sim- 
ple and  quick  method  of  ascertaining  the  nature  of  butter-fat  with- 
out recourse  to  chemical  analysis  is  that  by  means  of  the  butyro-refract- 
ometer or  other  instrument  designed  for  the  purpose  of  measuring  the 
refractive  index.     The  instrument  is  shown  in  Fig.  4,  with  the  prism 


Fig.  4. 


Zeiss  butyro-refractometer. 

casing  wide  open.  Its  application  requires  so  little  time  that,  after  a 
little  practice,  a  person  working  alone  can  examine  readily  15  or  20 
samples  in  an  hour.  The  method  of  use  is  as  follows  :  The  surface  A 
and  that  to  which  it  is  opposed  when  the  prism  casing  is  closed  should 
first  be  cleaned  by  means  of  a  soft  piece  of  linen  moistened  with  alcohol 
or  ether.  Place  the  instrument  so  that  the  surface  of  the  prism  B  is 
horizontal,  then  apply  2  or  3  drops  of  the  clear  fat,  best  from  a  small 
filter  paper  held  between  the  fingers.  Close  the  prism  casing  and  fasten 
it  by  means  of  the  pin  C.  The  surfaces  of  the  two  prisms  are  now 
separated  from  each  other  only  by  the  very  thin  layer  of  fat.  With 
the  instrument  in  its  original  ))osition,  the  mirror  I)  adjusted  so  as  to 
illuminate  tin;  field  clearly,  and  tlic  upper  part  of  the  ocular  so  iidjusted 
that  the  scale  within  is  most  clearly  defined,  read  off'  at  what  ])oint  of 
the  scale  the  line  between  light  and  shade  falls.     Since  the  degree  of 


132 


FOODS. 


refraction  is  influenced  by  the  temperature,  it  is  necessary  to  have  some 
means  of  determining  accurately  the  temperature  of  the  specimen 
between  the  prisms.  This  is  secured  in  the  following  manner  :  A  cur- 
rent of  warm  water  is  conducted  by  means  of  a  rubber  tube  connected 
Avith  the  inlet  E  into  the  prism  casing,  thence  through  the  rubber 
tube  F  to  the  upper  part,  from  which  it  escapes  through  the  outlet  G. 
The  bulb  of  a  thermometer  projects  into  the  current  of  water.  The 
standard  temperature  for  observations  with  this  instrument  is  25°  C, 
and  at  this  temperature  natural  butter,  which  has  a  refractive  index  of 
1.459-1.462,  will  give  a  reading  of  from  49.5  to  54  on  the  scale, 
while  oleomargarine,  which  has  a  refractive  index  of  1.465-1.470, 
will  show  58.6  to  66.4,  and  mixtures  of  the  one  with  the  other  wdll 
give  from  54  upward,  according  to  the  percentage  of  oleomargine 
present. 

According  to  Wollny,  to  whom  the  invention  of  the  instrument  is 
largely  due,  any  specimen  which  at  a  temperature  of  25°  C.  gives  a 
higher  reading  than  54  will  invariably  be  found  on  chemical  analysis 
to  be  adulterated ;  but  he  suggests  that,  in  order  to  remove  all  chance 
of  adulterated  butter  escapmg  detection,  this  limit  be  reduced  to  52.5, 
and  that  all  samples  giving  the  latter  reading  be  examined  chemically. 

With  temperatures  other  than  25°  C,  it  is  necessary  to  make  cor- 
rections of  0.55  of  a  scale  division  for  each  degree  C.  The  following 
table  shows  the  maximum  reading  for  pure  butters  at  different  tem- 
peratures : 


Temp. 

Sc.  div. 

Temp. 

Sc.  div. 

Temp. 

Sc.  div. 

Temp. 

So.  div. 

25° 

52.5 

31° 

49.2 

37° 

45.9 

43° 

42.6 

26 

51.9 

32 

48.6 

38 

45.3 

44 

42.0 

27 

51.4 

33 

48.1 

39 

44.8 

45 

41.5 

28 

50.8 

34 

47.5 

40 

44.2 

29 

50.3 

i   35 

47.0 

41 

43.7 

30 

49.8 

36  . 

46.4 

42 

43.1 

There  are  other  processes  for  the  investigation  of  the  character  of 
butter-fat,  including  the  detennination  of  the  specific  gravity,  melting- 
point,  iodine  absorption  number,  and  saponification  equivalent ;  but  for 
all  practical  purposes  the  determination  of  the  refractive  index  or  of 
the  volatile  fatty  acids  is  ordinarily  sufficient,  and  the  other  determi- 
nations are  merely  corroborative. 


CHEESE. 

For  thousands  of  years,  cheese  has  been  known  as  a  very  valuable 
food,  and  much  attention  has  been  paid  to  different  methods  of  manu- 
facture. At  the  present  time,  many  varieties  are  made,  their  nature 
depending  upon  that  of  the  raw  material,  the  method  of  producing  the 
curd,  the  proportions  of  the  several  constituents,  and  the  method  of 
ripening.  ]\Iost  varieties  are  made  from  cows'  milk ;  some  are  made 
from  that  of  ewes,  and  others  from  that  of  goats. 


A 


CHEESE.  133 

The  milk  is  used  either  in  its  natural  condition,  or  skimmed,  or  with 
the  addition  of  cream.  Generally,  it  is  used  in  its  natural  condition. 
Whatever  the  kind,  the  following  is  the  general  process  of  manufact- 
ure. The  milk,  with  or  without  coloring  matter  as  desired,  is  heated 
to  80°  F.  or  above,  and  then  curdled  by  means  of  rennet  or  by  the 
acids  formed  by  the  ordinary  milk  bacteria.  Usually,  rennet  is  em- 
ployed ;  sometimes,  sour  whey.  The  coagulation  should  be  complete 
in  from  forty  minutes  to  an  hour.  Too  rapid  coagulation  causes  the 
curd  to  be  hard,  tough,  and  unsuitable  for  the  subsequent  manipula- 
tion ;  too  slow  action  produces  a  soft  curd  difficult  to  work  and  not 
uniform  in  character.  After  the  process  of  coagulation  is  complete,  the 
curd  is  cut  or  broken  into  small  pieces,  and  the  whey  is  drawn  off. 
Then  the  curd  is  gathered  into  a  heap  and  covered,  and  allowed  to> 
stand  for  an  hour  or  longer,  during  which  time  its  increasing  acidity 
assists  in  its  hardening  and  promotes  the  separation  of  the  remaining 
whey.  When  the  curd  has  attained  the  proper  consistence,  it  is  placed 
in  a  cheese  press  and  subjected  to  gradually  increasing  pressure,  and. 
after  this  process  is  completed  it  is  removed  to  the  curing  place.  For 
the  proper  ripening  of  cheese,  it  is  essential  that  the  curd  be  of  the 
proper  consistence  throughout,  and  that  only  the  favorable  organisms 
be  present,  and  these  in  not  too  great  abundance. 

The  curd  produced  by  the  action  of  sour  whey  is  highly  acid  and 
inclined  to  be  greasy.  Owing  to  its  high  degree  of  acidity,  it  is  not  a 
favorable  ground  for  the  growth  of  many  of  the  bacteria  to  which, 
is  due  the  production  of  the  different  kinds  of  flavor,  and  so  the 
number  of  varieties  possible  of  manufacture  by  sour  whey  is  limited. 
Rennet,  on  the  other  hand,  produces  a  curd  which  is  elastic  and  not 
greasy  or  sticky,  and  which  is  a  good  culture  medium  for  the  bacteria 
whose  assistance  is  needed.  It  acts  best  in  milk  which  is  slightly  acid, 
for  if  the  milk  is  neutral  or  only  very  slightly  acid,  the  coagulation 
proceeds  very  slowly  and  the  curd  will  not  contract  sufficiently  to  expel 
the  whey ;  if  the  milk  is  too  acid,  the  process  of  coagulation  is  too 
rapid  and  the  product  too  tough.  A  soft  curd  retains  too  much  whey, 
and  the  fermentation  of  the  milk  sugar  of  the  whey  causes  "  huffing,'* 
or  swelling,  for  the  prevention  of  which,  preservatives  sometimes  are 
employed.  The  bacteria  concerned  in  the  process  of  ripening  exist  in 
the  original  milk  or  in  the  air  of  the  place  of  manufacture.  Sometimes 
the  varieties  which  produce  cheese  "  faults "  gain  a  foothold  on  the 
premises,  and  can  be  eradicated  only  by  means  of  thorough  cleaning 
and  disinfection.  The  ripening  process  is  carried  on  at  about  70°  F. 
It  is  essentially  a  process  of  decomposition,  in  which  enzymes,  bacteria, 
and  moulds  are  concerned ;  and  for  the  production  of  the  same  kind 
of  cheese  the  same  varieties  of  organisms  must  be  present,  and  the 
particular  variety  producing  a  particular  flavor  must  find  the  conditions 
such  as  are  favorable  to  its  i)redominance.  It  is  not  possible  to  start 
with  milk  that  is  entirely  sterile,  and  then  to  inoculate  with  the  par- 
ticular varieties  wanted,  since  to  sterilize  milk  completely  requires  the 
a[»])li(;ation  of  such  a  degree  of  heat  as  will  produce  changes  in  the 


134  FOODS. 

casein,  interfere  with  the  proper  action  of  the  rennet,  injure  the  con- 
sistence of  the  curd,  and  destroy  the  enzymes. 

Ripening  does  not  proceed  satisfactorily  when  the  curd  has  been 
produced  through  the  action  of  acids.  In  ordinary  ripening,  the  casein 
is  attacked  by  the  organisms  present,  and  ammonia,  leucin,  tyrosin,  and 
several  kinds  of  fatty  acids  are  produced.  The  latter  unite  with  the 
lime  salts,  which  up  to  this  point  have  been  in  combination  with  the 
casein.  The  acids  formed  include  butyric  and  valerianic.  From  the 
lactose,  we  have,  in  addition,  lactic  acid.  The  process  goes  on  at  differ- 
ent rates  with  different  kinds  of  cheese,  and  it  may  be  short  or  long. 
In  the  production  of  certain  forms  of  American  and  English  cheeses, 
the  individual  specimens  are  sealed  hermetically  in  tin  boxes  and  kept 
at  a  favorable  temperature  for  as  long  as  four  years,  the  boxes  being 
turned  each  day.  The  ordinary  grades  of  cheese,  however,  undergo 
comparatively  short  periods  of  ripening. 

Composition  of  Cheese. — The  composition  of  cheese  varies  very 
much  according  to  the  nature  of  the  raw  material  and  the  process 
of  manufacture.  The  fat  shows  the  greatest  variation  in  amount, 
according  as  the  cheese  is  made  from  whole  milk,  skimmed  milk,  or 
milk  enriched  with  cream.  The  most  common  American  cheese  is 
made  from  whole  milk,  as  are  also  the  leading  varieties  of  English 
cheese,  as  Cheddar  and  Cheshire.  The  flimiliar  Edam  (Dutch)  cheese 
is  made  from  partially  skimmed  milk.  English  Stilton  is  a  type  of 
cheese  made  from  milk  enriched  with  cream.  The  cheese  richest  of  all 
in  fat  is  what  we  know  as  cream  cheese,  but,  strictly  speaking,  this  is 
not  cheese  at  all,  being  simply  fresh  curd  very  rich  in  fat  and  not  sub- 
jected to  any  process  of  ripening.  The  cheeses  poorest  in  fat  are  those 
made  from  skimmed  milk.  They  are  tough,  dry,  and  of  but  little  flavor, 
and  such  as  they  have  is  inclined  to  be  unpleasant.  American  cheeses 
of  good  quality  may  be  said  in  general  to  contain  about  36  parts  of  fat, 
30  of  proteids,  30  of  water,  and  the  remainder  salts.  The  leading 
English  cheeses,  excepting  Stilton,  contain  rather  more  water  (about  35 
per  cent.),  and  correspondingly  less  fat.  Swiss  cheese  has  practically  the 
same  composition,  but  contains  rather  more  proteids  and  correspond- 
ingly less  fat.  Skimmed  milk  cheeses  are  particularly  rich  in  proteids, 
containing  often  as  high  as  50  per  cent.  With  the  exception  of  those 
made  from  skimmed  milk,  it  may  be  said  in  general  terms  that  cheese 
is  about  one-third  fat  and  one-third  proteids. 

Of  the  many  varieties  of  cheese  put  up  in  small  bulk,  mostly  for  use 
as  a  relish  rather  than  as  a  substantial  article  of  diet,  the  following 
may  be  mentioned  :  Roquefort  is  made  from  the  partly  skimmed  milk 
of  ewes  ;  it  does  not  vary  much  in  its  percentage  of  fat  and  proteids 
from  American  and  English  cheeses.  Gorgonzola  is  ^'ery  similar  to 
Roquefort  in  composition  and  also  in  the  method  of  manufacture. 
Both  are  ripened  with  the  assistance  of  moulds,  which  are  mixed  with 
the  curd  with  the  powdered  bread  crumbs  on  which  they  have  been  cul- 
tivated, and  the  cheeses  are  inoculated  also  after  being  shaped.  Parmesan 
cheese  is  made   from   partly  skimmed  goats'  milk  ;  it  is  very  rich  in 


ANALYSIS   OF  CHEESE.  135 

proteids  but  contains  only  about  half  as  much  fat  as  American  cheese. 
Camembert  cheese  is  a  soft  cheese  containing  rather  more  than  50  per 
cent,  of  water  and  about  20  per  cent,  each  of  fat  and  proteids.  It  is 
ripened  by  a  peculiar  process  which  gives  it  a  much  more  pronounced 
and  permeating  odor  than  almost  any  other  known  variety. 

Adulteration  of  Cheese. — At  the  present  time,  the  only  extensive 
form  of  adulteration  of  cheese  consists  in  the  substitution  of  lard  for 
the  usual  and  proper  kind  of  fat.  Lard  and  skimmed  milk  colored 
Avith  annatto  are  mixed  together,  heated  to  about  140°  F.  in  tanks, 
and  emulsionized  with  the  assistance  of  appropriate  machinery  ;  the 
mixture  then  is  coagulated  in  the  same  way  as  in  the  ordinary  process 
of  making  cheese.  Such  cheese  is  designated  in  the  United  States 
statutes  as  "  filled  cheese,"  which  includes  "  all  made  of  milk  or 
skimmed  milk  with  the  admixture  of  butter,  animal  oils  or  fats,  vege- 
table or  any  other  oils,  or  compounds  foreign  to  such  milk." 

A  decree  promulgated  in  Belgium  on  September  21,  1899,  defines 
cheese  as  a  product  obtained  from  pure  milk,  skimmed  milk,  milk  co- 
agulated by  the  aid  of  rennet  or  acidification,  or  any  other  product 
obtained  by  heating  milk  mixed  or  not  with  coloring  matter,  salt,  and 
spices,  and  subjected  to  pressure  and  fermentation.  It  forbids  the  sale, 
except  when  properly  labelled  in  such  way  as  to  reveal  its  true  nature, 
of  all  cheese  containing  any  other  substance  than  those  mentioned,  such 
as  oleomargarine  or  other  foreign  fat,  potatoes,  and  bread.  An  excep- 
tion is  made,  however,  in  favor  of  Roquefort,  in  which  bread  crumbs 
are  present,  not  as  an  adulteration,  but  for  the  serving  of  a  useful  pur- 
pose. The  sale  of  cheeses  mixed  with  mineral  matter  other  than  salt 
and  with  antiseptics  in  general  is  forbidden. 

In  some  parts  of  Germany,  bean  meal  and  potatoes  are  used  to 
some  extent  as  adulterants,  and  there  and  elsewhere  a  great  variety  of 
substances  are  said  to  have  been  used  to  a  greater  or  less  extent  in 
times  gone  by.  In  general,  it  may  be  said  that,  aside  from  lard  and 
other  foreign  fats,  the  only  adulteration  of  any  importance  consists  in 
the  admixture  of  preservatives.  These  are  added  more  commonly  to 
skimmed  milk  cheeses  than  to  those  of  good  quality. 


Analysis  of  Cheese. 

Determination  of  Water. — Cut  the  specimen  into  small  bits  or 
thin  slices.  Weigh  out  about  5  grams  in  a  platinum  dish  containing 
sand  or  asbestos  fiber,  and  dry  to  constant  weight. 

Determination  of  Ash. — Ignite  the  dried  residue  at  as  low  a  tem- 
|)f'ratui'(!  as  possible,  and,  after  cooling,  note  the  increase  in  weight  over 
tli;it  of  tli(!  disli  and  its  original  contents. 

Determination  of  Fat. — Triturate  about  25  grams  of  the  specimen 
in  a  mortar  with  an  equal  bulk  of  fine  beach  sand.  Transfer  the  whole 
to  a  Soxhlet  extractor,  and  proceed  in  the  manner  described  under  the 
Analysis  of  Milk. 


136  FOODS. 

Determination  of  Proteids. — Proceed  in  the  mauaer  mven  under 
Analysis  of  Milk,  using  about  2  grams  of  the  sample. 

Determination  of  the  Nature  of  the  Fat. — For  the  detection  of 
foreign  fats,  the  method  of  procedure  is  the  same  as  described  under 
the  Analysis  of  Butter,  after  obtaining  the  fat  in  a  pure  condition. 
The  residue  obtained  iu  the  determination  of  the  amount  of  fat  will 
serve  for  this  purpose. 

Cheese  as  a  Cause  of  Poisoning-. 

For  many  years,  cheese  has  been  known  to  be  an  occasional  cause  of 
single  and  multiple  cases  of  poisoning,  and  various  theories  concerning 
the  nature  of  the  poisonous  agent  have  been  promulgated.  It  was  not 
until  1884  that  the  cause  was  revealed  by  Professor  Y.  C.  Vaughan,, 
whose  attention  was  drawn  to  outbreaks  in  Michip-an  during  1883  and 
1884,  iu  which  more  than  300  persons  were  affected.  He  traced  the 
whole  trouble  to  twelve  different  cheeses,  from  several  of  which  he 
isolated  the  poisonous  principle,  a  ptoraain,  to  Avhich  he  gave  the  name 
"  tyrotoxicon."  The  symptoms  observed  in  the  outbreaks  referred  to 
included  vomiting,  diarrhoea,  abdominal  pain,  dryness  and  constriction 
of  the  throat,  feeble  and  irregular  pulse,  and  marked  cyanosis.  In 
some  cases,  vomiting  and  diarrhoea  were  followed  by  mark  eel  nervous 
prostration.     In  some  the  pupils  were  dilated. 

Within  a  short  time  after  Vaughan's  discovery,  the  poison  was  found 
by  Wallace ^  in  some  cheese  that  Mas  the  cause  of  poisoning  of  not  less 
than  50  persons  out  of  about  60  who  had  eaten  of  it.  The  onset  appeared 
in  from  two  to  four  hours.  The  most  constant  and  severe  symptoms 
were  vomiting  and  chills.  These  were  succeeded  by  severe  epigastric 
pain,  cramps  in  the  legs  and  feet,  purging  and  griping,  numbness  espe- 
cially marked  in  the  legs,  and  very  marked  prostration.  Vomiting  and 
diarrhoea  lasted  from  two  to  twelve  hours ;  chills  and  cramps  from  one 
to  two  hours.  No  deaths  occurred,  and  all  recovered  within  three  days. 
The  severity  of  the  symptoms  bore  no  relation  to  the  amount  eaten  ; 
some  of  the  severest  cases  were  of  persons  who  ate  but  sparingly. 

More  recent  work  by  Vaughan  and  his  associates  and  others  has 
demonstrated  that  tyrotoxicon  is  not  the  only  cause  of  cheese-,  milk-, 
and  ice-cream-poisoning,  and  that  it  is,  indeed,  a  somewhat  rare  poison. 
Other  toxic  substances  have  been  isolated  from  cheeses  that  yielded  uo 
tyrotoxicon. 

Section  4.     VEGETABLE   FOODS. 

The  vegetable  foods  may  conveniently  be  divided  into  several  classes 
as  follows  : 

1.  Farinaceous  seeds  : 

(a)  Cereals  ;  (6)  Legumes. 

2.  Farinaceous  preparations. 

3.  Fatty  seeds  (nuts). 

4.  Vegetable  fats. 

'  IMedical  News,  July  16,  1887,  p.  69. 


WHEAT.  137 

5.  Tubers  and  roots. 

6.  Herbaceous  articles  ("vegetables"). 

7.  Fruits  used  as  "  vegetables." 

8.  Fruits  in  the  narrower  sense. 

9.  Edible  fungi. 

10.  Saccharine  preparations. 

The  words  fruit  and  vegetable  are  capable  alike  of  broad  and  narrow 
meanings.  In  the  strict  sense,  the  cereals,  legumes,  nuts,  and  many  of 
the  articles  commonly  called  vegetables  are  fruits ;  but  popidar  usage 
has  narrowed  the  latter  term  to  include  the  pulpy  substance  enclosing 
the  seeds  of  various  trees  and  plants,  and  only  such  as  are  pleasant  to 
the  taste  and  edible  in  the  raw  state,  with  the  single  exception  of  the 
quince,  which  is  edible  only  when  cooked.  Vegetables  iu  the  ordi- 
nary sense  include  any  part  of  herbaceous  plants,  as  the  stem,  root, 
leaves,  and  fruity  products  used  commonly  in  the  cooked  state  or 
in  the  form  of  salads.  Thus,  in  the  popular  usage  of  the  terms^ 
squashes  and  melons,  which  are  the  fruits  of  plants  of  the  same  family, 
are  classed  respectively  as  vegetables  and  fruits,  and  the  cereals  and 
nuts  are  classified  under  neither  head. 

First  in  importance  of  vegetable  foods  are  the  farinaceous  seeds ; 
they  are  of  very  high  nutritive  value  and  easily  digested. 

1.  Farinaceous  Seeds. 

(rt)  CEREALS. 

The  cereals  include  wheat,  rye,  barley,  pats,  corn,  buckwheat,  and 
rice.  They  are  very  largely  starchy,  and  agree  in  general  composition  ; 
but  they  differ  m  the  proportions  in  which  their  several  constituents  are 
present.  These  include  proteids,  carbohydrates,  ether  extractives, 
mineral  matter,  and  moisture.  The  proteids  include  a  large  number  of 
closely  related  compounds,  as  yet  only  imperfectly  studied,  which  will 
be  mentioned  in  the  consideration  of  each  member  of  the  group.  The 
carbohydrates  include  those  which  are  soluble,  sugar  and  dextrin,  and 
those  which  are  insoluble,  starch,  cellulose,  pentosans,  and  gelactans 
(H.  W.  Wiley).  The  ether  extractives  include  fats,  resins,  chlorophyll, 
and  volatile  oil  "  which  constitutes  the  source  of  the  odorous  quality 
possessed  by  the  grain  "  (Wiley).  The  mineral  matters  are  chiefly 
phosphates  of  calcium,  and  magnesium,  silica,  and  salts  of  sodium  and 
potassium.  The  cereals  contain  also  certain  ferments,  the  most  impor- 
tant of  which,  and  the  only  one  which  has  been  studied  with  any 
tlioroughness,  is  diastase.  This  acts  upon  starch,  converting  it  into 
sugar.     The  others  include  some  which  act  upon  the  proteids. 


Wheat. 


Wheat  is  classed  very  properly  as  the  most  useful  of  the  vegetable 
fofjds.  The  grain  consists  of  a  hard  outside  layer  which  is  indi- 
gestible and  useless  as  food,  and  the  cortex,  softer  and  more  friable, 


138  FOODS. 

which  yields  flour  of  high  nutritive  vahie.  The  hard  outside  layer, 
which  coustitutes  the  greater  part  of  brau,  irritates  the  aliraeutary 
canal,  and,  while  useful  to  some  extent  in  conditions  of  habitual  con- 
stipation, should  be  avoided  in  all  irritable  conditions  of  the  bowel. 
It  causes  waste  by  unduly  promoting  peristalsis,  so  that  much  of  the 
nutritive  portion  is  hurried  along  in  an  undigested  condition. 

The  proteids  of  wheat  include,  according  to  Osborne  and  Voorhees,^ 
a  globulin,  an  albumin,  a  proteose,  gliadin,  and  gluteniu.  The  two 
last-mentioned  constitute  between  80  and  90  per  cent,  of  the  whole ; 
in  the  presence  of  water  they  unite  to  form  the  very  important  substance 
gluten,  so  essential  in  the  conversion  of  flour  into  bread.  According 
to  Wiley,  they  unite  in  almost  equal  proportions ;  but  in  the  opinion 
of  E.  Fleurent,^  the  closer  the  composition  of  gluten  approaches  the 
relation  of  25  parts  of  gluteniu  to  75  of  gliadin,  the  more  valuable 
the  flour. 

The  carbohydrates  constitute  the  greater  part  of  wheat  as  well  as  of 
the  other  cereals.  They  include  starch,  by  far  the  most  important, 
cellulose,  sugars,  dextrin,  and  a  number  of  other  compounds  of  com- 
parative unimportance.  The  starch  granules  are  exceedingly  variable 
in  size,  ranging  from  about  0.002  to  0.05  mm.  in  diameter.  Tliey  are 
circular  and  flat,  and  many  of  them  show  a  central  hilum  and  con- 
centric rings.  The  latter  apj^ear  with  greater  distinctness  in  flour  that 
has  been  subjected  to  heat,  as,  for  instance,  in  the  baking  of  crackers. 
The  wide  variations  in  size  are  illustrated  in  Plate  VII.,  Fig.  1.  The 
other  carbohydrates  exist  in  but  very  small  proportions. 

Composition  of  Wheat. — The  vast  number  of  analyses  of  wheat 
show  important  variations  in  the  percentage  of  its  several  constituents, 
for  its  quality  is  influenced  considerably  by  climate,  character  of  the 
soil,  and  other  conditions.  According  to  H.  AV.  Wiley,^  a  ty])ical 
American  wheat  of  the  best  quality  should  yield  approximately  the 
following  results  : 

Moisture 10.60 

Proteids 12.25 

Ether  extract 1.75 

Crude  fiber 2.40 

Starch,  etc 71.25 

Ash ■    1.75 

100.00 

These  figures  do  not  vary  materially  from  the  averages  of  a  large 
number  of  analyses  of  samples  of  miscellaneous  origin  compiled  by 
Kdnig,  excepting  m  the  proportions  of  moisture  and  starch,  in  which 
respects  Wiley's  typical  specimen  shows  superior  value,  being  less  rich 
in  the  one  and  richer  in  the  other  constituent. 

1  American  Chemical  Journal,  XV.,  p.  392. 

''■  Comptes  rend  us,  1898,  p.  126. 

^  U.  S.  Department  of  Agriculture,  Division  of  Chemistry,  Bull.  13,  Part  9,  p.  1189. 


■o 


PLATE  VII. 


Fig.    1. 


c 


Wheat   Starch.     X  28S. 


Fig.  2. 


.,    -^tl 


o 


M3 


<Qs 


o,;0 


Rye    Starch.      •'  285. 


WHEAT  FLOUR.  139 

Wheat  Flour. 

In  the  manufacture  of  flour,  the  wheat  kernels  are  subjected  first  to 
a  process  of  thorough  cleaning,  and  then  are  cracked,  crushed,  and 
ground  until  the  required  state  of  fineness  is  attained,  the  bran  and 
other  undesirable  portions  being  removed  by  bolting.  All  flour  is  by 
no  means  the  same  in  composition  and  quality ;  in  tact,  several  grades 
of  flour  may  be  made  from  the  same  wheat  by  the  employment  of 
different  processes  of  manufacture.  Flours  are  graded  according  to 
color  or  appearance,  those  which  make  the  whitest  bread  ranking  high- 
est, although  not  equal  in  nutritive  value  to  those  classed  as  low  grade. 
The  flours  of  the  several  grades  are  known  commercially  as  "  patent," 
^'  family,"  "  bakers',"  and  other  names  which  to  the  public  have  no 
special  significance.  Typical  flours  of  the  grades  known  as  "high- 
grade  patent "  and  "  bakers' "  should  have,  according  to  Wiley, 
approximately  the  following  composition  : 

Moisture.  Proteids.  Ether  extract.  Carbohydrates.       Ash. 

Patent 12.75  10.50  1.00  75^25  0.50 

Bakers'     .....      11.75  12.30  1.30  74.05  0.60 

The  average  composition  of  210  samples  of  wheat  flour  of  high  and 
medium  grades  and  of  grades  not  indicated  is,  as  given  by  Atwater 
and  Bryant,  as  follows  : 

Moisture 12.00 

Proteids 11.40 

Ether  extract 1.00 

Carbohydrates 75.10 

Ash 0.50 

100.00 
Thirteen  samples  of  low  grade  averaged  as  follows  : 

Moisture .    12.00 

Proteids 14.00 

Ether  extract 1.90 

Carbohydrates 71.20 

Ash  .    ' 0.90 

100.00 

It  will  be  noticed  that  the  high  grade  flours  are  poorer  in  proteids 
and  fat,  and  correspondingly  richer  in  starch.  Other  grades  of  flour 
include  those  known  as  graham  and  entire  wheat.  Graham  flour  is 
understood  generally  to  be  a  product  containing  all  of  the  constituents 
of  the  original  grain  in  their  same  proportions.  When  it  came  first 
into  use,  such,  indeed,  it  was ;  but  at  the  present  time  it  is  an  unbolted 
or  partially  bolted  product  of  thoroughly  cleaned  and  dusted  wheat. 
Entin-  wheat  flour  is  understood  also  to  contain  all  of  the  original  con- 
stituents of  the  grain,  but  is,  in  fact,  made  from  M^heat  deprived  of  its 
ontor  coverings.  It  makes  a  somewhat  dark-colored  bread  which  is 
very  palatable. 

Parenthetically,  it  may  not  be  out  of  ])\i\ce  to  refer  here  to  the 
absurd   views   maintained   by   a  large   part   of  tlie   community  as   to 


140  FOODti. 

the  superiority,  from  a  liygieuic  standpoint,  of  foods  containing  all  of 
the  constituents  of  the  cereals  from  which  they  are  prepared.  It  is 
difficult  to  understand  how  the  nutritive  value  of  any  food  can  be 
increased  by  the  retention  of  matters  which  are  completely  indigestible 
and  to  a  certain  extent  irritating  to  the  digestive  tract.  It  is  argued 
that  an  all-wise  Creator  made  wheat,  for  example,  in  the  form  in  which 
we  see  it,  and  that  it  is  not  for  us  to  attempt  to  improve  it,  as  we  think, 
by  discarding  the  outer  layers.  But  this  sort  of  reasoning  might  be 
extended  so  as  to  favor  the  consumption  of  the  peel  of  oranges,  the 
bones  of  fish,  the  feathers  of  birds,  and  other  innutritions  and  undesir- 
able ^vaste  products. 

Preparations  of  Wheat  Flour. — Bread. — First  in  importance  of 
the  preparations  of  wheat  flour  is  bread.  In  the  broad  sense,  bread 
includes  all  forms  of  baked  flour,  whether  leaveued  or  imleavened  ; 
m  the  common  use  of  the  term,  it  includes  only  those  in  wdiich  leaven- 
ing agents  are  used,  the  other  forms  being  designated  as  pilot  bread, 
crackers,  biscuits,  etc. 

The  adaptability  of  wheat  flour  for  bread-making  is  due  to  its  gluten 
content.  This  substance,  by  reason  of  its  tenacity,  is  capable  of  en- 
tangling the  gas  generated  in  the  process,  and  by  reason  of  its  solidifi- 
cation by  heat,  furnishes  a  porous  or  spongy  product  easily  penetrated 
and  acted  upon  by  the  gastric  juice.  Not  all  cereals  are  capable  of 
being  made  into  bread,  since,  as  will  be  seen,  in  most  of  them  this 
very  essential  agent  is  lacking. 

For  the  preparation  of  bread  of  good  quality,  the  flour  should  con- 
tain not  much  in  excess  of  the  average  amount  of  moisture,  and  should 
be  so  cohesive  that,  after  being  compressed  in  the  hand,  it  will  keep  its 
shape  on  being  released. 

In  the  making  of  bread,  the  flour  is  mixed  with  warm  water  or  milk, 
salt,  and  yeast,  kneaded  into  a  stift'  dough,  and  set  aside  in  a  warm 
place.  The  yeast  attacks  the  sugar  and  splits  it  into  alcohol  and  car- 
bonic acid  gas  ;  tlie  latter  by  its  evolution  and  expansion  causes  the 
dough  to  become  porous  and  to  ''  rise."  The  fermentative  process 
gives  rise  also  to  variable  amounts  of  lactic  and  acetic  acids.  The 
raised  dough  is  then  baked  in  suitable  pans,  and  its  porous  character 
i-;  increased  by  the  further  expansion  of  the  gas  by  heat  and  is  made 
]iermanent  by  the  solidification  of  the  gluten  by  the  same  influence. 
If  the  fermentation  is  not  allowed  to  proceed  far  enough,  the  resulting^ 
bread  will  be  soggy  or  "heavy";  if  too  far,  it  will  be  sour. 

In  place  of  yeast  as  a  leavening  agent,  bicarbonate  of  sodium,  com- 
monly known  in  the  household  as  saleratus,  and  baking  powders  are 
employed  verv  extensively.  For  the  evolution  of  carbonic  acid  gas 
from  sodium  bicarbonate,  the  presence  of  an  acid  is  necessary,  and  this 
is  secured  by  the  use  of  sour  milk.  First,  the  flour  is  mixed  thor- 
oughly with  the  bicarbonate  and  then  made  into  a  dough  with  the  milk. 
Bread  made  bv  this  process  is  rarely  of  good  quality,  since  it  is  difficult 
to  determine  the  proper  amounts  of  the  two  agents  for  the  best  results, 
and  any  excess  of  the  bicarbonate  causes  discoloration  and  disagreeable 


WHEAT  FLOUR.  141 

flavor.  A  better  plan  is  to  employ  baking  powder,  which  consists  of 
sodium  bicarbonate  and  an  acid  salt  combined  in  such  proportions  that 
all  of  the  available  gas  is  set  free  from  the  alkaline  salt  and  no  unpleas- 
antly tasting  residue  is  left.  The  only  advantage  possessed  by  baking 
powders  is  the  saving  of  time  and  labor ;  the  resulting  bread  is  dis- 
tinctly inferior  to  that  made  with  yeast.  The  composition  of  the  vari- 
ous classes  of  baking  powders  will  be  stated  farther  on. 

Another  process  of  securing  leavening  is  that  of  spontaneous  fermen- 
tation brought  about  by  the  enzymes  present  normally  in  flour.  This 
process,  known  as  "  salt  rising,"  is  not  in  common  use,  requires  much 
more  manipulation  than  any  other,  possesses  no  advantages,  and,  there- 
fore, deserves  no  further  mention. 

Freshly  baked  bread  is  much  less  digestible  than  that  which  has 
been  kept  a  day  or  two.  Its  softness  favors  its  clogging  during  mas- 
tication into  a  close  mass  which  is  attacked  less  easily  by  the  gastric 
juice.  In  this  country,  however,  it  is  the  almost  universal  custom 
to  eat  bread,  particularly  in  the  form  of  breakfast  rolls,  not  only  in 
the  fresh  condition,  but  also  hot  from  the  oven.  When  bread  is  kept 
for  a  day,  it  loses  part  of  its  moisture  and  acquires  increased  firmness 
and  friability,  which  help  maintain  its  porosity  during  mastication. 

Bread  may  acquire  unwholesome  properties  on  keeping,  due  to  changes 
brought  about  in  the  presence  of  moisture  by  micro-organisms.  Good 
bread  is  only  slightly  acid ;  but  if  kept  in  a  moist  state,  it  is  likely  to 
become  markedly  so,  and  then  may  cause  gastric  derangement  and 
diarrhoea  in  those  not  habituated  to  its  use.  Bread  in  this  condition  is 
undergoing  fermentative  changes  that  are  hastened  by  the  body  tem- 
perature, with  consequent  evolution  of  gaseous  products  which  cause 
flatulence  and  discomfort,  and  of  irritating  compounds  which  induce 
abdominal  pain  and  diarrhoea.  Bread  made  from  old  and  partially 
spoiled  flour  is  likely  to  have  a  distinctly  sour  taste  and  to  be  unwhole- 
some in  the  manner  above  described.  Mouldy  bread  also  is  likely  to 
be  a  cause  of  digestive  derangement. 

CompositiojST  of  AVheat  Bread. — Since  wheat  flour  itself  is  of  vari- 
able composition,  and  since  in  the  domestic  manufacture  of  any  article 
of  food  the  processes  employed  are  subject  to  slight  or  considerable 
variations,  analyses  of  wheat  bread  necessarily  must  show  great  differ- 
ences in  the  proportions  of  the  several  constituents.  Averages  obtained 
from  examination  of  samples  of  all  sorts  and  of  miscellaneous  origin 
can  hardly  represent  the  composition  of  bread  of  good  average  or  high 
quality.  Wiley  gives  the  following  as  the  approximate  composition  of 
a  "  typical  American  high-grade  yeast  bread  made  with  the  best  flour 
and  in  the  most  approved  manner  :" 

Moisture 35.00 

Proteids 8.00 

Ether  extract 75 

Ash 1.50 

Fiber 30 

Carbohydrates,  otiier  than  fiber 54.45 

100.00 


142  FOODS. 

From  analyses  of  bread  made  from  three  sorts  of  flour  from  the 
same  lot  of  wheat,  namely,  "  graham,"  "  entire  wheat,"  and  "  patent," 
Professor  H.  Snyder  ^  shows  that  the  nitrogen  content  is  highest  in 
graham  and  lowest  in  patent  flour ;  but  his  digestion  experiments 
prove  that  the  latter  has  the  highest  proportion  of  digestible  (available) 
protein.  The  lower  digestibility  of  the  protein  of  the  others  is  due  to 
the  fact  that  both  have  a  considerable  proportion  of  that  constituent  in 
the  coarser  particles  (bran),  and  that  these  resist  the  action  of  the 
digestive  juices  and  escape  digestion,  so  that  the  system  derives  less 
energy  therefrom. 

Toast. — In  the  process  of  toasting,  a  large  part  of  the  moisture  is 
driven  off,  the  surfaces  are  scorched,  greater  firmness  is  acquired,  and 
the  product  is  more  easily  digestible.  Good  toast  cannot  be  made  from 
perfectly  fresh  bread,  on  account  of  the  moisture  present,  which  causes 
sogginess ;  it  can  be  made  only  from  bread  at  least  a  day  old.  The 
slices  should  not  be  thick,  since  then,  while  the  surface  is  scorched,  the 
interior  acquires  increased  softness  under  the  action  of  heat  and  be- 
comes less  digestible  than  the  original  bread. 

Rusks  are  much  like  toast.  Instead  of  being  subjected  to  the  direct 
action  of  hot  coals,  the  bread  slices  are  baked  for  a  time  in  a  moderately 
hot  oven. 

Pulled  Bread  is  the  crumb  of  freshly  baked  loaves  pulled  out  in  small 
masses  and  baked  agam  like  rusks. 

Crackers,  or  biscuits,  are  preparations  made  from  unleavened  dough 
and  baked  so  dry  as  to  be  brittle.  They  keep  well  for  a  long  time 
without  losing  their  palatal^ility.  If  not  properly  stored  and  cared  for, 
they  may,  of  course,  become  damp,  musty,  and  mouldy.  In  composi- 
tion they  vary  but  little  from  the  flour  of  which  they  are  made ;  they 
are  drier,  and  what  they  lack  in  moisture  they  make  uj)  in  fat,  which, 
in  the  form  of  butter  or  lard,  is  added  to  prevent  them  from  becoming 
too  hard  and  dry. 

Other  preparations  of  wheat  flour  include  cakes,  which,  on  account 
of  the  contained  butter,  eggs,  and  sugar,  are  richer  than  bread ;  pastry, 
which,  on  account  of  its  content  of  lard,  is  more  difficult  of  digestion  ; 
and  flour  puddings,  which,  being  very  "  close,"  require  much  time  for 
digestion  and  often  cause  sensation  of  weight  and  oppression. 

Macaroni,  spaghetti,  and  vermicelli  are  preparations  made  with  hard 
wheat  rich  in  gluten.  The  flour  is  made  into  a  stiff  paste  with  hot 
water,  and  the  compound  then  is  pressed  through  holes  or  moulds  in  a 
metal  plate  and  dried.  They  are  exceedingly  nutritious,  but  they  are 
not  as  easy  of  digestion  as  other  preparations  of  wheat,  on  account  of 
their  closeness.  They  were  first  made  on  a  small  scale  in  Sicily,  but 
now  are  produced  in  enormous  amounts  in  Italy,  France,  Germany,  and 
other  countries.  In  their  manufacture,  American  wheats  are  not  held 
in  high  esteem,  containing  not  sufficient  gluten  and  too  much  starch. 
The  best  wheat  for  the  purpose  comes   from  a  particular  district  in 

1  Bulletin  No.  101,  Ofl&ce  of  Experiment  Stations,  U.  S.  Department  of  Agriculture, 
1901. 


WHEAT  FLOUR.  143 

Russia  and  from  Algeria.      Formerly,  a  grain  from  southern  Italy  was 
regarded  as  the  most  suitable. 

Adulteration  of  Flour. — Up  to  within  comparatively  recent  years, 
flour  has  not  been  much  subject  to  adulteration.  Occasionally,  certain 
mineral  substances,  as  magnesium  carbonate,  gypsum,  and  ground  chalk, 
have  been  reported  in  Euroj)ean  samples  ;  but  such  have  been  employed 
as  adulterants  very  rarely,  if,  indeed,  at  all  in  American  flours.  Alum 
has  been  added  sometimes  to  flour  of  inferior  quality  to  improve  its 
color  or  to  check  beginning  decomposition.  Whether  this  addition 
is  objectionable  from  a  hygienic  standpoint  is  a  subject  over  which  there 
is  decided  disagreement.  It  is  believed  by  some  that  the  amount  of 
alum  added  is  sufficient  to  exert  an  injurious  effect  on  the  digestive  tract 
on  account  of  its  astringent  action,  and  to  bring  about  constipation  and 
dyspepsia  ;  others  believe  that  it  can  do  no  harm  whatever,  either  to  the 
consumer  or  to  the  nutritive  value  of  the  food ;  and  still  others  hold 
that,  while  it  is  not  injurious  to  health,  it  lessens  the  nutritive  value  of 
the  flour  by  forming  insoluble  aluminum  phosphate,  and  thus  depriving 
the  system  of  the  phosphates  which  otherwise  would  be  absorbed.  It 
is  a  fact  that  flour,  treated  with  alum  on  account  of  begmning  deteriora- 
tion, has  caused  untoward  effects,  but  it  would  be  impossible  to  deter- 
mine how  much  influence  should  be  ascribed  to  the  alum  and  how  much 
to  the  products  formed  by  the  fermentative  processes  in  operation  before 
the  addition.  The  weight  of  evidence,  however,  is  in  favor  of  the  view 
that  alum  is  not  incapable  of  producing  injury  when  taken  into  the 
system  habitually  in  small  amounts,  and  that  it  should  be  excluded 
from  all  articles  of  food  intended  for  man. 

On  account  of  the  growing  tendency  to  mix  other  mill  products  of 
inferior  value  with  wheat  flour,  such,  for  instance,  as  rye  and  corn 
flour,  a  law  was  passed  by  Congress  in  June,  1898,  to  meet  the  evil, 
and  incidentally  to  make  it  a  source  of  revenue.  All  adulterated  flour 
is,  by  the  act  referred  to,  designated  as  "  mixed  flour,"  which  term  "  shall 
be  understood  to  mean  the  food  product  made  from  wheat  mixed  or 
blended  in  whole  or  in  part  with  any  other  grain  or  other  material,  or 
the  manufactured  product  of  any  other  grain  or  other  material  than 
wheat."  Under  the  provisions  of  the  law,  all  persons  engaged  in  the 
business  of  making  mixed  flour  are  required  to  pay  a  special  annual 
tax,  every  package  must  be  labelled  plainly,  the  names  of  the  ingred- 
ients being  set  forth,  and  upon  every  package  of  196  pounds  a  tax  of  4 
cents  shall  be  paid.  Under  the  regulations  of  the  Treasury,  the  term 
"  mixed  flour  "  is  held  not  to  include  "  the  milling  product  from  corn, 
rye,  buckwheat,  rice,  or  other  cereals  than  wheat  put  upon  the  market 
as  the  flour  or  meal  derived  from  such  cereals,  although  the  product 
may  contain  a  percentage  of  wheat  flour." 

The  detection  of  other  cereals  and  starches  in  wheat  flour  is  accom- 
plished best  by  means  of  the  microscope,  since,  as  will  appear,  each 
has  its  characteristic  appearance.  According  to  Vogel,  70  jier  cent, 
alcohol  containing  o  per  cent,  of  hydro(;hloric  acid  remains  colorless 
after   being    used    to    extract   })ure   wheat   or   rye,   turns   pale  yellow 


144  FOODS. 

if  barley  or  oats  be  present,  and  orange-yellow  if  mixed  with  pea 
tiour. 

Rye. 

In  external  appearance,  rye  presents  a  close  resemblance  to  wheat, 
but  the  kernels  are  darker  in  color  and  smaller  in  size.  It  is  by  no 
means  so  important  as  wheat  as  an  article  of  food  in  this  country,  but 
in  some  parts  of  Europe  it  constitutes  the  main  food  supply  of  the 
j^easantry. 

According  to  Wiley,  a  typical  American  rye  should  have  approx- 
imately the  following  composition  : 

Moisture 10.50 

Proteids 12.25 

Ether  extmct 1.50 

Crude  fiber 2.10 

Starch,  etc 71.75 

Ash L90 

100.00 

American  rye  is  smaller  than  that  grown  abroad,  and  contains  less 
moisture.  The  proteids  of  lye  are  more  like  those  of  wheat  than  those 
of  any  other  cereal,  and  in  consequence  rye  stands  next  to  wheat  in 
adaptability  for  bread-making.  The  yield  of  gluten  is  inferior  in 
amount  to  that  obtainable  from  wheat. 

The  starch  of  rye  is  much  like  that  of  wheat.  The  granules  are 
rather  more  variable  in  size,  the  smallest  of  each  kind  being  about 
equal,  but  the  largest  of  rye  somewhat  surpassing  those  of  wheat. 
There  is  but  one  point  of  difference  in  microscopic  appearance  which 
has  any  value  in  detecting  the  admixture  of  rye  with  wheat,  namely, 
that  a  certain  fair  proportion  of  the  larger  sized  granules  of  rye  present 
irregular  crosses  or  fractures.     This  is  illustrated  in  Plate  VII.,  Fig.  2. 

Bread  made  from  rye  flour  is  but  little  inferior  in  nutritive  value  to 
that  from  wheat,  but  it  is  less  pleasing  to  the  eye,  being  of  a  brownish 
tint,  and  it  has  a  peculiar  sour  taste,  not  altogether  agreeable  on  first 
acquaintance.  Not  uncommonly,  its  use  by  one  not  habituated  to  it 
causes  a  tendency  to  diarrhoea,  which,  however,  is  soon  overcome. 

Barley. 

This  important  cereal  is  used  mainly  in  the  manufacture  of  beer,  and 
but  to  a  limited  extent  as  a  food.  Deprived  of  its  husk  and  rounded 
and  polished  by  attrition,  it  is  known  as  "  pearl  barley,"  and  in  this 
form  is  used  more  or  less  in  the  preparation  of  barley-water,  a  drink 
for  invalids.  In  its  composition,  barley  is  very  similar  to  wheat  and 
rye,  but  as  its  proteids  yield  no  gluten,  it  cannot  be  made  into  bread. 
It  is  mixed  sometimes  with  wheat  flour  for  purposes  of  bread-making, 
but  the  product  is  less  palatable  and  less  digestible  than  ordinary 
bread. 

Wiley  gives  the  following  as  the  approximate  composition  of  a  typi- 
cal American  unhulled  barley  : 


PLATE  Vlll. 


h!: 


Fig.    1 


C 


^ 


'^ 


'> 


Barley   Starch.     X  285. 


Fig.  2. 


Oats   Starch.     X   285. 


OATS.  145 

Moisture 10.85 

Pioteids 11.00 

Ether  extract 2.25 

Crude  fiber ' 3.85 

Starch,  etc 69.55 

Ash 2.50 

100.00 

The  proteids  include,  as  in  all  cereals,  a  number  of  complex  sub- 
stances, chief  of  which  is  hordein.  The  starch  granules  are  like  those 
of  wheat,  but  are  less  variable  in  size.  (See  Plate  VIII.,  Fig.  1.)  In 
the  manufacture  of  malt  from  barley  for  brewing,  a  peculiar  nitroge- 
nous product,  diastase,  is  formed,  which  has  the  property  of  converting 
starch  to  sugar. 

Oats. 

Oats  are  much  used  as  human  food  in  the  form  of  oatmeal,  which  is 
the  product  of  grinding  the  kiln-dried  seeds  deprived  of  the  husk. 
The  meal  has  a  peculiar  taste,  which  is  both  sweet  and  bitter. 

The  composition  of  unhulled  American  oats,  as  given  by  Wiley, 
is  as  follows  : 

Moisture ; 10.00 

Proteids 12.00 

Ether  extract 4.50 

Crude  fiber 12.00 

Starch,  etc 58.00 

Ash 3.50 

100.00 
The  mean  composition  of  oatmeal,  according  to  Blyth,^  is  as  follows  ; 

Moisture 12.92 

Proteids 11.73 

Fat 6.04 

Sugar 2.22 

Dextrin  and  gum 2.04 

Starch 51.17 

Fiber 10.83 

Ash 3.05 

100.00 

The  proteids  of  oats  yield  no  gluten,  and  hence  this  article  of  diet 
cannot  be  made  into  bread,  though  with  water  it  can  be  made  into  thin 
cakes,  which  are  most  palatable.  Fat  is  present  is  greater  abundance 
than  in  any  other  cereal.  The  starch  granules  are  very  small  poly- 
hedra  which  show  neither  hilum  nor  concentric  rings.  They  tend  to 
adhere  together  in  masses  of  variable  size,  which  are  disintegrated 
easily  by  trituration  in  a  mortar.  The  single  granules  are  shown  in 
Plate  VIIL,  Fig.  2. 

Oatmeal  is  a  very  nutritious  article  of  diet,  used  largely  as  a  break- 
fast food  in  the  form  of  porridge.  It  has  a  somewhat  laxative  action, 
and,  therefore,  should  not  l)e  eaten  in  irritable  conditions  of  the  bowel. 
It  is  also  lik(;ly  to  disagree  with  some  dyspeptics,  because  of  its  ten- 
dency to  caiis(!  acidity  and  lieartburn. 

'  Foods :  Their  Composition  and  Analysis,  London,  1896,  p.  210. 
10 


146  FOODS. 


Com. 


In  the  American  usage  of  the  word,  corn  inchides  the  several  varie- 
ties of  Indian  corn  or  maize.  In  England,  the  term  is  applied  gener- 
ally to  wheat,  rye,  oats,  and  barley,  and  more  specifically  to  wheat ;  in 
Scotland,  it  commonly  means  oats.  In  the  United  Staties,  corn  is  in 
many  ways  the  most  important  of  the  cereals,  constituting  in  some 
parts  of  the  country  the  chief  bread  food,  and  bemg  the  main  source 
of  starch  and  glucose. 

The  chief  varieties  are  dent  corn,  showing  a  depression  in  the  outer 
end  of  the  kernel ;  flint  corn,  havmg  a  hard  smooth  exterior ;  sweet 
corn,  rich  in  sugar  and  shrivelling  when  ripe ;  and  pop-corn,  a  very 
flinty  variety  with  small  kernels,  which  contain  a  considerable  amount 
of  oil,  which,  in  the  process  of  roasting,  explodes  and  causes  the  extru- 
sion of  the  starchy  interior  in  the  form  so  universally  familiar.  The 
variety  in  most  common  use,  from  which  the  several  kinds  of  meal, 
hominy,  and  samp  aro  derived,  is  the  flint  corn.  Hominy  is  the  prod- 
uct obtained  by  grinding  coarsely  the  kernels  deprived  of  the  hull  by 
soaking.  Samp  is  the  whole,  or  practically  the  whole,  of  the  kernel 
minus  the  germ  and  hull.  Indian  meal,  or  corn  meal,  is  the  product 
obtained  by  grinding  the  kernels  between  stones  or  by  other  processes 
of  milling,  and  removing  more  or  less  of  the  bran  by  sifting  or  bolt- 
ing. According  to  the  process  employed,  we  have  coarse  and  fine,  and 
white  and  yellow  meal.  Prepared  without  removal  of  the  germ,  which  is 
rich  in  oil,  the  product  is  prone  to  become  rancid  and  mouldy  on  keeping. 

From  a  large  nimiber  of  analyses,  AViley  deduces  the  following  as 
the  approximate  composition  of  typical  Indian  corn  : 

Moisture 10.75 

Proteids 10.00 

Ether  extract 4.25 

Crude  fiber 1.75 

Starch,  etc 71.75 

Ash 1.50 

100.00 

The  average  of  19  analyses  of  samples  of  sweet  corn  by  Clifford 
Richardson,  quoted  by  Wiley,  shows  : 

Moisture 8.44 

Proteids 11.48 

Ether  extract 8.57 

Crude  fiber 2.82 

Starch,  etc 66.72 

Ash 1.97 

100.00 

The  composition  of  fine  meal  is  given  by  Wiley  as  follows  : 

Moisture 12.57  . 

Proteids 7.13 

Ether  extract 1.33 

Total  carbohydrates 78.36 

Ash 0.61 

100.00 


Corn   Starch.     >(  285. 


Fig.  2. 


'iH. 


^T    u 


C^ 


•|a.^      G 


<>'V.V 


>-4. 


^: 


■% 


Rice   Starch.     X  285. 


RICE.  147 

The  lowered  percentag:es  of  proteids  and  fats  here  shown  are  dae  to 
the  removal  of  the  germ,  rich  in  fat,  and  of  the  finer  envelopes,  rich 
in  proteids. 

The  proteids  of  corn,  as  determined  by  Chittenden  and  Osborne,  are 
made  up  of  several  globulins,  including  myosine  and  vitelline,  two 
classes  of  albumins,  and  t^v^o  of  zeins.  The  starch  granules  are  poly- 
hedral with  rounded  angles,  and  have  a  punctiform,  sometimes  stellated^ 
hilum.  They  are  much  larger  than  those  of  oats,  which  they  resemble 
somewhat  in  form.     They  are  shown  in  Plate  IX.,  Fig.  1. 

On  account  of  its  deficiency  in  gluten,  corn  meal  is  not  well  adapted 
to  the  making  of  leavened  bread,  Ijut  it  is  used  in  many  forms  of  sub- 
stitutes therefor.  It  is  mixed  with  salt  and  water,  sometimes  with  the 
addition  of  milk  or  eggs,  and  baked  into  not  over-thick  cakes,  which, 
according  to  the  method  of  preparation  and  baking,  are  known  as 
johnnycake,  corn  dodger,  corn  pone,  and  corn  bread.  Sometimes,  yeast 
and  baking  powder  are  employed.  Corn  meal  is  used  extensively  in 
the  form  of  hasty  pudding,  or  corn  mush,  and  of  Indian  pudding.  In 
whatever  form  used,  corn  meal  is  a  most  nutritious  and  wholesome  food.. 


Rice. 

Rice  is  the  principal  food  of  a  very  large  part,  estimated  at  about  a 
third,  of  the  human  race.  Being,  as  will  be  seen,  too  poor  in  proteids, 
fat,  and  mineral  matter  to  satisfy  alone  the  needs  of  the  body,  the  de- 
ficiencies are  met  by  other  vegetable  products,  as  beans  and  j)eas,  which 
are  rich  in  these  constituents. 

The  form  in  w^hich  rice  is  seen  in  the  household  is  the  result  of  a 
polishing  process  which  removes  the  reddish  cuticle  which  the  grain 
shows  on  removal  of  the  husk.  Wiley's  figures,  representing  the  com- 
position of  typical  polished  rice,  are  as  follows  : 

Moisture 12.40 

Proteids 7.50 

Ether  extract 0.40 

Crude  fiber 0.40 

Starch,  etc 78.80 

Ash 0.50 

100.00 

Rice  is  the  richest  of  the  cereals  in  starch,  and  the  poorest  in  all  other 
respects.  The  proteids  have  not  yet  been  studied  systematically.  Its 
starch  is  very  easily  digestible,  and  is  very  useful  in  all  disordered  con- 
ditions of  the  digestive  tract  when  other  solid  foods  cannot  be  borne. 
Under  the  microscope,  the  starch  granules  are  seen  to  be  much  like 
those  of  com,  but  are  much  smaller  and  have  sharper  angles.  They 
are  separated  less  easily  from  one  another,  and  are  commonly  in  grou]is 
of  variable  size.      They  are  shown  in  Plate  IX.,  Fig.  2. 

Rice  cannot  be  made  into  brciul,  but  sometimes  is  mixed  with  wheat 
flour,  in  order  to  give  whiteness  to  the  bread.  It  is  used  most  com- 
monly in  the  freshly  boiled  condition  or  in  the  form  of  puddings.    The 


148  FOODS. 

most  approved  method  of  cooking  it  is  steaming.  This  has  the  advan- 
tage of  not  taking  away  any  of  the  ah^eady  deficient  proteids  and  salts, 
which  to  some  extent  are  extracted  in  boiling,  and  also  that  it  leaves 
the  kernels  distinct  in  themselves,  and  not  aggregated  in  the  form  of  a 
soggy  mush,  such  as  is  produced  often  by  improper  boiling. 

Buckwheat. 

This  valuable  cereal  is  used  very  extensively  in  this  country  as  a 
breakfast  food  in  the  form  of  pancakes  eaten  hot  with  syrup  or  with 
butter  and  sugar.  As  it  is  devoid  of  gluten,  it  cannot  be  made  into 
bread. 

The  composition  of  typical  American  buckwheat  is  given  as  follows : 

Moisture 12.00 

Proteids 10.75 

Ether  extract 2.00 

Crude  fiber 10.75 

Starch,  etc 62.75 

Ash 1.75 

iuo.oo 

The  crude  fiber  is  removed  very  largely  in  the  milling,  and  is  almost 
wholly  absent  from  the  w^hite  flour,  a  samjjle  of  which,  analyzed  by 
Wiley,  bad  the  following  comjjositiou  : 

Moisture 11.89 

Proteids 8.75 

Ether  extract 1.58 

Crude  fiber 0.52 

Starch,  etc 75.41 

Ash 1.85 

100.00 

Buckwheat  is  the  most  expensive  of  the  cereals,  and  consequently  is 
the  most  subject  to  adulteration  with  the  cheaper  members  of  the  class. 
The  admixture  is  detected  readily  by  the  microscope,  since  the  starch 
granules  have  a  very  characteristic  appearance,  being  small  and  angu- 
lar, and  of  nearly  uniform  size.  Ordinarily  they  are  seen  in  fairly  large 
masses  which  are  not  disintegrated  in  the  process  of  milling.  The 
starch  is  shown  in  Plate  X.,   Fig.   1. 

{h)  LEGUMES. 

This  group  comprises  peas,  beans,  and  lentils.  It  is  characterized 
by  richness  in  proteids,  which  may  be  ]iresent  in  more  than  double  the 
amount  found  in  wheat.  The  chief  proteid  is  legumin,  which  much 
resembles  casein,  and  is  known  commonly  as  vegetable  casein.  Accord- 
ing to  E.  Fleurent,^  the  proteids  of  this  group  consist  of  vegetable 
casein,  composed  of  legumin  and  glutenin,  and  vegetable  fibrin,  com- 
posed of  albumin  and  gliadin.     Thus  : 

'  Comptes  reudus,  1898. 


PLATE  X. 


U   X>. 


Buckwheat   Starch.     ><  285. 


Fig,  2. 


Pea   Starch.     X  28S. 


PEAS.  149 

Vegetable  casein^    i*^*"^" oa'c? 

*=  (.glutenin 30.6o 

TT      4.  ui    ci,  •       f  albumin 0.64 

Vegetable  fibrin    jgij^din 7.76 

100.00 

Their  high  content  of  proteids  makes  them  more  satisfying  than  other 
vegetable  foods,  and  enables  them  to  act  as  a  fair  substitute  for  animal 
food.  The  millions  of  rice-eaters  who,  by  reason  of  poverty  or  religious 
scruples,  are  denied  the  use  of  animal  food,  depend  upon  the  legumes 
to  supply  the  demands  of  the  body  for  nitrogen.  The  East  Indian, 
for  instance,  has  no  difficulty  in  satisfying  his  bodily  needs  with  a  hand- 
ful of  beans  added  to  his  daily  ration  of  rice.  While  legumes  possess  a 
very  high  nutritive  value,  they  must  be  ranked  as  much  more  difficult 
of  digestion  than  the  cereals.  They  require  prolonged  boiling  when 
cooked  whole,  but  are  prepared  more  quickly  and  digested  more  com- 
pletely when  ground  into  meal  and  cooked  with  milk.  Even  under 
the  most  favorable  conditions,  a  large  part  of  the  proteids  is  lost  in  the 
excreta.  Rubner  has  shown  that  a  fifth  to  a  third  is  not  digested  and 
absorbed,  whereas  in  the  case  of  bread  the  proteid  loss  is  less  than  a 
seventh. 

Some  individuals  are  obliged  to  forego  the  use  of  peas  and  beans,  on 
account  of  flatulence  due  to  the  formation  of  sulphuretted  hydrogen 
from  the  sulphur  in  the  legumin.  This  objection  does  not  apply  to  leu- 
tils,  since  they  contain  no  sulphur. 


Peas. 

The  average  of  61  analyses  of  peas,  compiled  by  Konig,  is  as  follows  : 

Moisture 14.99 

Proteids 22.85 

Fat 1.79 

Crude  fiber 5.43 

Starch,  etc      52.36 

Ash ,    ■  2.58 

100.00 

When  dried  peas  become  old,  no  amount  of  boiling  will  make  them 
soft,  and  they  should  then  be  soaked  and  crushed  and  cooked  in 
some  other  way.  The  immature  pea,  so  highly  prized  as  a  spring  and 
summer  vegetable,  has  a  very  different  composition.  Five  analyses, 
compiled  by  Atwater  and  Bryant,^  yielded  the  following  average  results  : 

Moisture 74.6 

Proteids 7.0 

Fat 0.5 

Carbohydrates,  including  fiber 16.9 

Ash 1.0 

100.6 
'  Locf)  citato. 


150  FOODS. 

The  canned  pea  appears  to  contain  considerably  less  nutriment.  Of 
88  samples  reported  by  the  same  authorities,  none  contained  less  than 
77.5  per  cent,  of  water,  and  some  contained  as  much  as  92.7.  Their 
average  composition  was  as  follows  : 

Moisture 85.3 

Proteids 3.6 

Fat. 0.2 

Carbohydi-ates 9.8 

Ash 1.1 

100.0 

The  starch  granules  of  peas  are  represented  in  Plate  X.,  Fig.  2. 

Beans. 

There  are  many  varieties  of  beans  belonging  to  the  two  large  groups, 
the  broad  beans  and  the  kidney  beans,  but  their  composition  is  in  gen- 
eral quite  similar.  Forty-one  analyses  of  broad  beans  and  10  of  kid- 
ney beans  compiled  by  Konig  give  the  following  averages  : 

Broad.  Kidney. 

Moisture 14.76  13.74 

Proteids 24.27  23.21 

Fat 1.61  2.14 

Crude  fiber 7.09  3.69 

Starch,  etc 49.01  53.67 

Ash 3^  3.55 

100.00  100.00 

Eleven  analyses  compiled  from  American    sources  by   Atwater  and 
Bryant  yield  averages  not  materially  different. 

Five  analyses  of  string  beans  in  the  fresh  state  and  29  of  canned 
samples  yield  the  following  averages,  showmg,  as  in  the  case  of  peas, 
that  the  canned  variety  is  less  nutritious  : 

Fresh.  Canned. 

Moisture 89.2  93.7 

Proteids 2.3  1.1 

Fat 0.3  0.1 

Total  carbohydrates 7.4  3.8 

Ash O  1.3 

100.0  100.0 

The  Soja  bean,  which  has  been  recommended  highly  in  some  quarters 
as  a  suitable  food  for  diabetics,  is  remarkable  for  its  high  content  of 
fat,  and  contains,  in  addition,  so  large  an  amount  of  starch  as  to  make 
it  quite  unsuited  to  the  dietary  of  the  diabetic.  Konig  has  compiled 
21  analyses  from  all  sources,  and  Jenkins  and  Winton  ^  have  collected 
10  more  from  American  sources.  The  two  groups  give  the  followiug 
averages  : 

1  Experiment  Station  Bulletin,  No.  11,  Washington,  1892. 


''%■: 


Bean  Starch.     X  28S. 


v-v-.^^^^^x:ijv>^ 


)Or 


Arrowroot   Starch,     a.  285. 


TAPIOCA.  151 

Krinip-  Jenkins 

'^o^^e-  and  Winton. 

Moisture 9.51  10.80 

Proteids 33.41  33.98 

Fat 17.19  16.85 

Crude  fiber 4.71  4.79 

Starch,  etc 29.99  28.89 

Ash ■      5.19  4.69 

100.00  100.00 


Bean  starch  is  shown  in  Plate  XI.,  Fig.  1. 

Lentils. 

Lentils  are  the  most  nutritious  of  the  legumes,  but  are  not  a  popular 
food  in  this  country,  excepting  among  certain  of  the  foreign-born 
population.  Their  use  is,  however,  on  the  increase.  The  averages  of 
14  analyses  compiled  by  Konig  are  as  follows  : 

Moisture 12.34 

Proteids 25.70 

Fat 1.89 

Crude  fiber 3.57 

Starch,  etc 53.46 

Ash 3.04 

100.00 

2.  Farinaceous  Preparations. 
Under  this  head  are  included  sago,  tapioca,  and  arrowroot. 

SAGO. 

Sago  is  derived  from  the  pith  of  the  stems  of  a  number  of  species 
of  palms.  The  pith  is  extracted  and  ground  to  a  powder,  which  then 
is  mixed  with  water  and  strained.  The  starch  granules  pass  through 
with  the  water,  and  are  deposited  as  a  sediment,  which  constitutes  the 
sago  flour.  From  the  flour,  made  into  a  paste,  the  various  forms  of 
granulated  sago  are  prepared. 

Sago  is  an  important  starch  preparation,  and  serves  as  a  light  and 
digestible  food  for  invalids  and  dyspeptics,  but  its  use  is  not  restricted 
to  these  alone.  It  absorbs  the  liquid  in  which  it  is  cooked,  and  becomes 
soft  and  transparent,  but  retains  its  original  form. 

TAPIOCA. 

Tapioca  is  derived  from  a  thick  fleshy  tuberous  root  called  "  mani- 
hot."  The  starch,  which  is  extracted  by  a  method  similar  to  that  em- 
ployed in  th<;  preparation  of  sago,  is  heated  in  a  moist  state  on  hot 
plates  and  stirred  with  iron  rods,  and  thus  forms  irregular  masses  of 
transparent  granules.  In  the  process  of  heating,  many  of  the  starch 
graniil(!S  b(!Come  ruj^turcd,  and  are  then  partially  soluble  in  cold  water. 
Taj)ioca,  like  sago,  is  useful  for  both  sick  and  well. 


152  FOODS. 

ARROWROOT. 

Arrowroot  is  a  pure  form  of  starch  from  the  tuberous  root  of  the 
maranta.  Its  name  is  derived  from  the  fact  that  the  maranta  root  is 
believed  to  counteract  the  effects  of  arrow  poison.  It  is  used  chiefly 
as  a  bland  article  of  food  in  the  sick-room  in  the  form  of  light  pudding 
or  other  desserts,  but  may  be  combined  with  other  starch  foods  and 
made  into  bread.  There  are  several  varieties,  the  best  of  which  come 
from  Bermuda  and  Jamaica.  Corn  starch  is  employed  frequently  as  a 
fair  substitute.     Arrowroot  starch  is  shown  in  Plate  XI.,  Fig.  2. 

3.  Fatty  Seeds  (Nuts). 

Nuts  are  rich  in  fat  and  proteids,  but  contain  no  starch.  They  are 
of  high  nutritive  value,  but  on  account  of  their  richness  in  fat  they  are 
not  easily  digested,  even  when  reduced  to  a  finely  divided  state. 


ALMONDS. 

In  the  countries  where  they  are  produced,  the  almond  is  eaten  both 
in  the  green  and  dry  conditions.  The  ripe  kernel  has  a  skin,  with  a 
bitter  disagreeable  taste.  When  this  is  removed  by  soaking  for  a  time 
in  warm  water,  the  almond  is  kno^^^l  as  "  blanched." 

There  are  two  varieties  of  almond,  the  sweet  and  the  bitter,  both  of 
which  contain  more  than  50  per  cent,  of  oil,  about  half  as  much  pro- 
teid  material,  gum,  sugar,  and  crude  fiber.  Both  contain  emulsin,  a 
substance  which,  in  the  presence  of  water,  acts  upon  the  glucoside 
amygdalin,  present  only  in  the  bitter  variety,  to  form  hydrocyanic  acid, 
glucose,  and  benzoic  aldehyde.  On  account  of  this  reaction,  the  bitter 
almond  is  not  always  safe,  and  fatal  results  have  occurred  from  its 
ingestion. 

When  almonds  are  baked,  they  are  made  more  brittle,  and  are  re- 
duced more  easily  to  a  powder. 

COCOANUTS. 

The  fleshy  white  kernel  of  the  cocoanut  contains  about  70  per  cent, 
of  fat.  The  milky  interior  is  chiefly  water,  but  contains  nearly  7  per 
cent,  of  sugar. 

WALNUTS. 

All  of  the  trees  of  the  genus  Juglans  yield  nuts  classed  as  walnuts. 
The  different  varieties,  though  varying  in  outward  appearance  and  in 
taste,  have  practically  the  same  composition.  They  contain  about  60 
per  cent,  of  fat,  about  16  per  cent,  of  proteids,  and  about  7  per  cent, 
of  sugar  and  gum.  The  hazel  nut,  which  belongs  to  the  oak  family 
has  about  the  same  composition. 


OLIVE  OIL.  15S 

PEANUTS. 

The  peanut,  known  also  as  ground  nut  and  goober,  is  less  rich  in  fat, 
but  richer  in  proteids  than  other  nuts.  It  contains  about  45  per  cent, 
of  the  former  and  about  30  per  cent,  of  the  latter. 

CHESTNUTS. 

The  chestnut  is  not  of  this  class,  but  for  convenience  will  be  con- 
sidered here  rather  than  with  the  farinaceous  seeds,  in  which  class  it 
properly  belongs.  It  contains  but  little  fat  and  proteids,  about  15  per 
cent,  of  sugar,  about  25  per  cent,  of  starch,  and  about  50  per  cent,  of 
moisture.  It  is  very  indigestible  in  the  raw  state,  and  even  when 
cooked  is  very  trying  to  the  digestion  of  those  with  weak  stomachs. 
It  is  used  very  extensively  as  a  food  by  the  French,  Spanish,  and  Ital- 
ian peasantry  in  various  cooked  forms,  and  largely  in  the  form  of  bread. 

4.  Vegetable  Fats. 

The  vegetable  fats  include  the  oils  derived  from  the  olive,  cotton- 
seed, peanut,  and  other  seeds.  They  are  used  in  the  preparation  of 
salads  and  for  frying.    The  most  important  are  the  two  first  mentioned. 

OLIVE  OIL. 

Olive  oil  is  a  bland  fixed  oil  derived  from  the  fruit  of  the  many 
varieties  of  the  olive  tree.  It  is  known  by  various  names  which  desig- 
nate the  grade,  but  is  sold  for  the  most  part  as  virgin  oil,  which  is  the 
choicest  grade  of  all  and  not  extensively  marketed.  Virgin  oil  is  made 
from  the  choicest  olives,  about  three-fourths  ripe,  which  are  bruised  only 
slightly  in  the  mill,  so  that  only  the  olive  pulp,  and  not  the  stone,  is 
crushed.  The  crushed  mass  is  gathered  in  a  heap,  and  the  oil  is 
allowed  to  drain  away  without  pressure  or  other  influence  of  any  kind. 
The  product  has  a  greenish  tint  and  a  far  more  dehcate  taste  than  that 
made  in  the  manner  to  be  described. 

In  the  manufacture  of  the  grades  ordinarily  seen  in  the  market,  the 
olives,  both  pulp  and  stones,  are  ground  into  an  oily  paste,  which  is 
packed  into  bags  made  of  woven  grass.  These  are  placed  in  piles  and 
subjected  to  pressure.  As  the  oil  drains  away,  boiling  water  is  applied 
to  the  bags  to  keep  up  the  flow,  and  that  which  is  thus  obtained  con- 
stitutes the  lower  grade.  Sometimes,  the  pressed  pulp  is  thrown  into 
water  and  separated  from  the  broken  kernels,  which  sink  to  the  bottom. 
The  pulp  is  then  gathered  up  and  pressed  again. 

On  account  of  the  cost  of  pure  olive  oil,  adulteration  with  other 
cheaper  oils  is  practised  very  extensively.  The  principal  adulterant 
is  cotton-seed  f»i],  which  is  exported  frf)m  this  country  in  large  quantities 
for  this  and  other  purposes.  Much  of  tlie  oil  sold  in  this  country  as 
olive  oil  is  cotton-seed  oil  put  uj)  in  the  cheapest  kinds  of  bottles, 
adorned  with  gaudy  labels  bearing  inscriptions  often  not  remarkable  for 
accuracy  in  the  use  of  the  French  language.     The  autlior  has  seen,  for 


154  FOODS. 

example,  labels  which  indicated  that  the  contents  of  the  bottles  had 
been  "  virginated." 

Adulteration  of  olive  oil  to  only  a  slight  extent  with  the  cheaper 
oils  is  by  no  means  easy  of  detection,  but  when  the  fraud  is  fairly  ex- 
tensive it  may  be  shown  by  chemical  tests  and  by  the  use  of  the  re- 
fractometer,  the  refractive  index  of  olive  oil  being  less  than  that  of 
the  cheaper  substitutes.  The  iodine  number  and  saponification  equiv- 
alent of  olive  oil  are  both  less  than  those  of  its  adulterants.  The  be- 
havior of  olive  oil  in  contact  with  nitric  acid  or  with  alcoholic  solution 
of  nitrate  of  silver  is  markedly  different  from  that  of  the  cheaper  oils. 
Thus,  equal  volumes  of  strong  nitric  acid  and  olive  oil,  mixed  together 
and  agitated  in  a  flask,  give  a  product  which  has  either  a  greenish  tinge 
or  at  most  one  inclining  to  orange,  and  no  marked  change  is  perceptible 
on  standing  for  five  or  ten  minutes  ;  whereas  cotton-seed  oil  similarly 
treated  yields  almost  immediately  a  reddish  color,  which  shortly  darkens 
and  becomes  dark  brown  or  almost  black. 

Again,  if  12  cc.  of  a  suspected  sample  are  mixed  in  a  test  tube  with 
5  cc.  of  a  2.5  per  cent,  solution  of  nitrate  of  silver  in  95  per  cent, 
alcohol,  and  placed  in  a  beaker  of  boiling  water,  the  resulting  change 
of  color  gives  indications  as  follows :  if  olive  oil,  the  color  is  greenish  ; 
if  cotton-seed  oil,  it  becomes  black ;  if  sesame  oil,  it  is  dark  reddish- 
brown  ;  if  peanut  oil,  it  is  at  first  reddish  brown,  then  greenish  and 
turbid ;  if  poppy  oil,  it  is  greenish  yellow.  For  further  details  of 
chemical  tests,  the  reader  is  referred  to  the  standard  works  on  the 
adulteration  of  foods. 

COTTON-SEED    OIL. 

This  very  important  and  cheap  vegetable  fat  is  a  perfectly  whole- 
some and  desirable  article  of  food.  It  is  much  used  under  its  own 
name  as  a  suljstitute  for  lard  and  olive  oil  for  frying,  and  in  place  of 
the  latter  as  an  ingredient  of  dressings  for  salads.  It  lacks  the  fine 
flavor  of  olive  oil,  but  its  substitution  in  dressings  can  be  detected  only 
by  the  educated  palate.  From  a  hygienic  standpoint,  there  is  abso- 
lutely no  objection  to  its  use  in  the  preparation  of  foods.  The  same 
may  be  said  of  the  other  cheap  vegetable  oils. 

5.  Tubers  and  Roots. 

In  the  cooking  of  tubers,  roots,  and  other  vegetables,  the  albumins 
and  globulins  are  coagulated,  the  fibrous  matters  in  the  cell  walls  are 
softened  and  ruptured,  the  starch  granules  swell  and  burst,  the  starch 
itself  becomes  somewhat  changed  in  character,  and  the  whole  mass  is 
made  more  digestible.  When  boiling  is  the  process  employed,  part  of 
the  mineral  matter  and  more  or  less  of  the  other  soluble  substances, 
including  certain  proteid  material,  are  extracted  and  lost. 

POTATOES. 

The  potato  is  the  most  important  member  of  this  group.  It  was  intro- 
duced into  Spain  from  Peru  about  the  middle  of  the  sixteenth  century. 


PLATE  XII. 


Potato   Starch.     X  28J 


POTATOES.  155 

and  later,  in  1585,  into  Ireland  from  Virginia,  by  Sir  Walter  Raleigh, 
who,  in  the  following  year,  introduced  it  also  into  England.  Prior  to 
that  time,  and  even  later,  what  was  known  in  England  as  the  potato 
and  the  "common  potato"  mentioned  by  Gerard  in  his  Herbal  (1597), 
were  sweet  potatoes,  "  batata,"  introduced  from  Spain. 

The  averages  of  136  analyses  (American  samples)  compiled  by 
Atwater  and  Bryant  are  as  follows  : 

Moisture 78.3 

Proteids 2.2 

Fat 0.1 

Total  carbohydrates 18.4 

Ash LO 

100.0 

These  figures  differ  but  slightly  from  the  averages  of  178  analyses 
of  European  samples. 

The  proteids  of  the  potato  are  chiefly  in  the  albmninous  juice  be- 
tween and  in  the  cells.  Most  of  the  mineral  matter  is  salts  of  potas- 
sium, and  this,  too,  is  almost  wholly  in  the  juice.  The  starch  was  dis- 
covered by  Lenbert  and  Georgiewsky  to  be  acted  upon  much  more 
readily  by  the  salivary  enzyme  than  any  of  the  cereal  starches.  The 
starch  granules  are  much  larger  and  more  irregular  iu  shape  than  any 
of  those  thus  far  shown.  The  hilum  and  concentric  rings  are  quite 
distinct.      (See  Plate  XII.) 

In  the  process  of  cooking,  the  albuminous  juice  is  coagulated  and  its 
watery  part  is  absorbed  by  the  starch  granules,  which  swell  and  con- 
sequently distend  the  cells  in  which  they  are  lodged.  The  coherence 
of  the  cells  is  reduced,  and  then  they  are  separated  easily  into  a  mealy 
mass.  If  the  watery  part  of  the  juice  is  not  wholly  absorbed,  the  cells 
are  separated  with  more  or  less  difficulty,  the  potato  remains  firm  instead 
of  becoming  mealy,  and  is  then  spoken  of  as  close,  waxy,  or  watery. 
In  this  state  it  is  digested  much  less  easily,  and  may,  indeed,  be  very 
trying  to  the  stomach.  The  same  condition  is  noticed  in  the  case  of 
potatoes  which  have  been  frozen ;  they  are  very  watery  and  of  inferior 
flavor  however  they  are  cooked. 

According  to  Balland,^  the  mealy  condition  is  due  not,  as  supposed, 
to  an  especially  high  content  of  starch,  but  to  a  low  percentage  of  al- 
bumin, for  a  potato  rich  in  this  substance  keeps  its  shape  and  neither 
cracks  nor  falls  apart.  He  also  points  out  that  beneath  the  skin  there 
are  three  well-defined  layers,  which  may  readily  be  seen  by  holding  a 
thin  cross-section  against  a  strong  light.  The  outermost  is  richest  in 
starch  and  poorest  in  proteids,  but  in  the  innermost  these  conditions  are 
reversed ;  the  middle  layer  represents  the  mean  composition  of  the 
whole. 

The  loss  which  occurs  on  boiling  is  much  less  when  the  skins  are 
left  intact  than  when  removed ;  the  greatest  loss  occurs  when  the 
potatoes  are  peeled  first  and  then  soaked  in  cold  water.  When  cooked 
by  stoiiming,  there  is  no  loss  whatever.     The  material  lost  in  boiling 

'  Journal  de  Pharmacie  et  de  Cheniie,  1897,  VI. 


156 


FOODS. 


a,  fiber,  pectose,  fat,  etc. ;  5,  non-albuminoid  nitro- 
genous matter;  c,  albuminoid  nitrogenous  matter; 
d,  mineral  matter.  The  hatched  portion  represents 
the  loss.    (After  Snydek.) 


has  been  determined  by  H.  Snyder  ^  as  follows  :  Skins  removed,  soaked 
3  hours  :  total  nitrogen,  46  per  cent. ;  ash,  45.6  per  cent.  Skins  re- 
moved, not  soaked  :  total  nitrogen,  16.9  per  cent. ;  ash,  17.9  per  cent. 

Skins  not  removed  :  total  ui- 
FiG.  5.  trogen,  1  per  cent. ;  ash,  3.4 

per  cent. 

The  composition  of  the 
potato  and  the  loss  of  nutri- 
ents when  boiled  with  the 
skin  removed  are  shown  by 
Snyder  by  a  drawing,  which 
is  here  reproduced.  (See 
Fig.  5.) 

Potatoes  are  so  deficient  in 
nitrogen  that  alone  they  do 
not   constitute   a  proper  ra- 
tion, but  with  foods  rich  in  proteids,  such  as  meats,  beans,  or  peas, 
they  are  valuable  and   economical. 

The  juice  of  the  potato  contains  citric  acid  and  citrates  of  potassium, 
sodium,  and  calcium,  which  fact  accounts  for  the  antiscorbutic  value  of 
this  vegetable. 

Attention  has  often  been  called  to  the  fact  that  the  potato  belongs  to 
a  poisonous  botanical  family,  which  includes  belladonna,  stramonium, 
hyoscyamus,  and  tobacco,  all  powerful  narcotic  plants ;  and  it  has  been 
pointed  out  as  a  paradox  that  this  valuable  food  possesses  no  poisonous 
properties.  This,  however,  is  not  true,  for  the  potato  has  been  the  fre- 
quent cause  of  more  or  less  extensive  outbreaks  of  poisoning,  and  it 
has  long  been  known  that  the  normal  potato  contains  about  .006  per 
cent,  of  solanin,  and  that,  when  sprouting,  the  solanin  content  is  ma- 
terially increased.  Between  1892  and  1898,  many  outbreaks  of  poison- 
ing occurred  in  the  15th  (German)  Army  Corps,  which  were  traced  by 
Schmiedeberg  and  Meyer  ^  to  solanin  in  sprouting  or  completely  ripe 
potatoes.  Schmiedeberg's  assertion  that  solanin  formation  in  potatoes 
is  caused  by  bacteria  has  been  proved  by  R.  Weil,^  who  demonstrated 
that  at  least  two  organisms,  Bacterium  solanijerum  non-colorabile 
and  Bacterium  solanifernm  colorabile,  have  the  property  of  producing 
solanin  from  substances  normally  present. 

A  noteworthy  instance  of  potato-poisoning  is  that  recorded  by  Pfuhl.* 
Fifty-six  soldiers  of  a  company  of  the  German  Army  were  seized  with 
symptoms  of  acute  gastro-enteritis.  The  sickness  began  with  chills, 
fever,  headache,  colic,  vomiting,  and  diarrhoea.  In  a  number  of  cases 
there  was  collapse,  with  more  or  less  jaundice.  None  of  the  cases  ended 
fatally,  nor  were  there  any  relapses  or  sequelae.  Investigation  showed 
that  the  men  had  eaten  sprouting  potatoes,  a  sample  of  which  yielded 
.038  per  cent,  of  solanin,  and  that,  therefore,  those  who  had  eaten  their 

^  Department  of  Agfriculture,  Office  of  Experiment  Stations,  Bulletin  No.  43,  1897. 
^  Archiv  fiir  experimentelle  Pathologie  und  Pharmakologie,  1895. 
=>  Archiv  fur  Hygiene,  XXXVIII.  (1900),  p.  330. 
■•  Deutsche  medicinische  Wochensohrift,  1899,  p.  753. 


ROOTS. 


157 


full  portion  of  the  vegetable  had  ingested  about  0.3  gram  of  the  poison, 
a  quantity  which  may  easily  induce  serious  symptoms. 

SWEET  POTATOES. 

The  average  composition  of  sweet  potatoes  (95  analyses)  is  given  by 
Atwater  and  Bryant  as  follows  : 

Moisture 69.0 

Proteids 1.8 

Fat 0.7 

Total  carbohydrates 27.4 

Ash 1.1 

100.0 

Starch  constitutes   much  the  greater  part  of  the  carbohydrates ;    the 
remainder  is  mainly  sugar, 

ARTICHOKES. 
The  Jerusalem  artichoke  is  so  named,  not  after  the  city  of  Jerusa- 
"lem,  but  from  a  corruption  of  the  Italian  word  girasole,  meaning  sun- 
flower, to  which  family  the  plant  belongs.     This  tuber  is  quite  sweet 
to  the  taste,  but  it  is  not  so  agreeable  as  the  potato.  Yig.  6. 

It  contains  no  starch,  but  yields  about  15  per  cent, 
of  sugar.  It  is  about  twice  as  rich  in  proteids  as  the 
potato.     When  cooked,  it  becomes  soft  and  watery. 

ROOTS. 

The  carrot,  beet,  parsnip,  turnip,  oyster  plant,  and 
radish  agree  in  a  general  way  in  composition,  and 
may  be  considered  together.  They  are  very  poor 
in  proteids,  and  contain  but  a  small  amount  of  other 
nutrients.  All  of  them  are  valuable  on  account  of 
their  antiscorbutic  properties,  for  providing  variety 
in  the  diet,  and  for  flavoring  other  foods.  Their 
average  composition,  according  to  Atwater  and 
Bryant,  is  set  forth  in  the  following  table  : 


Carbo- 

No. of 
analyses. 

Water. 

Proteids. 

Fat. 

hydrates 
includ- 
ing fiber. 

Ash. 

Beets     .    .    . 

24 

87.5 

1.6 

0.1 

9.7 

1.1 

Carrots  .    .    . 

18 

88.2 

1.1 

0.4 

9.3 

1.0 

Oyster  plant  * 

1 

80.4 

1.0 

0.5 

17.1 

1.0 

Parsnips    .    . 

3 

83.0 

1.6 

0.5 

13.5 

1.4 

Kadishes  .    . 

4 

91.8 

1.3 

0.1 

5.8 

1.0 

Turnips    .    . 

19 

89.6 

1.3 

0.2 

8.1 

0.8 

a,  fiber,  starch,  fat, 
etc. ;  b,  sugar ;  c,  non- 
albuminoid  nitrogenous 
matter ;  d,  albuminoid 
nitrogenous  matter ;    e, 

Snyder  represents  diagrammatically  the  compo-  ™at"  h'?d  ^^lum  relre- 
.sition  of  the  carrot  and  the  loss  of  nutrients  when  fnum-sb!ed'pi^erw?rt 
boiled.  (See  Fig.  fj.)  On  account  of  the  general  re-  foiled.  (After  snydek.) 
semblance  in  composition,  this  diagram  may  be  taken  fiirly  to  represent 
the  whole  group, 

'  The  figures  for  oyster  plant  are  taken  from  Konig. 


158 


FOODS. 


6.  Herbaceous  Articles. 

These  include  various  leaves,  stems,  and  shoots.  They  contain  but 
little  nutriment,  but  are  valuable  for  their  salts,  and  for  the  variety 
which  they  give  to  the  diet.  It  is  to  be  noted,  however,  that  in  pro- 
teids  they  are,  as  a  class,  equal  or  superior  to  the  tubers  and  roots. 
They  contain  unimportant  amounts  of  fat  and  sugar.  The  cabbage  and 
allied  plants  are  not  easily  digested,  and  on  account  of  containing 
more  or  less  sulphur,  may  give  rise  to  disagreeable  flatulence,  and  are 
not  suited  to  weak  digestions.  Sjjinach  is  regarded  as  shghtly  laxative. 
Celery  is  not  easily  digested  in  the  raw  state,  but  is  easily  borne  when 
stewed.  Lettuce,  cresses,  and  similar  articles  for  salads  are  wholesome 
and  digestible.  Asparagus,  while  containing  but  little  nutriment,  is 
prized  particularly  for  its  delicate  flavor.  Onions  and  leeks,  being 
modified  stems,  belong  in  this  group.  They  contain  volatile  oils  which 
act  as  gentle  stimulants. 

The  following  table,  compiled  from  Atwater  and  Bryant,  gives  the 
composition  of  the  members  of  this  group  : 


Asparag-us 
Cabbaae  . 
Cauliliower 
Sprouts  .  . 
Celery  .  . 
Lettuce  .  . 
Spinach 
Beet  tops  . 
Dandelions 
Leeks  .  . 
Onions   .    . 


No.  of 
analyses 


3 

16 

2 

1 
5 
8 
3 
1 
1 
1 
15 


Water. 


91.6 
91.5 
92.3 
88.2 
94.5 
94.7 
92.3 
89.5 
81.4 
91.8 
87.6 


Proteids. 


2.1 
1.6 
1.8 
4.7 
1.1 
1.2 
2.1 
2.2 
2.4 
1.2 
1.6 


Fat. 


3.3 
0.3 
0.5 
1.1 
0.1 
0.3 
0.3 
3.4 
1.0 
0.5 
0.3 


Total 
carbo- 
hydrates. 


2.2 
5.6 
4.7 
4.3 
3.3 
2.9 
3.2 
3.2 
10.6 
5.8 
9.9 


Ash. 


0.8 
1.0 
0.7 
1.7 
1.0 
0.9 
2.1 
1.7 
4.6 
0.7 
0.6 


Fig.  7. 


a,  starch,  sugar,  fiber,  fat,  etc. ;  6, non-albuminoid  nitrogenou.s  matter;  c,  albuminoid  nitrogen- 
ous matter;  d,  mineral  matter.    The  hatched  portion  represents  the  loss.    (After  Snyder.) 


The  composition    of  the    cabbage  and    the    loss   incurred    through 
boiling    are  shown  in  the  accompanying  figure  (Fig.   7),  by  Snyder.. 


APPLES.  159 

In  a    general   way    it    may    be    accepted    as    representing    the    entire 
group. 

7.  Fruit  Products  Used  as  Vegetables. 

These  include  the  tomato,  cucumber,  squash,  pumpkin,  egg-plant, 
and  vegetable  marrow.  The  tomato  is  consumed  largely  in  the  raw 
state  as  a  salad,  and  in  several  cooked  forms.  It  contains  less  than 
6  per  cent,  of  solid  matter,  and  in  this  respect  has  about  the  same 
nutritive  value  as  celery  and  lettuce.  Its  chief  solid  matter  is  sugar. 
Its  mineral  constituents  are  free  from  earthy  salts.  The  cucumber  in 
the  raw  state,  in  which  condition  it  is  eaten  most  commonly,  is  not  easy 
of  digestion  ;  but  when  stewed,  is  light,  wholesome,  and  agreeable.  As 
a  nutriment  it  stands  even  lower  than  the  preceding,  containing  less 
than  5  per  cent,  of  solid  matter.  The  squash,  pumpkin,  vegetable 
marrow,  and  egg-plant  have  about  equal  nutritive  value.  They  con- 
tain about  90  per  cent,  of  water,  are  very  poor  in  proteids — less  than 
1  per  cent. — but  are  fairly  rich  in  carbohydrates. 

8.  Fruits. 

As  stated  above,  the  word  fruits  is  used  here  in  its  narrower  sense 
to  designate  those  products  which,  being  of  an  agreeable  taste  in  the 
raw  state,  are  suitable  for  use  as  a  dessert.  The  agreeable  taste  depends 
upon  the  relative  proportions  of  pectin,  sugar,  gum,  acids,  and  other 
constituents.  Some  fruits  with  hut  a  small  percentage  of  sugar  and 
considerable  acid  have  a  sweeter  taste  than  others  richer  in  sugar  and 
with  no  more  acid,  because  of  the  masking  of  the  free  acid  by  the  gum 
and  pectin.  Thus,  the  peach,  for  instance,  is  comparatively  poor  in 
sugar,  but  its  content  of  acid  is  prevented  from  being  prominent  by  the 
large  content  of  gum  and  pectin.  Some  fruits  contain  usually  but  little 
of  these  constituents. 

Fruits  contain  but  little  proteid  matter,  and  their  chief  food  value 
lies  in  the  sugar,  salts,  and  vegetable  acids  which  they  contain.  Eaten 
in  moderation,  they  exert  a  favorable  influence  on  the  system,  but  when 
taken  in  undue  proportion  to  other  foods,  and  especially  in  unripe  or 
too  ripe  states,  may  cause  digestive  derangements.  On  account  of 
their  richness  in  vegetable  acids  and  their  salts,  which  in  the  system 
are  decomposed  and  converted  to  carbonates,  they  tend  to  diminish  the 
acidity  of  the  urine. 

APPLES. 

In  the  raw  state,  apples  are  not  very  easy  of  digestion,  but  when 
cooked  they  are  much  more  so,  and  when  baked  are  reputed  to  be 
-liglitly  laxative  and,  therefore,  useful  in  habitual  constipation,  l)ut  not 
suitable  in  the  reverse  condition.  Fn^m  the  many  analyses  which  have 
been  compiled  by  various  authorities,  it  may  be  stated  that  this  fruit 
contains  about  85  per  cent,  of  water,  7.5  per  cent,  of  sugar,  1  of  malic 


160 


FOODS. 


acid,  0.4  of  ash,  besides  variable  amounts  of  pectin,  pectose,  fiber,  and 
other  matters. 

PEARS. 

Pears  are  somewhat  richer  than  apples  in  sugar  and  poorer  in  malic 
acid.     They  are  fairly  rich  in  pectin. 

PEACHES. 

In  this  fruit,  the  sugar  is  comparatively  low,  but  the  pectous  matter 
is  exceptionally  high  and  covers  the  acidity.  Peaches  contain  nearly 
1  per  cent,  of  malic  acid. 

APRICOTS. 

The  sugar  content  of  apricots  is  about  equal  to  that  of  peaches. 
The  pectous  matter  is  also  about  the  same  m  amount,  but  the  acidity 
Ls  higher. 

PLUMS. 

Plums  contain,  as  a  rule,  less  sugar  and  pectin  and  more  malic  acid 
than  are  found  in  peaches  and  apricots.  They  are  much  more  likely 
than  most  other  fruits  to  disagree  and  produce  derangement  of  digestion. 

CHERRIES. 

Cherries  are  notable  for  their  large  content  of  sugar,  over  10  per 
cent.,  surpassing  in  this  respect  all  of  the  foregoing.  They  contain 
somewhat  less  than  1  per  cent,  of  malic  acid  and  are  low  in  pectin. 
The  popular  idea  that,  even  in  ripe,  sound  condition,  they  are  a  danger- 
ous article  of  food  if  eaten  in  conj unction  with  milk,  has  no  foundation 
in  fact ;  but  when  unripe  or  imsound,  they  have  a  tendency  to  cause 
disorder  of  the  bowels. 

The  average  composition  of  the  foregoing  fruits  is  shown  in  the  fol- 
lowing table,  compiled  from  Konig  : 


Water. 

Sugar. 

Acid. 

Proteids. 

Pectin,  etc. 

Fiber. 

Ash. 

Apples 

83.79 

7.22 

0.82 

0.36 

5.81 

1.51 

0.49 

Pears  ...;.... 

83.03 

8.26 

0.20 

0.36 

3.54 

4.30 

0.31 

Pearhes 

80.03 

4.48 

0.92 

0.65 

7.17   ■ 

6.06 

0.69 

Apricots 

81.22 

4.69 

1.16 

0.49 

6.35 

5.27 

0.82 

Plums 

84.86 

3.56 

1.50 

0.40 

4.68 

4.34 

0.66 

Cherries 

79.82 

10.24 

0.91 

0.67 

1.56 

6.07 

0.73 

ORANGES. 

The  orange  contains  nearly  2.5  per  cent,  of  citric  acid  and  about  4.5 
of  sugar.  The  juice  is  particularly  agreeable  in  almost  any  condition 
of  health  or  sickness,  and  is  extremely  unlikely  to  cause  any  disturbance 
of  the  system. 


MELONS.  161 

The  average  composition  of  oranges  (23  analyses),  according  to 
Atwater  and   Bryant,  is  as  follows  : 

Water 86.9 

Proteids     .  ■ 0.8 

Fat 0.2 

Total  carbohydrates,  including  fiber 11.6 

Ash ■      0.5 

100.0 

GRAPES. 

The  juicy  pulp  of  the  grape  is  wholesome  and  refrigerant,  and  when 
eaten  in  large  amounts  exerts  a  gentle  laxative  action.  Since  the  num- 
ber of  varieties  reaches  into  the  thousands,  it  follows  that  wide  varia- 
tion in  composition  must  occur. 

Twelve  analyses  compiled  by  Konig  yield  the  following  averages  : 

Water 78.17 

Sugar       14.36 

Free  acid 0.79 

Proteids 0.59 

Pectous  matter 1.96 

Fiber 3.60 

Ash 0.53 

100.00 

Five  analyses  compiled  by  Atwater  and  Bryant  yield  averages  which 
are  expressed  somewhat  diiferently,  as  follows  : 

Water 77.4 

Proteids 1.3 

Fat •    ■. 1-6 

Total  carbohydrates,  including  fiber 19.2  -, 

Ash 05 

100.0 

When  dried  in  the  sun  or  in  ovens,  the  product  is  raisins.  Those 
dried  in  the  sun  are  the  better.  Raisins  are  less  digestible  than  grapes, 
and  are  not  infrequently  the  cause  of  derangement  of  the  intestinal 
canal. 

What  are  known  commonly  as  dried  currants  are  raisins  made  from 
small  seedless  grapes.  They  come  from  the  Levant,  and  are  shipped 
from  Corinth,  whence  their  name  in  a  corrupted  form.  They  are  ex- 
ceedingly indigestible,  and  are  likely  to  traverse  the  entire  digestive  tract 
without  undergoing  change. 

MELONS. 

TliG  edible  ])ortion  of  melons  is  very  watery,  but  the  small  amount 
of  nutriment  contained  is  not  unlikely  to  cause  in  many  persons  di- 
gestive disturbances  accompanied  by  annoying  eructations.  Not  many 
analyses  have  bc(!n  ref!orded.  Storer,'  quoted  by  Konig,  has  reported 
three  analyses,  which  give  the  following  averages  : 

'  liei)0il  of  Connecticut  Expciirncnt  Station,  1879,  p.  159. 

n 


162 


FOODS. 


Water  ....  - 88.09 

Proteids 0.92 

Fat 0.18 

Sugar,  etc 9.05 

Fiber 1.04 

Ash 0.72 

100.00 

Two  analyses  of  watermelons  noted  by  Atwater  and  Bryant  give  the 
following  averages  : 

Water 92.4 

Proteids 0.4 

Fat 0.2 

Total  carbohydrates,  including  fiber 6.7 

Ash •    •    .    .    .    .  0.3 

100.0 
BANANAS. 

Bananas  and  plantains  are  among  the  most  nutritions  of  fruits  ;  in 
many  parts  of  the  tropics,  they  constitute  the  chief  food  of  those  who 
are  too  lazy  to  perform  any  kind  of  manual  labor.  The  edible  part 
yields  about  20  per  cent,  of  sugar  (cane  and  invert),  about  2  of  pro- 
teids, 0.5  of  starch,  and  rather  more  of  fat. 

FIGS. 

The  fig  in  the  fresh  state  is  about  equal  to  the  banana  in  nutritive 
properties.  In  both  the  fresh  and  dried  forms,  it  is  esteemed  highly  as 
a  mild  laxative.  The  dried  fig  contains  about  30  per  cent,  of  water, 
50  of  sugar,  4  of  proteids,  and  3  of  ash  ;  the  remainder  is  chiefly  seeds 
and  fiber. 

BERRIES. 

The  various  berries  are  notable  for  their  content  of  free  acids  and 
sugar.  Two  kinds,  the  cranberry  and  the  barberry,  are  too  sour  to  be 
eaten  raw,  and  must  be  cooked  with  sugar  in  order  to  be  made  palata- 
ble. The  composition  of  the  several  members  of  this  group  is  set  forth 
in  the  following  table,  compiled  from  Konig  : 


Water. 

Sugar. 

Free 
acid. 

Proteids. 

Fiber, 
pectin,  etc. 

86.41 

4.44 

1.19 

0.51 

6.97 

89.59 

1.53 

2.34 

0.12 

6.27 

84.77 

6.38 

2.15 

0.51 

5.47 

85.74 

7.03 

1.42 

0.47 

4.92 

78.36 

5.02 

1.66 

0.78 

13.16 

84.71 

9.19 

1.86 

0.36 

3.22 

85.74 

3.86 

1.42 

0.40 

8.10 

87.66 

6.28 

0.93 

1.07 

3.25 

Ash. 


Blackberries 
Cranberries  . 
Currants  .  . 
Gooseberries 
Huckleberries 
Mulberries  . 
Raspberries  . 
Strawberries 


0.48 
0.15 
0.72 
0.42 
1.02 
0.66 
0.48 
0.81 


CANE  SUGAR.  163 

9.  Edible  Fungi. 

MUSHROOMS. 

Mushrooms  are  reputed  to  be  extremely  rich  in  nitrogen  and  other 
nutrients,  and  accordingly  they  are  recommended  as  a  valuable  food 
material.  It  is  true  that  they  are  somewhat  rich  in  nitrogen,  but  it 
should  be  said  that  a  large  proportion  of  this  element  present  is  in  com- 
binations (amido  compounds)  which  are  useless  as  food.  As  a  matter 
of  fact,  the  total  solid  matter  of  mushrooms  averages  about  1 2  per  cent., 
and  is  largely  ^voody  matter.  Mushrooms  are  rather  difficult  of  diges- 
tion, and  are  not  at  all  adapted  to  weak  stomachs.  They  have  been 
called  "  the  poor  man's  meat,"  and  much  has  been  done  to  encourage 
the  poor  to  seek  for  them  in  the  fields  and  woods,  in  order  to  add  to  the 
larder.  Inasmuch  as  the  market  price  of  mushrooms  for  the  tables  of 
the  rich  is  generally  high,  and  since  their  food  value  is  decidedly  over- 
rated, it  would  appear  that,  where  there  is  a  market  for  them,  the  poor 
can  do  much  better  for  their  nutrition  by  disposing  of  their  findings 
and  converting  the  proceeds  into  cheaper,  more  digestible,  more  nutri- 
tious, and  less  cloying  articles  of  food. 

Truffles  contain  more  nitrogen  than  is  found  in  mushrooms,  but  they 
are  very  much  more  woody,  and  can  hardly  be  looked  upon  as  valuable 
from  the  point  of  view  of  nutrition. 

10.  Saccharine  Preparations. 

Sugar  was  known  to  the  ancient  Greeks  and  Romans,  and  its  manu- 
facture has  been  conducted  by  the  Chinese  since  the  earliest  times.  It 
is  very  soluble  and  diffusible,  and,  therefore,  is  digested  easily.  Dex- 
trose is  ready  for  assimilation,  but  sucrose,  maltose,  and  lactose  must 
undergo  first  a  splitting  process  within  the  digestive  tract. 

CANE  SUGAR. 

Cane  sugar  is  obtained  from  the  sugar  cane,  sugar  beet,  sorghum, 
and  sugar  maple.  It  is  very  soluble  in  water,  but  quite  insoluble  in 
absolute  alcohol.  Heated  with  dilute  mineral  acids  or  with  citric  acid, 
it  splits  into  dextrose  and  lajvulose,  and  then  is  known  as  invert  sugar 
from  the  fact  that  the  polarization  becomes  inverted.  Cane  sugar 
rotates  the  plane  of  polarized  light  to  the  right ;  the  two  substances 
into  which  it  is  split,  dextrose  and  Isevulose,  rotate  respectively  to  the 
right  and  left,  but  the  action  of  Isevulose  is  so  much  the  stronger  that 
the  mixture  gives  left  polarization. 

Heated  above  180°  C,  sugar  yields  caramel,  which  is  not  a  simple 
substance,  but  a  complex  mixture  of  brown  products  of  dehydration. 
It  is  used  as  a  coloring  for  low-grade  milk  and  other  articles  of  food, 
and  somewhat  as  a  flavoring. 

Cane  sugar  is  sold  in  various  forms  :  cut  or  loaf  sugar,  granulated, 
and  powdered.    The  cheaper  grades,  known  from  their  color  as  "  brown 


164  FOODS. 

sugars,"  contain  variable   amounts  of  invert  sugar,  gummy  matters, 
and  other  impurities. 

Sugar  is  not  much  subject  to  adulteration,  though  there  is  a  popular 
idea  that  glucose  and  sand  are  common  admixtures.  It  is  probable 
that  sand  is  as  rare  an  adulterant  of  sugar  as  chalk  is  of  milk.  Glu- 
cose rarely  is  mixed  with  sugar,  but  is  used  considerably  as  a  sub- 
stitute for  it  in  the  manufacture  of  cheap  jellies,  jams,  and  candies. 
Sugars  that  are  somewhat  "  off  color  "  are  treated  sometimes  with  ultra- 
marine in  the  final  processes  of  manufacture.  This  corrects  the  fault 
and  makes  the  product  white.  Occasionally,  the  amount  added  is  suffi- 
cient to  cause  great  alarm  in  the  household  when  large  quantities  of 
sugar  are  made  into  syrup  with  hot  water  m  the  preparation  of  preserves 
and  jellies.  The  blue  material  comes  to  the  surface  as  a  scum,  and  its 
anlooked-for  appearance  gives  rise  to  suspicion  of  j)oison. 

MAPLE  SUGAR. 

This  form  of  cane  sugar  is  prized  highly  for  its  agreeable  flavor.  It 
is  a  much  more  expensive  article  than  ordinary  sugar  and  is  used  more 
as  a  confection.  In  the  form  of  syrup,  it  is  used  very  extensively  on 
buckwheat  cakes  and  with  other  cereal  breakfast  foods.  It  is  much 
subject  to  adulteration  and  substitution.  A  large  part  of  the  syrup  in 
the  market  is  wholly  artificial,  being  made  of  ordinary  sugar  or  glu- 
cose, appropriately  colored,  and  correctly  flavored  by  means  of  extract 
of  hickory  bark.  The  sugar  itself  is  imitated  in  the  same  way,  but  one 
not  infrequently  sees  specimeus  which  are  absolutely  devoid  of  any  flavor 
save  that  of  brown  sugar.  The  substitution  by  flavored  cane  sugar  is 
easily  proved  by  determining  the  amount  of  precipitate  of  lead  malate 
yielded  by  5  grammes  of  the  suspected  sample  in  10  c.c.  of  water  on 
the  addition  of  basic  lead  acetate  solution.  Five  grammes  of  pure 
maple  sugar  so  treated  should  yield,  after  centrifugation,  2.5  c.c.  of 
precipitate,  while  pure  cane  sugar  yields  none.  The  presence  of  glucose 
is  revealed  by  the  behavior  of  the  specimen  under  polariscopic  analysis. 

GLUCOSE.      DEXTROSE. 

Dextrose,  or  grape  sugar,  is  inferior  in  sweetening  power  to  cane 
sugar,  and  is  not  ciystallizable  to  the  same  extent.  It  is  much  less 
soluble  in  water,  but  is  soluljle  in  glycerin  and  in  alcohol  of  ordinary 
strength.  It  is  found  in  grapes  and  in  many  other  fruits  and  vege- 
tables, but  always  associated  with  Isevulose.  By  fermentation  with 
yeast,  it  splits  into  carbonic  acid  and  alcohol ;  in  the  presence  of  fer- 
ments which  disorganize  proteids,  it  yields  lactic  acid.  It  exerts  a 
strong  reducing  jDower  on  Fehling's  solution. 

Commercial  glucose  is  obtained  by  heating  starch,  usually  corn 
starch,  with  diastase  or  dilute  sulphuric  acid.  Before  the  final  process 
of  concentration  of  the  solution,  the  acid  is  neutralized  completely  by 
the  application  of  marble  dust,  and  the  resulting  sulphate  of  calcium 


HONEY.  165 

and  the  excess  of  the  neutralizing  agent  are  removed.  The  product 
always  contains  considerable  proportions  of  maltose  and  dextrin,  and  its 
rotatory  power  is,  therefore,  much  greater  than  that  of  pure  glucase, 
such  as  is  obtainable  from  diabetic  urine. 

Glucose  is  produced  in  enormous  quantities  both  in  the  solid  form 
and  as  a  thick  colorless  syrup.  It  is  used  in  the  manufacture  of  cheap 
candies,  jams,  and  preserves,  in  the  brewing  of  beer,  and  as  an  adul- 
terant of  molasses  and  honey  (see  under  Beer). 

MOLASSES. 

Molasses  is  a  thick,  viscid,  dark-colored  liquid,  which  drains  away  in 
the  process  of  the  manufacture  of  sugar.  It  contains  from  65  to  72 
per  cent,  of  sugar,  part  of  which  is  sucrose  and  part  fruit  sugar,  vari- 
ous salts,  gummy  matters,  extractives,  and  water.  It  is  graded 
according  to  color  from  the  cheapest,  almost  black  article  known  as 
"  black  strap,"  to  the  finest,  which  is  light  yellowish  brown.  When 
refined,  it  is  brilliant  and  transparent,  and  is  known  as  syrup. 

All  grades,  but  especially  the  higher,  are  adulterated  extensively 
with  glucose  syrup.  This  reduces  the  sweetening  power,  but  gives 
body  and  a  finer  appearance.  The  fraud  is  detected  readily  by  the 
use  of  the  polariscope,  since  the  adulterated  article  gives  a  much 
higher  reading,  and  on  inversion,  instead  of  giving  left  polarization, 
continues  to  give  a  reading  to  the  right  almost  as  high  as  before. 
Another,  and,  from  a  sanitary  point  of  view,  a  more  important  adul- 
terant of  molasses,  is  the  protochloride  of  tin,  known  also  as  "  tin 
crystal "  and  "  salts  of  tin."  This  is  added  for  the  purpose  of  reducing 
the  amount  of  color,  thus  giving  a  fictitious  added  value.  It  combines 
with  part  of  the  coloring  matters,  and  the  resulting  compound  separates 
and  tends  to  deposit.  Thus  a  large  proportion  of  the  amount  added 
to  a  hogshead  may  be  found  in  the  "  foot,"  or  sugar  sediment,  which  is 
used  quite  commonly  in  the  making  of  cheap  candies,  such  as  cocoanut 
taffy.  Only  a  part,  however,  is  deposited,  and  hence  a  specimen  thus 
adulterated  will  yield  notable  traces  of  the  salt  on  iucineration  and 
analysis.  It  is  useless  to  attempt  to  separate  the  tin  in  the  ordinary 
way  without  previous  incineration,  since  the  organic  matters  present 
prevent  precipitation  of  the  sulphide.  Inasmuch  as  the  protochloride 
of  tin  is  an  irritant  poison,  and  since  its  addition  can  serve  no  legiti- 
mate useful  purpose,  this  form  of  adulteration  should  be  prohibited  and 
punished.  Sometimes  tin  is  present  in  molasses,  not  as  an  adulterant, 
but  because  of  a  practice,  followed  by  some  makers  of  crude  sugar,  of 
treating  their  product  with  this  agent  to  improve  its  color  before  it  leaves 
the  centrifugal  machines,  and  thus  it  finds  its  way  into  the  by-product. 

HONEY. 

Honey  is  classed  sometimes  as  an  animal  food,  since  it  is  a  product 
stored  up  l)y  bees,  but  it  can  hardly  be  so  considered,  since  it  is  obtained 
from  the  nectaries  of  flowei's,  although  during  its  storage  in   the  bee's 


166  FOODS. 

crop  it  undergoes  some  change.  After  this  alteration  by  the  secretions 
of  the  crop,  it  is  disgorged  and  deposited  in  the  cell  of  the  honey-comb. 

Honey  is  a  concentrated  solution  of  sugars,  chiefly  dextrose  and 
Isevulose,  with  small  amounts  of  sucrose  and  mannite,  containing  also 
small  amounts  of  wax,  organic  acids,  proteids,  mineral  matter,  pollen, 
and  odorous  and  other  principles.  The  flavor,  color,  and  odor  vary 
according  to  the  nature  of  the  flowers  from  which  the  honey  is  obtained. 
Sometimes,  when  derived  from  poisonous  plants,  it  has  toxic  prop- 
erties ;  this  fact  has  been  noted  by  both  ancient  and  modern  writers. 
Xenophon,  for  example,  has  recorded  most  serious  symptoms  of  intoxi- 
cation due  to  its  ingestion,  and  a  number  of  small  outbreaks  resembling 
ptomain-poisoning  have  been  reported  by  recent  writers  in  this  country. 
Xenophon  ^  says  :  "  As  to  other  things  here,  there  was  nothing  at 
which  they  were  *  surprised  ;  but  the  number  of  beehives  was  extra- 
ordinary, and  all  of  the  soldiers  that  ate  of  the  combs  lost  their  senses, 
vomited,  and  were  affected  with  purging,  and  not  one  of  them  was  able 
to  stand  upright ;  such  as  had  eaten  only  a  little  were  like  men  greatly 
intoxicated,  and  such  as  had  eaten  much  were  like  madmen,  and  some 
like  persons  at  the  point  of  death.  Tliey  lay  upon  the  ground,  in  con- 
sequence, in  great  numbers,  as  if  there  had  been  a  defeat ;  and  there 
was  general  dejection.  The  next  day  not  one  of  them  was  found  dead  ; 
and  they  recovered  their  senses  about  the  same  hour  they  had  lost  them 
on  the  preceding  day ;  and  on  the  third  and  fourth  days  they  got  up  as 
if  after  having  taken  physic." 

Dioscoricles  speaks  of  a  kind  of  honey  that  made  those  that  ate  it 
mad,  and  ascribes  its  poisonous  properties  to  the  great  abundance  of 
rose-laurel  and  other  similar  poisonous  plants.  Strabo  speaks  of  honey 
that  made  men  stupid  and  melancholy ;  and  Diodorus,  of  a  certain  kind 
in  Colchos  which  produced  such  profound  weakness  in  those  that  ate  it 
"■  that  they  appeared  for  a  whole  day  together  like  dead  men." 

Honey  from  the  flowers  of  the  yellow  jasmine  has  been  known  to 
produce  serious  and  even  fatal  results,  and  that  derived  from  a  species 
of  rhododendron  growing  in  the  neighborhood  of  the  Black  Sea  has  long 
been  recognized  as  poisonous. 

The  power  of  honey  to  exert  a  medicinal  influence  is  sometimes 
turned  to  good  account.  Thus,  in  Abyssinia,  where  the  flowers  of  the 
cusso  tree  are  the  universal  remedy  for  tapeworm  and  ascarides,  with 
which  a  large  proportion  of  the  population  is  afllictecF,  swarms  of  bees 
are  kept  by  order  of  King  Meuelek  in  gardens  where  no  other  plant  is 
cultivated,  and  the  honey  which  they  store  has  been  found  to  have  all 
the  good  qualities  of  the  drug  with  none  of  its  unpalatability  or  un- 
pleasant effects,  such  as  nausea  and  vomiting. 

By  microscopic  examination,  which  will  show  numerous  pollen 
grains,  one  can  determine  easily  from  what  kind  of  flo^ver  a  honey 
Avas  gathered. 

Honey  contains  about  73  per  cent,  of  sugar.  In  consequence  of 
the  preponderant  influence  of  the  laevulose  on  the  rotation  of  the 
^  Anabasis,  Book  TV.,  Chap.  8. 


CONFECTIONERY.  167 

plane  of  polarized  light  the  polariscope  reading  of  a  pure  sample  is 
almost  always  to  the  left ;  when  not  to  the  left,  the  reading  is  not 
more  than  a  few  degrees  to  the  right.  The  percentage  of  water 
averages  about  18  or  19;  occasionally  specimens  are  found  to  contain 
as  much  as  25. 

Honey  is  an  important  sugar  food ;  it  is  very  agreeable  to  the  taste 
and  easily  assimilated.  On  account  of  its  comparatively  high  price, 
it  is  very  subject  to  adulteration  with  glucose  and  cane  sugar.  That 
which  is  sold  in  the  comb,  tlie  comb  still  in  its  frame,  is  almost  invari- 
ably genuine.  The  extracted  honeys  sold  in  bottles  and  tumblers  are 
very  commonly  mixtures  of  the  genuine  article  with  glucose  or  cane 
sugar,  and  often  contain  no  honey  whatever.  In  order  to  convey  the 
idea  of  genuineness,  it  is  a  common  practice  to  insert  a  small  piece  of 
comb.  At  least  one  ingenious  fabricator  of  glucose-honey  has  been 
known  to  add  to  each  tumbler  of  his  product  a  dead  bee,  to  serve  as  a 
silent  false  witness  of  its  origin. 

The  detection  of  adulteration  ^^ith  glucose  or  cane  sugar  is  an  easy 
matter,  since  all  samples  so  made  give  a  strong  reading  to  the  right  on 
polariscopic  examination.  On  inversion  of  the  sample,  the  right- 
handed  reading  persists  if  the  adulterant  is  glucose,  and  is  changed  to 
the  left  if  cane  sugar.  It  is  said  that  inverted  cane  sugar  sometimes  is 
mixed  in  proper  proportion  to  make  an  artificial  honey  which  will  give 
the  normal  polariscopic  test  of  the  genuine  article  ;  and  that  to  imitate 
the  latter  still  farther,  so  that  microscopical  examination  also  may 
attest  its  genuineness,  pollen  grains  are  added  in  sufficient  amoimts. 
The  ash  of  such  a  product  alone  will  reveal  the  fraud,  since  it  will 
contain  no  phosphoric  acid,  while  genuine  honey  contains  about  0.03 
per  cent,  of  that  substance. 

CONFECTIONERY. 

Candies  are  preparations  made  of  sugars  or  substances  containing 
them,  such  as  molasses  and  honey,  with  or  without  the  admixture  of 
other  food  materials,  such  as  nuts,  fruits,  and  chocolate,  starches  and 
fats  to  give  body  and  consistence,  and  flavoring  and  coloring  agents. 
The  addition  of  substances  which  serve  no  legitimate  useful  purpose, 
such  as  terra  all^a,  which  is  said  to  be  added  sometimes  to  lend  weight, 
and  of  injurioife  colors  and  flavors,  may  properly  be  regarded  as 
adulteration  ;  but  the  use  of  glucose  sugar,  cocoa  butter,  and  other 
substances  of  a  harmless  nature,  and  possessing  value  as  nutriment, 
cannot  be  so  regarded.  Many,  some  say  most,  of  the  cheaper  candies, 
contain  variable  amounts  of  glucose  and  starch,  but  nothing  is  to  be 
said  against  the  use  of  these  substances  on  the  score  of  wholesomeness. 
The  use  of  t(!rra  alba  is  suj)))osed  ])opular]y  to  be  very  common,  but 
numerous  analyses  by  many  chemists  tlu'oughout  the  country  sliow 
that  this  substance  is  an  exceedingly  uncommon  ingredient  of  even 
the  very  cheapest  candies. 

The  flavoring  agents  commonly  emj)loyed  are,  as  a  rule,  harmless. 


168  FOODS. 

The  colors  used,  however,  are  not  infrequently  of  a  poisonous  nature, 
especially  in  those  States  which  have  no  laws  against  food  adulteration, 
or  which,  having  them,  make  no  provision  for  their  enforcement.  These 
injurious  coloring  agents  include  the  cliromates  of  potassium  and  lead, 
tin  lakes,  and  certain  of  the  coal-tar  products,  such  as  Martins  yellow, 
dinitrocresol,  and  dinitroso-resorcinol.  The  employment  of  chromate 
of  lead  and  of  chromate  of  potassium  is  frequently  denied,  but  these 
substances,  nevertheless,  are  used  not  uncommonly,  and  have  been 
detected  by  the  author  in  many  specimens  of  yellow  sugars  used  for 
decorating  cakes,  and  in  yellow  candies  made  in  the  shape  of  beans. 
The  majority  of  the  colors  used  are,  however,  of  a  harmless  nature. 

JELLIES  AND   JAMS. 

Jellies  are  semi-solid  glutinous  preparations  made  by  boiling  fruit 
juices  with  sugar  and  allowing  to  cool ;  jams  are  somewhat  similar 
preparations,  which  include  the  pulp  of  the  fruit  as  well  as  the  juice. 

Many  of  the  jellies  found  in  the  shops  are  made  with  glucose  syrup, 
cane  sugar,  gelatin,  artificial  flavorings  and  colors,  and  extracts  made 
by  boiling  the  refuse  of  canning  establishments.  Jams,  likewise,  are 
largely  factitious,  being  made  with  glucose  syrup,  flavorings,  colorings, 
various  kinds  of  seeds,  and  nearly  tasteless  vegetable  tissues,  such  as 
summer  squash  and  boiled  white  turnips. 

Section  5.     BEVERAGES. 

Stimulant  Beverages  Containing  Alkaloids. 

These  include  tea,  coffee,  and  cocoa,  and  certain  others  not  used  to 
any  large  extent  in  this  country.  The  alkaloids  of  these  products  are 
Icnown,  respectively,  as  theine  and  caifeine,  which  are  chemically  iden- 
tical, and  theobromine,  which  is  very  closely  related. 

TEA. 

The  virtues  of  tea  were  discovered,  according  to  Chinese  tradition, 
more  than  2700  years  before  the  Christian  era.  It  was  used  first  in 
England  in  the  seventeenth  century  (about  1657),  and  came  there  into 
general  use  about  1675.      It  was  introduced  into  America  in  1711. 

Tea  is  the  dried  leaf  of  a  shrub,  Thea  Chinensis,  indigenous  to  China 
and  other  parts  of  Asia,  and  cultivated  in  India,  Japan,  and  Ceylon. 
Formerly,  the  varieties  of  the  plant  produced  by  different  methods  of 
long  cultivation  were  believed  to  be  distinct  species,  and  were  known 
as  T.  Bohea,  T.  viridis,  etc.  The  differences  in  the  varieties  found  in 
commerce  depend  upon  the  age  of  the  leaves  when  gathered  and  their 
position  on  the  stem,  and  upon  special  methods  of  drying  and  preparing 
them  for  the  market.  The  choicest  varieties,  for  example,  are  those 
which  include  only  the  terminal  leaves,  and  the  poorest  those  made  up 
of  the  largest  and  coarsest  leaves  from  the  lower  end  of  the  twig. 


TEA.  169' 

Tea  is  classed  commonly  as  green  or  black.  Both  kinds  come  from 
the  same  shrub,  but  are  different  in  point  of  age,  and  are  cured  in  dif- 
ferent ways.  Green  tea  is  made  from  young  leaves,  ^vhich  are  roasted 
quickly  shortly  after  being  gathered,  and  then  rolled  and  again  roasted. 
Black  tea  is  from  older  leaves,  which  are  allowed  to  wilt,  and  then  are 
gathered  into  heaps  and  left  without  farther  manipulation  for  about  a 
half  day,  during  which  time  they  undergo  a  fermentative  process  and 
change  color.  Next,  they  are  rolled  by  hand  and  then  heated,  and 
these  processes  may  be  repeated  several  times  alternately.  Finally, 
they  are  dried  slowly  over  burning  charcoal. 

The  composition  of  tea  is  very  variable,  and  it  is  impossible  to  give 
figures  which  may  be  accepted  as  indicating  the  apj)roximate  constitu- 
tion of  a  typical  specimen.  Konig  has  collected  16  analyses,  which 
give  the  following  averages  : 

Moisture 11.49 

Nitrogenous  matters 21.22 

Theine 1.35 

Volatile  oil 0.67 

Fat,  resin,  etc 3.62 

Gum,  dextrin,  etc 7.13 

Tannin 12.36 

Other  extractives 16.75 

Fiber 20.30 

Ash 5.11 

100.00 

But  it  should-  be  said  that  the  variations  in  the  amounts  of  individual 
constituents  of  these  16  specimens  are  very  wide  :  for  instance,  water, 
4.59  to  16.06  ;  theine,  0.40  to  4.94  ;  tannin,  4.10  to  20.88  ;  fiber,  15.11 
to  25.06.  Dragendorff  found,  in  23  specimens,  from  1.36  to  3.09  per 
cent,  of  theine,  7.10  to  12.66  of  moisture,  and  from  24.80  to  44.50 
per  cent,  of  total  soluble  constituents.  The  ash  of  pure  tea  is  fairly 
constant  in  amount,  and  ahiiost  never  reaches  as  high  as  7  j)er  cent. ; 
usually,  between  5  and  6  per  cent. 

Tea  should  be  used  only  in  the  form  of  an  infusion,  made  by  pouring 
boiling  water  upon  the  requisite  amount  of  leaves,  and  allowing  it  to 
stand  a  short  while  to  "  draw."  It  is  used  not  uncommonly  in  the  form 
of  a  decoction  ;  that  is,  by  boiling.  This  process  is  objectionable  in  two 
ways  :  first,  the  delicate  aroma  is  lost  by  the  expulsion  of  the  very 
volatile  essential  oil ;  and  second,  the  leaves  are  made  to  yield  all  their 
tannin  and  other  extractives,  which  tend  to  bring  about,  sooner  or 
later,  derangement  of  the  digestive  function  and  a  catarrhal  condition 
of  the  stomach.  The  finest  and  most  delicate  portion  of  an  infusion 
is  that  which  is  poured  off  within  three  or  four  minutes,  for  in  this 
will  be  found  a  maximum  of  flavor  with  a  minimum  of  bitterness  and 
astringency.  The  excellence  of  an  infusion  is  influenced  considerably 
by  the  cliaracter  of  the  water,  which,  if  very  hard,  is  slow  in  extracting 
the  desirabh;  soluble  constituents,  while,  if  very  soft,  it  extracts  not, 
only  these,  l)iit  far  too  rapidly  the  less  (l(!siral)le  ])rinci])les. 

W'lud    |)roperly  made,  tea  in  moderation  is  a  wholesome,  agreeable, 


170  FOODS. 

and  refreshing  stimulant  beverage,  particularly  grateful  in  conditions 
of  mental  or  physical  weariness.  Used  in  excess,  it  exerts  a  harmful 
influence  upon  the  nervous  system,  and  in  a  too  strong  form  injures  the 
dicrestive  tract  and  function. 

The  abuse  of  tea  as  a  beverage  leads,  according  to  Bullard,^  to  ring- 
ing in  the  ears,  tremor,  nervousness,  headache,  neuralgia,  hysteria, 
irregularity  of  the  heart,  dyspnoea,  dyspepsia,  and  constipation. 

Dr.  Hayes,  the  Arctic  explorer,  has  testified  to  the  value  of  tea  and 
coifee  in  enabling  men  to  endure  cold  and  hardship  of  all  sorts,  tea 
being  especially  soothing  at  the  end  of  a  hard  day's  work. 

While  tea  by  itself  can  hardly  be  looked  upon  as  an  article  afford- 
ing any  important  amount  of  nutriment,  as  commonly  consumed  it 
serves  as  a  vehicle  for  other  substances,  as  sugar,  milk,  and  cream, 
having  high  nutritive  value. 

Adulteration  of  Tea. — It  is  commonly  stated  and  generally  be- 
lieved that  tea  is  adulterated  extensively  with  other  khids  of  leaves, 
including  those  of  the  beech,  sloe,  willow,  and  hawthorn;  but  at 'the 
present  time,  it  is  extremely  improbable  that  such  adulterants  ever  are 
mixed  with  tea  known  to  be  intended  for  export  to  this  country. 
Whatever  the  conditions  may  have  been  prior  to  the  enactment  of  the 
national  law  governing  tea  importation,  the  fact  now  is  that  our  tea 
supply  is  practically  free  from  this  form  of  adulteration.  The  detec- 
tion of  spurious  tea  leaves  would  be  an  easy  matter,  since  the  genuine 
have  a  very  characteristic  appearance  which  can  hardly  be  confused 
with  that  of  any  of  the  possible  substitutes ;  and  even  when  broken 
into  small  bits,  the  characteristic  differences  in  venation  and  serration, 
and  in  the  stomata  as  well,  are  plainly  discernible. 

More  probable  forms  of  adulteration  include  the  admixture  of 
wholly  or  partially  exhausted  leaves  ;  the  addition  of  astringent  mat- 
ters, such  as  catechu,  to  lend  color  and  apj^arent  strength  to  the  infusion  ; 
the  presence  of  foreign  mineral  matter ;  and   the  practice  of  "  facing." 

The  presence  of  any  large  proportion  of  exhausted  leaves  can  be 
detected  by  the  low  amount  of  total  soluble  extract  and  by  the  small 
amount  of  soluble  ash,  which  should  not  be  less  than  3  per  cent,  of  the 
weight  of  the  leaves.  The  presence  of  important  amounts  of  accidental 
or  added  mineral  matters  is  shown  in  the  total  ash,  which  in  a  genuine 
specimen  rarely  amounts  to  7  and  never  to  8  per  cent.  The  substances 
most  often  found  are  sand  and  soapstone  ;  the  first  named  is  found  some- 
times in  amounts  exceeding  25  per  cent. 

Catechu  is  applied  occasionally  to  exhausted  tea  leaves  with  the  aid 
of  solutions  of  gummy  matters,  for  the  purpose  of  adding  astringency 
and  color  to  the  infusion.  Teas  so  treated  have  but  little,  if  any,  of 
the  true  aroma,  and  their  infusions  yield  a  sediment  in  M'hich  the  par- 
ticles of  catechu  can  readily  be  seen. 

The  object  of  "facing"  is  to  make  the  product  appear  to  be  of 
greater  value,  and  the  practice  is,  therefore,  properly  speaking,  one 
which  comes  within  the  definition  of  fraudulent  adulteration.  Damaged 
^  Boston  Medical  and  Surgical  Journal,  April  8,  1886,  and  September  8,  1887. 


COFFEE.  171 

or  otherwise  inferior  leaves  are  treated  with  Prussian  l)lue,  plumbago, 
iudigo,  and  other  substances,  and  the  small  amount  which  adheres  im- 
proves their  color  and  general  appearance.  This  amount  is  too  small 
to  be  of  any  sanitary  significance.  The  presence  of  facing  materials 
may  be  detected  by  the  use  of  the  microscope  and  by  chemical  analysis. 

COFFEE. 

Coffee  is  the  seeds  of  the  Coffea  Arabioa,  dried  and  deprived  of  their 
fleshy  covering.  The  fruit  is  a  small  pulpy  berry  containing,  usually, 
two  seeds.  The  tree  is  said  to  have  originated  in  Abyssinia,  where, 
however,  in  the  seventeenth  century  there  were  few,  if  any,  specimens, 
and  to  have  been  introduced  into  Arabia  in  the  fifteenth  century.  It 
is  now  grown  very  extensively  in  Brazil,  Java,  Peru,  Ceylon,  West 
Indies,  and  other  hot  countries.  The  first  European  to  mention  it  was 
Prosper  Alpinus,  of  Padua,  who  included  it  in  an  account  of  Egyptian 
plants,  published  in  1592.  The  first  work  devoted  wholly  to  coffee 
was  a  small  Latin  treatise,  De  saluberrima  potione  cahue,  by  Faustus 
Nairo,  Rome,  1671.  Coffee  was  first  sold  in  London  by  a  Levantine, 
in  1650,  and  some  years  afterward  was  introduced  into  France.  The 
first  whole  cargo  introduced  into  this  country  arrived  in  1809,  but 
coffee  houses  were  licensed  in  Massachusetts  as  early  as  1715. 

The  world's  production  of  coffee  for  the  year  ended  June  30,  1900, 
was  estimated  at  almost  900,000  tons.^  This  country  alone  consumes 
more  than  the  whole  of  Europe  :  in  1897  we  consumed  318,170  tons 
against  305,150.  The  total  consumption  by  Germany  was  136,390; 
by  France,  77,310;  by  England,  12,420;  and  by  Italy,  12,500  tons. 

As  is  the  case  with  tea,  coffee  must  undergo  a  process  of  roasting 
before  it  is  fit  for  use,  although  it  is  said  that  the  Arabians  and  other 
Eastern  peoples  make  a  decoction  of  the  raw  article  and  swallow  the 
grounds  as  well  as  the  liquid.  The  roasting  is  conducted  at  about 
200°  C.  until  the  natural  color,  which  is  greenish,  grayish,  or  drab,  is 
changed  to  a  rich  dark  brown.  During  the  process,  certain  volatile 
aromatic  principles  are  developed,  the  alkaloid  caffeine  is  dissociated 
from  its  union  with  tannin,  the  moisture  is  very  largely  expelled,  the 
sugar  is  caramelized,  gases  are  formed  (largely  carbonic  dioxide)  which 
cause  the  berry  to  swell,  and  much  rupturing  of  the  cell  layers  occurs. 
The  berry  thus  loses  in  weight  and  gains  in  bulk.  The  ])rocess  must 
be  conducted  carefully,  else  the  quality  will  not  be  what  is  desired,  since 
if  the  roasting  is  not  pushed  sufficiently  far,  there  will  be  insufficient 
development  of  aroma  ;  and  if  it  is  carried  too  far,  the  volatile  matters 
are  expelled  and  the  product  acquires  an  unpleasant  taste.  On  account 
<jf  the  volatile  nature  of  the  aromatic  principles  developed,  coffee 
should  be  roasted  only  as  the  demands  of  commerce  make  it  necessary. 
On  long  keeping,  except  in  hermetically  sealed  containers,  it  undergoes 
extensive  deterioration.  For  the  same  reason,  the  roasted  berries 
should  be  ground  only  as  needed. 

^  Consular  Reports,  Vol.  LX.,  p.  258. 


172  FOODS. 

Coffee  contains  less  caffeine  (theine)  than  is  found  in  tea  ;  thus,  Drag- 
endorff  found  the  amount  in  25  samples  to  vary  between  0.64  and  2.21 
per  cent.,  whereas  in  about  the  same  number  (23)  of  samples  of  tea, 
the  range  was  1.36  to  3.09.  It  contains  considerable  amounts  of  fat, 
generally  over  12  per  cent.,  about  the  same  amount  of  nitrogenous 
matters,  small,  quite  unimportant  amounts  of  sugars,  gummy  matters, 
and  other  substances,  and  about  40  per  cent,  of  fiber. 

Coffee  is  used  in  infusion  and  as  a  decoction.  Like  tea,  it  loses  its 
pleasant  aroma  when  boiled,  but  its  decoction  is  less  bitter  and  astrin- 
gent than  that  of  tea.  In  order  to  enjoy  both  the  fragrance  of  an  in- 
fusion and  the  strength  and  body  of  a  decoction,  it  is  not  an  uncommon 
practice  to  make  first  the  oue  and  pour  it  off,  and  then,  with  a  fresh 
portion  of  water,  to  boil  the  grounds  for  a  few  miniites,  and  then  to 
mix  the  two  liquids  together. 

Coffee  acts  as  a  decided  stimulant  to  the  nervous  system,  enables  one 
better  to  perform  arduous  work,  and  diminishes  the  sense  of  fatigue. 
In  small  amounts,  it  increases  the  force  and  frequency  of  the  pulse,  but 
taken  in  excessive  quantities,  it  causes  palpitation  and  intermission, 
besides  general  nervousness  and  derangement  of  digestion.  It  has  a 
marked  inhibitory  influence  on  gastric  digestion,  and  is  more  oppressive 
to  the  stomach  tlian  tea  and,  hence,  should  be  used  with  caution  by  dys- 
peptics. AVith  some  persons  it  stimulates  peristalsis,  and  thus  acts  as  a 
gentle  cathartic.     It  increases  the  secretions  of  the  skin  and  kidneys. 

Coffee  is  adulterated  very  extensively  with  a  variety  of  substances 
of  widely  different  nature,  inckiding  chicory,  dandelion,  and  other  roots, 
roasted  cereals  and  legumes,  sawdust,  date  stones,  red  slate,  acorns,  and 
other  cheap  articles.  It  is  not  alone  in  the  ground  form  that  it  is 
fiilsified,  for  even  the  beans  are  imitated  with  mixtures  of  flour  and 
other  materials,  moulded  to  the  correct  shape  and  carefully  roasted  and 
colored. 

The  detection  of  adulterants  in  coffee  requires  but  little  time.  Of 
great  assistance  is  the  fact  that  coflee  contains  absolutely  no  starch,, 
while  most  of  the  commoner  adulterants  contain  it  in  abundance. 
Therefore,  if  a  specimen  under  examination  is  boiled  and  filtered,  and 
the  filtrate  gives  a  dirty  blue  reaction  with  test-solution  of  iodine,  one 
may  be  sure  that  adulteration  has  been  practised.  But  not  all  of  the 
adulterants  are  starchy  in  their  nature  and,  therefore,  other  examination 
is  necessary.  Microscopical  examination  Avill  detect  not  only  the  starchy, 
but  the  non-starchy  matters  as  well.  Under  the  microscope,  ground 
coffee  has  a  characteristic  appearance  which  cannot  be  mistaken  for  any- 
thing else.  Chicory  and  other  roots,  date  stones,  and  all  other  berries 
and  seeds  have  their  own  characteristics.  For  the  mere  determination 
of  the  question  of  ])urity,  only  a  knowledge  of  the  microscopical  ap- 
pearance of  coffee  itself  is  required,  and  this  is  acquired  easily  and 
quickly  by  direct  study.  For  the  identification  of  the  adulterants 
present,  one  necessarily  should  be  familiar  with  the  appearance  of  all 
of  the  substances  used. 

Chicory  is  the  root  of  the  Cichormm  intyhus,  a  perennial  herb,  grow- 


COCOA.  173 

mg  wild  and  extensively  cultivated  in  this  country  and  in  Europe.  The 
roots  are  cleaned,  cut  into  pieces,  dried  in  kilns,  roasted  in  iron  cylin- 
ders, and  ground  into  a  coarse  powder.  Like  coffee,  chicory  when 
Toasted  contains  a  volatile  principle  and  a  bitter.  It  is  used  both  as 
an  adulterant  and  as  a  substitute  for  coifee.  Mixed  with  coffee,  it  lends 
both  color  and  flavor  to  the  infusion,  and  by  many  is  regarded  as  a 
desirable  addition.  It  itself  is  subject  to  adulteration  by  cheaper  roots, 
such  as  mangel wurzel  and  dandelion. 

Coffee  and  chicory  behave  very  differently  when  thrown  into  cold 
water  :  the  former  floats  and  retains  its  firm  consistence,  Avhile  the 
latter  absorbs  water  very  quickly  and  sinks,  and  in  its  descent  leaves 
streaks  of  color.  Coffee  which  has  been  roasted  too  much  will,  how- 
ever, sometimes  sink,  and  chicory  which  has  been  treated  with  fatty 
substances  will  float.  Mixtures  of  the  two  can  often  be  detected  by 
the  difference  in  resistance  when  placed  between  the  teeth.  The  par- 
ticles of  coffee  are  much  harder  than  those  of  chicory,  which  yield  very 
readily  to  pressure  and  also  have  a  sweetish  taste. 

Inferior  and  damaged  raw  coffees  not  infrequently  are  colored  and 
faced,  in  order  that  they  may  be  improved  in  appearance  or  be  made 
to  imitate  better  grades.  The  facing  agents  used  are  mixtures  contain- 
ing variable  amounts  of  ultramarine,  indigo,  clay,  gypsum,  chromate 
of  lead,  and  coal  dust. 

According  to  G.  Wirtz,^  inferior  grades  of  coffee  are  treated  largely 
at  Antwerp,  Rotterdam,  Hamburg,  Bremen,  and  elsewhere,  by  washing, 
coloring,  and  finally  drying  by  ceutrifugation  with  sawdust,  the  result 
being  a  fine  white  product  of  an  apparently  greater  value. 

Package  coffees  sold  under  various  names,  such  as  "  French  Break- 
fast Coffee,"  "  Vienna  Coffee,"  and  "  Eureka  Breakfast  Coffee,"  are 
rarely  anything  more  than  roasted  and  ground  cereals  and  peas.  It  is 
to  be  said,  however,  that  their  character  usually  is  indicated  in  the 
directions  for  use  printed  on  the  labels,  which  commonly  begin  by 
advising  the  use  of  "  a  third  more  than  you  would  use  of  genuine 
coffee."  Microscopical  examination  and  the  iodine  test  will  reveal 
their  composition  very  quickly. 

COCOA. 

Cocoa,  a  corruption  of  Cacao,  and  in  no  way  related  to  the  cocoanut, 
is  derived  from  the  seeds  of  the  Theobroma  cacao,  a  native  of  tropical 
America.  It  is  estimated  that  the  annual  production  of  the  seeds 
amounts  to  about  150,000,000  pounds,  more  than  a  fifth  of  which  is 
exported  by  Ecuador  alone.  Nearly  a  fifth  of  the  annual  crop  is  con- 
sumed within  the  United  States. 

The  fruit  of  the  cocoa  tree  is  a  pod,  about  a  foot  long  and  half 
as  wide,  filled  with  "  beans,"  or  "  chocolate  nuts,"  about  as  large  as 
almonds,  imb(;dded  in  five  rows  of  from  four  to  ten  each  in  a  ])ul])y 
matrix.  When  ripe,  the  pods  arc  gathered  and  collected  into  heaps, 
and  left  for  a  day  or  longer ;  then  they  are  cut  0])en  and  deprived  of 
'  '  Zeitschi-ift  fiir  Untersuchung  der  Nahrungs-  und  Genussmittel,  1898,  p.  248. 


174  FOODS. 

the  seeds,  which  are  allowed  to  undergo  a  process  of  fermentation 
in  earthen  vessels  or  in  holes  in  the  ground.  This  process,  which  mnst 
be  regulated  very  carefully,  has  for  its  object  the  removal  of  an  acrid, 
bitter  taste  and  consequent  improvement  in  flavor.  Sometimes,  the 
seeds  are  dried  in  the  sun  as  soon  as  removed,  but  the  product  is  then 
of  much  less  value ;  sometimes,  the  entire  pod  is  buried  until  the  pulp 
becomes  rotten  and  softened.  AVhen  the  fermentation  process  is  com- 
pleted, the  seeds  are  dried  carefully  in  the  sun,  and  then  become  hard, 
brittle,  and  reddish  or  reddish  brown  in  color. 

In  the  preparation  of  cocoa  for  the  market,  the  seeds  first  are  cleaned 
and  carefully  roasted.  As  is  the  case  with  coffee,  the  i^oasting  must 
be  carried  to  a  certain  point  to  insure  the  development  of  the  desired 
flavor,  but  not  so  far  beyond  as  to  impair  it.  During  this  process,  the 
thm  husks  of  the  seeds  become  more  detachable,  and  before  the  next 
operation  they  are  removed.  Then  the  seeds  are  crushed  lightly  and 
freed  from  their  hardened  germs,  and  in  this  form  are  known  as  "  nibs." 
These  are  ground  in  a  special  form  of  mill  into  a  paste  ("  flake  cocoa  "), 
which  is  moulded  into  cakes  and  allowed  to  harden.  In  this  form,  the 
product  is  known  as  plain  chocolate.  The  sweet  and  flavored  choco- 
lates are  made  with  the  addition  of  sugar,  vanilla  beans,  cinnamon  and 
other  spices.  Inferior  vanilla  chocolate  is  made  with  artificial  vanillin 
and  coumarin,  in  place  of  the  far  more  expensive  and  better  flavored 
vanilla  bean. 

For  the  preparation  of  powdered  cocoa,  it  is  necessaiy  to  remove  a 
part  of  the  oil,  which,  when  present  in  its  normal  amount,  favors  cak- 
ing. This  removal  is  accomplished  by  hydraulic  pressure,  and  the 
paste  is  then  passed  through  sieves  of  exceedingly  fine  mesh. 

The  so-called  soluble  cocoas  are  prepared  with  sugar  and  starches, 
particularly  arrowroot,  but  the  cocoa  itself  is  not  soluble  in  water.  The 
apparent  solubility  is  due  to  the  fineness  of  the  powder  and  to  the  in- 
crease in  the  specific  gravity  of  the  liquid  due  to  the  sugar  in  solution, 
both  these  conditions  favoring  prolonged  suspension  without  sedimen- 
tation. Some  of  the  Dutch  soluble  cocoas  are  treated  with  alkalies, 
for  the  removal  of  the  crude  fiber  and  for  their  effect  upon  the  coloring^ 
matters.  These  cocoas  thereby  lose  part  of  their  natural  flavor,  but  the 
loss  is  made  up  somewhat  by  the  addition  of  fragrant  foreign  matter. 

Cocoa  was  introduced  into  Europe  by  the  Spaniards  after  their  in- 
vasion of  Mexico  under  Cortez,  in  1519.  It  was  not  known  in  England 
until  1657,  when  it  was  sold  first  in  London  by  a  Frenchman.  In  this 
country,  it  first  was  prepared  and  sold  at  Danvers,  Massachusetts,  in 
1771,  from  raw  material  brought  from  the  West  Indies  by  the  fisher- 
men of  Gloucester. 

Unlike  tea  and  coifee,  which  in  themselves  can  hardly  be  regarded 
as  adding  any  nutriment  to  the  diet,  cocoa  is  an  exceedingly  valuable 
food,  which  possesses  the  advantage  of  much  nutriment  in  small  bulk, 
and  hence  is  particularly  suited  to  the  needs  of  those  engaged  in 
expeditions  removed  from  civilized  centers.  It  makes  a  wholesome, 
agreeable,  stimulant  beverage,  and  is  eaten  in  the  form  of  chocolate. 


BEER.  11  o 

and  as  an  addition  to  cakes,  pnddings,  and  other  compounds.  The 
cocoa  nibs  and  plain  chocolate  contain  about  50  per  cent,  of  a  whitish 
solid  fat  of  agreeable  taste  and  smell,  commonly  known  as  cocoa 
butter.  It  contains  variable  amounts  of  the  alkaloid  theobromine 
(dimethylxanthine),  which  is  related  very  closely  to  caffeine  and  theine 
(trimethylxanthine),  and  has  nearly  the  same  physiological  action, 
although  somewhat  less  stimulant  and  rather  more  diuretic.  The 
amount  is  said  to  average  about  1.50  per  cent.  Cocoa  is  rich  in  nitro- 
genous matter,  contains  more  than  10  per  cent,  of  a  starch  with  small 
round  granules.jaud  about  3.50  per  cent,  of  ash,  which- is  largely  phos- 
phate of  potassium. 

Sixteen  analyses  of  the  kernels,  compiled  by  Konig,  give  the  follow- 
ing averages  : 

Water 3.63 

Proteids 13.49 

Fat 49.32 

Starch 13.25 

Extractives 13.18 

Fiber       3.65 

Ash _3^8 

100.00 

The  husks,  commonly  known  as  "  shells,"  are  used  in  the  prepara- 
tion of  a  cheap  and  wholesome  beverage.  They  contain  little  fat,  but 
are  about  equal  to  cocoa  in  nitrogenous  matter,  and  contain  more  than 
40  per  cent,  of  nitrogen-free  extractives. 

Cocoa  and  chocolate  are  subject  to  extensive  adulteration  with  sub- 
stances having  much  less  commercial  value,  though  perhaps  equally 
nutritious.  Among  those  used,  are  starches  of  various  kinds,  as  wheat, 
rye,  potato,  arrowroot,  and  rice,  sugar,  vegetable  oils,  mutton  tallow 
and  other  fats,  Venetian  red,  clay,  and  brick  dust.  Various  flavorings 
are  employed,  such  as  vanillin,  coumarin,  clove,  mace,  cardamom,  and 
nutmeg ;  but  unless  these  are  used  under  the  name  of  vanilla  or  of 
other  flavorings  than  themselves,  they  cannot  be  regarded  as  adul- 
terations. 

Fermented  Alcoholic  Beverages. 
BEER. 

Beer  is  the  generic  term  which  includes  all  fermented  drinks  made 
from  malt — lager  beer,  ale,  porter,  and  stout.  As  commonly  under- 
stood, beer  is  an  infusion  of  malted  barley,  flavored  with  hops  and 
fermented  with  yeast ;  but  on  account  of  the  fact  that  wholesome  sub- 
stitutes for  malt  and  hops  may  be  employed  in  its  manufacture,  it  is 
defined  also  as  a  "  fermented,  saccharine  infusion  to  which  some  whole- 
some bitter  has  been  added."  In  this  country,  the  term  beer  is 
restricted  commonly  to  the  product  generally  known  as  lager  beer. 
Porter  is  a  beer  with  a  high  percentage  of  alcohol,  and  is  made  from 
malt  dried  at  a  high  temperature.  Stout  contains  less  alcohol  and  hops, 
but  more  malt  extract.    Ale  is  a  pale  beer  (containing  more  hop  extract 


176  FOODS. 

aud  less  malt  extract  than  porter  or  stout,  and  brewed  by  "  top  fermen- 
tation." 

Beer  was  made  by  the  Egyptians  many  centuries  before  the  Christian 
•era.  It  is  related  that,  for  public  reasons,  the  suppression  of  beer-shops 
Avas  attempted  by  their  government  more  than  forty  centuries  ago.  The 
■iirt  of  brewing  was  taught  by  them  to  the  ancient  Greeks  and  Romans  ; 
thus,  beer  was  a  common  drink  in  Greece  prior  to  700  B.  C,  and  was 
one  of  the  principal  beverages  of  the  soldiers  of  Csesar.  In  the  time 
of  Tacitus,  it  was  in  common  use  iu  Germany  ;  and  Pliny  speaks  of  its 
use  in  Spain.  The  ancient  Britons,  at  the  time  of  the  Boman  conquest, 
made  it  from  barley.  At  the  time  of  the  K^orman  conquest,  the  A\ords 
beer  and  ale  meant  in  England  the  same  thing  :  a  drink  made  of  malt 
without  hops.  Later,  the  word  beer  fell  into  disuse ;  but  in  the  fif- 
teenth and  sixteenth  centuries,  after  the  introduction  by  the  Flemish 
of  beer  made  with  hops,  the  term  was  revived,  and  tlien  meant  hopped 
ale.  The  use  of  hops  was  forbidden  in  1530  by  Henry  VIII.,  who 
regarded  them  as  an  adulterant,  and  in  the  first  year  of  the  reign  of 
Kichard  III.,  the  authorities  of  London  laid  a  fine  of  6s  8d  on  every 
barrel  of  beer  containing  them.     Later,  this  was  reduced  one-half. 

The  prejudice  against  the  use  of  hops  in  brewing  is  expressed  by  one 
of  the  earliest  English  writers  on  dietetics,  Andrew  Boorde,^  who  says  : 
"  Ale  is  made  of  malte  and  Avater ;  and  they  the  which  do  put  any  other 
thynge  to  ale  than  is  rehersed,  except  yest,  barme,  or  godesgood,  doth 
sofysticat  theyr  ale.  Ale  for  an  Englysshe  man  is  a  natural  drynke. 
Ale  must  haue  these  propertyes  :  it  must  be  fresshe  and  cleare,  it  muste 
not  be  ropy  nor  smoky,  nor  it  must  haue  no  weft  nor  tayle.  Ale  shuld 
not  be  drunk  under  v.  dayes  olde.  NcAve  ale  is  vnholsome  for  all  men. 
And  sowre  ale,  and  deade  ale  the  which  doth  stande  a  tylt,  is  good  for 
no  man.  Barley  malte  maketh  better  ale  than  oten  malte  or  any  other 
corne  doth  :  it  doth  engendre  grose  humoures  ;  but  yette  it  maketh  a 
man  stronge.  Bere  is  made  of  malte,  of  hoppes,  and  water :  it  is  the 
naturall  drynk  for  a  Dutche  man.  And  nowe  of  late  dayes  it  is  moche 
vsed  in  Englande  to  the  detryment  of  many  Englysshe  men  ;  specyally 
it  kvlleth  them  the  which  be  troubled  with  the  colycke,  and  the  stone, 
<fe  the  strangulion ;  for  the  drjuike  is  a  cokle  drynke ;  yet  it  doth  make 
a  man  fat,  and  inflate  the  bely,  as  it  doth  appere  by  the  Dutche  mens 
faces  &  belyes.  If  the  bere  be  well  serued,  and  be  fyned,  &  not  newe, 
it  doth  qualyfy  the  heat  of  the  lyuer." 

The  ancient  Germans  made  beer  from  all  kinds  of  grains,  and  for 
flavoring  used  oak  bark,  sage,  and  leaves  of  the  laurel,  ash,  and  tama- 
risk. Hops  were  used  more  or  less  from  the  ninth  century,  and  came 
into  general  use  in  the  eleventh. 

Beer  being  the  common  drink  of  most  European  peoples  before  the 
establishment  of  colonies  in  America,  it  followed  naturally  that  the 
early  settlers  of  this  country  brought  the  art  of  brewing  with  them. 
In  1629,  the  cultivation  of  hops  had  been  carried  on  for  some  time  in 

^  A  Compendyous  Kegyment,  or  A  Dyetary  of  Helth,  made  in  Mountpylier,  com- 
pyled  by  Andrewe  Boorde  of  Physyche  Doctour,  London,  1542. 


BEER.  \11 

New  Amsterdam,  and  bop  roots  were  sent  for  from  England  l^y  the 
authorities  of  Massachusetts.  In  nearly  all  the  colonies,  the  brewing 
of  beer  was  regarded  as  quite  as  essential  an  accomplishment  of  women 
as  the  ability  to  make  good  bread. 

The  first  law  regulating  the  sale  of  alcoholic  beverages  in  Massa- 
chusetts was  made  in  1633  ;  it  prescribed  that  no  person  should  sell 
wine  or  spirits  without  a  permit,  but  made  no  reference  to  beer.  In 
the  following  year,  it  was  ordered  that  no  one  should  charge  more  than 
a  penny  for  a  quart  of  beer,  and  in  1637,  that  no  inn-keeper  or  vic- 
tualler should  sell  any  intoxicating  drink  but  beer ;  and  this  they  were 
prohibited  from  brewing  themselves,  but  must  obtain  from  a  licensed 
brewer.  In  the  following  year,  owing  to  the  fact  that  the  only  one  of 
this  class  was  unable  to  meet  the  demand,  they  were  allowed  to  conduct 
the  process  themselves.  In  1649,  it  was  ordered  further  that  every 
inn-keeper  and  victualler  should  keep  always  on  hand  a  supply  of  good, 
wholesome  beer.  In  1651,  the  court  undertook  to  stimulate  the  pro- 
duction of  a  better  grade  of  beer  in  the  belief  that  thereby  the  growing 
tendency  to  the  use  of  wine  and  spirits  and  the  increasing  habit  of 
drunkenness  would  be  checked,  and  permission  was  granted  to  charge 
one,  two,  and  three  pence  per  quart,  according  to  the  amount  of  malt 
used  per  barrel. 

A  duty  of  a  shilling  per  bushel  of  imported  malt,  imposed  in  1654, 
called  forth  a  protest  from  Boston  merchants,  on  account  of  the  very 
great  importance  of  beer  as  a  beverage  of  the  people.  In  the  following 
year,  in  order  to  promote  home  production  of  malt,  importation  was 
prohibited,  but  this  order  was  repealed  in  1660.  In  1667,  the  use  of 
molasses  as  an  adulterant  of  beer  was  punishable  by  a  fine  of  five 
jjounds.  Similar  laws  relating  to  beer  Avere  passed  from  time  to  time 
by  the  authorities  of  all  the  original  colonies. 

Process  of  Manufacture  of  Beer. — The  first  step  in  the  brewing 
of  beer  is  the  preparation  of  the  malt.  The  barley  first  is  steeped  in 
water  for  several  days,  and  then  is  removed  and  arranged  in  heaps, 
Avhich,  after  a  time,  are  spread  out  and  turned  repeatedly  until  germi- 
nation has  proceeded  to  the  requisite  extent.  Next  it  is  dried  in 
kilns  at  a  temperature  below  or  about  90°  F.,  and  then  is  heated  to 
from  125°  to  180°,  according  to  the  color  desired.  This  process 
develops  flavor,  completely  checks  germination,  and  determmes  the 
•commercial  character  of  the  product.  The  steeping  of  the  malt  is 
done  best  in  water  containing  considerable  of  the  mineral  salts  that 
cause  hardness  ;  a  soft  water  exerts  too  much  solvent  action  on  the 
])roteid  matters,  which,  soon  after  extraction,  are  likely  to  undergo 
decomposition.  During  the  ])rogress  of  germination,  the  ferment 
diastase  is  develoj)ed,  and  proceeds  to  convert  the  starch  into  dextrin 
and  maltose.  After  the  germs  and  rootlets  have  heew  removed  by 
j)roper  screening  and  sifting,  the  malt  is  crushed,  and  then  an  infusion, 
the  "wort,"  is  made  with  water  at  about  160°  F.  This  is  drawn  off 
from  the  cxhanstccl  malt,  and  tlicn  boiled  for  an  hour  or  two  with  hops, 
wliifh,  Ijcsides  giving  a  characteristic  bitter  flavor,  assist  in  clarification 


178  FOODS. 

by  the  action  of  their  contained  tannin  on  some  of  the  proteid  matters. 
Then  the  boiled  bitter  wort  is  cooled  rapidly,  run  into  vats,  mixed 
with  yeast,  and  allowed  to  ferment  for  several  days,  during  which  time 
alcohol  and  carbonic  acid  are  formed  from  the  maltose.  The  nature 
of  the  product  is  influenced  very  largely  by  the  purity  of  the  yeast 
and  by  the  method  of  fermentation  followed.  Top  fermentation  is 
carried  on  rapidly,  and  at  a  comparatively  high  temperature,  the  yeast 
growing  at  the  surface ;  in  bottom,  or  sedimentary,  fermentation,  the 
yeast  grows  at  the  bottom,  the  process  is  slower,  and  is  carried  on  at  a 
lower  temperature.  The  chief  advantage  of  the  employment  of  yeast 
which  grows  at  a  low  temperature  is  that  other,  perhaps  undesirable, 
growths  may  be  unable  to  proceed.  AVhatever  the  process  of  fermenta- 
tion followed,  not  all  the  sugar  should  be  allowed  to  be  converted,  for 
then  the  flavor  would  be  not  what  it  should,  and  the  keeping  qualities 
would  be  impaired.  On  the  completion  of  fermentation,  the  beer  is 
separated  from  the  yeast  and  transferred  to  vats,  where  it  is  clarified. 
As  clarifying  agents,  a  variety  of  materials  are  used,  the  chief  of  which 
are  chips  or  shavings  of  certain  woods,  as  hazel  or  beech,  which  attract 
and  hold  the  particles  which  cause  turbidity.  These  materials  affect  in 
no  way  the  taste  of  the  beer.  Other  substances  used  include  gelatin, 
isinglass,  flax-seed,  and  carrageen.  After  clarification  is  accomj)lished, 
the  product  is  stored  for  a  time  in  storage  casks,  where  it  undergoes  a 
further  slow  fermentation  at  a  low  temperature,  after  which  it  is  ready 
for  use. 

Substitutes  for  Barley  Malt. — AVhile  barley  is  recognized  univer- 
sally as  the  grain  best  suited  to  the  brewing  of  wholesome  beer,  any 
other  cereal  may  be  used.  Sometimes,  unmalted  grains  are  added  to 
the  malt  before  the  infusion  is  made,  for  the  diastase  of  the  malt  is 
capable  of  converting  not  only  the  starch  with  which  it  naturally  is 
associated,  but  a  large  amount  of  other  starches ;  and  so,  rice,  corn, 
and  other  cereals  may  be  employed.  Glucose  and  cane  sugar  are  used 
somewhat,  but  the  product  is  decidedly  inferior  in  quality,  since  these 
substances  are  lacking  in  some  of  the  elements,  as  proteids  and  min- 
eral matters,  which  contribute  to  the  desirable  character  of  the  best 
beers. 

Concerning  the  use  of  glucose,  Avhich  adds  strength  to  the  wort,  there 
can  be  no  objection  on  the  score  of  being  in  any  way  deleterious  to 
health.  The  popular  belief  in  the  unwholesomeness  of  glucose  made 
from  corn  starch  led  the  U.  S.  Treasury  Department,  in  1882,  to 
request  an  investigation  of  the  subject  by  the  National  Academy  of 
Sciences.  This  was  conducted  by  a  committee  of  eminent  scientists,, 
including  Professors  Gibbs,  of  Harvard  ;  Brewer,  of  Yale  ;  Remsen,  oi" 
Johns  Hopkins  ;  Barker,  of  Pennsylvania  ;  and  Chandler,  of  Columbia, 
whose  conclusions  were  :  that  the  processes  employed  in  the  manufact- 
ure are  unobjectionable ;  that  the  product  is  of  exceptional  purity, 
and  in  no  way  inferior  in  healthfulness  to  cane  sugar ;  and  that  there 
was  no  evidence  adduced  to  show  that,  even  when  taken  in  large  quan- 
tities, either  in  its  natural  condition  or  fermented,  it  has  any  injurious 


BEER.  179 

effects  upon  the  system.  From  a  recent  experience  in  England  it 
appears,  however,  that  not  all  manufacturers  produce  a  pure  article ; 
and  that  if  sulplauric  acid  made  from  arsenical  pyrites  is  used  in  the 
process,  the  resulting  sugar  may  contain  sufficient  arsenic  to  cause  seri- 
ous and  even  fatal  poisoning.  In  November,  1900,  Dr.  E.  S.  Rey- 
nolds ^  called  attention  to  a  number  of  cases,  characterized  by  paralysis, 
wasting  of  certain  muscles,  and  loss  of  function  of  certain  sensory 
nerves,  which,  after  considerable  study,  he  decided  to  be  arsenical  poison- 
ing. Shortly  afterward,  an  increase  was  noticed  in  the  number  of  cases 
of,  and  deaths  from,  peripheral  neuritis  in  different  cities  and  towns,  and 
it  appeared  that,  in  Manchester  and  Salford  alone,  there  were  about 
3000  cases,  and  that  the  victims  were  drinkers  of  beer.  The  beer  in 
use  was  examined,  and  found  to  be  distinctly  arsenical,  and  it  was 
learned  that,  in  its  manufacture,  glucose  and  invert  sugar,  made  at  a 
factory  near  Liverpool,  had  been  employed.  Specimens  of  the  glucose 
were  found  to  contain  from  0.02  to  0.05  per  cent,  of  arsenious  oxide,  and 
examination  of  the  various  beers  made  therefrom  showed  from  0.10  to 
1.50  grains  of  arsenic  per  gallon.  The  amount  of  beer  consumed  by 
the  victims  varied  from  a  pint  to  two  gallons  per  day  ;  many  drank  a. 
gallon  each.  A  parliamentary  commission,  appointed  to  investigate: 
the  matter,  reported  finding  from  0.56  to  9.17  grains  of  arsenic  per 
pound  of  glucose,  1.40  to  4.34  grains  per  pound  of  invert  sugar,  0.25 
to  3  grains  per  gallon  of  beer,  and  1.40  to  2.60  per  cent,  of  arsenic  in 
the  sulphuric  acid  with  which  the  sugars  were  made.  Between  No- 
vember 25,  1900,  and  January  10,  1901,  there  were  no  less  than  36 
deaths  in  Manchester  alone,  which  were  attributed  to  arsenical  poison- 
ing. The  symptoms  observed  in  this  extensive  outbreak  began,  as  a 
rule,  with  disturbances  of  digestion,  followed  soon  by  laryngeal  and 
bronchial  catarrh  and  acute  skin  eruptions,  and  then  by  disturbances 
of  sensibility  and  motor  paralysis.  The  cases  were  grouped  into  those 
in  which  all  the  above  symptoms  were  fairly  well  marked,  and  those  in 
which  the  principal  lesions  were,  respectively,  of  the  skin,  heart,  and 
liver,  and  paralytic. 

Substitutes  for  Hops. — Various  substances  have  from  time  to  time 
been  reported  as  being  used  in  place  of  hops  to  give  bitterness  to  beer. 
These  include  nearly  everything  having  a  bitter  taste,  such  as  strych- 
nine, chirata,  calumba,  cocculus  indicus,  aloes,  and  picric  acid.  Cocculus 
indicus  was  mentioned  in  Holland  as  early  as  1620  as  an  adulterant. 
This  and  its  active  principle  picrotoxine,  and  picric  acid,  have  been 
employed  occasionally  in  England  and  elsewhere ;  but  at  the  present 
time,  it  is  safe  to  say,  none  of  these  substances  is  used.  Of  476  sam- 
ples of  beer  examined  for  the  State  Board  of  Health  of  New  York,  in 
1885,  not  one  was  found  to  contain  any  hop  substitutes  whatever. 

No  objections  can  be  alleged  against  such  wholesome  bitters  as  quassia, 
gentian,  calumba,  and  chirata.    Evidence  that  they  ever  are  employed  is 
exceedingly  slight.     As  a  matter  of  fact,  there  is  no  satisfactory  sub- 
stitute for  hops,  which  give  not  alone  bitterness,  but  other  flavors  and  u 
'  iJritish  Medifiil  J(Mima],  Nov.  24,  1900. 


180  FOODS. 

peculiar  aroma,  due  to  the  resinous  matter  which  they  contain.  In  the 
sixteenth  and  seventeenth  centuries,  various  other  flavorings  were  used, 
such  as  sage,  coriander,  laurel  leaves,  pepper,  grains  of  Paradise,  orris, 
and  essential  oils. 

Physical  Properties  and  Chemical  Composition  of  Beer. — Beer 
.should  be  perfectly  clear  and  bright.  The  presence  of  any  turbidity 
denotes  either  imperfect  brewing  or  the  occurrence  of  undesirable 
decomposition  processes.  The  latter  are  accompanied  generally  by  dis- 
agreeable odors.  The  taste  should  be  pleasantly  bitter  and  inclining  to 
sweetness  rather  than  to  acidity.  There  should  be  a  suflicient  amount 
of  carbonic  acid  to  make  a  pleasant  impression  in  the  mouth,  such  as  is 
not  produced  by  flat  beer.  The  specific  gravity  ranges  from  about  1.005 
to  1.025,  averaging  below  1.020.  In  bock  beer,  wliich  is  a  special 
brew  containing  a  considerable  increase  in  malt  extractives,  the  specific 
gravity  is  notably  higher,  running  as  high  as  1.035,  and  averaging 
more  than  1.021. 

The  most  important  constituents  of  beer  are  the  extract  and  alcohol. 
The  extract  includes  all  of  the  non-volatile  matters  hi  solution,  and 
consists  of  proteid  matters,  dextrin,  sugar,  hop  resin,  and  other  sub- 
stances left  as  a  residue  on  complete  evaporation.  The  amount  is  vari- 
able ;  it  is  highest  in  porter,  stout,  and  bock  beer,  and  lowest  in  the 
light-colored  lager  beers.  In  the  former,  it  averages  about  7.50,  and 
in  the  latter,  about  5.50  per  cent.  Twenty-eight  specimens  of  Amer- 
ican beers,  ales,  and  porter  collected  in  Washington,  and  analyzed  by 
Mr.  C.  A.  Crampton,^  averaged  5.53  per  cent. 

The  average  extract  of  182  analyses  of  specimens  of  beers  of  the 
lighter  kinds,  compiled  by  Konig,  is  stated  at  5.49  (rauge,  1.98-9.23); 
of  211  lager  beers  of  all  kinds,  at  5.78  ;  of  50  export  beers,  at  6.48  ; 
and  of  56  bock  beers,  at  7.20. 

The  amount  of  alcohol  is  also  variable.  The  specimens  examined 
bv  Crampton,  averaged  4.63  per  cent,  by  weight  and  5.79  by  volume. 
The  light  beers  above  mentioned  (Konig)  averaged  3.46  per  cent,  by 
weight ;  the  second  group,  3.95  ;  the  third,  4.31  ;  and  the  fourth,  4.74. 

Adulteration  of  Beer. — Beer  is  supposed  popularly  to  be  exten- 
sively adulterated,  and  the  substances  alleged  to  be  in  common  use 
make  up  a  list  remarkable  for  length  and  variety,  including  such  poi- 
sonous drugs  as  opium,  belladonna,  henbane,  and  strychnine,  many  of 
the  aromatics  and  aromatic  bitters,  corrosive  acids,  drastic  cathartics, 
and  many  other  substances.  The  actual  adulteration  of  beer,  however, 
is  restricted  practically  to  the  use  of  preservatives,  such  as  sodium 
fluoride  and  salicylic  acid,  of  sodium  bicarbonate  to  correct  acidity 
and  to  increase  the  "bead,"  and  of  salt  to  correct  bad  taste  and  to 
inspire  thirst  for  more. 

The  use  of  preservatives  is  the  only  form  of  adulteration  which  is 
of  practical  hygienic  importance,  and  in  several  countries  is  punish- 
able by  heavy  penalties.  In  Germany,  preservatives  are  interdicted 
very  strictly,  except  in  beer  intended  for  export ;  and  the  permission 
1  U.  S.  Department  of  Agriculture,  Division  of  Chemistry,  Bulletin  13,  p.  282. 


ANALYSIS  OF  BEER.  181 

exteiided  is  accepted  so  freely  that  it  is  rare  to  find  in  this  country  a 
specimen  of  German  bottled  beer  which  does  not  contain  a  liberal  dose 
of  salicylic  acid.  Many  American  brewers  use  this  agent  with  a  gen- 
erous hand,  under  the  benevolent  plea  that  it  is  a  prophylactic  against 
rheumatism.  By  the  same  process  of  reasoning,  one  might  contend  just 
as  well  that  opium  in  food  and  drink  would  prevent  pain,  and  biniodide 
of  mercury  keep  the  system  free  from  syphilitic  infection. 

Analysis  of  Beer. 

In  the  analysis  of  beer,  the  most  important  processes  are  the  deter- 
mination of  the  percentage  of  alcohol  and  of  extract,  and  the  detection 
of  preservatives. 

Determination  of  Alcohol. — For  the  determmation  of  the  percent- 
age of  alcohol,  a  sufficiently  large  portion  of  beer  should  be  shaken 
in  a  capacious  flask  until  the  carbonic  acid  is  expelled,  and  then  a 
measured  volume  should  be  subjected  either  to  distillation  or  to  partial 
evaporation  in  an  open  vessel. 

(a)  Determination  by  Distillation, — Introduce  into  a  flask  connected 
with  a  Liebig  condenser  100  cc.  of  the  well-shaken  beer,  at  60°  F., 
and  distil  into  another  flask  connected  with  the  discharging  end  of  the 
condenser  by  means  of  a  bent  glass  tube.  Continue  the  distillation  until 
somewhat  more  than  50  cc.  of  distillate  have  been  collected,  when  all 
of  the  contained  alcohol  will  have  been  expelled  and  condensed.  Add 
sufficient  water  to  the  distillate  to  make  100  cc.  at  60°  F.,  determine 
its  specific  gravity  by  means  of  a  picnometer  or  Westphal  balance  (a 
specific  gravity  spindle  is  not  sufficiently  accurate),  and  ascertain  from 
this,  by  reference  to  the  appended  table,  the  percentage  of  alcohol  by 
weight  or  volume. 

(6)  Determination  by  Open  Evaporation. — This  method  involves  less 
manipulation  and  gives  equally  accurate  results.  The  specific  gravity 
of  the  beer  is  determined  first  in  the  manner  above  mentioned.  Then 
place  100  cc.  at  60°  F.  in  a  glass  or  porcelain  evaporating  dish,  and 
by  the  application  of  heat  drive  ofP  rather  more  than  half  the  amount. 
Remove,  cool,  make  up  with  water  to  the  original  volume  at  60°  F., 
and  again  determine  the  specific  gravity.  Divide  the  original  gravity 
by  the  latter,  and  the  result  equals  that  of  the  alcohol  which  has  been 
expelled.  Refer  to  the  table,  and  obtain  therefrom  the  percentage  of 
alcohol  in  the  beer. 

The  following  table,  by  Mr.  Edgar  Richards,  is  the  one  used  by  the 
Association  of  Official  Agricultural  Chemists  :  '^ 

'  U.  S.  Department  of  Agriculture,  Division  of  Chemistry,  Bulletin  No.  46,  Wash- 
ington, Government  Printing  Office,  1899. 


182 


FOODS. 


TABLES    SHOWING    PEECENTAGE    OF    ALCOHOL    BY   WEIGHT    AND 

BY   VOLUME. 

{Recalculated  from  the  determinations  of  Gilpin,  Drinkivater,  and  Squibb, 
by  Edgar  Richards.) 


Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by  alcohol  by 

6U°  F. 

volume. 

weight. 

volume. 

weight. 

G0°  F. 

volume. 

weight. 

LOOOOO 

0.00 

0.00 

0.99629 

2.50 

1.99 

0.99281 

5.00 

4.00 

0.99992 

.05 

.04 

622 

.55 

2.03 

274 

.05 

.04 

984 

.10 

.08 

615 

.60 

.07 

268 

.10 

.08 

976 

.15 

.12 

607 

.65 

.11 

261 

.15 

.12 

968 

.20 

.16 

600 

.70 

.15 

255 

.20 

.16 

961 

.25 

.20 

593 

.75 

.19 

248 

.25 

.20 

953 

.30 

.24 

586 

.80 

.23 

241 

.30 

.24 

945 

.35 

,28 

579 

.85 

.27 

235 

,35 

.28 

937 

.40 

.32 

571 

.90 

.31 

228 

.40 

.32 

930 

.45 

.36 

564 

.95 

.35 

222 

.45 

.36 

.99923 

0.50 

0.40 

.99557 

3.00 

2.39 

.99215 

5.50 

4.40 

915 

.55 

.44 

550 

.05 

.43 

208 

.55 

.44 

907 

.60 

.48 

543 

.10 

.47 

202 

.60 

.48 

900 

.65 

.52 

536 

.15 

.51 

195 

.65 

,52 

892 

.70 

.56 

529 

.20 

.55 

189 

.70 

.56 

884 

.75 

.60 

522 

.25 

,59 

182 

.76 

.60 

877 

.80 

.64 

515 

.30 

.64 

175 

,80 

.64 

869 

.85 

.67 

508 

.35 

.68 

169 

,86 

,68 

861 

.90 

.71 

501 

.40 

.72 

162 

.90 

,72 

854 

.95 

,75 

494 

.45 

.76 

156 

.95 

,76 

.99849 

1.00 

0.79 

.99487 

3.50 

2.80 

.99149 

6.00 

4.80 

842 

.05 

.83 

480 

.55 

.84 

143 

.05 

,84 

834 

.10 

.87 

473 

.60 

.88 

136 

.10 

.88 

827 

.15 

.91 

466 

.65 

.92 

130 

.15 

.92 

819 

.20 

.95 

459 

.70 

.96 

123 

.20 

.96 

812 

.25 

.99 

452 

.75 

3.00 

117 

.25 

5.00 

805 

.30 

1.03 

445 

.80 

.04 

111 

,30 

.05 

797 

.35 

.07 

438 

.85 

.08 

104 

.35 

.09 

790 

.40 

.11 

431 

.90 

.12 

098 

.40 

.13 

782 

.45 

.15 

424 

.95 

.16 

091 

.45 

.17 

.99775 

1.60 

L19 

.99417 

4.00 

3.20 

.99085 

6,50 

5.21 

768 

.55 

.23 

410 

.05 

.24 

079 

,55 

.25 

760 

.60 

.27 

403 

.10 

.28 

072 

.60 

.29 

753 

.65 

.31 

397 

.15 

.32 

066 

,65 

.33 

745 

.70 

.35 

390 

.20 

.36 

059 

,70 

.37 

738 

.75 

.39 

383 

.25 

.40 

053 

.75 

.41 

731 

.80 

.43 

376 

.30 

.44 

047 

.80 

.45 

723 

.85 

.47 

369 

.35 

.48 

040 

.85 

.49 

716 

.90 

.51 

363 

.40 

.52 

034 

.90 

.53 

708 

.95 

.55 

356 

.45 

.56 

027 

,95 

.57 

.99701 

2.00 

1.59 

.99349 

4.50 

3.60 

.99021 

7.00 

5.61 

694 

.05 

.63 

342 

.55 

.64 

015 

,05 

.65 

687 

.10 

.67 

335 

.60 

.68 

009 

,10 

.69 

679 

.15 

.71 

329 

,65 

.72 

002 

.15 

,73 

672 

.20 

.75 

322 

.70 

.76 

.98996 

.20 

.77 

665 

.25 

.79 

315 

.75 

.80 

990 

.25 

.81 

658 

.30 

.83 

308 

.80 

.84 

984 

.30 

.86 

651 

.35 

.87 

301 

.85 

.88 

978 

,35 

.90 

643 

.40 

.91 

295 

.90 

.92 

971 

,40 

.94 

636 

.45 

.95 

288 

.95 

.96 

965 

.45 

.98 

ANALYSIS  OF  BEER. 


183 


Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by  alcohol  by 

(iu°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

00°  F. 

volume. 

weight. 

0.98959 

7.50 

6.02 

0.98603 

10.50 

8.45 

0.98273 

13.50 

10.90 

953 

.55 

.06 

597 

.55 

.49 

267 

.55 

.94 

947 

.60 

.10 

592 

.60 

.53 

262 

,60 

.98 

940 

.65 

.14 

586 

.65 

.57 

256 

.65 

11.02 

934 

.70 

.18 

580 

.70 

.61 

251 

.70 

,06 

928 

.75 

.22 

575 

.75 

.65 

246 

.75 

,11 

922 

.80 

.26 

569 

.80 

.70 

240 

.80 

.15 

916 

.85 

.30 

563 

.85 

.74 

235 

.85 

.19 

909 

.90 

.34 

557 

.90 

.78 

230 

.90 

.23 

903 

.95 

.38 

552 

.95 

.82 

224 

.95 

.27 

.98897 

8.00 

6.42 

.98546 

11.00 

8.86 

.98219 

14.00 

11.31 

891 

.05 

.46 

540 

.05 

.90 

214 

.05 

.35 

885 

.10 

.50 

535 

.10 

.94 

200 

.10 

.39 

879 

.15 

.54 

529 

.15 

.98 

203 

.15 

.43 

873 

.20 

.58 

524 

.20 

9.02 

198 

.20 

.47 

867 

.25 

.62 

518 

.25 

.07 

193 

.25 

.52 

861 

.30 

.67 

513 

.30 

.11 

188 

.30 

.56 

855 

.35 

.71 

507 

.35 

.15 

182 

.35 

.60 

849 

.40 

.75 

502 

.40 

.19 

177 

.40 

.64 

843 

.45 

.79 

496 

.45 

.23 

172 

.45 

.68 

.98837 

8.50 

6.83 

.98491 

11.50 

9.27 

.98167 

14.50 

11.72 

831 

.55 

.87 

485 

.55 

.31 

161 

.55 

.76 

825 

.60 

.91 

479 

.60 

.35 

156 

.60 

.80 

819 

.65 

.95 

474 

.65 

.39 

151 

.65 

.84 

813 

.70 

.99 

468 

.70 

.43 

146 

.70 

.88 

807 

.75 

7.03 

463 

.75 

.47 

140 

.75 

.93 

801 

.80 

.07 

457 

.80 

.51 

135 

.80 

.97 

795 

.85 

.11 

452 

.85 

.55 

130 

.85 

12.01 

789 

.90 

.15 

446 

.90 

.59 

125 

.90 

.05 

783 

.95 

.19 

441 

.95 

.63 

119 

.95 

.09 

.98777 

9.00 

7.23 

.98435 

12.00 

9.67 

.98114 

15.00 

12.13 

771 

.05 

.27 

430 

.05 

.71 

108 

.05 

.17 

765 

.10 

.31 

424 

.10 

.75 

104 

.10 

.21 

759 

.15 

.35 

419 

.15 

.79 

099 

.15 

.25 

754 

.20 

.39 

413 

.20 

.83 

093 

.20 

.29 

748 

.25 

.43 

408 

.25 

.87 

088 

.25 

.33 

742 

.30 

.48 

402 

.30 

.92 

083 

.30 

.38 

736 

.35 

.52 

397 

.35 

.96 

078 

.35 

.42 

730 

.40 

.56 

391 

.40 

10.00 

073 

.40 

.46 

724 

.45 

.60 

386 

.45 

.04 

068 

.45 

.50 

.98719 

9.50 

7.64 

.98381 

12.50 

10.08 

.98063 

15.50 

12.54 

713 

.55 

.68 

375 

.55 

.12 

057 

.55 

.58 

707 

.60 

.72 

370 

.60 

.16 

052 

.60 

.62 

701 

.65 

.76 

364 

.65 

.20 

047 

.65 

.66 

695 

.70 

.80 

359 

.70 

.24 

042 

.70 

.70 

689 

.75 

.84 

353 

.75 

.28 

037 

.75 

.75 

683 

.80 

.88 

348 

.80 

.33 

932 

.80 

.79 

678 

.85 

.92 

342 

.85 

.37 

026 

.85 

.83 

672 

.90 

.96 

337 

.90 

.41 

021 

.90 

.87 

666 

.95 

8.00 

331 

.95 

.45 

016 

.95 

.91 

.98660 

10.00 

8.04 

.98326 

13.00 

10.49 

,98011 

16.00 

12.95 

654 

.05 

.08 

321 

.05 

.53 

005 

.05 

.99 

649 

.10 

.12 

315 

.10 

.57 

001 

.10 

13.03 

643 

.15 

.16 

310 

.15 

.61 

97996 

.15 

.08 

637 

.20 

.20 

305 

.20 

.65 

991 

.20 

.12 

632 

.25 

.24 

299 

.25 

.69 

986 

.25 

.16 

626 

,30 

.29 

294 

.30 

.74 

980 

.30 

.20 

620 

.35 

.33 

289 

.35 

.78 

975 

.35 

.24 

614 

.40 

.37 

283 

.40 

.82 

970 

.40 

.29 

609 

.45 

.41 

278 

.45 

.86 

965 

.45 

.33 

184 


FOODS. 


Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by  alcoliol  byj 

gravity  at 

alcohol  by  j  alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

60°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight- 

0.97960 

16.50 

13.37 

0.97658 

19.50 

15.84 

0.97355 

22.50 

18.34 

955 

.55 

.41 

653 

.55 

.88 

350 

.55 

.38 

950 

.60 

.45 

648 

.60 

.93 

345 

.60 

.42 

945 

.65 

.49 

643 

.65 

.97 

340 

.65 

.47 

940 

.70 

.53 

638 

.70 

16.01 

335 

.70 

.51 

935 

.75 

.57 

633 

.75 

.05 

330 

.75 

.55 

929 

.80 

.62 

628 

.80 

.09 

324 

.80 

.59 

924 

.85 

.66 

623 

.85 

.14 

319 

.85 

.63 

919 

.90 

.70 

618 

.90 

.18 

314 

.90 

.68- 

914 

.95 

.74 

613 

.95 

.22 

309 

.95 

.72 

.97909 

17.00 

13.78 

.97608 

20.00 

16.26 

.97304 

23.00 

18.76 

904 

.05 

.82 

603 

.05 

.30 

299 

.05 

.80 

899 

.10 

.86 

598 

.10 

.34 

294 

.10 

.84 

894 

.15 

.90 

593 

.15 

.38 

289 

.15 

.88 

889 

.20 

.94 

588 

.20 

.42 

283 

.20 

.92 

884 

.25 

.98 

583 

.25 

.46 

278 

.25 

.96 

879 

.30 

14.03 

578 

.30 

.51 

273 

.30 

19.01 

874 

.35 

.07 

573 

.35 

.55 

268 

.35 

.05 

869 

.40 

.11 

■568 

.40 

.59 

263 

.40 

.09 

864 

.45 

.15 

563 

.45 

.63 

258 

.45 

.13 

.97859 

17.50 

14.19 

.97558 

20.50 

16.67 

.97253 

23.50 

19.17 

853 

.55 

.23 

552 

.55 

.71 

247 

.55 

.21 

848 

.60 

.27 

647 

.60 

.75 

242 

.60 

.25 

843 

.65 

.31 

542 

.65 

.80 

237 

.65 

.30 

838 

.70 

.35 

537 

.70 

.84 

232 

.70 

.34 

833 

.75 

.40 

532 

.75 

.88 

227 

.75 

.38 

828 

.80 

.44 

527 

.80 

.92 

222 

.80 

.42 

823 

.85 

.48 

522 

.85 

.96 

216 

.85 

.46 

818 

.90 

.52 

517 

.90 

17.01 

211 

.90 

.51 

813 

.95 

.56 

512 

.95 

.05 

206 

.95 

.55 

.97808 

18.00 

14.60 

.97507 

21.00 

17.09 

.97201 

24.00 

19.59 

803 

.05 

.64 

502 

.05 

.13 

196 

.05 

.63 

798 

.10 

.68 

497 

.10 

.17 

191 

.10 

.67 

793 

.15 

.73 

492 

.15 

.22 

185 

.15 

.72 

788 

.20 

.77 

487 

.20 

!26 

180 

.20 

.76 

783 

.25 

.81 

482 

.25 

.30 

175 

.25 

.80 

778 

.30 

.85 

477 

.30 

.34 

170 

.30 

.84 

773 

.35 

.89 

472 

.35 

.38 

165 

.35 

.88 

768 

.40 

.94 

467 

.40 

.43 

159 

.40 

.93 

763 

.45 

.98 

462 

.45 

.47 

154 

.45 

.97 

.97758 

18.50 

15.02 

.97457 

21.50 

17.51 

.97149 

24.50 

20.01 

753 

.55 

.06 

451 

.55 

.55 

144 

.55 

.05 

748 

.60 

.10 

446 

.60 

.59 

139 

.60 

.09 

743 

.65 

.14 

441 

.65 

.63 

133 

.65 

.14 

738 

.70 

.18 

436 

.70 

.67 

128 

.70 

.18 

733 

.75 

.22 

431 

.75 

.71 

123 

.75 

.22 

728 

.80 

.27 

426 

.80 

.76 

118 

.80 

.26 

723 

.85 

.31 

421 

.85 

.80 

113 

.85 

.30 

718 

.90 

.38 

416 

.90 

.84 

107 

.90 

.35 

713 

.95 

.39 

411 

.95 

.88 

102 

.95 

.39 

.97708 

19.00 

15.43 

.97406 

22.00 

17.92 

.97097 

25.00 

20.43 

703 

.05 

.47 

401 

.05 

.96 

092 

.05 

.47 

698 

.10 

.51 

396 

.10 

18.00 

086 

.10 

.51 

693 

.15 

.55 

391 

.15 

.05 

081 

.15 

.56 

688 

.20 

.59 

386 

.20 

.09 

076 

.20 

.60 

683 

.25 

.63 

381 

.25 

.13 

071 

.25 

.64 

678 

.30 

.68 

375 

.30 

.17 

065 

.30 

.68 

673 

.35 

.72 

370 

.35 

.21 

060 

.35 

.72 

668 

.40 

.76 

365 

.40 

.26 

055 

.40 

.77 

663 

.45 

.80 

360 

.45 

.30 

049 

.45 

.81 

ANALYSIS  OF  BEER. 


185 


Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

60°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

0.97044 

25.50 

20.85 

0.96715 

28.50 

23.38 

0.96360 

31.50 

25.94 

039 

.55 

.89 

709 

.55 

.42 

353 

.55 

.98 

033 

.60 

.93 

704 

.60 

.47 

347 

.60 

26.03 

028 

.65 

.98 

698 

.65 

.51 

341 

.65 

.07 

023 

.70 

21.02 

692 

.70 

.55 

335 

.70 

.11 

018 

.75 

.06 

687 

.75 

.60 

329 

.75 

.16 

012 

.80 

.10 

681 

.80 

.64 

323 

.80 

.20 

007 

.85 

.14 

675 

.85 

.68 

316 

.85 

.24 

001 

.90 

.19 

669 

.90 

.72 

310 

.90 

.28 

.96996 

.95 

.23 

664 

.95 

.77 

304 

.95 

.33 

.96991 

26.00 

21.27 

.96658 

29.00 

23.81 

.96298 

32.00 

26.-37 

986 

.05 

.31 

652 

.05 

.85 

292 

.05 

.41 

980 

.10 

.35 

646 

.10 

.89 

285 

.10 

.46 

975 

.15 

.40 

640 

.15 

.94 

279 

.15 

.50 

969 

.20 

.44 

635 

.20 

.98 

273 

.20 

.54 

964 

.25 

.48 

629 

.25 

24.02 

267 

.25 

.59 

959 

.30 

.52 

623 

.30 

.06 

260 

.30 

.63 

953 

.35 

.56 

617 

.35 

.10 

254 

.35 

.67 

949 

.40 

.61 

611 

.40 

.15 

248 

.40 

.71 

942 

.45 

.65 

605 

.45 

.19 

241 

.45 

.76 

.96937 

26.50 

21.69 

.96600 

29.50 

24.23 

.96235 

32.50 

26.80 

932 

.55 

.73 

594 

.55 

.27 

229 

.55 

.84 

926 

.60 

.77 

587 

.60 

.32 

222 

.60 

.89 

921 

.65 

.82 

582 

.65 

.36 

216 

.65 

.93 

915 

.70 

.86 

576 

.70 

.40 

210 

.70 

.97 

910 

.75 

.90 

570 

.75 

.45 

204 

.75 

27.02 

905 

.80 

.94 

564 

.80 

.49 

197 

.80 

.06 

899 

.85 

.98 

559 

.85 

.53 

191 

.85 

.10 

894 

.90 

22.03 

553 

.90 

.57 

185 

.90 

.14 

888 

.95 

.07 

547 

.95 

.62 

178 

.95 

.19 

.96883 

27.00 

22.11 

.96541 

30.00 

24.66 

.96172 

33.00 

27.23 

877 

.05 

.15 

535 

.05 

.70 

166 

.05 

.27 

872 

.10 

.20 

529 

.10 

.74 

159 

.10 

.32 

866 

.15 

.24 

523 

.15 

.79 

153 

.15 

.36 

861 

.20 

.28 

517 

.20 

.83 

146 

.20 

.40 

855 

.25 

.33 

511 

.25 

.87 

140 

.25 

.45 

850 

.30 

.37 

505 

.30 

.91 

133 

.30 

.49 

844 

.35 

.41 

499 

.35 

.95 

127 

.35 

.53 

889 

.40 

.45 

493 

.40 

25.00 

120 

.40 

.57 

833 

.45 

.50 

487 

.45 

.04 

114 

.45 

.62 

.96828 

27.50 

22.54 

.96481 

30.50 

25.08 

.96108 

33.50 

27.66 

822 

.55 

.58 

475 

.55 

.12 

101 

.55 

.70 

816 

.60 

.62 

469 

.60 

.17 

095 

.60 

.75 

811 

.65 

.67 

463 

.65 

.21 

088 

.65 

.79 

805 

.70 

.71 

457 

.70 

.25 

082 

.70 

.83 

800 

.75 

.75 

451 

.75 

.30 

075 

.75 

.88 

794- 

.80 

.79 

445 

.80 

.34 

069 

.80 

.92 

789 

.85 

.83 

439 

.85 

.38 

062 

.85 

.96 

783 

.90 

.88 

433 

.90 

.42 

056 

.90 

28.00 

778 

.95 

.92 

427 

.95 

.47 

049 

.95 

.05 

.96772 

28.00 

22.96 

.96421 

31.00 

25.51 

.96043 

34.00 

28.09 

766 

.05 

23.00 

415 

.05 

.55 

036 

.05 

.13 

761 

.10 

.04 

409 

.10 

.60 

030 

.10 

.18 

755 

.15 

.09 

403 

.15 

.64 

023 

.15 

.22 

749 

.20 

.13 

396 

.20 

.68 

016 

.20 

.26 

744 

.25 

.17 

390 

.25 

.73 

010 

.25 

.31 

7.38 

..30 

.21 

384 

.30 

.77 

003 

..30 

.35 

7.32 

.35 

.25 

378 

.35 

.81 

.95996 

.35 

.39 

726 

.40 

.30 

372 

.40 

.85 

990 

.40 

.43 

721 

.45 

.34 

366 

.45 

.90 

983 

.45 

.48 

186 


FOODS. 


Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

6u°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

0.95977 

34.50 

28.52 

0.95560 

37.50 

31.14 

0.95107 

40.60 

33.79 

970 

.55 

.56 

552 

.56 

.18 

099 

.66 

.84 

963 

.60 

.61 

545 

.60 

.23 

091 

.60 

.88 

957 

.65 

.65 

638 

.65 

.27 

083 

.65 

.93 

950 

.70 

.70 

531 

.70 

.32 

075 

.70 

.97 

943 

.75 

.74 

623 

.76 

.36 

067 

.75 

34.02 

937 

.80 

.78 

516 

.80 

.40 

059 

.80 

.06 

930 

.85 

.83 

609 

.85 

.45 

052 

.85 

.11 

923 

.90 

.87 

502 

.90 

.49 

044 

.90 

.15 

917 

.95 

.92 

494 

.95 

.64 

036 

.95 

.20 

.95910 

35.00 

28.96 

.95487 

38.00 

31.58 

.95028 

41.00 

34.24 

903 

.05 

29.00 

480 

.05 

.63 

020 

.05 

.28 

896 

.10 

.05 

472 

.10 

.67 

012 

.10 

.33 

889 

.15 

.09 

466 

.15 

.72 

004 

.15 

.37 

883 

.20 

.13 

457 

.20 

.76 

.94996 

.20 

.42 

876 

.25 

.18 

450 

.25 

.81 

988 

.25 

.46 

869 

.30 

.22 

442 

.30 

.86 

980 

.30 

.60 

862 

.35 

.26 

435 

.35 

.90 

972 

.35 

.66 

855 

.40 

.30 

427 

.40 

.94 

964 

.40 

.69 

848 

.45 

.35 

420 

.45 

.99 

956 

.45 

.64 

.95842 

35.50 

29.39 

.95413 

38.60 

32.03 

.94948 

41.50 

34.68 

835 

.55 

.43 

406 

.55 

.07 

940 

.55 

.73 

828 

.60 

.48 

398 

.60 

.12 

932 

.60 

.77 

821 

.65 

.52 

390 

.65 

.16 

924 

.65 

.82 

814 

.70 

.67 

383 

.70 

.20 

916 

.70 

.86 

807 

.75 

.61 

375 

.75 

.26 

908 

.76 

.91 

800 

.80 

.65 

368 

.80 

.29 

900 

.80 

.95 

794 

.85 

.70 

360 

.85 

.33 

892 

.86 

35.00 

787 

.90 

.74 

363 

.90 

.37 

884 

.90 

.04 

780 

.95 

.79 

345 

.95 

.42 

876 

.95 

.09 

.95773 

36.00 

29.83 

.96338 

39.00 

32.46 

.94868 

42.00 

35.13 

766 

.05 

.87 

330 

.05 

.60 

860 

.06 

.18 

759 

.10 

.92 

323 

.10 

.56 

862 

.10 

.22 

752 

.15 

.96 

315 

.16 

.69 

843 

.16 

.27 

745 

.20 

30.00 

307 

.20 

.64 

836 

.20 

.31 

738 

.25 

.05 

300 

.25 

.68 

827 

.25 

.36 

731 

.30 

.09 

292 

.30 

.72 

820 

.30 

.40 

724 

.35 

.13 

284 

.35 

.77 

811 

.35 

.46 

717 

.40 

.17 

277 

.40 

.81 

802 

.40 

.49 

710 

.45 

.22 

269 

.45 

.86 

794 

.45 

.54 

,95703 

36.50 

30.26 

.95262 

39.50 

32.90 

.94786 

42.50 

35.58 

695 

.55 

.30 

254 

.55 

.96 

778 

.56 

.63 

688 

.60 

.35 

246 

.60 

.99 

770 

.60 

.67 

681 

.65 

.39 

239 

.65 

33.04 

761 

.66 

.72 

674 

.70 

.44 

231 

.70 

.08 

753 

.70 

.76 

667 

.75 

.48 

223 

.75 

.13 

745 

.75 

.81 

660 

.80 

.52 

216 

.80 

.17 

737 

.80 

.85 

653 

.85 

.57 

208 

.85 

.22 

729 

.85 

.90 

646 

.90 

.61 

200 

.90 

.27 

720 

.90 

.94 

639 

.95 

.66 

193 

.95 

.31 

712 

.95 

.99 

.95632 

37.00 

30.70 

.95185 

40.00 

33.36 

.94704 

43.00 

36.03 

625 

.05 

.74 

177 

-     .05 

.39 

696 

.06 

.08 

618 

.10 

.79 

169 

.10 

.44 

687 

.10 

.12 

610 

.15 

.83 

161 

.15 

.48 

679 

.15 

.17 

603 

.20 

.88 

154 

.20 

.63 

670 

.20 

.21 

596 

.25 

.92 

146 

.26 

.57 

662 

.25 

.23 

589 

.30 

.96 

138 

.30 

.61 

654 

,30 

.30 

581 

.35 

31.01 

130 

.36 

.66 

646 

.35 

.35 

574 

.40 

.05 

122 

.40 

.70 

6.37 

.40 

.39 

567 

.45 

.10 

114 

.46 

.75 

628 

.45 

.44 

ANALYSIS  OF  BEER. 


187 


Specific 

Per  cent. 

Per  cent. 

Sppcific 

Per  cent. 

Per  cent. 

Specific 

Per  cent. 

Per  cent. 

gravity  at 

alcohol  by  alcohol  by 

gravity  at 

alcohol  by 

alcohol  by 

gravity  at 

alcohol  by  alcohol  by 

6U°  F. 

volume. 

weight. 

60°  F. 

volume. 

weight. 

6U°  F. 

volume. 

weight. 

0.94()20 

43.50 

36.48 

0.94188 

46.00 

38.75 

0.93824 

48.00 

40.60 

612 

.55 

.53 

179 

.05 

.80 

815 

.05 

.65 

60o 

.60 

.57 

170 

.10 

.84 

805 

.10 

.69 

595 

.65 

.62 

161 

.15 

.89 

796 

.15 

.74 

586 

.70 

.66 

152 

.20 

.93 

786 

.20 

.78 

578 

.75 

.71 

143 

.25 

.98 

777 

.25 

.83 

570 

.80 

.75 

134 

.30 

39.03 

768 

.30 

.88 

561 

.85 

.80 

125 

.35 

.07 

758 

.35 

.92 

553 

.90 

.84 

116 

.40 

.12 

749 

.40 

.97 

544 

.95 

.89 

107 

.45 

.16 

739 

.45 

41.01 

,94536 

44.00 

36.93 

.94098 

46.50 

39.21 

.93730 

48.50 

41.06 

527 

.05 

.98 

089 

.55 

.26 

721 

.55 

.11 

519 

.10 

37.02 

080 

.60 

.30 

711 

.60 

.15 

510 

.15 

.07 

071 

.65 

.35 

702 

.65 

.20 

502 

.20 

.11 

062 

.70 

.39 

692 

.70 

.24 

493 

.25 

.16 

053 

.75 

.44 

683 

.75 

.29 

484 

.30 

.21 

044 

.80 

.49 

679 

.80 

.34 

476 

.35 

.25 

035 

.85 

.53 

664 

.85 

.38 

467 

.40 

.30 

026 

.90 

.58 

655 

.90 

.43 

459 

.45 

.34 

017 

.95 

.62 

645 

.95 

.47 

.94450 

44.50 

37.39 

.94008 

47.00 

39.67 

.93636 

49.00 

41.52 

441 

.55 

.44 

.93999 

.05 

.72 

626 

.05 

.57 

433 

.60 

.48 

990 

.10 

.76 

617 

.10 

.61 

424 

.65 

.53 

980 

.15 

.81 

607 

.15 

.66 

416 

.70 

.57 

971 

.20 

.85 

598 

.20 

.71 

407 

■    .75 

.62 

962 

.25 

.90 

588 

.25 

.76 

398 

.80 

.66 

953 

.30 

.95 

578 

.30 

.80 

390 

.85 

.71 

944 

.35 

.99 

569 

.35 

.85 

381 

.90 

.76 

934 

.40 

40.04 

559 

.40 

.90 

373 

.95 

.80 

925 

.45 

.08 

550 

.45 

.94 

.94364 

45.00 

37.84 

.93916 

47.50 

40.13 

.93540 

49.50 

41.99 

355 

.05 

.89 

906 

.55 

.18 

530 

.55 

42.04 

346 

.10 

.93 

898 

.60 

.22 

521 

.60 

.08 

338 

.15 

.98 

888 

.65 

.27 

511 

.65 

.13 

329 

.20 

38.02 

879 

.70 

.32 

502 

.70 

.18 

320 

.25 

.07 

870 

.75 

.37 

492 

.75 

.23 

311 

.30 

.12 

861 

.80 

.41 

482 

.80 

.27 

302 

.35 

.16 

852 

.85 

.46 

473 

.85 

.32 

294 

.40 

.21 

842 

.90 

.51 

463 

.90 

.37 

285 

.45 

.25 

833 

.95 

.55 

454 

.95 

.41 

.94276 

45.50 

38.30 

267 

.55 

.35 

258 

.60 

.39 

250 

.65 

.44 

241 

.70 

.48 

232 

.75 

.53 

223 

.80 

.57 

214 

.85 

.62 

206 

.90 

.66 

197 

.95 

.71 

Determination  of  Extract. — The  extract  may  be  determined  di- 
rectly or,  with  the  aid  of  a  table,  from  the  specific  gravity  of  the  de- 
alcoholized  beer.  The  direct  method  is  the  more  accurate,  and  is  carried 
out  as  follows  :  Into  an  accurately  weighed  platinum  dish,  such  as  is 
u.sed  in  the  analysis  of  milk,  wcsigh  5  grams  of  beer;  evaporate  to  com- 
plete dryness,  and  multi})ly  the  weight  of  the  residue  by  20. 


188 


FOODS. 


Approximately  accurate  results  are  obtained  by  reference  to  the  fol- 
lowing table,  after  Schultze-Ostermann  : 


BEEB 

EXTRACT  TABLE 

Specific 
gravity. 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1.011 

2.87 

2.90 

2.92 

2.95 

2.97 

3.00 

3.03 

3.06 

3.08 

3.11 

2 

3.13 

3.16 

3.18 

3.21 

3.24 

3.26 

3.29 

3.31 

3.34 

3.37 

3 

3.39 

3.42 

3.44 

3.47 

3.49 

3.52 

3.55 

3.57 

3.60 

3.62 

4 

3.65 

3.67 

3.70 

8.73 

3.75 

3.78 

3.80 

3.83 

3.86 

3.88 

5 

3.91 

3.93 

3.96 

3.98 

4.01 

4.04 

4.06 

4.09 

4.11 

4.14 

6 

4.16 

4.19 

4.21 

4.24 

4.27 

4.29 

4.32 

4.34 

4.37 

4.39 

7 

4.42 

4.44 

4.47 

4.50 

4.52 

4.55 

4.57 

4.60 

4.62 

4.65 

8 

4.67 

4.70 

4.73 

4.75 

4.78 

4.80 

4.83 

4.85 

4.88 

4.90 

9 

4.93 

4.96 

4.98 

5.01 

5.03 

5.06 

5.08 

5.11 

5.13 

5.1(> 

1.020 

5.19 

5.21 

5.24 

5.26 

5.29 

5.31 

5.34 

5.36 

5.39 

5.41 

1 

5.44 

5.47 

5.49 

5.52 

5.54 

5.57 

5.59 

5.62 

5.64 

5.67 

2 

5.69  . 

5.72 

5.74 

5.77 

5.80 

5.82 

5.85 

5.87 

5.90 

5.92 

3 

5.95 

5.97 

6.00 

6.02 

6.05 

6.08 

6.10 

6.13 

6.15 

6.18 

4 

6.20 

6.23 

6.25 

6.28 

6.30 

6.33 

6.35 

6.38 

6.40 

6.43 

5 

6.45 

6.48 

6.50 

6.53 

6.55 

6.58 

6.61 

6.63 

6.66 

6.68 

6 

6.71 

6.73 

6.76 

6.78 

6.81 

6.83 

6.86 

6.88 

6.91 

6.93 

7 

6.96 

6.98 

7.01 

7.03 

7.06 

7.08 

7.11 

7.13 

7.16 

7.18 

8 

7.21 

7.24 

7.26 

7.29 

7.31 

7.34 

7.36 

7.39 

7.41 

7.44 

9 

7.46 

7.49 

7.51 

7.54 

7.56 

7.59 

7.61 

7.64 

7.66 

7.69 

1.030 

7.71 

7.74 

7.76 

7.79 

7.81 

7.84 

7.86 

7.89 

7.91 

7.94 

1 

7.99 

8.01 

8.04 

8.06 

8.09 

8.11 

8.14 

8.16 

8.19 

8.21 

The  fignres  at  the  head  of  the  several  columns  represent  the  fourth 
decimal  place  of  the  specific  gravity.  Example :  Specific  gravity, 
1.0187  ;  referring  to  1.018  in  the  left-hand  column  and  running  out 
to  the  column  headed  by  the  figure  7,  we  find  4.85  as  the  percentage 
of  extract  for  that  gravity. 

Detection  of  Preservatives. — The  principal  preservative  used  in 
beer  is  salicylic  acid  ;  next  in  imj^ortance  is  fluoride  of  sodium,  which, 
however,  is  not  used  to  any  considerable  extent  as  yet  in  this  country. 

Salicylic  Acid. — The  ordinary  method  of  extracting  by  means  of 
ether  and  testing  the  residue  left  on  evaporation  of  the  latter  with 
ferric  chloride,  cannot  be  used  in  the  examination  of  beer,  since  kiln- 
dried  malt  contains  a  principle  which  gives  a  reaction  identical  with 
that  of  salicylic  acid.  The  following  method,  devised  by  Spica,  is, 
however,  satisfactory  and  reliable  :  Acidify  1 00  cc.  with  sulphuric  acid, 
extract  with  ether,  allow  the  separated  ether  to  evaporate  sponta- 
neously, and  warm  the  residue  gently  with  a  drop  of  strong  nitric  acid, 
whereby,  if  salicylic  acid  is  present,  picric  acid  is  formed.  The  addi- 
tion of  a  few  drops  of  ammonia  or  of  sodium  hydrate  produces  the 
corresponding  picrate  with  its  bright-yellow  color,  which  may  be 
imparted  to  a  woollen  thread  immersed  in  the  liquid. 

Fluorides. — Several  methods  are  recommended,  and  among  them  the 
following  : 

Method  of  Hefelmann  and  Mann. — Expel  the  carbonic  acid 


WINES.  189 

from  500  cc.  of  beer,  and  then  add  1  cc.  of  a  solution  containing  5  per 
cent,  each  of  calcium  and  barium  chlorides,  and  follow  it  ^vith  0.5  cc. 
of  20  per  cent,  acetic  acid  and  50  cc.  of  90  per  cent,  alcohol.  Let 
stand  twenty-four  hours  and  filter.  Dry  the  filter  and  precipitate  c(j1- 
lected  thereon  without  washing,  and  transfer  to  a  platinum  crucible. 
Add  strong  sulphuric  acid,  and  cover  the  crucible  with  a  waxed  watch- 
glass  with  some  lines  scratched  through  the  wax  coating,  then  heat  at 
100°  C  for  two  hours,  and  obsers^e  the  effect  on  the  exposed  glass. 
This  method  is  said  to  be  of  sufficient  delicacy  to  detect  the  presence 
of  7   milligrams  in  a  liter. 

Beand's  Method. — To  100  cc.  of  beer  made  slightly  alkaline  with 
ammonium  carbonate  and  heated,  add  2  or  3  cc.  of  a  10  per  cent,  so- 
lution of  calcium  chloride.  Boil  for  a  few  minutes,  filter,  and  dry  the 
iilter  and  contents.  Then  proceed  as  in  the  method  just  described.  In 
either  process,  it  is  best  to  place  a  lump  of  ice  in  the  concavity  of  the 
watch-glass  to  keep  the  latter  cool ;  the  water  should  be  removed  from 
time  to  time  by  means  of  a  pipette  so  that  it  may  not  overflow. 

Other  Determinations. — Of  minor  interest  are  the  determinations 
of  acidity  and  ash. 

Total  Acidity. — To  10  cc.  of  beer  freed  from  carbonic  acid  by  shak- 
ing, add  a  few  drops  of  neutral  litmus  solution,  and  then  add  decinor- 
mal  sodium  hydrate  until  the  end  reaction  is  observed.  Express  the 
results  in  parts  of  acetic  acid.  One  cc.  of  decinormal  sodium  hydrate 
equals  0.006  gram  of  acetic  acid. 

Fixed  and  Volatile  Acidity. — Concentrate  10  cc.  of  beer  to  a  third 
of  its  bulk  by  evaporation,  add  water  up  to  the  original  volume,  and 
proceed  as  above.  The  difference  in  results  is  due  to  the  acetic  acid 
which  has  been  driven  off.  The  fixed  acidity  is  due  chiefly  to  lactic 
acid,  and,  if  desired,  may  be  so  expressed.  One  cc.  of  the  decinormal 
solution  is  equivalent  to  0.009  gram  of  lactic  acid.  The  other  acids 
present  include  succinic,  malic,  and  tannic. 

Ash. — The  residue  obtained  in  the  direct  determination  of  the  ex- 
tract may  be  utilized  for  the  estimation  of  the  ash.  It  should  be  ignited 
very  cautiously  and  at  as  low  a  temperature  as  possible  until  the  ash 
becomes  white. 

WINES. 

Properly  speaking,  wine  is  the  fermented  juice  of  grapes,  though  the 
term  is  applied  also  to  other  products  of  fermentation  of  saccharine 
liquids  and  fruit  juices.  It  has  been  in  use  as  a  drink  from  the  very 
earliest  periods  of  civilization.  At  the  present  time,  wines  are  pro- 
duced in  infinite  variety  and  of  many  qualities.  The  character  and 
properties  (kpend  upon  a  great  number  of  factors,  including  the  variety 
of  the  grape,  the  nature  of  the  soil  upon  which  the  vine  is  cultivated, 
the  climate  in  general,  and  the  state  of  the  weather  in  particular  when 
the  grapes  are  ripening,  the  degree  of  ri])eness  when  gathered,  the 
mt'tliod  followed  in  the  ))rej);trati()ii  of  the  must,  and  the  care  with 
wliidi  the  other  steps  in  the  making  of  the  final  pi'oductare  conducted. 


190  FOpDS. 

Of  very  great  influence  is  the  extent  to  which  the  seeds,  skins,  and 
stems  of  the  fruit  are  allowed  to  be  acted  upon.  The  seeds  yield  con- 
siderable amounts  of  tannic  acid,  and  the  skins  lend  color,  flavor,  and 
to  some  extent  astringency.  The  most  important  constituent  of  the 
juice  of  the  grape  is  the  sugar,  and  this  is  present  in  greatest  abun- 
dance when  the  fruit  is  fully  ripe. 

In  the  making  of  wine,  the  first  step  is  the  preparation  of  the  must. 
The  grapes,  with  or  without  preliminary  careful  examination  and  sort- 
ing, usually  without,  are  crushed  by  machinery  or  by  the  naked  feet 
of  men,  so  that  the  juice  is  set  free.  Sometimes,  the  stems  are  first 
carefully  eliminated,  and  particularly  good  individual  grapes  are  cut 
out  and  set  aside  for  special  use.  In  the  crushing  of  the  fruit,  the 
method  of  treading  has  in  its  favor  the  fact  that  the  seeds  are  not 
thereby  affected,  and  so  do  not  give  up  so  much  of  their  astringent 
principle.  If  a  white  wine  is  to  be  made,  the  must  is  freed  at  once 
from  the  skins  and  stalks ;  but  if  the  product  is  to  be  red,  these  are 
retained  during  the  process  of  fermentation.  The  juice  of  both  the 
white  and  the  black  varieties  of  grapes  is  practically  without  color ; 
but  when  the  dark  skins  are  left  in  contact  with  the  fermenting  mass, 
the  alcohol  formed  extracts  the  yellow  and  blue  coloring  matters,  which 
become  red  under  the  action  of  the  free  acids  formed  at  the  same  time. 
The  constituents  of  the  must  are  water,  sugar,  proteid  matters,  gununy 
substances,  pectous  matter,  organic  acids  and  their  salts,  and  mineral 
matters. 

The  must,  with  or  without  the  skins  and  seeds,  is  fermented  in  vats 
of  wood,  marble,  or  stone,  the  process  starting  very  quickly,  being  in- 
duced by  organisms  which  grow  on  the  skin  itself.  The  temperature 
at  which  this  is  allowed  to  proceed  exerts  an  important  influence  in 
determining  the  character  of  the  wine:  conducted  between  5°  and  15° 
C,  the  process  is  comparatively  slow  and  the  aroma  of  the  wine  is  rich  ;; 
while  at  higher  temperatures,  the  rate  is  more  rapid  and  the  bouquet  is 
less  marked.  The  termination  of  the  process  is  made  evident  by 
cessation  of  the  evolution  of  carbonic  acid,  the  diminution  of  specific 
gravity,  and  the  sinking  of  matters  which  before  had  formed  part 
of  the  scum. 

Whether  all  of  the  sugar  is  used  up,  depends  somewhat  upon  the 
amount  of  proteid  nutrient  material  for  the  growth  of  the  organisms 
by  which  the  conversion  is  carried  on.  If  this  is  exhausted  first,  there 
will  be  a  residue  of  sugar,  and  the  product  will  be  correspondingly 
sweet ;  if  there  is  an  abundance  of  proteid  matter,  the  sugar  will  be  the 
first  to  be  exhausted,  and  the  wine  will  be  "  dry."  It  is  sometimes 
necessary  to  add  nitrogenous  matter,  such  as  egg  albumin  or  gelatin,  in 
order  to  keep  the  process  from  ceasing  too  early. 

As  the  percentage  of  alcohol  in  the  fermenting  must  rises,  the  bitar- 
trate  of  potassium  present  is  deposited  gradually,  owing  to  its  insolu- 
bility in  alcohol.  The  deposit  is  known  commercially  as  argol,  and  is 
the  source  of  cream  of  tartar. 

AVheu  the  first  fermentation  is  completed,  the  alcoholic  liquid  is  drawn 


WINES.  191 

off  into  casks,  in  which  it  is  kept  for  a  number  of  months,  the  vessels 
being  kept  constantly  filled.  It  now  undergoes  a  second  slow  fermen- 
tation, which  brings  about  changes  which  are  not  understood  excepting 
in  their  gross  result,  which  is  the  production  of  the  "  bouquet "  or 
flavor.  In  this  second  process,  there  occur  a  farther  deposition  of 
argol  and  an  oxidation  of  aldehyde  to  acetic  acid.  The  bouquet  is  due 
to  a  combination  of  ethers,  the  chief  of  which  is  oenanthic  ether,  sup- 
posed to  be  produced  from  the  alcohol  through  the  agency  of  the  organic 
acids  normally  present. 

The  wine  next  is  racked  off  into  other  casks,  and  in  some  cases  it  is 
necessary  to  do  this  several  times.  Sometimes,  the  appearance  of  the 
wine  is  such  that  "fining"  is  necessary.  This  consists  in  the  addition  of 
egg  albumin,  isinglass,  or  other  gelatinous  matter,  which  in  its  descent 
attracts  and  enmeshes  the  fine  particles  of  matter  which  not  only  pre- 
vent brilliancy,  but  later  on  may  impair  the  keeping  quality  of  the 
wine. 

Classification  of  Wines. — Wines  are  classified  variously  according 
to  color,  strength,  sweetness,  and  content  of  carbonic  acid.  Accord- 
ing to  color,  they  are  classed  as  red  or  white,  the  latter  term  applying 
not  only  to  the  very  light,  almost  colorless  kinds,  but  also  to  those 
having  a  decided  yellowish  or  even  yellowish-brown  color,  such  as  is 
possessed  by  "  white  port."  The  red  wines  include  those  generally 
known  as  Clarets  and  Burgundies,  though  both  these  kinds  exist  in  the 
white  forms.  The  white  wines  include  the  white  Clarets  commonly 
designated  as  Sauternes,  white  Burgundies  of  which  Chablis  is  a  type, 
the  Rhine  and  Moselle  wines,  and  others. 

According  to  strength,  wines  are  classed  as  natural  and  fortified. 
The  natural  wines  contain  of  alcohol  only  that  which  is  formed  in  the 
process  of  natural  fermentation ;  the  fortified  wines,  such  as  Sherry, 
Port,  and  Madeira,  contain,  besides,  a  considerable  amount  in  the  form 
of  added  spirits. 

According  to  their  content  of  sugar,  wines  are  classed  as  sweet  or  dry. 
Some  of  the  sweet  wines  contain  added  sugar  and  that  which  has 
escaped  the  action  of  the  yeast  plant.  In  the  dry  wines,  all  or  nearly 
all  of  the  sugar  has  been  converted  into  alcohol.  Not  all  of  the  sugar, 
however,  in  any  wine  is  converted  into  alcohol  and  carbonic  acid,  small 
amounts  going  to  form  glycerin  and  succinic  acid. 

According  to  their  content  of  carbonic  acid,  wines  are  classed  as  still 
or  sparkling  (effervescent).  The  natural  wines  contain  practically  no 
carbonic  acid  ;  the  sparkling,  or  effervescent,  wines,  as  Champagne  and 
sparkling  Moselle,  are  in  a  sense  artificial  in  that  they  are  subjected  to 
a  process  of  fermentation  in  the  bottle,  sugar  being  added  for  the  pur- 
pose.    They  are  flavored  also  with  liqueurs. 

Composition  of  Wines. — Alcohol. — The  most  important  constitu- 
ent, the  iu'tive  pi-iii(;iple,  of  wIik;  is  etliylic  alcohol.  The  higlier 
;ilcoli(»l.s,  propylic,  butylic,  and  amylic,  are  always  present  in  traces. 
Tlic  ;imoniit  of  alcohol  is  variable,  ranging  in  natural  wines  from  6 
t'l  1  +  |K'r  fciit.  by  w(!ight,  but  ordinarily  present  between  the  limits  of 


192 


FOODS. 


9  and  12  per  cent.      In  fortified  wines,  the  amount  ranges  from  12  to 
about  22  per  cent.,  but  is  usually  about  17  per  cent. 

Sugar. — While  the  amount  of  sugar  in  the  original  must  ranges  be- 
tween 12  and  33  per  cent.,  in  the  natural  finished  product  it  is  as  a 
rule  quite  low,  ordinarily  considerably  under  0.5  per  cent.,  and  often 
none  at  all.  The  sweet  Tokays  contain  exceedingly  variable  amounts, 
ranging  from  3  to  26  per  cent..  Ports  and  Madeiras  about  4,  and 
Sherries  somewhat  less ;  but  American  Ports,  Sherries,  and  Madeiras 
are  commonly  fairly  rich  in  sugar.  Domestic  Champagnes,  also,  con- 
tain notable  amounts,  but  those  of  foreign  origin,  even  those  ordinarily 
classed  as  sweet,  contain  but  small  amounts,  the  impression  of  sweet- 
ness being  largely  due  to  the  flavorings  of  the  liqueurs  added.  Four 
specimens  analyzed  by  the  author,  one  of  which  (No.  4)  is  well  known 
as  an  extra  sweet  wine,  yielded  the  following  results  : 


Brand. 

Sugar. 

Extract. 

Alcohol  by- 
weight. 

1.  Brut  Imperial  (Moet  &  Chandon) 

2.  St.  Marceaux 

3.  Dry  Imperial  (Moet  &  Chandon) 

4.  White  vSeal  (Moet  &  Chandon) 

1.35 
1.52 
1.56 
4.76 

3.27 
3.21 
3.18 
6.88 

11.15 

10.38 
10.85 
10.23 

Extract. — The  extract,  or  residue,  represents  the  sum  of  the  non- 
volatile constituents,  including  sugar,  nitrogenous  matters,  tartaric  and 
other  acids,  mineral  and  organic  salts,  coloring  and  astringent  prin- 
ciples, glvcerin,  etc.,  all  of  ^hich  are  present  in  but  small  quanti- 
ties. In  sweet  wines,  the  princijial  constituent  of  the  residue  is  sugar. 
The  actual  food  value  of  the  residue  is,  apart  from  the  sugar,  practi- 
cally nil. 

Adulteration  of  Wines. — Wines  have  been  subject  to  a  wide 
variety  of  adulterations  from  the  earliest  times,  and  measures  against 
the  practice  of  their  sophistication  were  enforced  long  before  those 
against  the  adulteration  of  bread  and  other  foods  were  thought  of. 
The  ancient  Greeks  and  Eomans,  for  example,  enacted  stringent  laws 
and  appointed  officials  whose  duty  was  to  detect  and  punish  those  who 
oifended. 

At  the  present  time,  adulteration  of  wines  is  practised  very  exten- 
sively, and  includes  the  addition  of  water,  of  coloring  agents,  of  pre- 
servatives, of  glycerin  to  impart  sweetness  and  body,  of  alum  to  heighten 
color  and  of  decolorizing  agents  to  remove  it,  the  substitution  of  wholly 
artificial  compounds,  and  processes  for  the  "  improvement "  of  the 
natural  product.  The  flavoring  and  coloring  agents  are  as  a  rule  quite 
harmless.  They  are  employed  chiefly  in  the  manufacture  of  factitious 
wines,  and  not  uncommonly  the  same  agent  serves  in  both  capacities. 
Prunes,  raisins,  dried  apples  and  peaches,  and  dates  are  commonly  so 
employed.  Various  berries,  logwood,  alkanet,  red  beets,  coal-tar 
products,  and  a  wide  variety  of  other  substances  are  said  to  be  used 
for  imparting  color. 


WJNES.  193 

The  addition  of  alcohol  is  recognized  as  a  legitimate  practice  in  the 
oase  of  the  fortified  wines  ;  that  of  glycerin  has  no  sanitary  significance. 
The  amount  of  alum  used  for  heightening  color  is  so  small  as  to  be 
productive  of  no  harm.  The  employment  of  decolorizing  agents  is, 
like  the  substitution  of  artificial  products,  a  fraud  pure  and  simple ; 
but  the  use  of  preservatives,  such  as  salicylic  acid,  formaldehyde,  and 
sulphites,  is  objectionable  on  account  of  danger  to  health. 

For  the  improvement  of  wines,  a  number  of  processes  are  in  vogue. 
Ohief  of  these  is  "  plastering,"  which  consists  in  the  addition  of  gyp- 
sum to  the  must  for  the  purpose  of  securing  a  more  brilliant  appear- 
ance and  increasing  the  keeping  qualities.  This  agent  decomposes  the 
potassium  bitartrate,  forming  tartrate  of  calcium  and  acid  sulphate  of 
potassium,  which  latter  eventually  is  converted  into  the  neutral  sulphate. 
Chaptalizing  consists  in  the  neutralization  of  the  acidity  of  the  must  by 
the  use  of  marble  dust,  and  the  addition  of  cane  sugar  or  glucose.  This 
process  diminishes  the  natural  acidity  and  increases  the  yield  of  alcohol. 
Gallizing  consists  in  diluting  the  must  so  as  to  reduce  its  acidity  to  a 
given  standard,  and  adding  a  sufficient  amount  of  cane  sugar  or  glucose 
to  insure  the  production  of  the  proper  alcoholic  strength. 

The  Pasteur  treatment  of  wines  is  resorted  to  sometimes  as  soon  as 
evidence  of  untoward  fermentations  producing  the  so-called  "  wine  dis- 
eases" appears.  The  wine,  best  in  the  bottle,  is  heated  to  from  55° 
to  65°  C.  according  as  the  alcoholic  strength  is  high  or  low,  whereby 
the  existing  germs  are  killed  and  the  preservation  of  the  wine  is  made 
permanent. 

The  manufacture  of  artificial  wines  is  carried  on  extensively  in  this 
country  and  abroad,  in  spite  of  the  fact  that  fair  grades  of  the  genuine 
product  are  obtainable  at  very  low  prices.  A  number  of  hand-books 
and  guides  to  the  "  art  of  blending  and  compounding "  are  pub- 
lished for  the  use  of  wholesalers  and  retailers  of  wines  and  liquors,  and 
from  several  of  these  the  following  are  selected  as  examples  of  the 
methods  given:  (1)  Port:  cider,  30  gallons;  alcohol,  5  gallons; 
syrup,  4  gallons  ;  kino,  ^  pound  ;  tartaric  acid,  ^  pound ;  port  wine 
flavor,  6  ounces.  (2)  Claret :  California  hock,  40  gallons  ;  extract  of 
kino,  8  ounces ;  essence  of  malvey  flower,  8  ounces.  (3)  Sherry : 
equal  parts  of  Spanish  sherry  and  California  hock,  (4)  White  wine  : 
dissolve  25  pounds  of  grape  sugar  and  1  of  tartaric  acid  in  25  quarts 
of  hot  water,  add  75  quarts  of  cold  water  and  50  pounds  of  grape 
pulp,  stir,  cover,  let  ferment  for  four  or  five  days,  and  strain. 

In  France,  an  artificial  substitute  for  wine,  known  as  "  piquette,"  is 
manufactured  very  extensively  from  raisins  and  dried  apples.  It  is 
estimated  that  in  1898  no  less  than  50,000,000  gallons  were  made  and 
consumed.  The  process  is  exceedingly  simple.  To  each  gallon  of 
water  used  are  added  1  pound  of  raisins  and  1  of  dried  apples ;  the 
mixture  is  placed  in  an  open  vc^sscl  and  allowed  to  stand  three  days, 
it  is  tlien  botth'd  with  ^  ttjaspoonful  of  sugar  and  a  small  piece  of 
cinnamon  in  each  bottle.  It  is  said  to  be  a  pleasant  and  harmless 
beverage. 


19.1:  FOODS. 

Analysis  of  Wines. 

Determination  of  Alcohol. — The  process  for  the  determination  of 
alcohol  is  the  same  as  that  follo'sved  in  the  analysis  of  beer,  except 
that  the  distillation  or  evaporation  is  carried  farther.  At  least  60,  or 
better  75  cc,  are  collected  by  distillation  or  driven  off  by  open  evapo- 
ration. 

Determination  of  Extract. — The  specific  gravity  of  the  de-alcohol- 
ized wine  gives,  as  with  beer,  an  approximate  estimate  of  the  amount 
of  extract,  and  the  same  table  may  be  used.  The  direct  determination 
is  made  by  evaporating  50  cc.  of  the  wine  in  a  weighed  platinum  dish 
on  a  water-bath  and  drying  to  constant  weight  in  an  air-bath.  With 
sweet  wines,  a  smaller  amount  is  preferable. 

Determination  of  Acidity. — The  total  acidity,  due  to  bitartrate  of 
potassium,  tartaric,  malic,  and  other  acids,  is  reckoned  as  tartaric  acid. 
Twenty-five  cc.  of  the  wine  are  titrated  in  the  usual  way  with  decinor- 
mal  sodium  hydrate,  1  cc.  of  which  equals  0.0075  gram  of  tartaric 
acid. 

The  volatile  acids  are  reckoned  as  acetic  acid.  Fifty  cc.  of  the  wine 
are  placed  in  a  distilling  flask  connected  by  means  of  its  outlet  tube 
with  a  Liebig  condenser,  and,  by  means  of  a  bent  tube  passing  through 
its  stopper  and  projecting  well  below  the  surface  of  the  wine,  with  a 
flask  containing  250  cc.  of  water.  The  contents  of  both  flasks  are 
brought  to  the  boiling-point,  and  then  the  flame  beneath  the  wine  is 
turned  down  and  the  current  of  steam  passed  through  until  200  cc. 
of  distillate  are  collected.  This  is  titrated  with  decinormal  sodium 
hydrate,  and  the  result  is  expressed  as  acetic  acid.  The  determination 
of  the  amounts  of  the  individual  acids  is  of  no  hygienic  interest. 

Determination  of  Sugar. — The  amount  of  sugar  in  wine  is  deter- 
mined by  reduction  of  Fehling's  solution,  by  the  method  of  Allihn,  and 
by  polariscopy.  For  the  details  of  these  methods,  the  reader  is  referred 
to  any  of  the  standard  works  on  wine  analysis,  for  the  small  amount 
of  sugar  ordinarily  present  is  of  but  little  hygienic  interest,  and  the 
description  of  the  processes  would  require  an  amount  of  space  vastly 
out  of  proportion  to  the  importance  of  the  subject. 

Determination  of  Ash. — The  residue  obtained  in  the  determination 
of  extract  can  be  utilized  for  the  determination  of  the  ash.  It  should 
be  ignited  at  as  low  a  temperature  as  possible. 

Detection  of  Coal-tar  Colors. — While  the  presence  of  coal-tar 
colors  is  not  difficult  of  detection,  the  identification  of  the  individual 
members  of  the  group  is  by  no  means  easy.  The  following  tests  give 
reliable  indications  of  the  presence  of  this  class  of  colors.  Equal 
volumes  of  wine  and  ether,  agitated  in  a  flask,  and  let  stand  and  sepa- 
rate, will  show  in  the  ether  layer  a  red  coloration,  if  anilin  colors  are 
present.  In  place  of  ether,  nitro-benzene  may  be  used ;  this  removes 
fuchsin,  eosin,  and  methylen-blue,  but  does  not  take  up  any  of  the 
vegetable  colors,  safranin,  or  indigo-carmine.  Amyl  alcohol,  also,  will 
become  reddened  when  agitated  with  wine  containing  anilins,  but  the 


WINES.  195 

wiue  must  first  be  made  slightly  alkaline.  If  white  woollen  threads 
are  immersed  for  some  time  in  the  colored  liquids,  they  will  take  up 
the  colors  and  become  dyed. 

Cazeneuve's  test  is  performed  as  follows:  To  10  cc.  of  wine  add 
0.20  gram  of  mercuric  oxide,  then  shake  for  one  minute,  boil,  let 
stand,  and  filter.  The  filtrate  should  be  clear,  and  in  the  absence 
of  anilins  should  be  colorless ;  if  it  is  red,  an  anilin  color  is  present. 
Absence  of  color  is,  however,  not  conclusive  evidence  of  purity,  since 
a  number  of  the  anilin  colors,  as  eosin,  methylen-blue,  and  others,  are 
wholly  precipitated,  and  so  do  not  appear  in  the  filtrate  Safranin, 
methyl-eosin.  Ponceau  red,  and  a  number  of  other  colors  are  precipi- 
tated partially  or  completely. 

A  number  of  these,  including  safranin,  Bordeaux  red,  and  Ponceaa 
red,  may  be  separated  by  the  following  process  :  To  200  cc.  of  wine 
from  which  the  alcohol  has  been  expelled,  add  4  cc.  of  10  per  cent, 
hydrochloric  acid  and  some  white  woollen  threads,  and  boil  for  five 
minutes.  Withdraw  the  threads  and  wash  them  with  cold  water  acidu- 
lated with  hydrochloric  acid,  next  with  hot  water  similarly  acidulated, 
and  lastly  with  distilled  water  alone.  Boil  the  threads  in  50  cc.  of 
distilled  water  containing  2  cc.  of  strong  ammonia  water,  remove  them, 
and  immerse  new  ones.  Make  acid  with  hydrochloric  acid  and  boil 
for  five  minutes.  Varying  shades  of  rose-red  will  be  imparted  to  the 
threads  if  any  of  these  colors  are  present. 

Fuchsin  may  be  detected  by  the  following  methods  :  (1)  To  100  cc. 
of  wine  add  5  cc.  of  ammonia  water  and  30  cc.  of  ether,  and  shake. 
Remove  the  ether,  which  will  have  no  color,  place  it  in  a  watch-glass 
with  a  white  woollen  thread,  and  let  it  evaporate  to  dryness.  If  even 
a  trace  of  fuchsin  is  present,  the  thread  will  show  a  distinct  rose-col- 
oration. (2)  Mix  2  volumes  of  wine  and  1  of  solution  of  basic  ace- 
tate of  lead,  warm  gently,  and  shake.  Filter,  add  to  the  filtrate  a 
small  amount  of  amyl  alcohol,  shake  again,  and  remove  the  amyl  alco- 
hol. If  this  has  a  red  color,  it  may  be  due  to  fuchsin  or  to  orseille. 
To  a  portion  of  the  colored  liquid  add  hydrochloric  acid ;  if  the  color 
is  discharged,  it  was  due  to  fuchsin.  To  another  portion  add  ammonia 
water ;  if  the  color  is  changed  to  purple  violet,  it  was  due  to  orseille. 

Detection  of  Preservatives. — Salicylic  Acid. — Spica's  method  for 
detecting  salicylic  acid  in  Avine  is  as  follows  :  Acidify  10  cc.  of  wine 
with  a  few  drops  of  hydrochloric  acid,  and  shake  with  an  equal  volume 
of  ether.  Remove  the  ether,  filter  it  if  necessary,  and  evaporate  to 
dryness.  Add  a  drop  of  nitric  acid,  warm  gently,  and  add  an  excess 
of  ammonia  and  1  cc.  of  water.  Immerse  a  white  woollen  thread, 
apply  gentle  heat,  and  then  withdraw  the  thread,  wash  it,  and  dry  it 
between  pieces  of  blotting-paper.  A  yellow  color  indicates  that  sali- 
cylic acid  waf?  present  in  the  wine. 

Another  method,  for  which  great  delicacy  is  claimed,  even  to  a  tenth 
of  a  milligram  in  a  liter,  is  the  following  :  Acidify  50  cc.  of  wine, 
beer,  or  other  liquid  with  sulphuric  acid,  and  shake  it  with  an  equal 
volume  of  a  mixture  of  equal  parts  of  ether  and  naphtha.     Separate 


196  FOODS. 

the  ether,  filter,  and  evaporate  down  to  5  cc.  ;  then  add  3  ce.  of  water 
ai;d  a  few  drops  of  very  dilute  solution  of  ferric  chloride,  and  filter 
through  a  wet  filter.  In  the  presence  of  salicylic  acid,  the  watery  jjor- 
tion  will  have  a  violet  color.  A  modification  of  this  method  consists 
in  extracting  with  ether  alone,  and  then  extracting  the  ether  residue 
yvith  naphtha ;  the  residue  on  evaporation  of  the  naphtha  is  treated 
with  water  and  very  dilute  ferric  chloride. 

Formaldehyde. — To  10  cc.  of  wine,  add  a  few  drops  of  milk  known 
to  be  free  from  formaldehyde,  and  shake  in  a  test-tube.  Next  pour 
down  the  side  of  the  tube  about  4-5  cc.  of  strong  commercial  sul- 
pturic  acid,  and  note  the  color  at  the  line  of  contact  of  the  two  liquids. 
(See  under  Milk.) 

Sulphites. — To  200  cc.  of  wine  (or  beer)  add  5  cc.  of  phosphoric 
acid;  distil  100  cc,  using  a  Liebig  condenser  with  a  bent  delivery  tube 
\vhich  dips  below  the  surface  of  20  cc.  of  decinormal  solution  of  iodine. 
By  distilling  in  a  current  of  washed  CO,,  the  danger  of  back  suction 
is  avoided.  The  reaction  which  is  brought  about  is  as  follows : 
SO,  +  2HP  +  1,  =  H„SO,  -r  2HI.  The  amount  of  SO^,  may  be 
determined  by  estimating  the  excess  of  iodine  by  means  of  standard 
sodium  thiosulphate,  or  the  distillate  may  be  acidified  with  hydrochloric 
jicid  and  the  contained  sulphuric  acid  precipitated  as  barium  sulphate 
by  the  addition  of  barium  chloride.  One  milligram  of  barium  sul- 
j)hate  is  equivalent  to  0.2748  milligram  of  SO,. 

CIDER. 

Cider,  or  apple  wine,  is  the  fermented  juice  of  the  apple.  It  is  made 
very  extensively  wherever  apples  are  grown,  and  is  a  very  important 
product,  viewed  either  as  a  beverage  or  as  the  basis  of  Avhat  is  regarded 
generally  as  the  best  kind  of  vinegar. 

A  very  large,  if  not  the  greater,  part  of  the  cider  produced  is  made 
without  special  care  by  a  very  simple  process.  The  apples  used  are 
ordinarily  those  not  marketable  on  account  of  small  size,  greenness, 
over-ripeness,  or  bruises  ;  but  often  perfect  fruit  is  used  when  the  crop 
is  so  abundant  that  there  is  more  profit  in  converting  it  into  cider  and 
vinegar  than  in  sending  it  in  barrels  to  market.  The  fruit  is  ground 
to  a  pulp  and  pressed,  and  the  juice  is  drawn  into  barrels  and  allowed 
to  ferment.  If  the  same  amount  of  care  is  taken  as  is  given  to  the 
making  of  wine  from  grapes,  the  product  is  of  a  superior  grade,  and 
keeps  very  well ;  but  as  ordinarily  made  in  the  country,  its  life  is 
short,  unless  treated  with  salicylic  acid  or  other  preservative  to  check 
fermentation.  In  France,  where  the  yearly  yield  is  very  great,  the 
best  grades  are  made  with  due  regard  lo  the  temperature  at  which  the 
fermentation  proceeds,  and  to  the  importance  of  racking  off  and  fining. 

Cider  of  good  quality  contains  usually  from  3  to  5  per  cent,  and 
sometimes  as  much  as  8  per  cent,  by  weight  of  alcohol.  Very  new 
sweet  cider  may  contain  less  than  1  per  cent.  The  total  extract,  which 
is  largely  sugar,  is  in  inverse  proportion  to  the  amount  of  alcohol  ;  in 


DISTILLED  ALCOHOLIC  BEVERAGES.  197 

average  samples,  it  amounts  to  from  4  to  6  per  cent.,  while  in  new 
sweet  cider  it  is  commonly  nearer  9  per  cent.  The  free  acids,  chiefly 
malic,  amount  to  less  than  0.75  per  cent.,  and  average  about  0.40. 

The  adulterants  of  cider  are  water  and  salicylic  acid.  The  latter  is 
found  very  commonly  in  that  which  reaches  the  city  markets. 

PERRY. 

Perry,  or  "pear  cider,"  is  the  fermented  juice  of  pears.  It  is  made 
in  the  same  way  as  cider.  Pear  juice  being  richer  in  sugar  than  apple 
juice,  it  follows  that  the  average  content  of  alcohol  is  somewhat  higher 
than  in  cider. 

Distilled  Alcoholic  Beverages. 

Spirits,  or  distilled  liquors,  are  the  product  of  distillation  of  fer- 
mented sugar  solutions.  Their  most  important  constituent  is  ethylic. 
alcohol,  which  is  ordinarily  present  to  the  extent  of  about  45  per  cent.. 
When  freshly  made,  they  contain  variable  small  quantities  of  higher- 
alcohols,  furfurol,  fatty  acids,  and  other  volatile  principles,  whick 
together  constitute  what  is  known  as  fusel  oil,  the  chief  constituent  of 
which  is  amylic  alcohol. 

Each  kind  of  grain  or  other  raw  material  from  which  the  ferment- 
able sugar  solution  is  obtained  yields  a  different  kind  of  fusel  oil ;  dif- 
ferent because  of  the  changing  relative  proportions  of  its  constituents, 
which  include  butylic,  propylic,  and  amylic  alcohols,  and  their  corre- 
sponding acids,  butyric,  propionic,  and  valerianic,  and  other  matters. 
That  which  is  found  in  potato  spirits  is  richest  in  amylic  alcohol,  and 
is  the  most  toxic,  while  that  from  grapes  contains  by  far  the  least  and 
produces  the  least  harm.  During  the  process  of  aging,  the  constituents 
of  the  fusel  oil  undergo  chemical  changes  which  result  in  the  formation 
of  oenanthic,  acetic,  and  butyric  ethers,  acetate  and  valerianate  of  amyl, 
and  other  compounds,  which  together  constitute  the  aroma  or  "bou- 
quet." Thus,  a  spirit  is  improved  in  two  ways  by  long  storage  :  it 
loses  in  toxicity  and  gains  in  flavor. 

The  relative  toxicity  of  the  several  alcohols  and  of  other  constituents 
of  fusel  oil  has  been  determined  by  Dujardin-Beaumetz  and  others, 
who  show  that  the  poisonous  properties  increase  with  the  boiling-point 
and  molecular  weight.  Jeifroy  and  Serveaux  ^  determined  the  amounts 
in  grams  necessary  per  kilogram  to  kill  a  rabbit,  as  follows  :  ethvlic 
alcohol,  11.70;  propylic  alcohol,  3.40;  butylic  alcohol,  1.45;  amylic 
alcohol,  0.63;  furfurol,  0.24.  Daremberg-  found  by  experiment  that 
artificial  spirits  and  wines  made  with  pure  rectified  alcohol  are  less  toxic 
than  the  genuine  products,  by  reason  of  the  absence  of  the  constituents 
of  fusel  oil.  Roubinowitch,"  speaking  of  the  greater  toxicity  of  tlie 
higher  alcohols,  calls  attention  to  the  fact  that  the  distillates  from  cider, 
perry,  and  ffirmcnted  grains,  potatoes,  and  molasses,  are  much  more 
toxic  than   brandy. 

'  Arfliives  de  Mddecine  expc^iiiuontale  et  d'Aiiiitomie  pathologiqne,  1895,  p.  569. 
^  Ibidem,  p.  719.  •*  (Jjizetle  dos  Jlopitaiix,  1895,  p.  237. 


198  FOODS. 

Most  spirits  are  colored  artificially  by  the  addition  of  harmless  col- 
oring agents,  the  most  widely  used  of  which  is  caramel.  As  the  prac- 
tice of  coloring  is  in  response  to  the  demand  of  the  consumer  for  a 
darker  color  than  can  be  obtained  otherwise,  it  can  hardly  be  regarded 
as  an  adulteration. 

BRANDY. 

Brandy  is  obtained  by  distilling  wanes  of  the  poorer  qualities,  often 
mixed  with  the  "  lees,"  or  dregs  from  the  wine  casks,  and  the  "  marc," 
or  solid  refuse  left  after  pressing  the  grapes.  The  lees  and  marc  are 
used  also  alone  for  the  production  of  a  highly  odorous  brandy,  which  is 
much  used  for  improving  the  flavor  of  other  brandies,  and  for  giving 
flavor  to  the  artificial  brandies  made  from  pure  alcohol  and  water. 
From  this  marc  brandy  is  obtained  the  oily  substance,  oenanthic  ether, 
which  is  known  commercially  as  "  oil  of  wine." 

Brandy  is  produced  ver}'  largely  in  France,  and  much  less  exten- 
sively in  Spain,  Portugal,  and  Germany  ;  in  California  and  in  the  wine- 
growing region  of  the  Ohio  and  Mississippi  Valley,  it  is  produced  in 
large  quantities  and  of  most  excellent  quality. 

The  colorless  distillate  is  stored  for  some  time  in  oaken  casks,  from 
which  a  small  trace  of  tannin  and  a  varying  depth  of  amber  (tolor  are 
acquired.  The  flavor,  which  in  general  depends  upon  the  kind  of 
grapes,  their  condition  when  pressed,  and  the  care  observed  in  the 
making  of  the  Avine,  becomes  improved  during  storage.  The  liquor  is 
then  colored  and  bottled  for  the  market. 

Good  brandy  should  contain  from  39  to  47  per  cent,  of  alcohol  by 
weight,  should  have  an  agreeable  odor  and  taste,  and  should  be  free 
from  substances  added  to  impart  sharp  taste  and  apparent  strength. 
The  nearly  dry  residue  from  100  cc.  very  slowly  evaporated  on  a  water- 
bath  should  have  a  pleasant  odor,  and  its  taste  should  be  neither  sweet 
nor  sharp  ;  a  sharp  odor  points  to  the  presence  of  fusel  oil  derived  from 
potato  or  cereals  ;  a  sweet  taste  is  indicative  of  added  sugar  or  glycerin ; 
and  a  sharp  taste  is  suggestive  of  cayenne  or  other  spice. 

Much  of  the  brandy  of  commerce  is  a  purely  artificial  product  made 
from  alcohol  or  potato  spirits,  water,  and  flavorings.  The  formulae  for 
making  brandy  are  very  numerous,  and  not  a  feAV  require  what  is  known 
as  brandy  essence,  an  article  made  wdth  ethers  and  other  substances  in 
varying  proportions.  By  one  formula,  it  is  made  with  5  parts  of  oenan- 
thic ether,  4  of  acetic  ether,  3  of  tincture  of  galls,  1  of  tincture  of  pi- 
menta,  and  100  of  alcohol ;  by  another,  it  consists  of  15  parts  of  acetic 
•ether,  12  of  sweet  spirit  of  nitre,  and  1  of  rectified  wood  spirit.  One 
part  of  either  of  these  mixtures  is  sufficient  to  flavor  a  mixture  of  1000 
parts  of  alcohol  and  600  of  water. 

As  examples  of  the  way  in  which  factitious  brandy  is  made,  the  fol- 
lowing will  serve :  (1)  Boil  5  ounces  of  raisins  and  6  of  St.  John's 
bread  in  water,  filter,  and  make  up  to  10  quarts  ;  mix  this  with  20 
quarts  of  alcohol,  10  ounces  of  brandy  essence,  and  |  ounce  of  essence 
of  violet  flowers.     (2)  Dissolve  1  pound  of  argols  and  3  of  sugar  in  a 


WHISKEY.  199 

gallon  of  water,  add  40  gall(Mi.s  of  alcohol,  i  pound  of  acetic  ether,  2 
ounces  of  tincture  of  kino,  6  pounds  of  bruised  raisins,  and  a  sufficient 
amount  of  caramel,  and  let  stand  for  fourteen  days  ;  strain  and  bottle. 

WHISKEY. 

Whiskey  is  the  product  of  distillation  of  the  fermented  mash  of 
grain  or  potatoes.  The  raw  materials  from  which  the  mash  is,  made 
include  malt,  wheat,  rye,  corn,  oats,  and  potato.  In  the  process  of 
mashing,  the  starch  of  the  grain  is  changed  to  sugar  by  the  diastase  of 
the  malt ;  and  since  this  ferment  is  capable  of  converting  other  starch 
than  that  with  which  it  is  associated,  it  is  customary  to  mix  malt  and 
raw  grain  in  the  proportion  of  1  to  from  5  to  9  parts.  A  bushel  of 
grain  makes  about  2.5  gallons  of  spirits.  In  this  country,  the  grains 
employed  are  chiefly  corn,  wheat,  and  rye ;  in  Great  Britain,  barley, 
oats,  and  rye  are  used  together ;  potatoes  are  used  to  a  greater  or  less 
extent  on  the  continent.  The  mash  for  Scotch  whiskey  is  very  com- 
monly prepared  from  2  parts  of  malt,  7  of  barley,  and  1  each  of  oats  and 
rye ;  that  for  Irish  whiskey  is  the  same,  with  the  exception  of  the  rye. 

As  soon  as  the  fermentation  of  the  mash  through  the  agency  of  yeast 
is  complete,  the  distillation  is  begun.  The  first  distillate,  known  as 
^'  low  wine,"  is  re-distilled.  The  second  distillate  is  stronger  and  less 
rich  in  fusel  oil,  which,  being  less  volatile  than  ethylic  alcohol,  comes 
over  chiefly  in  the  later  portions.  The  new  whiskey  is  stored  for  sev- 
eral years,  in  order  that  it  may  acquire  the  flavor  due  to  the  formation 
of  new  compounds  from  the  constituents  of  the  fusel  oil.  During  stor- 
age, it  takes  up  a  trace  of  tannin  from  the  oak  of  the  casks. 

The  flavor  of  whiskey  depends  upon  the  nature  of  the  raw  material, 
and  largely  upon  the  aging  process.  The  disagreeable  flavor  and  odor 
of  new  whiskey  are  due  to  fusel  oil ;  the  smoky  taste  of  Scotch  and 
Irish  whiskies  is  due  to  the  smoke  of  the  peat  and  turf  fires  over  which 
the  malt  is  dried.  Indian  corn  whisky  has  a  much  different  flavor 
from  that  of  rye  whiskey ;  this  flavor  is  regarded  highly  by  many  to 
Avhom  rye  whiskey  is  unpalatable  and  insipid,  and  at  the  same  time  it 
is  so  full  that  to  others  it  is  rank  and  nauseating.  The  peculiar  flavor 
of  Bourbon  whiskey,  so-called  because  originally  produced  in  Bourbon 
County,  Kentucky,  is  due  to  the  corn  from  which,  with  rye,  the  mash 
is  prepared. 

Whiskey  of  good  quality  should  contain  about  45  per  cent,  of  alco- 
hol by  weight,  and  should  yield  not  more  than  0.25  per  cent,  of  resi- 
due, which  should  have  a  slightly  aromatic  odor  and  but  little  taste. 

Whiskey  is  manufactured  very  largely  from  alcohol,  water,  and 
various  flavoring  compounds,  some  of  which  can  hardly  be  looked  upon 
as  wholly  innocuous.  The  following  directions  are  taken  from  a  small 
work,  tiie  object  of  which  is,  according  to  the  preface,  "  to  give  the  dis- 
penser of  lifjuors  thorough  and  practical  information  by  wliich  he  will 
be  enabled  to  comp(Hind,  and  blend  ll({Uors  for  his  own  purposes,  and 
thus  secure  the  additional  profit." 


200  FOODS. 

1.  Bourbon  Oil. — Take  of  fusel  oil,  64  ounces  ;  acetate  of  potassium 
and  sulphuric  acid,  each,  4  ounces ;  and  black  oxide  of  manganese,  1 
ounce.  Dissolve  ^  ounce  each  of  sulphate  of  copper  and  oxalate  of 
ammonium  in  4  ounces  of  water,  mix  all  in  a  glass  percolator,  and  let 
rest  for  twelve  hours.  Then  percolate  and  put  into  a  glass  still,  and 
distil  64  ounces. 

2.  Hye  Oil. — Mix  64  ounces  of  fusel  oil,  8  each  of  oenanthic  ether, 
chloroform,  and  sulphuric  acid,  and  2  of  chlorate  of  potassium  in  8  of 
water,  place  in  a  glass  still,  and  distil  64  ounces. 

3.  Beading  Oil. — Mix  together  48  ounces  of  oil  of  sM^eet  almonds 
and  12  of  sulphuric  acid,  and  when  cool  neutralize  with  ammonia  and 
dilute  with  double  the  volume  of  proof  spirit.  "  This  is  used  to  put 
an  artificial  bead  on  inferior  liquors."  For  making  the  lowest  grade 
of  whiskey,  one  is  directed  to  mix  32  gallons  of  alcohol  and  16  of  water^ 
4  ounces  of  caramel  and  1  of  beading  oil.  By  adding  oil  of  rye  or  oil 
of  Bourbon,  "making  the  result  rye  whiskey  or  Bourbon,  as  the  case 
may  be,"  the  value  is  said  to  be  increased. 

From  another  similar  source  the  following  recipes  for  factitious 
whiskey  are  taken  : 

1.  Bourbon  Whiskey — Proof  spirit,^  100  gallons  ;  pear  oil,  4  ounces  ; 
pelargonic  ether,  2  ounces;  oil  of  wintergreen,  13  drachms  in  ether; 
wine  vinegar,  1  gallon  ;  caramel  color,  a  sufficient  quantity. 

2.  Old  Bourbon. — Alcohol,  40  gallons ;  Bourbon  whiskey,  5  gal- 
lons ;  sweet  spirit  of  nitre,  2  ounces ;  fusel  oil,  2  ounces.  Mix  and 
let  stand  four  days. 

3.  Old  Rye. — Soak  a  half  peck  of  roasted  dried  peaches,  put  them 
into  a  Avoollen  l)ag  and  leach  with  common  whiskey  sufficient  for  a 
barrel,  and  add  12  drops  of  strong  ammonia. 

4.  Scotch  miiskey. — Alcohol,  46  gallons;  genuine  Scotch,  8  gal- 
lons; water,  18  gallons;  ale,  1  gallon;  creasote,  5  drops  in  2  ounces 
of  acetic  acid ;  pelargonic  ether,  1  ounce  ;  honey,  3  pounds. 

5.  Irish  Whiskey. — Same  as  above,  substituting  Irish  for  Scotch,, 
and  omitting  the  honey. 

RUM. 

Rum  is  made  by  distilling  fermented  molasses  or  the  skimmings  of 
sugar  boilers,  with,  not  uncommonly,  other  substances,  as  pineapples 
and  guavas,  to  give  flavor.  The  characteristic  flavor  of  rum  is  due  to 
butyric  ether.  The  alcoholic  content  of  rum  is  very  variable,  ranging 
from  30  to  over  60  per  cent,  by  weight.  Like  other  spirits,  rum  is 
very   largely   an   artificial   product   of  alcohol,  water,  and  flavorings 

'  Proof  spirit  is  defined  by  an  act  of  Parliament  as  a  diluted  spirit  which  at  51°  F. 
shall  weigh  exactly  twelve-thii-teenths  as  much  as  an  equal  measure  of  distilled  water. 
It  contains  half  its  volume  of  alcohol  of  sp.  gr.  0.7939  at  60°  F.,  or  49.5  per  cent,  by 
weight,  or  57.27  per  cent,  by  volume  of  absolute  alcohol.  Its  sp.  gr.  is  0.91984.  Over 
and  under  proof  mean  that  a  spirit  is  stronger  or  weaker  than  proof  spirit,  and  the 
excess  or  deficiency  is  expressed  as  so  many  degrees  over  or  under  proof.  The  expres- 
sion, for  example,  25  under  proof,  means  that  the  specimen  consists  of  25  parts  of  water- 
and  75  of  proof  spii'it ;  25  over  proof  means  that  100  parts  may  be  diluted  with  25  of 
water  to  bring  it  to  the  strength  of  proof  spiiit. 


LIQUEURS.  201 

known  as  rum  essence.  One  of  these  consists  of  15  parts  of  butyric 
ether,  2  each  of  acetic  ether,  essence  of  vanilla,  and  essence  of  violet, 
and  90  of  alcohol.  Another  consists  of  32  parts  each  of  rum  ether 
and  acetic  ether,  8  of  butyric  ether,  16  of  extract  of  saffron,  and  ^  of 
oil  of  birch  cut  in  strong  alcohol.  The  rum  ether  required  is  a  product 
of  the  distillation  of  alcohol,  sulphuric  acid,  pyroligneous  acid,  and 
black  oxide  of  manganese.  Prune  juice  is  also  a  common  addition  to 
factitious  rum  for  its  flavor  and  color. 


GIN. 

Gin  is  an  alcoholic  liquor  flavored  with  juniper  berries  and  a  great 
variety  of  otlier  substances,  including  cardamom,  coriander,  cassia  buds, 
calamus,  orris,  angelica  root,  orange  peel,  licorice  powder,  and  sugar. 
It  should  contain  about  40  per  cent,  of  alcohol,  and  not  over  6  per 
cent,  of  total  residue,  including  sugar. 

.    Liqueurs. 

Liqueurs,  or  cordials,  are  manufactured  compounds  of  alcohol,  essen- 
tial oils,  cane  sugar,  and  coloring  matter.  They  contain  usually  about 
40  per  cent,  of  alcohol  by  weight,  and  from  25  to  50  per  cent,  of  cane 
sugar.  The  colorings  are,  as  a  rule,  of  vegetable  origin,  but  sometimes 
the  coal-tar  colors  are  employed.  Even  in  the  small  amounts  ordi- 
narily taken,  their  use  can  hardly  be  advised,  in  view  of  the  adverse 
report  (March  10,  1903)  of  the  Committee  of  the  Academic  de  M6de- 
cine,  to  whom  the  question  of  their  wholesomeness  was  referred  by  the 
French  government.  The  essential  oils  are  the  objectionable  ingredi- 
ents, apart  from  the  alcohol.  Especially  deleterious  is  one  which  is 
taken  commonly  with  considerable  water  before  meals,  namely,  absinthe. 
By  some  the  poisonous  constituent  is  held  to  be  the  oil  of  wormwood 
(^Artemisia  absinthiuvi),  by  others  the  oil  of  star  anise  (Illiciuin), 
both  of  which  it  contains.  To  which  constituent  the  blame  belongs 
is  of  no  great  consequence,  the  drink  being  one  w^hich  should  be 
shunned  above  all  others  as  a  poison,  without  regard  to  the  innoc- 
uousness  of  most  of  its  constituents ;  but  it  is  unlikely  that  its 
disastrous  effects  are  due  to  wormwood,  which  as  a  drug  has  lit- 
tle or  no  action,  and  which  enters  into  the  composition  of  another 
drink,  vermuth,  which  enjoys  a  good  reputation,  but  is  not  a  cor- 
dial. It  is  a  fortified  white  wine  in  which  certain  herbs  and  other 
vegetable  matters  have  been  infused.  The  ordinary  French  vermuth 
is  made  from  wormwood,  bitter-orange  peel,  water  germander,  orris 
root,  chamomile,  Peruvian  bark,  aloes,  cinnamon,  nutmeg,  centaury,  and 
raspberry,  but  many  other  substances  are  used  by  different  makers. 
The  fresh  product  has  a  very  pronounced  flavor,  which  is  mellowed 
by  age.  The  wines  most  used  in  making  French  vermuth  are  from 
the  Rhone  Valley,  Picpoul,  and  from  the  southernmost  parts  of  France. 
Italian   vermuth   differs    materially  from   the  French ;    it    is    a  much 


202  FOODS. 

weaker  infusion  with  a  far  more  bitter  taste.  The  materials  used  are 
in  the  main  the  same,  but  they  are  employed  in  very  diiferent  propor- 
tions.    Vermuth  contains  about  17  per  cent,  of  alcohol. 

Section  6.     CONDIMENTS,  SPICES,  AND  BAKERS' 
CHEMICALS. 

The  condiments  include  a  large  number  of  food  accessories  which, 
Avhile  they  are  themselves  of  no  nutritive  value  in  the  amounts  which 
it  is  possible  to  eat,  serve  a  very  useful  purpose  in  imparting  flavor, 
and  in  stimulating  appetite  and  digestion.  Among  them  are  some 
which  act  through  free  acids,  some  through  volatile  oils,  some  through 
resinous  matters,  and  one,  per.haps  the  most  important  of  all,  common 
salt,  through  itself  alone.  Some  are  simple  substances  ;  as  vinegar,  salt, 
and  the  spices  ;  while  others  are  combinations  of  a  number  of  ingredi- 
ents blended  according  to  definite  and,  as  a  rule,  secret  formulas ;  as 
sauces,  chutneys,  catsups,  and  curries.  Only  when  these  compounded 
articles  contain  substances  injurious  to  health  can  they  be  regarded  as 
adulterated.  The  tomato  catsups  are  preserved  very  commonly  with 
salicylic  acid  or  other  preservatives,  and  colored  with  anilin  dyes. 
Thus,  of  25  samples  of  different  makes  examined  in  1897  by  the  health 
authorities  of  San  Francisco,  20  contained  salicylic  acid,  2  contained 
this  agent  together  with  borax,  and  1  contained  formaldehyde;  16  were 
artificially  colored,  mostly  with  coal-tar  colors.  Of  39  examined  by 
the  Massachusetts  State  Board  of  Health  during  1899,  15  contained 
salicylic  acid  and  13  benzoic  acid. 

VINEGAR. 

Vinegar  is  a  weak  solution  of  acetic  acid  resulting  from  the  acetous 
fermentation  of  saccharine  solutions  which  have  undergone  alcoholic 
fermentation.  It  contains,  in  addition  to  acetic  acid,  small  and  unim- 
portant amounts  of  alcohol  and  aldehyde,  and  extractive  matters  in 
varying  amounts,  according  to  the  nature  of  the  original  liquid.  The 
acetic  acid  contained  is  the  product  of  oxidation  of  alcohol  through 
the  agency  of  Mycoderma  aceti,  a  fungus  which  forms  what  is  known 
as  the  "  mother  of  vinegar."  Thus,  the  change  from  sugar  to  acetic 
acid  involves  two  separate  fermentative  changes  through  the  agency  of 
two  different  organisms,  Saccharomyces  cereviske  and  Mycoderma  aceti. 

There  are  several  kinds  of  vinegar  in  common  use,  as  follows  : 

Cider  Vinegar. — In  this  country,  cider  vinegar  is  regarded  very 
generally  as  the  most  desirable  kind.  It  contains  no  aldehyde,  about 
4.50  to  5.50  per  cent,  of  acetic  acid,  marked  traces  of  malic  acid,  and 
about  2  per  cent,  of  total  residue,  or  "  cider-vinegar  solids." 

Wine  Vinegar. — In  wine-producing  countries,  the  vinegar  in  com- 
mon use  is  made  from  the  cheaper  kinds  of  wine.  It  has  color  or  not, 
according  to  the  kind  of  wine  from  which  it  is  made.  The  so-called 
white  wine  vinegar  in  common  use  in  this  country  among  the  foreign- 


VINEGAR.  203 

born  population  is  a  colorless  product  of  the  oxidation  of  dilute  spirits. 
Wine  vinegar  contains  rather  more  acetic  acid  than  cider  vinegar,  but 
far  less  residue. 

Malt  Vineg"ar. — In  England,  which  is  neither  a  cider-producing 
nor  a  wine-producing  country,  the  vinegar  in  commonest  use  is  made 
from  a  wort  prepared  from  malt  and  unmalted  grain.  It  is  less  strong 
in  acetic  acid  than  the  vinegars  already  described,  but  commonly  con- 
tains sulphuric  acid,  which,  under  the  English  law,  is  a  permissible 
admixture  to  the  extent  of  not  exceeding  0.10  per  cent. 

Molasses  Vinegar. — A  very  large  part  of  the  domestic  supply 
of  vinegar  is  manufactured  from  fermented  molasses.  It  is  made  to 
imitate  cider  vinegar  in  color,  and  is  sold  commonly  under  the  name 
of  that  article.  It  yields  about  the  same  amount  of  acid,  but  is  very 
deficient  in  residue.  The  latter  has  a  very  bitter  taste,  and  after  com- 
plete ignition  yields  an  ash  containing  no  potassium  salts,  Avhile  that 
from  cider  vinegar  gives  a  decided  indication. 

Spirit  Vinegar. — Spirit  vinegar,  also  known  as  "  Quick  Process  " 
vinegar,  is  made  from  diluted  alcohol.  The  process  used  is  the  same 
as  that  employed  in  the  making  of  malt  vinegar  and  molasses  vinegar. 
A  series  of  suitable  vats  is  constructed  and  filled  with  beech  or  birch 
shavings  or  twigs,  which  by  appropriate  treatment  become  coated  with 
31ycoderma  aceti.  The  alcoholic  liquid  is  allowed  to  percolate  through, 
and  in  its  passage  the  alcohol  is  transformed.  The  temperature  of  the 
room  is  maintained  at  about  70°  F. 

Adulterations  of  Vinegar. — The  principal  adulterations  of  vinegar 
are  the  addition  of  water  and  the  coloring  of  inferior  grades  so  that 
they  may  be  sold  as  cider  vinegar.  Where  laws  are  in  force  establish- 
ing standards  of  acidity  and  residue  for  cider  vinegar,  a  very  common 
fraud  is  the  addition  of  cider  jelly  or  of  a  preparation  made  from  apple 
pomace  to  a  cheap  vinegar  of  the  proper  strength,  colored,  if  necessary, 
with  caramel.  Such  compounds  always  show  but  slight  or  no  reaction 
when  tested  for  malic  acid.  The  addition  of  mineral  acids  is  not  a 
common  practice  in  this  country. 

Examination  of  Vinegar. — Acidity. — To  6  cc.  of  the  specimen 
in  a  porcelain  casserole,  add  a  few  drops  of  phenolphthalein  solution 
and  about  20  cc.  of  distilled  water.  Titrate  with  decinormal  sodium 
hydrate  solution,  adding  little  by  little  until  the  appearance  of  a  faint 
pink  coloration.  The  number  of  cc.  of  the  reagent  used,  divided  by 
10,  equals  the  percentage  of  absolute  acetic  acid. 

Residue. — Evaporate  5  grams  in  an  accurately  ■  weighed  platinum 
dish  to  complete  dryness  over  boiling  water.  After  the  residue  is 
weighed,  it  may  be  ignited  for  its  yield  of  ash. 

Genuine  cider  vinegar  should  give  no  more  than  a  faint  cloudiness 
on  being  tested  with  nitrate  of  silver  and  chloride  of  barium  (absence 
of  more  than  traces  of  chlorides  and  sulphates),  and  should  yield  a 
fairly  cf^pious  pr<!cipitat(!  with  solution  of  subacctate  of  lead  (jirescnce 
of  malic  acid).  The  residue  should  n(jt  taste  bitter  (absence  of  caramel). 
Cid(;r  vinegar  to  which  water  has  been  added  is  likely,  according  to 


204  FOODS. 

the  nature  of  the  water,  to  show  more  than  the  usual  results  on  test- 
ing for  chlorides  and  sulj)hates,  and  to  yield  notable  traces  of  lime. 
Molasses  vinegar  generally  yields  marked  indications  of  lime  salts  and 
a  more  or  less  pronounced  odor  of  rum. 

LEMON  JUICE  AND  LIME  JUICE. 

Lemon  juice  is  the  expressed  juice  of  the  ripe  fruit  of  Citrus  limonum. 
It  is  a  somewhat  turbid  yellowish  liquid,  with  a  very  acid  taste  and  a 
slight  agreeable  odor,  due  in  part  to  the  presence  of  a  small  trace  of 
volatile  oil  from  the  rind.  It  should  contain  about  7  to  10  per  cent, 
of  citric  acid,  and  should  yield  from  0.50  to  1.00  per  ceut.  of  ash.  Its 
specific  gravity  should  be  not  less  than  1.030,  and  is  usually  above 
1.040.  As  it  is  quick  to  undergo  decomposition  in  its  natural  con- 
dition, a  number  of  methods  have  been  proposed  for  its  preservation, 
the  best  of  which  appears  to  be,  first  to  clarify  it  by  means  of  strong 
alcohol,  next  to  filter  or  decant  from  the  precipitated  matters,  and  then 
to  expel  the  alcohol  by  heat.  The  clear  juice  may  then  be  bottled  and 
sterilized. 

Lime  juice  is  the  expressed  juice  of  the  sour  lime.  Citrus  acida,  and 
of  the  sweet  lime,  C.  limetta.  It  contains  usually  somewhat  less  acid 
than  lemon  juice,  and  has  a  lower  specific  gravity.  It  is  preserved  by 
the  same  method. 

As  antiscorbutics,  lemon  juice  and  lime  juice  are  of  about  equal  value,, 
and  far  superior  to  vinegar. 

Adulteration. — Lemon  juice  is  much  more  subject  to  adulteration 
than  lime  juice,  but  both  are  falsified  and  imitated  extensively.  In 
fact,  it  would  not  be  overstating  tlie  case  to  say  that  by  far  the  larger 
part  of  the  lemon  juice  sold  in  this  country  is  wholly  factitious.  Com- 
monly, it  is  nothing  more  than  an  aqueous  solution  of  citric  acid  ;  some- 
times, it  is  flavored  with  oil  of  lemon.  Its  taste  is  much  sharper  and 
less  agreeable  than  that  of  the  genuine  article.  The  residue  is  very 
diiferent  in  character  and  appearance,  and  leaves  practically  no  ash  on 
ignition.  Other  acids  are  used  sometimes  in  place  of  or  in  addition  to 
citric  acid.  The  one  most  commonly  employed  is  said  to  be  tartaric  ; 
this  is  detected  readily  by  the  gradual  formation  of  bitartrate  of  potas- 
sium on  addition  of  the  acetate.  The  mineral  acids  are  said  to  be  added 
not  infrequently ;  they  are  detected  without  difficulty  by  the  common 
tests. 

SALT. 

The  best  grades  of  common  salt  are  white,  dry,  free  from  dirt,  and 
completely  soluble  in  water.  Many  specimens  of  good  quality  contain 
traces  of  chloride  of  magnesium,  which  causes  caking.  In  humid 
weather,  even  the  best  grade  of  salt  absorbs  moisture  sufficient  in 
amount  to  cause  it  to  lose  its  dry,  powdery  nature.  The  addition 
of  about  10  per  cent,  of  corn  starch  serves  to  keep  it  dry  and  pow- 
dered. 


CLOVES.  205 


MUSTARD. 


Mustard  is  the  flour  of  the  seed  of  the  black  and  the  white  mustard, 
Sinapis  niger  and  S.  alba.  The  first  mentioned  is  much  the  more  pun- 
gent of  the  two ;  on  being  wet  with  water,  a  volatile  oil  is  developed 
from  two  of  its  constituents.  The  white  mustard  yields  no  volatile 
oil  by  this  treatment,  but  develops  an  acrid  principle.  Both  varieties 
of  seeds  contain  a  bland  fixed  oil  to  the  extent  of  20—25  per  cent.  As 
this  adds  nothing  to  the  flavor,  makes  grinding  more  difiicult,  and 
exerts  an  injurious  influence  on  the  keeping  qualities,  it  is  removed 
from  the  whole  seeds  by  pressure. 

Mustard  is  largely  subject  to  adulteration  with  wheat,  rice,  and  corn 
ilour,  with  the  farther  addition  of  turmeric  to  restore  the  color  lost  by 
■dilution.  These  substances  are  detected  very  easily  by  means  of  the 
jnicroscope.  Furthermore,  since  starch  is  wholly  absent  from  pure 
mustard  flour,  if  a  small  portion  of  a  suspected  sample,  boiled  in  a 
little  water  in  a  test-tube  and  cooled,  gives  a  blue  or  bluish-black 
oolor  on  the  addition  of  compound  iodine  solution,  it  unquestionably  is 
adulterated. 

PEPPER. 

Pepper  is  the  fruit  of  Piper  nigrum,  a  perennial  climbing  shrub. 
The  unripe  berries,  dried  for  several  days  after  being  picked,  are  known 
as  Black  Pepper.  The  ripened  berries,  dried  and  decorticated,  are 
known  as  White  Pepper.  In  the  powdered  form,  in  which  they  are 
retailed  most  commonly,  both  are  adulterated  very  extensively  with 
substances  of  a  harmless  nature.  These  include  ground  shipbread, 
cornmeal,  cocoanut  shells,  rice,  buckwheat,  oatmeal,  mustard  hulls, 
charcoal,  olive  stones,  and  a  variety  of  other  substances  of  little  or  no 
value,  capable  of  being  reduced  to  powder. 

The  simplest  method  of  determining  the  purity  of  this  or  any  other 
form  of  spice  is  to  reduce  a  specimen  of  the  genuine  unground  sub- 
stance to  powdered  form  and  study  its  appearance  under  the  microscope, 
and  then  to  compare  it  with  the  sample  in  question.  Each  kind  has  its 
characteristic  appearance,  and  so  with  a  little  practice  one  is  enabled  to 
determine  very  quickly  the  question  of  purity.  By  a  similar  study  of 
the  microscopic  appearances  of  the  common  adulterants,  these  may 
readily  be  identified  in  the  mixture.  The  chemical  analysis  is  intricate 
and  tedious,  and  not  always  conclusive. 

CLOVES. 

Cloves  are  the  flower  buds  of  Eugenia  caryophyllata,  picked  while 
red  and  dried  in  the  sun.  They  contain  about  16  per  cent,  of  volatile 
oil,  easily  removed  and  of  considerable  value.  In  the  powdered  form, 
cloves  are  adulterated  commonly  with  allspice,  clove  stems,  spent 
cloves,  cocoanut  sliells,  and  other  worthless  matter.  The  presence  of 
sjH'nt  cloves  can  be  d(^tcrmin('d  only  by  estimation  of  the  amount  of 
volatile  oil  present.     Clove  stems  show  micros(!opieally  a  very  large 


206  FOODS. 

proportion  of  the  so-called  stone  cells.     Other  substances  are  detected 
in  the  manner  described  under  Pepper. 

CINNAMON  AND   CASSIA. 

Cinnamon  is  the  inner  bark  of  Cmnamomum  zeylanicum.  Cassia  is. 
the  bark  of  several  species  of  Cinnamomum.  In  the  unground  state^ 
cinnamon  is  thin  and  delicate ;  cassia  is  thick  and  comparatively 
coarse.  Cinnamon  is  the  richer  in  volatile  oil,  and  for  this  reason  and 
because  it  is  found  much  less  abundantly,  is  considerably  more  expen- 
sive than  cassia.  Ground  cinnamon  is  practically  never  found  in  the 
market,  the  substance  sold  under  that  name  being  almost  invariably 
cassia.  The  common  adulterants  of  cassia  include  ground  shipbread, 
nut  shells,  and  cedar  sawdust. 

ALLSPICE  OR  PIMENTO. 

Allspice  is  the  dried  unripe  berries  of  Pimenta  officinalis.  Although 
one  of  the  cheapest  of  spices,  it  is  adulterated  extensively  with  ground 
shipbread,  charcoal,  nut  shells,  clove  stems,  and  mustard  hulls. 

GINGER. 

Ginger  is  the  rhizome  of  Zingiber  officinale.  It  is  one  of  the  most 
commonly  adulterated  of  condiments.  The  substances  used  include 
ground  shipbread,  rice,  mustard  hulls,  cayenne,  turmeric,  cornmeal, 
clove  stems,  and  exhausted  ginger  from  the  manufacture  of  the  tincture. 
It  is  very  rich  in  starch,  which  is  differentiated  easily  from  other 
starches. 

NUTMEG. 

Nutmeg  is  the  inner  kernel  of  the  fruit  of  3Iyristica  fragrans.  It  is 
not  commonly  sold  in  the  powdered  condition,  but  when  so  sold  is. 
generally  adulterated  with  the  substances  used  as  admixtures  of  other 
spices. 

MACE. 

Mace  is  the  dried  membranous  covering,  the  arillode,  of  the  nutmeg. 
It  is  adulterated  with  wild  mace,  cornmeal,  and  other  cheap  materials. 

CAYENNE  PEPPER. 

Cayenne  is  not  a  true  pepper,  but  the  powdered  pods  of  several 
species  of  Capsicum,  including  C.  annuum  and  C.  fastigiatum.  Its 
appearance  under  the  microscope  is  very  characteristic.  The  common- 
est adulterant  is  cornmeal.  Among  others  are  rice,  mustard  hulls, 
turmeric,  and  ground  shipbread. 

BAKING  POWDERS. 

Baking  powders,  like  condiments,  are  in  no  sense  foods,  but  being 
employed  in  the  preparation  of  bread,  in  which  are  retained  the  ulti- 


BAKING  POWDERS.  207 

mate  products  of  the  reactions  of  their  component  parts  upon  each 
other,  they  are  of  hygienic  interest.  They  are  employed  for  the  produc- 
tion, within  a  short  time,  of  a  result  which,  when  caused  by  the  action 
of  yeast,  is  only  slowly  brought  about ;  namely,  the  leavening  of  bread. 
Yeast  produces  the  leavening  gas,  carbon  dioxide,  through  slow  fermenta- 
tion of  a  part  of  the  carbohydrates  ;  while  with  the  use  of  baking 
powders,  this  gas  is  disengaged  as  a  result  of  chemical  action  of  one  of 
the  constituents  upon  another  in  the  presence  of  moisture,  and  chemical 
substances  foreign  to  yeast-leavened  bread  are  left  as  a  residuum  in  the 
bread.  Whether  this  residuum  is  objectionable  on  the  score  of  its  in- 
fluence upon  the  system,  depends  upon  the  nature  of  the  ingredients  of 
the  powder ;  but  aside  from  the  question  of  disadvantage  or  inferiority 
on  this  account,  it  is  a  fact,  generally  acknowledged,  that  bread  made 
with  baking  powder  is  lacking  in  a  certain  agreeable  flavor  developed 
by  the  action  of  yeast. 

Baking  powders  are  combinations  of  an  acid  or  acid  salt  with 
sodium  bicarbonate  in  about  the  proper  proportions  for  chemical  union, 
together  with  an  amount  of  starch  sufficient  to  keep  the  ingredients  in 
a  dry  state,  and  hence  mutually  inactive.  When  the  combination  is 
introduced  directly  into  the  flour,  and  water  is  added  to  make  the  dough, 
the  reaction  occurs  and  carbon  dioxide  is  set  free.  They  are  known, 
according  to  the  nature  of  the  acid  salt,  as  tartrate,  phosphate,  and  alum 
powders.  Tartrate  powders  are  made  usually  with  "cream  of  tartar" 
(potassium  bitartrate),  but  occasionally  with  tartaric  acid,  which  is  not 
only  more  expensive,  but  is  objectionable  from  a  practical  standpoint 
on  account  of  its  readier  solubility,  which  causes  a  too  rapid  evolution 
of  gas.  The  reaction  which  occurs  between  potassium  bitartrate  and 
sodium  bicarbonate  has,  as  results,  carbon  dioxide,  water,  and  potas- 
sium sodium  tartrate,  or  "  Rochelle  salt "  ;  as  follows  : 

KHC,H406+NaHC03=KNaC4H,06+C02+H20. 

The  commercial  advocates  of  other  kinds  of  powders  dwell  upon  the 
undesirability  of  aperient  substances  in  bread,  but  the  residuum  of 
Rochelle  salt  in  the  amount  of  bread  which  one  could  eat  in  a  day 
would  be  very  much  under  the  minimum  dose  from  which  any  results 
could  be  expected. 

Cream  of  tartar,  as  retailed,  is  adulterated  very  commonly  with  gyp- 
sum, chalk,  alum,  and  starch  ;  but  as  furnished  to  the  manufacturer  by 
the  refiners,  it  contains  but  a  very  small  percentage  of  a  normal  im- 
purity, tartrate  of  calcium.  The  usual  chemical  tests  and  microscopic 
examination  reveal  fraudulent  adulteration  very  quickly.  Good  speci- 
mens contain  at  least  94  per  cent,  of  bitartrate ;  and  2  decigrams, 
dissolved  in  hot  water  and  titrated  with  decinormal  sodium  hydrate, 
require  for  complete  neutralization  not  less  than  10  nor  more  than  10.6 
cc.  The  presence  of  a  small  amount  of  tartrate  of  calcium  is  of  no 
sanitary  importance  whatever,  statements  to  the  contrary  in  advertising 
matter  notwithstanding. 

The  phosphate  powders  are  made  with  acid  phosphate  of  calcium, 


208  FOODS. 

which  contains  ordyiarily  more  or  less  sulphate  as  a  natural  impurity. 
The  reaction  with  sodium  bicarbonate  is  expressed  as  follows  : 

CaH^CPO,)^  +  2NaHC03  =  CaHPO^  +  NaaHPO,  +  200^  +  2H2O. 

There  is  no  well-grounded  objection  to  the  use  of  this  class  of 
powders. 

Alum  powders  are  made  usually  with  soda  alum  and  a  very  large 
amount,  frequently  as  high  as  50  per  cent.,  of  starch  "  filling."  Their 
leavening  power  is  almost  invariably  far  below  that  of  tartrate  and 
phosphate  powders  of  good  quality.  The  cheapest  class  of  powders, 
the  sale  of  which  is  promoted  by  gifts  or  "  premiums "  of  cheap 
crockery  and  glass,  are  made  with  alum  and  the  maximum  amount  of 
filling.  The  reaction  between  alum  and  sodium  bicarbonate  is 
€xpressed  as  follows  : 

Na,Al2(SOj4  +  eXaHCOj  =  AlAHg  +  4Na2SO,  +  GCOj. 

Whether  the  alum  exerts  any  injurious  effect  upon  the  bread  itself, 
and  whether  the  resulting  hydrate  or  any  excess  of  alum  has  any  sani- 
tary importance,  are  questions  which  have  been  the  subject  of  extensive 
controversy.  Without  reproducing  the  arguments  and  claims  of  both 
sides,  it  should  be  said  that  the  weight  of  scientific  evidence  is  decidedly 
against  the  employment  of  alum  in  the  making  of  bread.  Some  of 
those  who  believe  alumina  to  be  harmless  in  the  amounts  consumed, 
regard  powders  containing  both  alum  and  potassium  bitartrate  as  highly 
objectionable,  the  complete  precipitation  of  alumina  being  prevented. 
Powders  containing  alum  and  acid  phosphate  are  held  also  to  be  objec- 
tionable, on  account  of  the  formation  of  aluminum  jjhosphate,  M'hich  is 
supposed  to  inhibit  gastric  digestion. 

In  addition  to  sodium  bicarbonate,  ammonium  carbonate  is  used 
more  or  less  as  a  source  of  leavening  gas.  While  this  agent  when 
administered  therapeutically  may  exert  a  marked  temporary  influence, 
the  amount  used  in  baking  powders  is  too  small  to  be  hurtful  to  the 
system. 

The  amount  of  starch  filling  used  in  making  baking  powders  is  very 
variable.  The  best  grades  contain  considerably  under  20  per  cent., 
and  anything  over  that  amount  may  rightly  be  regarded  as  in  the 
nature  of  unnecessary  and  fraudulent  dilution. 

Section  7.     FOOD   PRESERVATION. 

Foods  of  a  perishable  nature  are  preserved  in  many  different  ways, 
but  not  all  methods  are  equally  applicable  to  all  foods.  Thus,  freezing 
and  salting,  while  well  suited  to  meats  and  fish,  can  hardly  be  employed 
M^ith  fruit  and  vegetables ;  and  preservation  in  sugar  syrup,  while  well 
adapted  to  fruits,  is  not  suited  to  meats.  The  methods  in  general  use 
include  the  employment  of  low  temperatures,  desiccation,  salting, 
smoking,  canning,  and  chemical  treatment. 


FOOD  PRESERVATION.  209 

Cold. — For  the  best  results  of  preservation  by  cold  it  is  not  always 
essential  that  the  food  shall  be  frozen  ;  but  unless  the  temperature  to 
which  it  is  exposed  is  near  or  below  the  freezing-point,  the  influence  is 
only  temporary.  Packing  in  ice  serves  very  well  for  short  periods  to 
ship  meats  and  fish  through  long  distances,  and  to  keep  them  in  satis- 
fiictory  condition  for  reasonable  periods  in  the  homes  of  the  consumers. 
There  are  several  methods  of  applying  cold  on  a  large  scale  in  cold- 
storage  warehouses,  ocean  steamers,  and  public  markets,  the  principal 
one  being  known  as  the  ammonia  process,  by  means  of  which  any 
desired  temjDerature  down  to  0°  F.  may  be  obtained  with  but  slight 
fluctuation,  provided  the  walls,  floor,  and  roof  of  the  space  occupied 
are  rendered  non-conducting  by  hair-felt,  air  spaces,  and  other  means. 
Meats  and  fish  are  preserved  indefinitely  and  without  deterioration  when 
frozen,  but  should  not  be  allowed  to  thaw  and  freeze ;  eggs  and  fruits 
may  be  kept  many  months  in  dry  air  at  just  above  the  freezing-point. 

The  advantages  of  cold  as  a  preserving  agent  are  that,  unlike  any 
other,  it  involves  neither  the  abstraction  of  any  constituent  of  the  food 
nor  the  addition  of  any  foreign  matter ;  it  neither  imparts  a  new  taste 
nor  alters  the  natural  flavor ;  it  causes  neither  a  loss  of  nutriment  nor 
diminished  digestibility ;  and  on  the  withdrawal  of  its  influence  the 
material  is  left  in  its  original  condition.  It  should  be  said,  however, 
that  after  restoration  to  the  natural  condition,  the  keeping  qualities 
appear  to  be  somewhat  impaired,  and  in  consequence  the  material 
should  be  used  within  a  shorter  time  than  is  the  case  with  similar  fresh 
food  that  has  not  been  frozen. 

Drying'. — Drying  is  efficient  according  to  the  thoroughness  of  the 
process.  The  method  is  not  so  well  adapted  to  meats  as  to  vegetables, 
since  it  leads  to  more  or  less  loss  of  the  natural  flavors,  which  are  likely 
to  be  replaced  by  others  less  agreeable  in  character.  Dried  meats  are, 
moreover,  considerably  less  digestible  than  fresh  meats.  When  thor- 
oughly dried  and  properly  stored,  both  meats  and  vegetable  products 
oan  be  kept  without  limit  of  time.  Drying  does  not  insure  safety 
against  parasites. 

Salting". — In  the  process  of  salting,  the  soluble  organic  constituents 
of  meat  and  fish  are  removed  in  large  part,  and  the  fibers  become 
hardened.  The  nutritive  value  and  digestibility,  therefore,  are  dimin- 
ished correspondingly.  Brine  salting  of  fish  is  one  of  the  oldest  proc- 
esses of  preservation  known. 

Smoking. — Smoking  consists  in  exposing  the  meat  or  fish  to  the 
action  of  the  smoke  of  wood  fires  after,  as  a  rule,  a  preliminary  salt- 
ing. The  exposed  material,  already  deprived  of  part  of  its  natural 
moisture,  becomes  dried  still  farther,  and  is  partly  penetrated  by  acetic 
acid,  creosote,  and  other  preservative  elements  of  smoke.  In  the 
quick  smoking  ])roc(?ss,  the  meat  is  brushed  over  witli  or  dipped  into 
pyroligiK'ous  acid  at  definite  intervals,  and  finally  dried  in  the  air. 

Canning. — In  1  804,  M.  Appert,  of  Paris,  discovered  that  meats  and 
other  foods  in  sealc^d  vessels  .would  kec))  ind(!finitely,  if,  after  being 
sealed,   they  were  kept  for  an  hour  in   boiling  water.     In   1810,  he 

14 


210  FOODS. 

introduced  the  method  of  sealing  the  vessel  after  the  heating  process 
has  driven  out  the  air  and  replaced  it  with  steam,  so  that  when  cooled 
a  vacuum  is  formed.  At  the  present  time,  the  chief  method  followed 
is  to  pack  the  cans  full  and  close  them  completely,  excepting  a  small 
hole,  then  to  subject  them  to  the  temperature  of  boiling  water,  or 
higher,  and  to  close  the  hole  with  solder.  They  are  then  reheated  and 
finally  allowed  to  cool. 

Much  has  been  said  for  and  against  this  method  of  preserving  foods. 
The  chief  objections  have  been  that  the  natural  acids  of  the  foods  may 
corrode  the  inner  surface  of  the  cans  and  form  metallic  salts,  and  that 
terne  plates,  that  is  to  say,  sheet  iron  or  steel  coated  with  an  alloy  of 
two  parts  of  lead  to  one  of  tin,  may  be  used  instead  of  the  best  quality 
of  tin  plates.  As  to  the  latter  objection,  while  there  is  in  this  country 
no  legal  restriction  as  to  the  character  of  the  tin  employed,  it  is  a  fact 
that  terne  plates  are  never  used.  With  regard  to  the  possibility  of 
corrosion  of  the  metallic  surface,  it  must  be  admitted  that  not  only  the 
very  acid  foods,  but  even  those  which  are  neutral  and  even  alkaline  in 
reaction,  almost  invariably  will  yield  traces  of  tin  ;  but  there  is,  at  the 
same  time,  absolutely  no  evidence  that  the  small  amount  present  in  the 
entire  contents  of  a  can  is  capable  of  causing  the  slightest  injury. 

There  are,  it  is  true,  numerous  cases  of  poisoning  reported  as  due  to 
metallic  contamination  of  canned  foods,  but  not  one  of  those  which 
have  fallen  under  the  view  of  the  author  will  stand  the  test  of  exclu- 
sion of  other  possible  and  more  probable  causes.  Of  the  small  amounts 
of  tin  found  in  canned  foods,  Professor  Attfield  says  that  they  are 
undeserving  of  serious  notice,  and  he  questions  that  they  represent  the 
amount  regidarly  worn  oif  of  tin  saucepans  and  kettles.  Furthermore, 
it  is  the  nearly  unanimous  opinion  of  writers  of  works  on  toxicology 
that  the  only  compounds  of  tin  that  are  in  any  way  poisonous  are  the 
chlorides,  and  even  these  are  ignored  completely  by  most  of  the  lead- 
ing authorities. 

On  the  other  hand,  there  is  no  limit  to  the  testimony  regarding  the 
very  great  value  of  canned  foods,  especially  in  military  operations  on  a 
large  scale,  and  in  expeditions  of  various  kinds  away  from  market  cen- 
tres and  other  sources  of  supply.  Lieutenant  Greely,  Dr.  Nauseu,  and 
other  Arctic  explorers  are  unanimous  in  their  praise.  Greely,  for  ex- 
ample, says  :  "  No  illness  of  any  kind  occurred  prior  to  our  retreat,  and 
those  most  inclined  to  canned  fruits  and  vegetables  were  the  healthiest 
and  strongest  of  the  party."  Lord  AVolseley,  in  speaking  of  their  use- 
fulness in  hot  climates,  says  that  "  tinned  provisions,  meat  or  vegetables 
put  up  separately  or  combined  in  the  form  of  soups,  are  practically  un- 
damageable  by  any  climatic  heat "  provided  they  are  of  the  best  quality 
and  have  been  properly  cooked  and  enclosed  in  perfectly  sound  air- 
tight tins.  "  Given  these  conditions,  nothing  can  be  more  admirable  ; 
failing  them,  nothing  more  deleterious."  In  military  operations  in  the 
tropics,  where  beef  cattle  cannot  be  taken  along  on  the  hoof  and  re- 
frigerated beef  cannot  be  transported  overland  on  account  of  speedy 
decomposition,  canned  meats  are  indispensable. 


FOOD  PRESERVATION.  211 

How  long  properly  canned  foods  will  remain  in  good  condition,  can 
hardly  be  determined,  but  the  evidence  at  hand  points  to  indefinite 
preservation.  In  1824,  according  to  Letheby,  a  number  of  tins  of 
mutton  were  cast  ashore  from  the  wreck  of  a  ship  at  Prince's  Inlet ;, 
eight  years  later,  they  were  found  by  Sir  John  Hoss,  and  those  which 
he  opened  were  in  good  condition,  although  exposed  during  this  time 
to  alternate  freezing  and  thawing.  Sixteen  years  afterward,  they  again 
were  found  by  men  from  the  ship  Investigator  ;  and  in  1868,  forty-four 
years  from  the  time  they  were  cast  ashore,  the  remaining  tins,  opened 
by  Letheby,  were  found  to  be  in  a  perfectly  sound  state.  Tyndall ' 
makes  mention  of  tins  in  the  Hoyal  Institution  that  had  remained  irt 
good  condition  sixty-three  years. 

Professor  A.  H.  Chester,  of  Hamilton  College,  relates  that  in  the 
summer  of  1875  he  hid  a  number  of  cans  of  corned  beef  under  a 
stump  in  woods  in  the  northern  part  of  Minnesota,  and  five  years  later 
found  them  to  be  perfectly  sweet,  although  they  had  been  exposed  to 
the  heat  and  cold  of  five  successive  summers  and  winters.  Again,  a 
number  of  cans  of  meat  and  fruit,  washed  into  the  Genessee  River  in 
1865,  were  dug  out  of  the  mud  sixteen  years  later,  and  found  to  be 
unaltered. 

It  is  an  unfortunate  fact  that  the  cupidity  of  some  of  our  largest 
packing-houses  has  led  to  the  canning  of  what  is  practically  refuse 
meat,  from  which  the  constituents  to  which  the  desirable  flavors  are 
due  have  been  extracted,  and  that  in  consequence  the  public  mind  has 
largely  become  imbued  with  a  prejudice  against  canned  meats  in  gen- 
eral. But  it  is  not  alone  in  this  country  that  canned  meats  are  some- 
times not  what  they  purport  to  be.  It  is  related  that  in  France,  in 
1899,  a  packer  of  meats  was  sentenced  to  pay  a  fine  and  to  serve 
eight  months  in  prison  for  putting  upon  the  market  an  immense  amount 
of  canned  game  and  poultry,  all  of  which  had  been  made  from  the 
flesh  of  broken-down  cab  horses. 

Chemical  Treatment. — Chemical  preservatives  are  substances  or 
combinations  added  to  foods  with  the  object  of  delaying  or  preventing 
their  decomposition.  They  are  used  on  the  assumption  that,  while 
they  accomplish  the  desired  object,  they  are  incapable  of  exerting  any 
harmful  influence  upon  the  system  of  the  consumer — an  assumption 
that  has  not  been  demonstrated  as  based  on  sound  reasoning.  It  is 
assumed  that  bad  effects  cannot  be  caused,  because  they  are  not  mani- 
fested at  once  after  the  ingestion  of  small  doses  by  persons  in  good 
health  ;  but  this  is  no  proof  that  continued  use  may  not  result  in  serious 
trouble  which  may  be  referred  to  some  other  possible  cause. 

It  is  said  that  the  preparations  employed  are  in  common  use  as 
valuable  remedies  in  the  treatment  of  the  sick;  but  it  should  be  taken 
into  consideration  that,  when  used  as  rem(;dies  in  morbid  conditions, 
they  are  given  for  only  a  limited  time,  for  the  pur])ose  of  countera(!tiiig 
abnormal  influences,  and  that  the  doses  are  regulated  carefully  under 
proper  professional  supervision.  Their  action  in  conditions  of  health 
'  l'"l(j;itiiig  Mattei-H  in  tlie  Air,  New  York,  1882,  p.  293, 


212  FOODS. 

and  disease  may  be  very  different ;  but  wlietber  so  or  not,  one  can  find 
no  excuse  for  the  ingestion  of  curative  remedies  by  a  person  in  a 
state  of  health,  whose  system  needs  no  such  aid,  for  indefinite  periods 
and  with  no  regulation  of  the  size  of  the  dose.  Salicylic  acid,  for 
example,  is  a  remedy  holding  a  high  position  in  the  treatment  of  rheu- 
matism, but  its  value  in  this  condition  is  no  valid  excuse  for  its  admin- 
istration day  in  and  day  out  to  those  who  never  have  felt  the  twinges 
and  pain  of  this  disease.  It  is  much  more  reasonable  to  assume  that 
drugs  which  exert  a  powerful  influence  for  good  in  morbid  states  will 
exert  an  equal  degree  of  influence  for  harm  in  conditions  of  health. 
Moreover,  it  is  to  be  considered  that  the  object  of  chemical  treatment 
of  foods  is  not  to  benefit  the  unconscious  consumer,  but  to  bring  the 
largest  possible  financial  return  to  the  manufacturer  and  purveyor,  to 
whom  the  health  of  the  consumer  may  be  a  matter  of  little  concern. 
In  all  fairness  to  the  consumer,  chemically  preserved  foods  should  be  so 
labelled  that  the  purchaser  may  be  informed  of  the  nature  and  amount  of 
the  added  substance,  so  that  those  who  object  to  the  dietetic  use  of  drugs 
may  not  have  the  same  forced  upon  them  without  their  knowledge. 

The  addition  of  preservatives  to  foods  offered  for  sale  is  forbidden  in 
almost  all  civilized  countries,  and  several  governments  have  enacted  laws 
specially  directed  against  individual  drugs.  Thus,  France  names  boric 
acid,  borax,  salicylic  acid,  and  sodium  bisulphite ;  Austria  names  sali- 
cylic acid  ;  Germany  prohibits  all  antiseptics,  and  especially  boric  acid 
and  borates,  and  imposes  additional  penalties  for  the  sale  of  chemically 
preserved  foods  to  the  navy.  Massachusetts  prohibits  all  preservatives 
except  salt,  sugar,  niter,  vinegar,  and  alcohol,  unless  the  purchaser  is 
informed  of  the  nature  of  the  substance  used.  In  milk,  all  preserva- 
tives whatsoever  are  prohibited  unconditionally. 

The  substances  used  as  chemical  preservatives  include  boric  acid 
and  borax,  salicylic  acid,  sulphurous  acid,  sulphites  and  sulphates, 
benzoic  acid,  formaldehyde,  hydrogen  peroxide,  sodium  fluoride,  and 
others  of  minor  importance.  Many  of  the  commercial  preparations  in 
common  use  are  combinations  of  two  or  more  of  these  and  other  sub- 
stances. Thus,  Venzke  and  Schorer  ^  report  the  ingredients  of  38  meat 
preservatives,  analyzed  by  them,  as  follows  :  Salt,  sugar,  and  saltpeter, 
(1);  salt  and  sodium  sulphite  and  sulphate  (4);  sodium  sulphite  and 
sulphate  (4) ;  the  same,  plus  sugar  and  salt  (1) ;  salt  and  sodium  bi- 
carbonate and  nitrate  (1) ;  salt,  boric  acid,  saltpeter,  and  sodium  sul- 
phate (3) ;  salt,  boric  acid,  and  sodium  sulphate  (1) ;  salt,  boric  acid, 
gypsum,  and  sodium  sulphate  (1) ;  salt  and  boric  acid  (6) ;  salt,  salt- 
peter, sodium  and  calcium  sulphates,  and  cochineal  (1) ;  salt  and  borax 
(1) ;  salt,  borax,  and  saltpeter  (2) ;  salt,  borax,  and  sodium  nitrate  (2) ; 
salt,  borax,  sodium  and  calcium  sulphates,  and  salicylic  acid  (1) ;  borax 
and  sugar  (2).     The  rest  consisted   of  single  substances. 

A  large  proportion  of  24  meat  preservatives  examined  by  Kammerer 
were  found  to  be  mixtures  of  borax  and  boric  acid,  and  borax  and  so- 
dium sulphite  ;  31  others  examined  by  Kionka  were,  as  a  rule,  sodium 
1  Deutsche  Fleischerzeitunff,  1893,  XXI.,  Nos.  20,  21,  and  24. 


FOOD  PRESERVATION.  213 

sulphite  and  sulphate,  but  14  liquid  preparations  consisted  chiefly  of 
calcium  sulphite  and  sulphate,  and  sodium  sulphite,  bisulphite,  and  sul- 
phate. Kirchmaier  has  reported  one  as  consisting  of  salicylic  acid 
and  sodium  salicylate  and  phosphate.  Polenske  found  boric  acid 
(about  60  per  cent.),  saltpeter  (about  12—14  per  cent.),  sugar,  salt,  and 
sodium  salicylate  (about  7.50  per  cent.)  in  a  specimen  of  sausage  salt, 
and  in  a  number  of  other  preparations  sold  under  fancy  names.  Of  7 
other  meat  preservatives  examined  by  him,^  one  contained  salt,  sodium 
sulphite  and  sulphate,  iron  chloride,  and  vanillin,  and  the  rest  were 
combinations  already  described. 

A.  C.  Chapman  ^  has  reported  a  most  extraordinary  combination  of 
aluminum  sulphate,  salt,  sodium  nitrate,  benzoic  acid,  iodic  acid,  sul- 
phurous acid,  and  chloral. 

Another,  examined  by  Tollner,  proved  to  be  ammonium  bromide, 
boric  acid,  borax,  and  sugar.  Another,  known  as  "  Mayol,"  contained 
wood  alcohol,  ethylic  alcohol,  boric  acid,  ammonium  fluoride,  and  glyc- 
erin. Meats  preserved  by  means  of  it  are  said  to  show  no  trace  of 
boric  acid  or  ammonium  fluoride  beneath  the  brown  coating,  which 
forms  to  a  depth  of  a  millimeter. 

In  this  country,  the  favorite  mixture  is  one  of  borax  and  boric  acid, 
and  this  is  sold  under  many  different  names. 

Boric  Acid  and  Borax. — These  substances  generally  are  used  together, 
for  the  reason  that,  although  the  acid  has  greater  power  as  an  antiseptic 
than  the  salt,  the  combination  of  the  two  is  still  more  efficient.  It  is 
used  very  largely  in  butter  to  the  extent  of  about  a  tenth  of  an  ounce 
to  the  pound,  and  is  dispensed  with  a  generous  hand  in  oysters,  clams, 
and  other  fish,  in  sausages  and  other  meat  products,,  and  in  milk. 

With  regard  to  the  effects  of  boric  acid  and  borax  on  the  system, 
there  is  a  decided  difference  of  opinion  among  those  who  have  investi- 
gated the  subject,  but  it  should  be  said  that  a  number  of  the  reports 
favorable  to  the  use  of  these  agents,  published  by  commercial  houses, 
suggest  that  the  conclusions  arrived  at  were  inspired  somewhat  by 
financial  considerations.  Our  knowledge  of  possible  ill  effects  is  de- 
rived chiefly  from  the  clinical  experience  of  those  who  have  used  the 
drugs  internally  and  as  washes  and  injections.  It  is  a  fact  that  many 
patients  can  take  large  doses  of  both  substances  for  long  periods 
with  no  apparent  harm,  but  it  is  equally  true  that  small  doses  and 
local  applications  have  been  a  frequent  cause  of  serious  and  even  fatal 
results.  Deaths  have  been  reported  from  the  use  of  5  per  cent,  solu- 
tions in  washing  out  the  pleural  cavity  and  lumbar  abscesses,  and 
from  washijig  out  a  stomach  with  a  solution  of  half  that  strength. 
Numerous  cases  of  troublesome  cutaneous  eruptions  and  of  serious 
gastro-intestinal  disturbances  following  internal  and  external  use  have 
been  re])orted  within  recent  years.  Plant '^  has  shown  that  internal  use 
may  be  followed  by  acute  parenchyma  tons  nephritis,  and  his  conclusions 
have  been  endorsed  by  the  experience  of  Fere,  mentioned  below. 

*  Arbeiten  aus  dem  kaiserlichen  (ieHuiulheitsamte,  Vlff.,  p.  686. 

*  AnalyHt,  Dec,  1898.  '  I lui  11^111-1 1  (lisscr(;ilion,  Wiirzhui'^',  1889. 


214  FOODS. 

In  1876,  the  admixture  of  borax  to  butter  was  sanctioned  officially 
in  France ;  but  seven  years  later,  a  committee  of  scientists,  who  in- 
vestigated the  matter  with  great  care,  concluded  that  continued  inges- 
tion is  likely  to  cause  deterioration  of  the  blood  corpuscles ;  and  when, 
somewhat  later,  this  finding  was  confirmed  by  the  investigations  of 
Pouchet,  the  use  of  borax  was  prohibited  by  the  government,  not  only 
in  butter,  but  in  all  articles  of  food.  In  1 891,  the  subject  was  presented 
by  the  Kensington  Vestry  to  Sir  Andrew  Clark,  Sir  Henr}"  Thompson, 
and  Professor  Lauder  Brunton,  who  concurred  in  pronouncing  boric  acid 
in  large  doses,  or  in  small  doses  taken  for  long  periods,  as  dangerous  to 
health.  The  Local  Government  Board,  in  1891,  reported  that,  while 
large  doses  are  undoubtedly  injurious,  they  had  not  sufficient  evidence 
to  hold  that  minute  amounts  added  to  foods  can  affect  the  system  harm- 
fully. 

As  is  well  known,  borax  has  been  used  extensively  in  the  treatment 
of  epilepsy  and  other  diseases  of  the  nervous  system.  Professor  H.  C. 
AVood  states  that,  in  his  experience,  the  most  marked  result  from  its 
use  in  this  direction  was  severe  gastro-intestinal  irritation.  Dr.  Fer^  ^ 
Las  given  a  valuable  report  of  his  results  in  the  treatment  of  122  cases 
of  epilepsy  by  this  drug,  which  was  given  in  beginning  doses  of  30 
grains,  increased  to  as  much  as  5  drachms  a  day.  In  more  than  70  per 
<;ent.  of  the  cases,  the  treatment  had  no  beneficial  result ;  in  about 
20  per  cent.,  some  temporary  or  doubtful  improvement  was  seen ; 
and,  in  9  per  cent.,  there  was  distinct  gain.  But  the  great  draw- 
back was  the  frequency  of  toxic  effects  and  the  danger  of  producing 
or  aggravating  lesions  of  the  kidneys,  even  when  given  in  small 
doses.  Among  the  most  common  results  were  loss  of  appetite  and 
burning  pain,  followed  by  nausea  and  vomiting.  Cutaneous  affections 
were  veiy  common,  and  complete  baldness  was  caused  not  infrequently. 
(This  result  has  been  noted  by  many  other  practitioners.)  In  some 
cases,  a  cachectic  condition,  characterized  by  wasting,  a  waxy  tint  of 
the  skin,  puffiness  of  the  face,  and  even  general  oedema,  was  observed. 
In  a  number  of  cases  of  general  oedema,  uraemia  developed  with  some 
suddenness. 

Dr.  Grumpelt  ^  has  reported  a  case  in  which  headache,  nausea,  and 
intense  dryness  of  the  skin  followed  the  use  of  an  injection  containing  a 
tablespoonful  of  boric  acid  to  the  pint.  The  effects  disappeared  with 
cessation  of  the  treatment,  but  came  on  again  with  its  renewal.  Dr.  J. 
J.  Evans  ^  has  found,  as  a  common  result  of  the  continued  use  of  boric 
acid  in  cystitis  and  urethritis,  an  erythema  followed  by  desquamation. 
Internal  doses  of  10  to  20  grains  twice  daily  for  five  weeks  caused  in 
one  instance  total  baldness. 

Experiments  on  man  and  animals,  by  Professors  Mattern,  Forster, 
Chittenden,  and  Schlenker,  have  demonstrated  that  boric  acid  and 
borax  interfere  with  digestion  and  nutrition.  Mattern  reported 
profound  disturbances  in  dogs  after  a  few  daily  doses  of   8  grains  ; 

^  Revue  de  Medecine,  September,  1895. 

=*  British  Medical  Journal,  Jan.  7,  1899.  '  Ibidem,  Jan.  28,  1899. 


FOOD  PRESERVATION.  215 

diarrhoea  and  other  signs  of  gastro-intestinal  irritation,  and  in  some 
instances  even  fatal  results  were  caused.  He  himself  took  30 
grains,  and  suffered  violent  abdominal  pain  and  diarrhoea.  Forster 
and  Schlenker  have  shown  that  doses  of  8  grains  have  a  decided 
effect  in  preventing  absorption  of  nutriment  and  causing  intestinal 
irritation. 

Dr.  Annett,  of  Liverpool,  fed  a  number  of  kittens  with  milk 
containing  20  grains  of  boric  acid  to  the  quart,  and  all  of  them  died 
in  an  emaciated  condition  at  the  end  of   the    third  or  fourth  week. 

As  to  the  effect  of  these  agents  on  the  different  processes  of  diges- 
tion, there  is  no  agreement.  Chittenden,  for  example,  believes  that 
boric  acid  increases  the  digestion  of  proteids,  and  that  even  25  per  cent, 
will  not  check  gastric  digestion  of  egg  albumin.  He  has  noted  also  a 
marked  stimulant  effect  on  pancreatic  digestion  of  proteids  following 
the  use  of  borax.  Leffmann  and  Beam,  and  others,  however,  have 
observed  effects  directly  contrary  to  those  reported  by  Chittenden. 
Chittenden's  first  experiments  were  made  to  determine  the  possible 
influence  of  borax  and  boric  acid  upon  the  processes  of  salivary, 
gastric,  and  pancreatic  digestion.  He  calls  attention  to  the  fact  that 
his  results  throw  no  light  upon  the  influence  of  the  agents  upon  the 
secretion  of  the  digestive  fluids.  He  shows  that  borax  inhibits  the 
action  of  saliva  on  starch,  and  boric  acid  in  small  amounts  increases  it, 
and  also  the  power  of  the  gastric  juice  to  digest  proteids.  Later 
experiments  by  Chittenden  and  Gies  ^  lead  them  to  the  conclusion  that 
the  two  substances  have  no  peculiar  action  on  nutrition,  and  that,  since 
elimination  is  complete  within  thirty-six  hours,  the  possibility  of 
cumulative  action  must  be  very  small,  even  when  moderate  amounts 
are  ingested  daily. 

Tunnicliflfe  and  Rosenheim  ^  concluded,  from  a  series  of  metabolism 
experiments  on  young  children,  that  boric  acid  in  doses  up  to  1  gram 
per  day,  continued  for  some  time,  exerts  no  influence  on  proteid  or 
phosphorus  metabolism,  has  no  effect  on  the  assimilation  of  fat,  and 
exerts  no  inhibitory  effect  on  intestinal  putrefaction  ;  that  borax  in  con- 
tinued doses  of  1.5  grams  may  or  may  not  improve  assimilation  of  fat, 
and  tends  to  increase  intestinal  putrefaction  ;  that  both  boric  acid  and 
borax  are  eliminated  quickly  ;  and  that  neither  will  affect  the  general 
health  and  well-ljeing. 

Halliburton,'*  experimenting  with  borax  and  milk  in  vitro,  found  that 
1  part  of  borax  in  1000  completely  prevents  the  action  of  rennet,  and 
that  smaller  amounts  delay  it. 

On  the  other  hand,  Ijiel:)reich,*  experimenting  with  dogs,  found  that 
neither  borax  nor  l)oric  acid  has  any  influence  on  metabolism  ;  that 
boric  acid  in  saturated  solution  has  no  effect  on  the  mucous  membranes 
of  the  stomach  and  intestine,  while  borax  in  2  per  cent,  solution  has  a 

^New  York  Medii;il  .Jcunml,  Fchniiny  20,  1898. 
2  .Journal  of  TTvKi.-nc,  April,  UK)],  p.  UiK. 

*  Britisli  M<;(liciil  .Journal,  July  7,  lUOO,  j).  1. 

*  Vieiteljaliixsclirift  f'iir  gcii(;li"tlic)ie  Mediein,  1900,  p.  83. 


216  FOODS. 

markedly  injurious  eifect,  though  not  so  much  as  1  per  cent,  of  sodium 
hydrate  or  0.5  per  cent,  of  saltpeter ;  that  5  per  cent,  of  boric  acid  and 
0.25  per  cent,  of  borax  have  no  influence  on  gastric  digestion,  but  0.5 
per  cent,  of  borax  has  slight  inhibitory  action  ;  that  neither  has  any 
effect  on  the  digestion  of  starches  ;  and  that  both  are  eliminated  quickly, 
and  have  no  tendency  to  accumulate  in  the  system. 

During  a  period  of  19  weeks  the  author^  fed  borated  meat  to  6  of 
12  healthy  cats,  which  were  kept  in  separate  cages  under  precisely  sim- 
ilar conditions.  Of  the  other  6,  1  was  kept  as  a  control,  and  5  were 
fed  on  meat  containing  another  kind  of  preservative.  The  average 
daily  dose  of  borax  ranged  from  544  to  857  milligrams.  During  the 
experiment  only  3  of  the  12  cats  showed  any  acute  sickness,  but  they 
were  all  members  of  the  borax  group.  One  of  them  died  at  the  end 
of  the  sixth  week,  but  the  others  recovered  and  were  apparently  well 
w^hen  the  experiment  was  brought  to  a  close.  The  cats  were  killed  and 
all  (including  the  one  that  died)  were  subjected  to  careful  microscopical 
examination.  The  control-cat  showed  no  lesions  whatever,  and  those 
fed  on  non-borated  food  showed  only  slight  and  inconstant  changes  ia 
various  organs  ;  but  the  borax-fed  animals  showed  without  exception 
lesions  of  the  kidneys  of  the  same  general  character,  yet  differing  in 
intensity,  and  analogous  to  those  found  in  subacute  and  chronic  neph- 
ritis in  man.  In  some  cases  the  degeneration  was  of  an  intense  char- 
acter. 

Considering  all  the  evidence,  conflicting  though  it  be,  and  the  many 
reports  of  untoward  results  of  large  and  small  medicinal  doses  and 
from  absorption  of  both  agents  from  local  applications,  it  seems  not 
unreasonable  to  conclude  that  the  daily  ingestion  of  variable  amounts 
in  food  and  drink  by  persons  of  all  ages  cannot  be  wholly  free  from 
objection.  A  very  common  practice  is  the  addition  of  a  mixture  of 
the  two  or  of  either  alone  to  milk,  in  the  proportion  of  1  part  in  50Q 
or  1000  ;  a  pint  will,  therefore,  contain  a  fair-sized  adult  dose,  an 
amount  which,  taken  twice  daily,  or  oftener,  by  a  bottle-fed  child,  can 
hardly  fail  to  have  some  eflect  not  wholly  for  its  well-being. 

Salicylic  Acid. — Salicylic  acid  is  more  efficient  than  borax  and  boric 
acid  as  a  preservative,  but  cannot  be  used  so  generally,  because  of  its 
tendency  to  cause  unpleasant  flavors  in  foods  having  a  bland  taste.  It 
is  used  extensively  in  jams,  jellies,  tomato  catsups,  bottled  beers  (es- 
pecially those  from  Germany),  the  heavy  beers  innocently  consumed  by 
total  abstainers  under  the  name  of  "malt  extracts,"  fruit  juices,  soda- 
water  syrups,  cider,  wines,  and  other  saccharine  preparations,  and  pre- 
served vegetables.  Concerning  its  objectionable  nature  as  an  addition 
to  foods,  there  is  practical  unanimity.  It  not  only  exerts  an  inhibitory 
action  on  digestion,  but  acts  also  as  an  irritant,  especially  to  the  kid- 
neys, by  which  organs  it  is  excreted.  Its  addition  in  any  quantity  to 
articles  of  food  or  drink  is  forbidden  expressly  in  many  European  and 
South  American  countries.  Its  addition  to  beer  and  other  articles  in- 
tended for  export  is  permitted  in  Germany. 

^American  Journal  of  the  Medical  Sciences,  September,  1904. 


FOOD  PRESERVATION.  217 

Sulphites. — Sodium  sulphite  and  bisulphite  and  sulphurous  acid  are 
used  more  or  less  extensively  for  preserving  meat,  beer,  wine,  and  for 
bleaching  vegetables  (especially  asparagus  and  corn),  put  up  in  cans 
and  glass  jars.  Sendtner  has  found  from  26.4  to  482.6  milligrams  of 
sulphurous  acid  in  32  specimens  of  such  vegetables,  and  Kammerer 
and  others  have  reported  amounts  ranging  from  3  to  250  milligrams 
per  liter  in  red  and  white  wines.  The  author^  found  from  0.061  to 
1.225  (average  0.335)  per  cent,  by  weight  of  sodium  sulphite  in  50 
specimens  of  "  Hamburg  steak  "  bought  in  the  markets  of  Boston. 

Kionke  ^  has  shown  that  large  doses  of  sulphites  exert  a  marked  and 
sometimes  fatally  poisonous  action  on  warm-blooded  animals,  and  that 
small  doses,  long  continued,  may  affect  dogs  very  seriously.  The 
author^  fed  a  number  of  cats  for  20  weeks  with  meat  containing  0.20 
per  cent,  of  sodium  sulphite,  which  is  the  amount  recommended  as  a 
preservative,  and  at  the  expiration  of  that  time  the  cats  were  killed 
and  examined.  In  each  case  the  kidneys  showed  extensive  degenera- 
tive changes. 

Sodium  sulphite  is  used  very  commonly  in  sausages  and  chopped 
meat  (Hamburg  steak),  both  as  a  preservative  and  to  cause  the  bright- 
red  color  of  the  fresh  meat  to  be  retained  unaltered.  Chopped  meat 
keeps  its  color  but  a  very  short  time,  and  as  the  purchaser  will  not 
accept  it  when  not  bright  red,  the  vendor  is  driven  to  make  its  appear- 
ance acceptable.  Thus,  the  purchaser,  insisting  upon  having  what  to 
his  eye  is  freshly  chopped  wholesome  meat,  may  be  served  with  stale 
meat  containing  a  most  undesirable  chemical  preservative.  In  1898, 
the  Imperial  Board  of  Health  of  Germany  forbade  the  use  of  sodium 
sulphite  in  foods,  because  of  its  dangerous  properties. 

Formaldehyde. — On  account  of  its  property  of  hardening  tissues,^ 
formaldehyde  does  not  lend  itself  to  general  use  as  a  food  preservative. 
Fish  and  meats  are  rendered  so  hard  by  very  dilute  solutions,  even  1 
to  5,000,  as  to  be  worthless  commercially.  It  is  used  most  com- 
monly in  milk  and  other  liquids,  and  acts  most  efficiently  in  delaying 
and  preventing  decomposition.  Its  use  in  milk  is,  however,  far  from 
commendable,  for  although  efficient  as  a  preservative,  it  alters  the  char- 
acter of  the  proteids,  which  are  thereby  made  less  digestible.  The 
casein,  when  precipitated,  does  not  separate  in  fine  clots,  but  in  tough, 
heavy  curds,  which  yield  only  with  much  resistance  to  pepsin  and 
hydrochloric  acid.  Weigle  and  Merkel  *  have  shown  that  the  proteids 
are  made  much  less  digestible,  and  their  conclusions  are  in  agreement 
with  those  of  most  investigators  of  the  subject.  Bliss  and  Novy,* 
after  a  most  careful  and  exhaustive  inquiry  into  the  effects  of  formal- 
dehyde on  the  digestive  ferments,  found  that  pepsin  and  trypsin  have 
diminished  action  upon  fibrin  which  has  been  altered  by  it  in  very 
weak  solution  ;  that  casein   is  altered  rapidly,  and,  as  a  result,  is  not 

'  Boston  Medical  and  8nif,'ical  .Journal,  May  25,  1904. 
^  Zeitsclirift  fiir  Hygiene  iind  Infectionskrankheiten,  XXII.,  p.  351. 
■'  lujrHcliunf^shorichtc  iibur  Lebensiiiittel,  etc.,  1895.,  II.,  p.  91. 
'Journal  of  Experimental  Medicine,  1899, p.  47. 


218  FOODS. 

coagulated  by  rennet  or,  at  best,  very  slowly,  and  is  not  readily  digested 
by  the  proteolytic  ferments  ;  and  that  pepsin  and  rennet  are  themselves 
not  affected  by  fairly  strong  (4  and  5  per  cent.)  solutions  acting  for 
several  weeks.  Pepsin  was  found  to  be  affected  quickly  by  very 
dilute  solutions,  trypsin  to  be  afPected  according  to  the  amount  of 
organic  matter  present,  and  amylopsin  and  ptyalin  to  be  not  destroyed 
by  very  dilute  solutions.  The  latter,  however,  were  found  to  be  de- 
stroyed by  strong  solutions. 

Halliburton  ^  found  that  0.5  per  cent,  of  formalin  renders  gastric 
digestion  of  fibrin  almost  impossible ;  and  that  0.05  per  cent,  consid- 
erably delays  it.  Its  effects  on  pancreatic  digestion  were  even  more 
marked. 

Tunnicliflfe  and  Rosenheim,^  experimenting  with  young  children, 
found  that,  in  doses  of  1  part  in  5,000  of  milk  or  1  in  9,000  of  total 
food  and  drink,  formaldehyde  exerts  no  appreciable  effect  on  nitrogen 
and  phosphorus  metabolism  or  on  fat  assimilation,  but  in  larger  doses, 
or  long  continued,  it  may  tend  to  diminish  phosphorus  and  fat  assim- 
ilation, on  account  of  its  effect  on  pancreatic  digestion.  With  delicate 
children,  the  1  :  5000  dose  has  a  measurable  deleterious  effect  on  the 
nitrogen,  phosphorus,  and  fat  assimilation,  and  exerts  a  slight  irritant 
action  on  the  intestine.  They  conclude,  however,  that,  as  used,  the 
substance  has  no  influence  on  the  general  health  and  well-being  of 
children.  On  the  other  hand,  feeding  experiments,  conducted  by  Dr. 
Annett  with  kittens,  demonstrated  that,  as  the  amount  mixed  with  the 
milk  was  increased,  the  retarding  action  on  their  development  was 
more  marked. 

Whatever  may  be  the  results  of  experiments  tending  to  show  the 
effects  of  formaldehyde  on  metabolism  and  growth,  everybody  who  has 
occasion  to  handle  even  very  dilute  solutions  can  testify  to  its  irritant 
effects  on  the  skin  ;  and,  this  being  the  case,  it  seems  hardly  reasonable  to 
assert  that  the  much  more  delicate  mucous  membranes  of  the  digestive 
tract  can  be  subjected  to  its  action  and  wholly  escape  injury.  Formal- 
dehyde is  not  generally  regarded  as  a  poison  in  small  doses,  but  a  num- 
ber of  deaths  have  been  attributed  to  its  use  as  a  milk  preservative, 
though  it  should  be  said  that  the  evidence  in  these  cases  will  hardly 
bear  critical  analysis.  One  undoubted  case  of  non-fatal  poisoning  has 
been  recorded  by  J.  Kliiber.^  The  subject  was  a  man  of  forty-seven, 
who  swallowed  some  aperient  water  into  which  formalin  had  been  intro- 
duced accidentally  He  lay  for  a  long  time  in  a  state  of  coma,  and 
had  anuria  nineteen  hours.  Formic  acid  was  eliminated  in  the  urine 
during  recovery. 

Hydrogen  Peroxide. — This  agent  is  recommended  as  the  least  danger- 
ous of  all  chemical  preservatives,  and  is  believed  by  some  to  exert  no 
deleterious  effect  whatever.  It  is  well  adapted  for  use  in  wine,  beer, 
and  fruit  juices.     One  part  in  1,000  is  said  to  prevent  entirely  the 

'  Loco  citato. 

^  Journal  of  Hygiene,  July,  1901,  p.  321. 

^  Miinchener  medicinische  Woclienschrift,  October  9,  1900. 


CONTAMINATION  OF  FOODS  BY  METALS.  219 

alcoholic  fermentation  of  glucose  solutions,  and  in  somewhat  larger 
amounts  to  prevent  the  formation  of  lactic  acid  in  milk. 

Sodium  Fluoride. — So  far  as  is  known,  sodium  fluoride  exerts  no 
poisonous  action,  but  its  eifect  on  digestion  has  not  been  studied  thor- 
oughly. Perret  ^  asserts  that  it  has  a  decided  influence  in  inhibiting  the 
■development  of  lactic  and  butyric  ferments.  Using  himself  and  a 
number  of  dogs,  he  undertook  a  series  of  feeding  experiments,  and 
concluded  therefrom  that  the  salt  is  in  no  way  poisonous,  and  may  be 
used  without  danger  as  a  food  preservative.  Specimens  of  milk  con- 
taining 3  parts  in  1,000  and  kept  at  38°  C,  remained  unchanged  long 
after  the  controls  had  become  coagulated.  A  dozen  tubes  of  milk  con- 
taining it,  and  planted  with  butyric  ferment,  and  another  dozen  con- 
taining untreated  milk  similarly  planted,  were  kept  side  by  side  at  38° 
C  ;  on  the  day  following,  the  latter  were  coagulated,  but  the  former 
were  unchanged.  Subcutaneous  injections  of  the  salt  to  the  extent  of 
0.08  gram  per  kilogram  of  weight  caused  in  a  dog  slight  salivation  and 
diuresis ;  but  larger  doses  caused  marked  salivation,  diuresis,  thirst, 
and  refusal  of  food.  Intravenous  injections  of  0.10  per  kilogram  caused 
immediate  rise  of  pulse  and  respiration,  followed  by  abundant  saliva- 
tion, nausea,  convulsions,  and  death  in  thirty-five  minutes.  LeiFmann 
and  Beam  ^  have  noted  that  sodium  fluoride  interferes  but  little  with 
the  digestion  of  starch. 

Sodium  fluoride  appears  to  be  weak  as  a  general  preservative,  but 
prevents  alcoholic  fermentation  completely  when  present  to  the  extent 
of  1  part  in  2,000.  The  fluorides  and  hydrochloric  acid  are  used  by 
some  brewers  for  the  prevention  of  undesired  fermentations. 

Sodium  Bicarbonate. — This  agent  seems  to  be  as  little  objectionable 
as  any,  but  it  is  very  weak  in  its  preservative  action  and  is  too  ineffec- 
tive for  general  use.  It  is  used  somewhat  in  Sweden  in  conjunction 
with  sugar  for  meat  and  fish.  A  more  common  use  is  to  overcome 
beginning  acidity  of  milk ;  against  this  is  urged  the  possibility  of 
purgative  effects  in  infants,  through  the  sodium  lactate  produced. 


Section  8.     CONTAMINATION  OF  FOODS  BY  METALS. 

Not  infrequently,  small  amounts  of  metallic  salts  are  present  in 
foods,  either  through  accident  or  by  reason  of  intentional  admixture 
for  some  definite  end.  The  most  common  are  compounds  of  copper 
and  of  lead,  and  these  are  regarded  as  of  greater  hygienic  importance 
than  the  salts  of  zinc,  tin,  and  nickel  occasionally  present. 

Copper. — Copper  gains  entrance  through  the  improper  use  of  cook- 
ing utensils  of  brass  and  copper,  and  through  the  use  of  its  salts  for 
greening  peas  and  other  vegetables  ("  reverdissage  "),  and  for  improv- 
ing flour  of  inferior  grade.  Copper  and  brass  kettles  yield  small 
amounts  to  acid,  fatty,  and  otluT  foods  allowed  to  stand  therein,  espe- 

'  AnruilcH  (VUv^'um-  el  <U-  Modccine  l.^tf:ilc,  .June,  1898,  p.  497. 
''  .Joiirn;il  of  l'\u;  Fr;inkliii  liistiliitt;,  1899. 


220  FOODS. 

cially  if  the  contents  are  exposed  to  the  air.  Their  yield  is  much 
greater  if  they  are  not  kept  thoroughly  clean  and  well  polished. 
Lehmann  ^  found  36.8  milligrams  of  copper  in  a  liter  of  broth  made 
in  a  brass  vessel  and  allowed  to  stand  24  hours,  8.7  mgr.  in  100  cc. 
of  rancid  fat  allowed  to  stand  2  weeks,  21  mgr.  in  a  liter  of  sour 
wine,  and  61  in  the  same  volume  of  vinegar  after  24  hours.  Mair  has 
reported  24  mgr.  in  a  liter  of  rice  soup  after  24  hours. 

The  use  of  copper  for  greening  vegetables  is  exceedingly  common. 
It  serves  no  useful  purpose  other  than  to  please  the  eye.  The  peas  or 
other  vegetables  are  boiled  in  a  very  dilute  solution  of  copper  sulphate, 
drained,  washed,  and,  finally,  put  up  in  cans  or  glass  jars.  The  arti- 
ficial color,  which  is  often  much  more  intensely  green  than  the  natural, 
is  due  to  an  organic  compound  of  copper  which  is  insoluble  in  water. 
The  claim  sometimes  urged,  that  the  copper  serves  to  fix  the  chloro- 
phyll, and  is  not  itself  retained,  is  preposterous,  for  if  a  solution  of 
chlorophyll  is  heated  with  dilute  copper  sulphate,  the  color  is  destroyed 
and  a  brown  precipitate  is  produced  ;  while  if  perfectly  white  beans  are 
boiled  for  a  short  time  in  a  solution  of  the  same  strength,  they  take  on 
a  deep-green  color  through  the  formation  of  a  new  compound  with  the 
contained  legumin  or  some  other  proteid.  Potatoes,  being  very  poor 
in  proteids,  are  affected  but  slightly  by  similar  treatment,  but  eggs  may 
be  colored  intensely  green. 

The  liquor  of  canned  greened  vegetables  is  commonly  free  from 
copper,  and  the  testing  of  specimens  by  adding  ammonia  to  a  portion 
of  the  liquor,  in  the  expectation  of  producing  a  blue  color  in  case  the 
vegetable  has  been  so  treated,  is,  therefore,  without  result.  In  order 
to  determine  tlie  presence  of  copper,  a  few  grams  of  the  substance  may 
be  incinerated  in  a  porcelain  capsule,  the  residue  therefrom  treated  with 
dilute  hydrochloric  acid,  and  the  filtrate  subjected  to  the  usual  tests. 

The  question  of  the  hygienic  mijDortance  of  small  amounts  of  copper 
has  been  the  subject  of  a  number  of  extensive  investigations  on  the  part 
of  individuals  and  foreign  governments,  and  while  it  can  hardly  be  said 
to  be  proved  that  danger  can  arise  therefrom,  nevertheless  no  good 
reason  can  be  advanced  in  favor  of  the  practice  of  greening.  Two  stu- 
dents in  Lehmann's  laboratory  took  daily  doses  of  copper  salts  with  no 
perceptible  disturbance ;  one  took  39  milligrams  of  copper  sulphate 
daily  for  50  days,  and  then  double  that  amount  for  30  more ;  the  other 
took  the  acetate  for  51  days  in  doses  ranging  from  16  to  96  milligrams. 
These  amounts  are  larger  than  an  average  eater  would  be  likely  to  take 
into  his  system  from  canned  vegetables  in  the  course  of  a  day,  for  the 
entire  contents  of  an  ordinary  tin — somewhat  less  than  half  a  pound — 
commonly  yield  less  than  50  milligrams  of  copper. 

According  to  Baum  and  Seelinger,^  whose  numerous  experiments 
extended  over  a  period  of  three  years,  small  daily  doses  are,  as  a  rule, 
completely  absorbed  and  again  eliminated ;  larger  doses  are  not  com- 
pletely absorbed.     Complete  elimination   may  require  as  long  as  five 

^  Seventh  International  Congress  of  Hygiene,  1891. 
^  Zeitschrift  fiir  ofientliche  Chemie,  1898,  p.  181. 


CONTAMINATION   OF  FOODS  BY  METALS.  221 

months  from  the  date  of  the  last  dose.  Long-continued  ingestion  of 
small  doses  may  bring  about  a  condition  of  chronic  poisoning. 

Copper  appears  to  be  a  normal  constituent  of  some  articles  of  food. 
The  assertion,  made  originally  by  Meyer,  of  Copenhagen,  that  wheat 
and  oats  often  contain  minute  traces,  especially  in  their  husks,  has  re- 
peatedly been  proved.  According  to  Lehmanu,'  the  species  of  plants 
has  far  less  influence  on  the  amount  taken  up  than  the  amount  of  copper 
present  in  the  soil.  He  found  the  metal  in  a  great  variety  of  plants 
growing  in  a  copper  soil  :  rye,  oats,  hops,  potatoes,  dandelion,  juniper, 
violets,  cherries,  etc.  In  woody  plants,  the  greatest  amount  of 
copper  is  in  the  bark.  According  to  Karsten,^  the  spraying  of  grape- 
vines with  copper  solutions  is  not  wholly  free  from  objection,  since 
that  which  adheres  to  the  fruit  may  be  sufficient  to  make  their  yield  of 
wine  toxic.  He  instances  a  number  of  cases  of  diarrhoea  and  vomiting 
due  to  wine  which  yielded  traces  of  copper. 

Lead. — Traces  of  lead  are  of  common  occurrence  in  various  articles 
of  food,  especially  those  wrapped  in  foil  or  enclosed  in  cans  having  ex- 
posed seams  of  lead  solder.  A  number  of  specimens  of  wrapping-foil, 
analyzed  by  Dr.  Charles  P.  Worcester,^  yielded  lead  in  amounts  rang- 
ing from  traces  to  89  per  cent.  They  are  used  largely  for  wrapping 
cream  cheeses,  chocolate,  and  other  foods.  The  metallic  caps  used  for 
closing  glass  jars  of  preserved  fruits  and  vegetables  are  also  sources  of 
danger.  One  specimen  examined  by  Worcester  contained  93.5  per 
cent,  of  lead.  Patent  stoppers,  consisting  of  a  metallic  disk  with  a 
border  of  rubber,  used  in  bottles  for  summer  beverages  known  to  the 
trade  as  "soft  drinks,"  commonly  contain  lead,  as  is  shown  by 
Worcester's  examination  of  28  specimens,  which  yielded  from  3.5  to 
50.7  per  cent.  The  contents  of  the  several  bottles  yielded  lead  with- 
out exception  ;  the  largest  amount  was  1.05  milligrams. 

Dr.  William  R.  Smith*  has  drawn  attention  to  the  common  occur- 
rence of  lead  in  citric  and  tartaric  acids.  The  former  is  used  consid- 
erably in  making  summer  drinks,  and  the  latter  in  effervescing  powders 
and  baking  powders.  Of  a  dozen  specimens  examined  by  him,  only 
one  was  uncontaminated ;  the  highest  amount  found  was  0.037  per 
cent. 

At  the  present  time,  canned  foods  are  less  likely  to  show  traces  of 
lead  than  formerly,  when  the  cans  were  made  with  less  care.  In  1893, 
Wiley''  reported  traces  in  132  out  of  248  samples  examined. 

Concerning  the  hygienic  importance  of  small  daily  doses  of  lead, 
there  is  but  one  opinion.  It  is  quite  improbable  that  the  occasional 
use  of  canned  vegetables  containing  but  a  fraction  of  a  milligram  in  an 
entire  can  will  lead  to  serious  injury,  but  the  constant  daily  ingestion 
of  appreciable  amounts  of  lead  is  likely  to  lead  to  serious  consequences 
in  at  least  a  fair  proportion  of  cases. 

'  Archiv  fiir  \\yn\iiWi,  XXVII.,  p.  1. 

'■*  ('lierriikcr-Zcitimf^,  IS'.lfi,  p.  'VI. 

■■  2'.nh  Aiiniiiil  Jicport  of  the  State  Board  of  Health  of  MassaclnisettH,  p.  570. 

*  .Journal  of  State  Medicine,  Oetoher,  1892. 

■'  ])epaitrnent  of  Agrieiiltiire,  Division  of  Chemistry,  JiuUetin  N(j.  13,  Part  VIII. 


222  FOODS. 

Especially  to  be  avoided  are  the  acid  drinks  contained  in  bottles 
with  lead  stoppers.  The  amount  of  lead  present  is  small,  and  an  occa- 
sional indulgence  is  unlikely  to  cause  harm ;  but  cases  of  serious  injury- 
have  occurred.  In  one,  in  which  the  cause  of  the  trouble  was  investi- 
gated by  the  author,  the  patient,  a  temperance  lecturer,  had  for  some 
weeks  been  passionately  addicted  to  the  use  of  a  particular  brand  of 
effervescent  drink  known  as  "  strawberry  tonic,"  a  carbonated,  acidu- 
lated solution  of  sugar,  flavored  with  an  artificial  compound  ether,  and 
colored  with  an  anilin  dye.  Evidence  of  chronic  lead  poisoning  de- 
veloped with  some  suddenness,  and  in  a  short  time  not  only  wrist-drop, 
but  also  toe-drop  appeared.  Specimens  of  the  beverage  were  examined. 
The  stoppers  were  almost  pure  lead,  and  the  contents  of  each  bottle 
yielded  notable  traces  of  the  metal. 

Zinc. — Zinc  sometimes  occurs  in  small  traces  in  canned  foods  from 
the  use  of  the  chloride  in  soldering.  With  improved  methods,  in  which 
another  flux  is  employed,  this  contamination  is  becoming  uncommon  in 
this  class  of  foods.  It  appears  to  be  a  common  accidental  impurity  in 
dried  apples,  from  contact  with  galvanized  iron  wire  racks  on  which 
they  are  cured.  Kammerer  ^  found  it  in  4  out  of  9  specimens  of 
American  dried  apples ;  the  average  amount,  reckoned  as  malate,  was 
0.0656  per  cent.  Bujard  ^  found  it  in  37  out  of  54  ;  in  20,  the  amount 
present  ranged  from  0.03  to  0.49  gram  to  the  kilogram,  reckoned  as 
oxide ;  in  17,  it  was  present  only  in  traces.  We  have  no  evidence  that 
these  small  amounts  are  of  the  slightest  sanitary  importance. 

Nickel. — Nickel  is  employed  sometimes  in  place  of  copper  for  green- 
ing peas.  About  a  quarter  of  a  gram  of  the  sulphate  suffices  for  a 
kilogram  of  j)eas.  It  is  dissolved  in  boiled  water  to  which  10  cc.  of 
a  2  per  cent,  solution  of  ammonia  are  added,  and  then  the  solution  is 
diluted  with  boiled  water  in  sufficient  amount  to  cover  the  peas,  which 
then  are  boiled  for  a  few  minutes,  drained,  and  washed.  According  ta 
E.  Ludwig,'^  nickel  is  given  off  in  small  amounts  to  all  sorts  of  foods 
cooked  in  nickel  dishes.  He  found  from  traces  to  12.9  milligrams 
per  100  grams  of  the  food  examined.  There  is  no  evidence  that  tliese 
amounts  can  produce  injury. 

Tin. — Contamination  with  compounds  of  tin  is  exceedingly  common, 
and,  so  far  as  is  known,  is  harmless  and  unimportant,  the  compounds, 
other  than  the  chloride,  being  apparently  incapable  of  producing  any 
physiological  or  local  action. 

Metallic  Contamination  from  Kitchen  Utensils. — Much  has  been 
said,  from  time  to  time,  concerning  the  possible  danger  of  poisoning  by 
small  amounts  of  lead  and  other  metals  taken  up  by  foods  from  kitchen 
utensils,  and  especially  from  glazed  earthenware ;  but  a  number  of 
extensive  investigations  have  demonstrated  that  this  danger  is  very 
remote.     Mussi  *  has  shown  that,  if  the  firing  of  lead-glazed  pottery 

^  Chemiker-Zeitung,  1897,  p.  721. 

^  Forschungsbericht  iiber  Lebensmiltel,  etc.,  1897,  IV.,  p.  218. 

'^  Oesterreiche  Chemische  Zeitung,  1898,  I. 

*  Giornale  della  K.  Societa  Italiana  d'igiene,  January  30,  1900,  p.  1. 


CONTAMINATION  OF  FOODS  BY  METALS.  223 

has  been  done  properly,  no  trace  of  lead  will  be  taken  up  by  acid  foods, 
such  as  tomato  soup,  or  even  vinegar  ;  but  he  advises  that  all  new 
vessels  should  be  cleansed  very  carefully  before  using,  on  account  of  the 
common  presence  of  lead  dust  on  the  glaze  when  fresh  from  the  kiln. 
Riche '  also  determined  that  with  properly  fired  ware  the  danger  of 
solution  of  lead  is  practically  nil,  the  specimens  used  yielding  no  traces 
to  boiling  dilute  acetic  and  nitric  acids  and  salt  solutions.  But  im- 
properly fired  ware  will  yield  traces. 

Enamelled  ware  is  believed  commonly  to  contain  lead ;  and  the 
enamel,  having  a  different  coefficient  of  expansion  from  that  of  the 
iron,  being  likely  to  crack  and  chip  oflP,  especially  with  careless  hand- 
ling, is  thought  to  be  dangerous  ;  but  Barthe  ^  found  no  trace  of  lead 
in  a  number  of  enamels  examined,  and  asserts  that  very  hard  enamels 
need  neither  lead  nor  any  other  poisonous  compounds  in  their  prepara- 
tion. This  accords  with  the  experience  of  the  author  and  other 
American  investigators,  and  it  may  confidently  be  said  that  the 
enamelled  ware  in  common  use  is  lead-free. 

Aluminumware,  which  has  of  late  come  into  extensive  use,  is  less 
acted  upon  by  acid  foods  than  tin,  but  is  affected  considerably  by 
alkalies,  the  impurities  present  in  commercial  aluminum  acting  as 
favoring  agents  to  its  corrosion.  But  the  resulting  compounds  are 
innocuous  in  the  small  amount  ingested.  This  kind  of  ware  is  kept 
clean  very  easily  and  offers  the  great  advantage  of  lightness. 

Nickelware  is  attacked  but  slightly  by  ordinary  food  materials,  and 
the  amounts  taken  up  are  without  sanitary  significance.  But  its  cost 
is  against  its  extensive  use,  and,  moreover,  it  imparts  sometimes  a 
greenish  tint,  which  is  repugnant  to  the  eye. 

1  Revue  d' Hygiene,  August  20,  1900,  p.  704. 

'  Journal  de  Pharmacie  et  de  Chemie,  1898,  p.  105. 


CHAPTEE  II. 
AIR. 

Air  is  a  mixture  of  gases,  and  not  a  chemical  compound.  Until 
the  latter  part  of  the  seventeenth  century  (1669),  it  was  supposed 
to  be  an  element,  but  Jean  Mayow  then  proved  it  to  be  a  mixture 
of  gases ;  and  later,  Lavoisier  discovered  the  two  gases,  oxygen  and 
nitrogen,  which,  a  hundred  years  later,  Avere  separated  by  Priestley  and 
by  Scheele. 

Air  is  a  colorless  and  apparently  odorless  mixture  of  oxygen,  nitro- 
gen, argon,  carbonic  acid,  aqueous  vapor,  and  traces  of  other  substances. 
It  is  not,  however,  under  ordinary  conditions  odorless,  but,  on  the  con- 
trary, it  contains  various  scents,  to  which  we  are  so  accustomed  that, 
unless  present  in  unusual  degree,  owing  to  local  conditions,  they  are 
not  perceived.  This  is  noticed  on  returning  to  an  ordinary  atmosphere 
from  one  where  the  causes  of  the  usual  odors  are  absent  or  nearly  so, 
as,  for  instance,  from  deep  subterranean  caves ;  or  from  a  room  where 
the  air  is  foul  and  oppressive,  as,  for  instance,  from  a  heated,  over- 
crowded hall  or  street  car.  The  air  of  the  Arctic  regions  contains  but 
little  odor,  on  account  of  the  absence  of  bodies  which  give  rise  to  odors, 
and  the  proximity  of  any  source  of  smell  is  noticed  quickly.  The  ex- 
plorer Nansen  ^  speaks  of  the  pervading  smell  of  soap  which  he  noticed 
when,  after  months  of  wandering,  he  met  Jackson,  who  had  been  housed 
comfortably  with  all  the  common  necessities  of  man. 

While  air  is  a  mixture  of  gases,  it  is  one  of  tolerably  constant  com- 
position, particularly  in  the  case  of  its  chief  constituent,  nitrogen. 
Under  the  conditions  of  life,  the  more  important,  but  less  abundant 
element,  oxygen  is  subject  to  more  or  less  variation.  In  the  presence 
of  vegetable  life,  particularly  by  day,  it  is  increased  slightly  ;  in  the 
presence  of  animal  life,  it  is  diminished  more  or  less. 

OXYGEN. 

The  normal  amount  of  oxygen  is  stated  usually  at  just  below  21  per 
cent,  by  volume.  A.  Leduc  gives  it  at  exactly  21,  Avith  78.06  of  nitro- 
gen and  0.94  of  argon.  Different  observers  have  reported  the  follow- 
ing as  averages  of  large  numbers  of  analyses  of  pure  outdoor  air : 

20.99  .    .    .  • Scotland. 

20.98 Scotland. 

20.94 Sweden. 

20.92 France. 

20.94 Germany. 

20.92 Norway. 

20.95 England. 

20.95 Ohio. 

1  Farthest  North,  V'>1.  II.,  p  529. 
224 


OXYGEN.  225 

The  meau  of  a  number  of  analyses  by  Bunsen  was  20.924  by  volume, 
and  of  a  hundred  at  Paris  by  E-egnault,  20.960.  For  the  sake  of 
convenience,  we  may  disregard  the  very  slight  difference  between  21 
and  the  figures  obtained  by  exact  analysis,  a  difference  in  the  second 
place  of  decimals,  and  accept  21  as  a  normal.  At  great  heights,  the 
proportion  of  oxygen  is  less  than  at  the  surface.  For  instance,  on  the 
Faulhorn,  in  Switzerland,  20.77  has  been  observed  as  the  mean  of  a 
number  of  determinations.  Under  certain  conditions,  there  is  very 
i?lightly  more  than  21  parts  ;  for  instance,  in  the  immediate  vicinity  of 
vegetation,  especially  by  day,  there  may  be  an  excess  of  oxygen,  but 
it  is  very  small;  sea  air,  taken  in  mid-ocean,  has  yielded  21.59,  but 
■ordinarily  contains  less  than  21.  It  is  less,  by  very  small  fractions, 
in  the  streets  of  cities  than  in  the  open  country,  and  in  towns  than 
at  sea. 

Oxygen  is  the  element  in  air  that  supports  all  life.  It  is  constantly 
being  withdrawn  from  the  air  in  the  process  of  respiration,  and  is  re- 
turned to  it  in  chemical  union  with  carbon  as  carbon  dioxide.  This  is 
absorbed  by  vegetation  and  split  up,  the  carbon  being  retained,  and  the 
oxygen  for  the  most  part  released  and  returned  to  the  air.  Thus,  the 
processes  of  animal  and  vegetable  life  combine  to  maintain  the  equilib- 
rium. 

All  animals  do  not  breathe  in  the  same  degree ;  birds  have  the 
most  active  respiration,  and  next  come  mammals ;  and  all  consume 
more  oxygen  when  active  than  when  asleep. 

Oxygen  is  essential  to  the  germination  of  seeds,  and  to  the  growth 
of  plants.  Although  plants  take  up  carbon  dioxide  and  exhale  oxygen, 
they  also  breathe  as  do  animals,  absorbing  the  latter  and  exhaling  the 
former.  Even  the  anaerobic  organisms  consume  oxygen,  although 
living  where  air  is  wanting,  for  they  split  up  combinations  of  oxygen 
and  other  elements.  Thus,  in  dilute  sugar  solutions  they  withdraw 
some  of  the  oxygen  and  split  up  the  sugar  into  carbon  dioxide  and 
alcohol. 

For  sustaining  animal  life,  it  is  essential  that  the  air  shall  contain 
not  far  from  the  normal  amount  of  oxygen ;  that  is,  that  it  shall  be 
neither  much  diminished  nor  yet  over-rich  in  that  element.  Human 
life  is  impossible  in  air  which  contains  but  four-fifths  of  the  normal 
amount,  and  equally  so  in  an  artificial  atmosphere  containing  materially 
more  than  the  normal. 

In  man  and  animals,  the  tissues  do  not  receive  oxygen  in  the  free 
condition,  for  when  the  air  is  inspired,  the  oxygen  is  taken  up  by  the 
red  blood  corpuscles  and  unites  with  the  haemoglobin  to  form  an  un- 
stable compound,  oxyhseraoglobin,  which,  as  the  blood  circulates  through 
the  tissues,  is  decomposed ;  the  oxygen  is  then  taken  up  by  the  cells, 
and  eventually  returned  to  the  blood  in  the  form  of  carbon  dioxide,  and 
eliminated  as  such  from  the  body.  In  an  artificial  atmosphere  con- 
taining an  excessive  amount  of  oxygen,  the  liicmoglol^in  becomes  sat- 
urated with  the  gas,  part  of  which  becomes  dissolved  in  the  blood  serum, 
and  then  acts  as  a  poison  to  the  tissues  and  destroys  them. 

15 


226  AIE. 

Inspired  air  loses  about  a  fourth  of  its  oxygen,  and  is  returned  to 
the  atmosphere  rich  in  impurity  ;  but  diffusion  occurs  so  rapidly  that 
the  atmosphere  of  a  thickly  settled  city  shows  no  very  material  varia- 
tion from  that  of  the  open  country. 

The  lungs  are  never  filled  with  pure  air  after  the  first  respiration 
at  birth,  since  they  are  never  wholly  emptied,  and  they  consequently 
contain  an  impure  residue  of  air  after  each  expiration.  The  upper 
part  of  the  respiratory  tract  is  the  only  part  that  receives  strictly  pure 
air.  Professor  Richet  has  demonstrated  that,  if  the  respiratory  tract 
be  lengthened  artificially  by  means  of  a  rubber  tube,  pure  air  will  never 
reach  even  the  upper  air-passages,  and  the  animal  will  die  of  asphyxia. 

The  amount  of  oxygen  absorbed  varies  with  age,  condition  of  health, 
and  activity.  According  to  Professor  Foster,  an  average  person  inhales 
in  24  hours  about  34  pounds  of  air,  which  corresponds  to  a  little  more 
than  7  pounds  of  oxygen  ;  and  as  the  lungs  absorb  about  a  fourth  of 
the  oxygen  inhaled,  it  appears  that  the  average  amount  of  oxygen 
absorbed  daily  is  nearly  2  pounds. 

NITROGEN. 

The  principal  constituent  of  the  air,  nitrogen,  takes  no  part  in- 
respiration,  and  is  not  m  creased  in  expired  air ;  but  although  it  is 
indifferent  and  inert,  it  is,  nevertheless,  by  no  means  unimportant. 
In  the  first  place,  it  serves  to  dilute  the  oxygen,  so  that  the  latter  is 
respirable ;  and  in  the  second  place,  it  plays  an  important  part  in  the 
groAvth  of  plants,  the  original  source  of  all  nitrogenous  food,  for  that 
which  we  consume  in  the  form  of  meat  is  from  animals  that  have  built 
up  their  tissues  from  vegetable  food.  As  a  diluent  of  oxygen,  it  serves 
to  prevent  too  great  activity  of  that  element,  which  cannot  be  breathed 
with  impunity  for  any  length  of  time  when  present  in  an  atmosphere 
to  a  greater  extent  than  its  normal  amount. 

How  nitrogen  is  absorbed  by  plants,  we  know  only  in  part.  Certain 
low  forms  (mycelia,  etc.)  seem  to  absorb  it  directly  from  the  atmosphere 
when  exposed  freely  to  light  and  air.  Some  of  the  higher  forms  (peas, 
beans,  clover,  etc.)  acquire  it  through  the  agency  of  certain  micro- 
organisms which  are  present  in  nodules  in  their  roots,  and  without  which 
they  will  not  thrive.  These  micro-organisms  take  the  nitrogen  from 
the  atmosphere  and  give  it  in  some  form  to  the  plants.  That  this  is 
so,  is  proved  by  the  fact  that  the  plants  will  thrive  in  a  soil  quite  free 
from  nitrogen  (in  clean  sand,  for  instance),  and  store  up  in  their  tissues 
an  amount  of  nitrogen  far  in  excess  of  that  which  was  originally  pres- 
ent in  the  seeds,  provided  these  micro-organisms  are  present  in  the 
nodules  of  the  roots.  If  they  are  not  preseot,  the  plants  will  not 
thrive,  but  may  be  made  to  do  so  by  the  application  of  water  contain- 
ing cultures  of  the  organisms.  Of  the  doubtless  many  species  which 
can  fix  atmospheric  nitrogen,  or  which  aid  in  doing  so,  the  following 
may  be  mentioned  :  B.  megatherium,  B.  fluorescens  /Iquefaciens,  B.  pro- 
teus  vulgaris,  B.  butyricus,  B.  mycoides,  B.  mesentericuf;  vulgatus. 


CARBON  DIOXIDE  {CARBONIC  ACID).  227 

On  the  other  hand,  certain  plants,  grown  in  the  open  air  in  soils 
free  from  nitrogen,  and  j^rotected  from  receiving  ammonia  and  nitrates 
from  the  rain,  will  show  no  more  nitrogen  in  their  whole  organization 
than  was  present  in  the  seeds  from  which  they  sprang.  The  subject  is 
one  which  has  been  investigated  but  partly,  and  future  research  will 
doubtless  show  that,  under  natural  conditions,  all  plant  life  takes  up 
in  some  way  more  or  less  nitrogen  from  the  atmosphere,  as  well  as  from 
nitrogenous  compounds  in  the  soil. 

ARGON. 

Up  to  the  time  of  its  discovery,  the  element  argon  was  included 
under  nitrogen  in  the  tables  of  composition  of  the  air.  How  much  is 
present,  is  not  yet  accurately  determined.  It  was  discovered  in  1894, 
by  Lord  Rayleigh  and  Professor  Ramsay,  by  whom  later  it  was  esti- 
mated as  composing  about  0.75  per  cent,  of  the  atmosphere.  Leduc 
gives  its  amount  as  0.94,  and  Schloesing  as  0.84.  It  is  quite  inert, 
and  cannot  be  made  to  combine  with  any  other  element,  although  it  has 
been  combined  by  Berthelot  with  benzene  under  the  influence  of  electric 
discharge. 

HYDROGEN. 

According  to  the  extensive  researches  of  Armand  Gautier,  hydrogen 
is  present  in  sea  air  and  other  pure  air  in  fairly  constant  amount — about 
0.015  per  cent.  It  is  believed  to  be  due  to  various  fermentative  proc- 
esses, and  to  be  contributed  also  by  mineral  springs  and  volcanoes. 
So  far  as  known,  its  presence  is  devoid  of  sanitary  importance. 

Other  elements,  as  krypton,  neon,  and  metargon,  also  discovered  by 
Professor  Ramsay,  coronium,  discovered  by  IN^asini,  and  several  others, 
are  interesting  solely  from  a  purely  scientific  standpoint. 

CARBON  DIOXIDE   (CARBONIC  ACID). 

All  air  contains  carbon  dioxide  as  a  constant  constituent.  The  nor- 
mal average  amount  in  pure  air  is  but  slightly  in  excess  of  3  parts  in 
10,000,  or  about  0.03  per  cent.,  and  not  4  parts,  as  commonly  is  stated. 
As  little  as  2.03,  and  even  1.72,  has  been  observed  in  the  air  on  moun- 
tain-tops, although  generally  we  expect  more  rather  than  less  than  the 
normal  amount  at  high  elevations. 

Carbon  dioxide  is  a  result  of  oxidation  of  organic  matter,  and  owes 
its  presence  in  the  atmosphere  to  respiration,  fermentation,  combustion, 
and  chemical  action  in  the  soil.  An  average  man  exhales  about  20 
liters  in  an  hour,  and  very  nearly  a  kilogram  in  a  day  ;  women  exhale 
less,  and  children  and  aged  persons  still  less.  The  amount  exhaled  is 
increased  by  nmscular  exertion  and  diminished  by  rest.  Birds  send  out 
more  in  proportion  to  weight  than  other  animals.  The  respiration  of 
millions  and  millions  of  human  beings  and  animals  is  constantly  throw- 


228  AIR. 

ing  iuto  the  atmosphere  countless  tons  of  the  gas  ;  every  ton  of  coal 
in  burning  yields  more  than  67,000  cubic  feet ;  every  cubic  foot  of 
coal  gas  yields  about  double  its  volume ;  every  pound  of  candle  nearly 
three  times  its  weight  (2.769) ;  every  gallon  of  oil  and  kerosene,  and 
■every  piece  of  wood  used  as  fuel,  contributes  its  proportion.  Huge 
volumes  are  sent  forth  continually  by  the  soil  air,  which  contains  it 
in  abundance,  and  by  mineral  springs,  the  waters  of  which  contain  it 
under  pressure.  It  has  been  estimated  that,  from  all  sources,  5,000 
niilliou  tons  are  discharged  annually  into  the  atmosphere.  It  is  slightly 
more  abundant  in  cities  than  in  the  country,  and  at  night  than  by  day. 
It  is  highest  in  amount  at  a  given  location  during  autumn,  and  lowest 
in  winter.  It  is  more  abundant  inland  than  on  the  coast.  It  increases 
somewhat  as  we  ascend  from  sea-level — according  to  Schlagintweit,  up 
to  11,000  feet.  Its  removal  from  the  atmosphere  is  mostly  through 
the  agency  of  growing  vegetation,  but  materially  also  by  absorption  by 
bodies  of  water,  which,  at  ordinary  temperature  and  pressure,  will  take 
up  its  own  volume  of  the  gas.  It  has  been  calculated  that  the  ocean 
contains  about  ten  times  as  much  as  the  whole  atmosphere.  All  green 
plants  absorb  it  by  day,  and  by  means  of  their  chlorophyll  break  it  up 
into  carbon  and  oxygen,  the  former  being  used  in  building  tissue,  and 
the  latter  returned  to  the  air  as  a  waste  product.  This  process  of  nutri- 
tion goes  on  only  under  the  Influence  of  light,  and  consequently  by 
day ;  but  there  is  also  a  respiratory  function  that  is  active  both  day 
find  night,  and  has  the  same  effect  on  air  as  that  of  the  respiration  of 
unimals  ;  namely,  the  consumption  of  oxygen  and  discharge  of  car- 
bonic acid.  But  the  respiratory  process  has  but  a  trivial  influence  in 
comparison  with  the  chlorophyllian  function.  It  is  estimated  that  an 
acre  of  woodland  withdraws  in  one  season  about  four  and  a  half  tons, 
retains  more  than  one  and  one-fifth  tons  of  carbon,  and  returns  three 
and  a  quarter  tons  of  oxygen  to  the  air.  The  slight  increase  at  night 
is  due  supposedly  in  part  to  its  exhalation  by  plants  in  their  respira- 
tion, and  also  to  currents  of  soil  air,  which  ascends  as  soon  as  the  air 
at  the  surface  becomes  colder,  and  consequently  heavier,  than  itself. 
During  the  day,  the  soil  air  is  colder  and  remains  stationary. 

Carbon  dioxide  is  a  heavy  gas,  incapable  of  supporting  combustion 
or  respiration,  and  serving  no  useful  purpose  in  animal  tissues.  It 
constitutes  about  4  per  cent,  of  expired  air,  in  which  it  is  an  excretion 
of  the  body.  It  is  in  itself  inert,  and  incapable  of  exerting  any  poi- 
sonous action,  but  will  cause  asphyxia  when  present  in  sufficient  amount 
to  interfere  with  the  atmospheric  oxygen  in  the  performance  of  its 
function. 

An  atmosphere  of  respired  air,  containing  4  per  cent.,  of  carbon 
dioxide  and  about  1 6  per  cent,  of  oxygen,  will  not  support  life  longer  than 
a  short  time,  since  the  blood  cannot  get  sufficient  oxygen  for  the  needs 
of  the  cells  and  tissues,  and,  in  addition,  cannot  rid  itself  of  its  COg. 
Gas  exchange  between  the  blood  and  inspired  air  depends  upon  the 
tension  of  the  gas  in  both  media,  and,  therefore,  as  soon  as  the  tension 
of  the  CO2  in  the  atmosphere  exceeds  that  of  the  CO2  of  the  blood,  the 


OZONE.  229 

blood  corpuscles  cannot  excrete  it,  but  must  retain  it.  In  consequence, 
asphyxia  occurs. 

The  question  as  to  how  much  CO2  is  permissible  in  air,  has  been  an- 
swered variously.  We  assume  3  parts  in  10,000  as  the  normal  amount, 
and  all  in  excess  as  impurity  due  to  respiration  and  combustion.  A 
total  of  6  or  7  parts  in  10,000  is  regarded  by  the  best  authorities  as 
the  permissible  limit,  and  10  in  10,000  as  distinctly  harmful.  When 
the  amount  reaches  10  parts  in  10,000,  the  air  begins  to  be  "close"  ;, 
and  when  it  reaches  15  in  10,000,  it  is  likely  to  cause  headache  in  those 
unaccustomed  to  impure  air.  In  crowded  assembly  rooms,  as  churches,, 
theatres,  and  schools,  the  amount  may  reach  100  parts  in  10,000  ;  and 
more  than  twice  as  much  has  been  found  in  a  Swiss  stable  crowded 
with  men  and  animals.  The  air  of  the  hall  in  which  the  German 
Public  Health  Society  (Deutscher  Verein  fiir  offentliche  Gesundheits- 
pflege)  met  in  Nuremberg  in  October,  1890,  contained  24.10  in  10,000 
at  the  beginning  of  one  of  the  addresses,  and  43.20  at  its  close. 

A  large  amount  of  carbon  dioxide  may  be  present  in  aii'  without 
producing  any  ill  effects,  if  there  is  plenty  of  oxygen  present.  Thus, 
Regnault  and  Reiset  have  proved  that  animals  can  live  in  a  mixture 
of  25  per  cent,  carbonic  acid,  30-40  per  cent,  oxygen,  and  nitrogen. 

It  has  been  held  generally  that  CO2  up  to  20  :  10,000  is  in  itself 
harmless  ;  that  the  deleterious  agents  in  polluted  air  are  organic  mat- 
ters thrown  off  by  the  skin  and  lungs  in  company  Avith  it ;  and  that  it 
serves  as  a  convenient  index  of  their  amount.  It  has  been  the  custom 
to  say,  "  The  more  carbonic  acid  we  find,  the  more  organic  matter  we 
infer."  These  poisonous  organic  matters,  however,  though  much  sought 
after,  have  never  been  isolated,  although  a  number  of  observers,  using 
faulty  methods,  have  from  time  to  time  obtained  erroneous  results. 
This  subject  will  be  considered  farther  on. 

OZONE. 

Ozone  is  a  normal  but  by  no  means  constant  constituent  of  the  air. 
It  is  generally  absent  from  the  air  of  large  towns  and  cities,  and  is 
almost  never  present  in  the  air  of  an  inhabited  room  or  near  decom- 
posing matter.  It  is  found  in  minute  amounts  (maximum,  1  :  700,000) 
in  the  open  air  of  the  country  and  sea.  It  is  most  abundant  at  sea  and 
near  woods,  and  somewhat  more  abundant  on  mountains  than  in  valleys 
and  on  plains.  It  is  more  abundant  in  the  morning  in  the  colder 
mouths,  and  in  the  evening  during  hot  weather ;  it  is  more  abundant 
in  winter  than  in  summer.  It  is  stated  that  it  is  most  abundant  di- 
rectly after  a  thunder-storm,  but  lieyond  the  fact  that  it  is  produced  by 
the  passage  of  the  electric  spark,  there  is  nothing  to  substantiate  this 
statement.  As  a  matter  of  fact,  the  origin  of  ozone  in  the  atmosphere 
is  imknown. 

Ozone  is  an  allotropic  form  of  oxygen,  consisting  of  molecules  con- 
taining three  atoms  of  that  element.  It  has  been  liquefied  under  great 
prf-«iirf  n27  atmospheres),  and  in   that  condition,  and,  indeed,  in   the 


230  AIR. 

gaseous  form,  has  a  deep-blue  color.  It  is  produced  by  the  passage  of 
the  electric  spark,  by  slow  oxidation  of  phosphorus,  and  in  the  electrol- 
ysis of  water ;  but,  as  has  been  said,  its  origin  as  a  normal  constituent 
of  the  atmosphere  has  not  been  explained  satisfactorily.  It  has  an  odor 
not  unlike  that  of  diluted  chlorine.  It  has  very  strong  oxidizing  power, 
much  more  so  than  oxygen,  which  it  exercises  most  actively  both  on 
metals  and  on  organic  matter ;  hence  its  absence  from  the  air  of  inhab- 
ited rooms  and  of  densely  populated  areas,  charged  with  organic  matter 
and  dust  of  all  sorts,  is  easily  explainable.  To  this  property,  its  dimi- 
nution in  autumn,  when  decomposition  products  are  generated  most 
actively,  may  properly  be  attributed.  Its  presence  in  the  air  of  any 
place  is  fair  evidence  of  freedom  from  oxidizable  matters. 

Ozone  has  an  exceedingly  irritating  effect  on  the  respiratory  mucous 
membranes,  and  when  inhaled  with  oxygen  in  the  proportion  of  1  part 
in  240,  quickly  produces  death  in  animals  subjected  to  it.  It  is  be- 
lieved to  exert  a  pernicious  influence  in  inflammatory  conditions  of  the 
lungs  and  bronchi,  even  when  present  in  not  much  more,  if  any,  than 
the  ordinary  amount  in  the  atmosphere.  We  actually  know  little  or 
nothing  of  the  efiects  of  ozone  on  the  system  in  the  amounts  ordinarily 
present  in  air,  but  the  absurdity  of  the  expression  so  often  used,  that 
one  has  "  gone  to  breathe  the  pure  ozone  "  at  a  health  resort  is  manifest. 

Peroxide  of  Hydrogen  (H2O2)  is  believed  to  exist  in  minute 
traces  in  the  atmosphere,  and  to  exert  some  influence  in  the  process  of 
oxidation. 

AMMONIA. 

Ammonia  is  constantly  present  in  the  air  in  very  slight  traces.  It 
exists  in  the  free  state  and  in  combination  as  nitrate  and  carbonate. 
Daily  analysis  of  the  air  at  Montsouris  for  five  years  gave  as  a  mean 
for  ammonia  2.2  milligrams  per  100  cubic  meters.  It  proved  to  be 
highest  in  amount  in  summer  and  lowest  in  winter.  It  is  diminished 
in  rainy  weather,  because  it  is  absorbed  by  the  rain  during  passage 
through  the  atmosphere ;  it  is  increased  with  rising  temperature  some 
time  after  rain  has  ceased  falling.  As  it  is  one  of  the  products  of 
decomposition  of  nitrogenous  organic  matter,  perhaps  nowhere  more 
observable  than  in  stables,  where  it  is  plainly  perceptible  to  the  sense 
of  smell,  it  is  hardly  necessary  to  point  out  that  its  sources  are  various 
and  innumerable. 

NITROGEN  ACIDS. 

Nitrous  and  nitric  acids  are  also  present  in  small  traces,  due  in  part 
to  the  union  of  atmospheric  oxygen  and  nitrogen  through  the  agency 
of  electrical  discharges,  and  in  part  to  the  action  of  ozone  on  ammonia. 
Nitric  acid  is  found  in  comparative  abundance  in  buildings  lighted  by 
means  of  the  arc  light,  but  it  is  not  probable  that  the  amount  present 
is  of  sanitary  importance. 


AQUEOUS   VAPOR.  231 

AQUEOUS  VAPOR. 

Aqueous  vapor  is  a  normal  constituent  which  occurs  in  variable 
amounts,  influenced  by  a  number  of  natural  conditions,  the  chief  of 
which  is  the  temperature.  It  is  an  invisible  gas,  lighter  than  air  and 
very  unequally  diffused.  Its  sources  are  numerous  ;  some  comes  from 
the  evaporation  of  water,  some  from  soil  moisture,  some  from  the 
lungs  and  skin  of  animals  and  man,  some  from  the  leaves  of  growing 
plants,  some  from  combustion.  Indoors,  a  considerable  amount  is  com- 
municated to  the  air  through  the  combustion  of  illuminants. 

According  to  Professor  Foster,  an  adult  man  gives  oif,  under  ordi- 
narily favorable  •  conditions,  about  4  pounds  of  watery  vapor  from  the 
skin  and  lungs  during  twenty-four  hours  ;  2|  pounds  by  the  skin,  and 
the  remainder  (Petteukofer  and  Voit  say  10  ounces)  by  the  lungs.  An 
adult  healthy  tree  of  fair  size  gives  off  an  amount  which  is  enormous  in 
comparison.  The  amount  of  water  exhaled  by  plants  has  been  esti- 
mated by  Hellriegel  to  vary  from  250  to  400  times  the  weight  of  the 
dry  organic  matter  formed  during  the  same  time,  which  means  that 
during  the  growth  of  each  ton  of  green  grass  or  leaves  of  any  kind, 
there  have  been  exhaled  therefrom  many  tons  of  water,  and  that  in  the 
production  of  each  jjound  of  dry  matter,  an  average  of  325  pounds  of 
water  has  been  discharged.  The  evaporation  of  water  from  foliage  has, 
among  other  important  functions,  that  of  keeping  the  temperature  be- 
low the  point  where  the  vital  processes  would  be  interfered  with. 

The  amount  of  aqueous  vapor  which  a  volume  of  air  will  absorb  and 
retain  depends  on  the  temperature.  For  each  degree  of  temperature,  a 
volume  of  air  can  take  up  a  definite  amount  of  vapor,  and  no  more ; 
and  when  it  has  taken  up  this  amount  it  is  said  to  be  "  saturated." 
The  higher  the  temperature,  the  greater  the  amount  it  can  hold ;  and 
hence  when  a  volume  of  air  completely  saturated  is  subjected  to  a 
change  in  temperature,  one  of  two  things  will  occur  :  if  the  temperature 
is  increased,  it  can  take  up  more  vapor,  and  hence  is  no  longer  saturated  ; 
if  it  is  diminished,  the  aqueous  vapor  is  in  excess  of  the  amount  re- 
quired for  saturation  at  the  new  temperature,  and  the  excess  will  be 
condensed  and  precipitated  as  moisture.  At  0°  C,  a  volume  of  air 
takes  up  yw-q  of  its  weight  of  aqueous  vapor ;  at  15°,  it  takes  up  twice 
as  much;  at  30°,  four  times,  at  45°,  eight  times,  and  at  60°,  sixteen 
times  as  much.  Thus  it  appears  that,  with  each  increase  of  15°  C.  in 
temperature,  the  capacity  for  aqueous  vapor  is  doubled.  At  15°  C. 
(59°  F.),  a  cubic  foot  of  air  will  hold  nearly  6  grains  of  water  vapor ; 
at  30°  C  (86°  F.)  it  will  hold  twice  as  much. 

Evaporation  cannot  go  on  when  the  surrounding  air  is  saturated  ; 
therefore,  the  presence  of  a  body  of  water  will  add  nothing  to  a  satu- 
rated atmosphere.  But  plants  and  animals  can  continue  to  give  oflF 
the  vapor  to  an  already  saturated  atmosphere,  which,  however,  con- 
denses and  deposits  the  excess  at  once,  perhaps  on  the  very  surface 
where  it  is  originated,  as  on  the  leaf  of  a  tree  or  on  the  skin  of  man. 
The  difference   between    evaporation   and   transpiration,  which    is  the 


232  AIR. 

proper  term  for  the  giving  off  of  vapor  by  animals  and  plants,  is  that 
the  one  is  merely  physical,  while  the  other  is  a  vital  process  due  to  the 
action  of  living  cells. 

The  rate  of  elimination  of  water  by  the  body  in  a  state  of  rest  de- 
pends upon  the  amount  of  humidity  present  in  the  air.  Determina- 
tions by  Rubner  and  von  Lewaschew  ^  demonstrated  the  great  influ- 
ence of  humidity  in  this  particular.  At  15°  C.  in  moist  air,  the  daily 
elimination  fell  to  216  grams,  while  in  dry  air  at  the  same  temperature 
it  rose  to  871.  The  rate  rises  with  the  temperature  in  both  moist 
and  dry  air,  and  the  more  promptly,  the  greater  the  dryness.  The 
outer  air  contains  commonly  from  60  to  75  per  cent,  of  the  amount 
necessary  for  saturation.  In  some  places  noted  for  the  dryness  of 
the  air,  the  amount  is  much  below  ;  in  others,  where  the  opposite  is  the 
case,  it  is  above. 

Relative  humidity  is  the  degree  of  approach  to  saturation  at  any 
given  temperature.  Thus,  "  relative  humidity  80  "  means  that  at  the 
observed  temperature,  the  air  holds  but  80  per  cent,  of  the  amount 
which  it  can  take  up.  Absolute  humidity  is  the  actual  weight  of  moist- 
ure in  a  given  air  space. 

Acjueous  vapor  exerts  a  most  important  influence.  By  day,  it  ab- 
sorbs part  of  the  sun's  heat  and  tempers  it ;  by  night,  it  acts  as  a  pro- 
tecting blanket  to  the  earth  by  preventing  too  great  loss  of  heat  by 
radiation.  At  night,  the  earth  gives  up  jiart  of  the  heat  which  it  has 
absorbed  during  the  day ;  and  when  the  air  is  very  dry  and  the  sky 
very  clear,  the  temperature  falls  much  more  than  when  there  is  more 
vapor  present  to  prevent  loss  by  radiation.  In  the  Sahara,  after  the 
hottest  days,  the  nights  are  generally  very  cool,  the  temperature  fall- 
ing sometimes  30  to  40  degrees  C.  in  a  few  hours.  At  high  altitudes 
also,  where  the  blanket  of  vapor  is  thin,  the  fall  in  temperature  at 
night  is  very  marked.  Absence  of  aqueous  vapor  permits  the  cooling 
process  to  begin  as  soon  as  the  sun  gets  low,  and  ice  may  form  in  a 
few  hours  M^here,  during  the  day,  the  sun's  heat  had  been  intolerable. 
This  is  seen  in  the  great  deserts  and  at  high  altitudes. 

It  is  noticed  commonly  that  the  first  frosts  of  autumn  and  those 
which  come  occasionally  in  the  middle  and  later  parts  of  spring  occur 
only  on  very  clear  nights  with  low  humidity. 

An  amount  of  watery  vapor  approaching  saturation  gives  rise  to  dis- 
comfort, whether  the  temperature  be  high  or  low.  The  "  sticky  "  days 
of  summer  and  the  "  raw  "  ones  of  winter  owe  their  disagreeableness 
to  their  high  relative  humidity.  In  a  hot  saturated  atmosphere,  while 
transpiration  can  proceed,  evaporation  cannot,  and  hence  the  cooling 
influence  of  evaporation  is  missing.  The  sweat  stays  on  the  skin  in 
■  the  liquid  form  instead  of  passing  into  the  air  as  a  vapor,  and  the  word 
"  sticky  "  becomes  singularly  appropriate.  On  the  other  hand,  with 
low  humidity  and  high  temperature,  the  sweat  does  not  condense  and 
remain  on  the  skin,  but  passes  into  the  air,  and  transpiration  is  not 
impeded  in  the  lungs.     Hence  the  great  bearability  of  dry  heat  as 

^  Archiv  fiir  Hygiene,  XXIX.,  p.  1. 


DUST  AND  MICRO-ORGANISMS.  233 

compared  with  moist.  Saturation  at  low  temperature  has  as  great,  if 
not  greater,  influence  on  bodily  comfort.  It  does  not  follow  that  since 
one  feels  the  heat  more  acutely  with  high  relative  humidity,  this  condi- 
tion will  enable  one  to  withstand  the  opposite  discomfort  of  cold. 
Indeed,  the  reverse  is  true.  At  low  temperatures,  saturated  air  causes 
a  greater  withdrawal  of  heat  than  dry  air,  and  intensifies  the  sensation 
of  cold ;  for  moist  air  is  a  much  better  heat  conductor.  Cold  dry  air 
is  much  more  comfortable  than  air  some  degrees  warmer  but  materially 
moist.  In  the  very  cold  climate  of  eastern  Siberia,  the  air  is  so  dry 
that  50°  to  60°  below  zero  F.  is  no  hardship,  provided  one  wears  com- 
pletely dry  clothing,  while  with  moist  clothing  one  would  perish  in  a 
very  short  time.  Some  parts  of  Siberia  are  both  cold  and  damp,  and 
hence  uninhabitable.  Atmospheric  moisture  has,  therefore,  directly 
opposite  eifects  ;  it  intensifies  the  effects  of  heat  and  also  those  of  cold. 

DUST  AND  MICRO-ORGANISMS. 

Another  normal  constituent  of  the  atmosphere — one  of  enormous 
importance — is  dust ;  normal,  because  it  is  everywhere  in  the  atmos- 
phere, and  because  a  perfectly  dustless  air  is  an  artificial  product  obtained 
only  with  the  observance  of  great  care.  The  individual  particles  are 
very  small,  but  at  the  same  time  very  variable  in  size,  ranging  from 
those  plainly  discernible  to  the  naked  eye,  to  those  of  extreme  minute- 
ness. 

Dust  is  organic  and  mineral,  and  has  its  origin  in  countless  processes. 
It  includes  particles  of  animal  matter,  vegetable  substances  of  every 
kind  including  bacteria  and  moulds,  sea  salt,  matters  swept  from  the 
soil  by  the  action  of  winds,  those  discharged  by  volcanoes,^  others  from 
manufacturing  establishments,  from  chimneys,  and  from  the  millions 
of  meteorites  which  daily  fall  from  interplanetary  space.  The  ordi- 
nary combustion  of  illuminating  gas  yields  millions  and  millions  of 
particles  of  carbon  for  every  individual  cubic  foot. 

Organic  dust  exists  only  in  the  lower  strata  of  the  atmosphere,  but 
that  of  mineral  origin  is  everywhere.  Micro-organisms  are  very 
abundant  in  the  air  of  inhabited  rooms,  and  in  general  in  that  of  towns 
and  cities,  less  abundant  in  the  country,  and  least  at  great  heights  and 
at  sea.  Experiments  have  shown  that  at  an  elevation  above  6,300  feet 
the  air  is  free  from  them.  Pasteur  exposed  a  large  number  of  flasks 
of  broth  at  an  altitude  of  6,000  feet,  and  obtained  a  growth  in  but  one. 
Tyndall  exposed  27  flasks  at  8,000  feet,  and  got  no  growth  whatever. 
Dr.  Fisher^  has  shown  that  on  the  ocean,  120  miles  from  land,  the  air 
is  usually  free  from  organisms,  and  that  at  lesser  distances — 90  miles, 
for  example — it  contains  but  few. 

The  air  of  cities  contains  thousands  in  every  cubic  meter,  against 

'After  the  great  cniptinn  in  Jjiva  in  ISSo,  a  liaze  of  extremely  fine  i)arti('les  of 
pumice,  estimated  to  \>f  from  seven  to  more  tlian  twenty  miles  above  the  earth,  was 
visible  in  all  parts  of  tlu^  world  foi- several  months. 

^  Zij^itselirifl  fiir  Hygiene,  i.,  p.  410. 


234 


AIR. 


less  than  a  hundred  in  the  same  volume  of  country  air.  It  has  been 
calculated  that,  in  densely  populated  places,  such  as  London  and  Man- 
chester, an  individual  inhales  in  the  course  of  an  hour  upward  of 
4,000,000  of  germs  and  spores.  But  this  figure  is  enormously  in  excess 
of  the  figure  given  by  Flugge,^  who  estimates  that  in  seventy  years  a 
man  may  inhale  25,000,000  bacteria,  which,  he  says,  is  about  what  one 
swallows  in  25  cc.  of  ordinary  milk. 

The  number  of  bacteria  in  air  is  influenced  very  greatly  by  dry  winds 
and  aqueous  vapor.  The  former,  sweeping  them  up  from  the  surface, 
increases  their  number ;  the  latter,  by  condensing  on  them  and  on  the 
dust  particles  to  which  they  adhere,  causes  them  to  fall  to  the  ground. 
Thev  are  washed  out  of  the  air  by  rain,  and  are  killed  by  long  exposure 
to  bright  sunshine.  Moulds,  on  the  other  hand,  have  been  observed  by 
Miquel  to  increase  rapidly  after  a  rainstorm,  and  to  be  much  less 
affected  by  winds. 

The  average  number  of  organisms  found  at  Montsouris  in  an  inves- 
tigation which  lasted  six  years  was  455  per  cubic  meter.     The  lowest 

results  were  observed  in  Februar}'  and  the 
highest  in  July.  During  the  same  period, 
the  number  in  the  air  at  the  center  of  Paris 
was  3,910  ;  the  smallest  figures  were  yielded 
in  January  and  the  highest  in  May. 

All  organisms  are  less  numerous  in  the  air 
at  niffht,  since  then  there  is  less  mechanical 
disturbance  of  the  earth's  surface. 

While  the  number  of  bacteria  in  outdoor 
air  may  be  fairly  high,  it  should  be  borne  in 
mind  that  the  majority  of  them  are  of  the 
harmless  varieties,  and  that  the  pathogenic 
kinds  constitute  only  an  infinitesimal  pro- 
portion. 

Dust,  as  has  been  said,  is  of  enormous  im- 
portance. Without  it  there  would  be  no  rain, 
no  fog,  no  clouds ;  the  air  would  be  satu- 
rated with  moisture,  and  every  object  would 
be  continually  wet. 

Dust  is  largely  hygroscopic,  and,  there- 
fore, attracts  the  watery  vapor  of  the  atmos- 
phere, thus  becoming  the  nucleus  for  a  drop 
of  rain  or  particle  of  mist.  Were  it  not  for 
its  presence  in  the  air,  the  aqueous  vapor 
would  condense  without  rain  on  every  tree  and  plant,  every  ^  rock, 
every  dwelling,  every  living  creature,  and,  m  short,  on  every  object  to 
which  air  has  access. 

That  atmospheric  dust  is  necessary  for  the  production  of  rain  and 
fog,  may  be  demonstrated  very  simply  by  condensing  moisture  from  a 
saturated  atmosphere  through  lowering  of  the  temperature,  and  noting 
^  Grundriss  der  Hygiene,  1897. 


Apparatus  for  demonstrating  the 
relation  of  dust  to  rain  and  fog. 


CARBON  MONOXIDE,  ETC.  235 

what  occurs  when  rlust  is  present  or  absent.  For  this  purpose,  a  simple 
apparatus  such  as  is  shown  in  Fig.  8  is  all  that  is  required.  This  con- 
sists of  a  large  flask  fitted  with  a  rubber  stopper,  through  which  pass 
two  pieces  of  glass  tubing,  to  the  free  ends  of  which  pieces  of  rubljer 
tubing  with  pinchcocks  are  attached.  The  glass  tubes  project  beyond 
the  shoulder  into  the  body  of  the  flask.  If  we  pour  into  the  flask  an 
amount  of  water  rather  more  than  sufficient  to  fill  the  neck  when  the 
flask  is  inverted  with  the  stopper  in  position,  we  have  the  conditions 
necessary  for  complete  saturation  of  the  confined  air  with  watery  vapor. 
If  now  we  withdraw  by  suction  through  one  of  the  rubber  tubes  a 
small  amount  of  the  contained  air,  the  temperature  falls  at  once ;  and 
inasmuch  as  the  air  within  is  already  saturated,  and  since  the  lowering 
of  the  temperature  of  a  saturated  atmosphere  is  accompanied  by  con- 
densation of  part  of  its  moisture,  such  a  condensation  occurs  within  the 
flask,  and  is  manifested  by  the  formation  of  a  distinct  haze  which  fills 
the  whole  air  space.  If  next  we  restore  the  original  pressure  by  read- 
mitting sufficient  air  to  abolish  the  partial  vacuum,  the  mist  disappears 
instantly.  The  production  and  dissipation  of  the  mist  cloud  may  be 
repeated  indefinitely  so  long  as  nothing  is  done  to  remove  the  dust  from 
the  air ;  but  if  we  wash  the  air  thoroughly  by  shaking  the  flask  vigor- 
ously for  a  few  minutes,  and  then  repeat  the  experiment,  no  visible 
mist  is  produced. 

CARBON  MONOXIDE,  ETC. 

Other  matters  found  in  air  include,  under  certain  conditions,  traces 
of  sulphuretted  hydrogen,  sulphurous,  sulphuric,  and  hydrochloric  acids, 
carbon  disulphide  from  rubber  factories,  marsh  gas,  carbon  monoxide 
from  illuminating  gas,  fumes  of  zinc,  arsenic,  and  phosphorus,  organic 
vapors  from  offensive  trades,  and  other  gaseous  and  solid  matters  too 
numerous  to  mention. 

The  most  important  of  these  is  carbon  monoxide,  a  very  powerful 
poison,  often  present  in  the  air  of  inhabited  rooms  from  leaking  gas 
pipes,  imperfect  combustion  of  illuminating  gas,  and  defects  in  heating 
apparatus  fed  with  coal.  It  is  yielded  in  great  abundance  by  burning 
charcoal,  and  is  given  off"  in  small  amounts  from  stoves  of  cast  iron, 
which  material  in  a  red-hot  condition  absorbs  it  in  considerable  amounts 
from  burning  coal.  This  was  noticed  first  by  Dr.  Garret,^  of  Chambery, 
who  described  an  outbreak  of  sickness  traced  by  him  to  this  cause. 
Later,  this  property  of  cast  iron  was  established  beyond  a  doubt  by 
others.  Another  by  no  means  insignificant  source  is  burning  tobacco, 
1  gram  of  which,  according  to  Grehant,^  yields  82  cc.  of  the  gas.  Its 
presence  in  the  air  of  rooms  in  which  smoking  is  carried  on  was  illus- 
trated by  Kunkel,'  in  1888,  before  a  society  of  scientists,  by  exposing 
a  small  amount  of  blood  solution  to  two  puffs  of  tobacco  smoke,  and 
demonstrating  the  absoqjtion  of  the  gas  by  means  of  the  spectroscope. 

'  Coinptes  rend  IIS,  1805,  p.  793. 

'  Annal(.-s  iV\\\i(\lxu-  piihli(|iR",  1871),  jj.  115. 

•*  Sitzu(ii,'sl)criclit  flci'  i)liysik;(liscli-riii'(licini.sche  Gesellschaft  zii  Wiirzburg,  1888,  p.  89. 


236  AIR. 

The  most  important  source  of  all  is  illuminating  gas,  which  contains 
it  in  varying  amounts,  according  to  its  mode  of  manufacture.  Under 
ordinary  conditions,  the  leakage  of  gas  from  the  mains  into  the  soil  and 
thence  into  the  atmosphere  is  enormous.  Pettenkofer  ^  reckoned  that 
in  badly  jointed  systems  at  least  a  fifth  of  the  annual  output  is  lost  in 
the  ground,  and  Wasserfuhr^  has  calculated  the  annual  loss  in  Paris 
due  to  leaks  as  15,000,000  cubic  meters.  Leakage  occurs  from  im- 
perfect joints,  faulty  cocks,  and  corroded  iron  pipes.  Besides  that  due 
to  leakage,  we  have  to  reckon  with  that  due  to  imperfect  combustion. 
While  an  Argand  or  other  burner  acting  normally  gives  off  no  trace 
of  carbon  monoxide,  a  certain  proportion  of  the  gas  Mall  escape  oxida- 
tion and  mingle  Avith  the  air  of  the  room  together  with  other  impuri- 
ties, if  the  gas  supply  is  not  properly  regulated.  The  use  of  gas 
stoves  is  responsible  for  more  or  less  contamination  due  to  imperfect 
combustion,  for  when  a  cold  object  is  put  into  the  flame,  the  latter  is 
cooled,  and  part  of  its  carbon  monoxide  is  given  oflP  as  such.  Imper- 
fect combustion  of  kerosene  is  still  another  source  which  should  not  be 
overlooked,  for  a  smoking  lamp  exerts  a  very  decided  influence  on 
the  respirability  of  the  air  of  a  room,  aside  from  the  discomfort  caused 
by  the  particles  of  soot. 

Less  than  0.25  per  cent,  by  volume  in  the  air  will  cause  poisoning, 
and  but  1  per  cent,  is  rapidly  fital  to  animal  life,  owing  to  the  fact  that 
it  unites  very  readily  with  the  haemoglobin  of  the  blood  corpuscles, 
forming  a  stable  chemical  compound,  carboxyhsemoglobin,  which  will 
neither  take  up  and  carry  oxygen  to  the  tissues  nor  promote  the  elim- 
ination of  carbon  dioxide.      As  a  consequence,  asphyxia  occurs. 

In  fatal  cases  of  poisoning,  carbon  monoxide  produces  a  rapid  par- 
enchymatous degeneration  of  the  liver,  kidneys,  spleen,  and  heart. 

Carbon  monoxide  has  been  proved  by  L.  de  Saint  Martin  ^  to  be 
present  in  minute  amounts  in  the  blood  of  animals  living  in  cities. 
Nicloux  *  has  gone  farther,  and  demonstrated  its  existence  in  that  of 
animals  in  the  country,  and,  indeed,  in  about  the  same  amounts  (0.16 
volume  per  cent.).  Nicloux  finds  by  experiment  that  it  is  not  derived 
from  the  air,  but  is  developed  directly  in  the  system,  and  that  its 
amount  is  diminished  by  bringing  about  slight  asphyxiation.  Potain 
and  Drouin ''  have  shown  that,  at  ordinary  temperatures,  it  is  oxidized 
gradually  to  carbon  dioxide. 

Contamination  of  the  air  of  dwellings  with  gas  from  leaking  street 
mains  is  quite  common,  and  fatal  results  are  not  infrequent,  the  gas 
travelling  through  the  soil  for  considerable  distances  and  being  draAvn 
up  through  cellars  by  the  force  of  aspiration  brought  into  play  by  the 
difference  between  internal  and  external  temperatures.  Many  cases  of 
fatal  poisoning  have  been  recorded  in  which  the  gas  was  aspirated 
through   the   soil   for  more   than  a  hundred  feet.     Such  accidents  are 

^  Ueber  die  Vergjftung  mit  Leuchtgas.     Nord  und  Sud,  January,  1884. 

^  Deutsche  Vierteljahrsschrift  fiir  oftentliche  Gesundheitspflege,'  XVIL,  1885,  p.  309. 

^  Comptes  rendus,  CXXVI.,  p.  1036. 

'  Ibidem,  CXXVI.,   pp.  1526,  1595. 

*  Ibidem,  C:XXVI.,  p.  938. 


"SEWEE  GAS."  237 

naturally  more  likely  to  occur  in  streets  which,  l)eing  well  paved, 
present  an  obstacle  to  the  escape  of  the  gas  upward.  The  odorous 
constituents  of  the  gas  serve  a  very  useful  purpose  in  pointing  out  the 
danger,  but  sometimes  they  are  held  back  by  the  earth  and  cannot  per- 
form that  office. 

Dr.  J.  S.  Haldane  has  pointed  out  that  air  vitiated  by  gas  combus- 
tion to  such  an  extent  as  to  show  30  parts  of  CO2  in  10,000  will  con- 
tain about  1  part  of  SO2  per  500,000,  and  that  this  amount  is  suffi- 
cient to  cause  marked  discomfort.  The  air  of  a  room  lighted  with  oil 
was  not  unpleasant,  except  for  the  heat,  when  the  COg  content  rose  to 
75  ;  but  when  gas  was  burned  it  was  distinctly  unjjleasant  when  the 
CO2  rose  to  40  in  10,000. 

"  SEWER  GAS." 

Another  impurity  is  what  commonly  but  improperly  is  called  "  sewer 
gas."  This  is  simply  sewer  air  which  may  be  more  or  less  foul  by 
reason  of  containing  the  emanations  of  sewage  matters.  Its  chemical 
composition  depends  upon  the  extent  to  which  the  gases  of  decomposi- 
tion are  generated,  and  upon  the  rate  of  ventilation.  It  may  be  almost 
as  pure  as  the  outside  air ;  it  may  be  as  rich  in  carbon  dioxide  as  the 
air  of  badly  ventilated  rooms ;  and  it  may  be  much  worse.  From 
10  to  30  volumes  of  CO^  in  10,000  are  found  quite  commonly.  Dr. 
W.  J.  Russell  found  as  high  as  51  volumes  in  10,000  in  the  air  of  one 
of  the  London  sewers,  and  Letheby  as  high  as  53.2  in  that  of  another, 
while  in  an  unventilated  sewer  in  Paris  as  high  as  340  volumes  have 
been  reported.  Sulphuretted  hydrogen  and  ammonium  sulphide  are 
ordinarily  present  in  small  amounts  or  mere  traces,  and  may  be  wholly 
absent ;  but  in  old  unventilated  sewers,  they  may  be  present  in  notable 
amounts.  The  highest  recorded,  299  volumes  in  10,000,  was  found  by 
Parent-Duchatelet  in  an  old  choked  sewer  in  Paris.  Marsh  gas, 
ammonia  and  compound  ammonias,  and  other  gaseous  products  of  de- 
composition of  organic  matter,  may  be  present  in  variable  amounts, 
according  to  circumstances. 

Sewer  air  contains  micro-organisms  and  animal  and  vegetable  debris, 
just  as  does  the  outer  air ;  but,  as  a  matter  of  fact,  the  number  of 
bacteria  is  invariably  small,  and  they  are  often  wholly  absent.  This 
was  shown  first  in  1883  by  Miquel,  whose  results  have  been  corrob- 
orated by  those  of  a  number  of  other  investigators,  including  Carnelly 
and  Haldane,  Laws  and  Andrews,  and  Percy  Frankland.  The  first 
mentioned  conducted  a  most  elaborate  chemical  and  bacteriological  ex- 
amination of  sewer  air,  and  proved  that  from  both  points  of  view  it 
compares  favorably  with  the  air  of  schools  and  small  dwellings,  and 
that  bacteriologically  it  is,  indeed,  far  superior.  It  contains  fewer 
organisms  than  the  air  of  the  streets  above  or  of  any  kind  of  dwelling, 
and  such  as  are  ])resent  come  entirely  or  chiefly  from  the  outer  air,  and 
not  from  the  sewage. 

Laws  and  Andrews  arrived  at  the  same  conclusions  after  a  similar 
research.     In  each  sample  of  sewage  examined,  B.  coli  communis  was 


238  AIR. 

foimd  in  numbers  varying  from  20,000  to  200,000  per  cc,  and  closely 
allied  species  in  even  greater  abundance  ;  but  neither  the  one  nor  any  of 
the  others  was  found  in  the  many  samples  of  air  examined.  They 
found,  farther,  that  the  number  of  organisms  existing  in  sewer  air 
depends  entirely  upon  the  number  present  in  the  outside  air  in  the 
immediate  vicinity,  and  that  while  sewage  bacteria  are  largely  of  the 
liquefying  varieties,  such  are  practically  absent  in  the  air. 

The  chief  importance  of  "  sewer  gas  "  lies  not  in  its  power  to  pro- 
duce disease,  but  in  its  capacity  for  being  the  vehicle  for  odors  which 
make  the  air  disagreeable,  but  not  necessarily  dangerous  to  health, 
except  that  appetite  and  digestion,  and  hence  general  nutrition,  may  be 
interfered  with. 

As  a  matter  of  fact,  sewer  air  has  served  for  a  long  time  as  a  most 
convenient  scapegoat  in  investigations  of  the  cause  and  spread  of  out- 
breaks of  typhoid  fever  and  other  infectious  diseases,  and  as  a  most 
useful  aid  in  explaining  obscure  questions  of  various  sorts.  Many  be- 
lievers in  the  sewer-air  theory  of  dissemination  of  typhoid  fever  hold 
that  the  coarser  dust  particles  carry  the  germs  on  their  surface,  and 
may  be  blown  about  through  considerable  distances  before  the  organisms 
lose  their  vitality ;  but  the  great  objection  to  this  explanation  is  that  in 
sewers  and  cesspools  the  typhoid  bacillus  is  destroyed  speedily  by  other 
organisms,  and  that,  even  though  it  be  present  in  an  active  state  in 
liquid  se\vage,  it  is  extremely  unlikely  that  it  will  be  released  therefrom 
into  the  air.  No  ordinary  stirring  up  of  the  water  will  throAV  the 
germs  into  the  air  ;  although,  according  to  the  researches  of  Frankland,^ 
the  bursting  of  gas  bubl)les  generated  by  decomposition  will  throw  into 
the  air  traces  of  chemical  salts  which  have  been  mixed  and  dissolved  in 
the  sewage,  and  in  the  same  way  may  throw  out  bacteria  as  well.  But 
it  has  been  shown  by  Nageli  that  bacteria  cannot  be  given  oflP  from 
moist  surfaces. 

Another  explanation,  offered  by  Dr.  C.  R.  C.  Tichbourne,^  is 
that  the  disease  germs  are  scattered  into  the  air  by  the  fermenting 
sewage,  and  carried  by  a  mist  formed  when  the  warm  sewer  air, 
saturated  with  moisture,  meets  the  colder  external  air  at  the  points 
where  ventilating  outlets  are  placed.  Then  each  minute  droplet  of 
mist,  carrying  one  or  more  microbes,  is  transported  through  longer  or 
shorter  distances  in  the  air,  perhaps  into  dwellings,  and  eventually, 
by  the  influence  of  the  heat  of  the  sun  or  by  other  natural  agency, 
becomes  dissipated  as  vapor,  and  leaves  the  organisms  suspended  in  the 
atmosphere. 

The  majority  and  the  best  of  the  German  investigators,  as  Flugge, 
Rubner,  Gartner,  Soyka,  Prausnitz,  and  others,  maintain  that  sewer 
air  and  sewer  gases  are  incapable  of  conveying  the  germs  of  typhoid 
fever  and  other  infective  diseases.  It  is  true  that  some  of  the 
gases  given  off  in  the  putrefactive  processes  which  go  on  in  sewers 
are  more  or  less  poisonous,  but  whether  they  are  capable  of  produc- 

^  Proceedings  of  the  Eoyal  Society,  1879. 

^  Dublin  Journal  of  Medical  Sciences,  July,  1897. 


"SEWER   GAS."  239 

ing  injurious  effects  depends  very  much  on  the  amount  inhaled  and 
on  the  degree  of  concentration.  In  any  event,  they  are  certainly  in- 
capable of  producing  any  infective  disease  in  the  absence  of  the  specific 
germ. 

In  any  well-constructed  and  properly  ventilated  sewer,  no  great 
amount  of  putrefaction  will  go  on,  since  the  sewage  matters  soon  pass 
on  and  are  discharged  ;  consequently  not  much  gas  will  be  evolved, 
and,  with  proper  ventilation,  whatever  is  evolved,  is  soon  dissipated  in 
the  outer  air.  Offensive  gases  and  odors  are  much  more  likely  to  be 
given  off  by  unclean  unventilated  house-plumbing  than  by  well-built 
sewers. 

It  is  asserted  commonly  that  the  inhalation  of  small  amounts  of  this 
air  will  produce  headache,  anaemia,  loss  of  appetite,  sore  throat,  albu- 
minuria, diarrhoea,  and  other  symptoms,  and  that  it  may  be  the  exciting 
or  auxiliary  cause  of  typhoid  fever,  measles,  diphtheria,  scarlet  fever, 
dysentery,  and  other  infective  diseases.  But  in  the  cases  which  are 
accepted  as  proving  the  causal  relation,  inference  has  taken  the  place  of 
proof,  no  other  means  of  infection  being  ascertainable.  In  not  a  single 
case  has  the  supposed  relation  been  demonstrated  bacteriologically. 

In  answer  to  the  well-known  stubborn  fact  that  the  workmen  em- 
ployed in  all  the  large  systems  of  sewerage — men  whose  occupation 
involves  the  daily  and  constant  inhalation  not  of  traces,  but  of  large 
volumes,  of  sewer  air — are  as  a  class  unusually  healthy  and  strong,  with 
a  high  mean  age  at  death  and  a  low  death-rate,  it  is  asserted  that  they 
become  immunized  by  daily  contact,  and  thus  escape.  If  we  accept  this 
theory,  however,  we  should  go  farther,  and  say  that  large  doses  are  a 
benefit  in  that  they  confer  immunity,  and  that,  therefore,  all  precau- 
tions against  the  admission  of  sewer  air  to  the  air  of  dwellings  are  mis- 
directed, and  should  be  abandoned. 

The  air  of  properly  constructed  sewers  is  in  constant  motion,  brought 
about  by  differences  in  temperature  and  mechanically  through  influx 
of  sewage.  During  the  colder  months,  the  temperature  within  the 
sewer  is  higher  than  that  of  the  air  above,  and  it  is  influenced  materially 
by  the  fact  that  the  entering  sewage  is  largely  warm  ;  therefore,  sewer  air 
tends  to  rise  and  escape  through  the  openings  in  the  man-hole  covers. 
During  the  warm  season,  the  natural  interchange  is  much  lessened,  since 
then  the  conditions  as  to  temperature  are  reversed.  At  night,  however, 
at  all  seasons,  the  temperature  of  the  air  of  the  sewer  is  higher  than 
that  of  the  atmosphere  above,  and  thus  ventilation  goes  on  by  natural 
laws  the  year  round.  Much  air  is  displaced  by  the  entering  sewage  ; 
in  fact,  disregarding  the  effect  produced  by  the  warmth  of  the  sewage, 
for  every  cubic  foot  of  sewage  which  enters,  a  cubic  foot  of  air  is  forced 
out,  and  as  the  sewage  is  discharged,  more  air  enters  to  take  its 
place. 

Owing  to  the  prevailing  belief  in  the  noxious  character  of  sewer  air, 
it  was  formerly  the  custom  to  place  baskets  of  charcoal  in  the  out- 
let shafts  of  the  man-holes,  })ut  as  this  material  loses  its  absorptive 
property  with  access  of  moisture,  the  plan  was  abandoned.    It  was  also 


240  -  AIR. 

regarded  as  an  advantage  to  connect  the  sewer  with  chimneys,  which 
act  as  ventilators,  but  in  the  light  of  farther  knowledge  and  because 
of  excessive  action,  that  method  of  ventilation  fell  into  disuse. 

ORGANIC  MATTERS. 

Among  other  impurities  given  off  to  the  air,  the  organic  matters 
from  the  processes  of  the  body  are,  in  a  way,  of  considerable  impor- 
tance. These  include  particles  of  epithelium,  the  constituents  of  sweat 
(butyric,  capric,  capronic,  and  caprylic  acids,  lactate,  butyrate,  and 
other  salts  of  ammonium),  and  volatile  matters  from  foul  mouths, 
decaying  teeth,  and  the  digestive  tract,  and  excrementitious  matters 
deposited  on  unclean  clothing.  In  addition  to  these,  it  has  been 
asserted  that  other  matters  of  a  poisonous  character  are  given  off  in 
the  process  of  respiration,  which  matters  will  be  referred  to  later  on  in 
the  discussion  of  the  effects  of  impure  air  on  health.  That  the  air  of 
inhabited  confined  spaces  may  contain  organic  animal  matter,  is  appar- 
ent to  the  senses  when  one  enters  such  an  atmosphere  from  one  not 
thus  contaminated. 

Effects  of  Vitiated  Air. 

The  effects  of  foul  air  on  the  system  are  of  great  importance,  and 
vary  in  degree  within  very  wide  limits.  For  proper  aeration  of  the 
blood,  it  is  necessary  that  the  oxygen  of  the  air  shall  be  present  in  the 
normal  proportion  in  the  free  state,  and  not  in  chemical  union  with 
carbon  as  a  waste  product.  Farther,  it  is  necessary  for  the  proper  ex- 
cretion of  the  carbon  dioxide  of  the  blood  that  the  difference  in  the 
tension  of  that  gas  in  the  air  and  of  that  in  the  blood  shall  be  as  wide 
as  possible ;  that  is  to  say,  the  less  the  amount  of  carbon  dioxide  in 
the  inspired  air,  the  greater  the  facility  with  which  the  blood  can  dis- 
engage that  which  it  carries  to  the  lungs.  Any  interference  with  this 
most  important  function  of  the  body  must  have  an  injurious  effect  on 
the  general  health,  and  it  is  accepted  generally  that  unpurity  of  the  air 
is,  without  doubt,  the  most  important  of  the  predisposing  causes  of 
disease. 

It  is  well  known  that,  other  conditions  being  equal,  in  proportion  as 
a  people  are  drawn  to  employments  indoors,  the  disease-rate  and  death- 
rate  are  increased.  This  is  particularly  true  as  regards  phthisis,  which 
is  preeminently  associated  with  overcrowding. 

Overcrowding  means  the  association  of  two  or  more  people  in  a 
space  so  confined  as  to  preclude  the  admission  of  a  constant  supply  of 
fresh  air  sufficient  in  amount  to  maintain  a  proper  dilution  of  their 
excretory  products  and  a  normal  supply  of  free  oxygen.  It  was  recog- 
nized long  ago  as  a  most  important  factor  in  the  production  of  a  high 
death-rate  among  occupants  of  crowded  jails,  barracks,  and  hospitals ; 
and  experience  has  demonstrated  repeatedly  that  increase  in  space 
allowance  is  followed  always  by  decrease  in  sickness-  and  death-rates. 
At  one  time,  for  example,  the  English  army  averaged  11.9  deaths  per 


EFFECTS   OF   VITIATED  AIR.  241 

1,000  men  annually,  from  phthisis  alone ;  more  efficient  barrack  ven- 
tilation and  increase  of  average  air  space  caused  immediate  improve- 
ment, and  the  phthisis-rate  fell  gradually  to  1.2  per  1,000.  The 
same  general  result  has  been  observed  in  the  armies  of  France,  Russia, 
Germany,  and  Belgium. 

What  is  true  of  overcrowding  applies  not  alone  to  human  beings, 
but  to  animals  as  well,  and  it  is  a  well-known  fact  that  crowded  stables 
show  high  mortality  among  cows  and  horses.  It  has  such  a  remark- 
able influence  on  egg  production  and  growth  of  fowls  that  practical 
poultrymen  are  exceedingly  careful  on  this  point. 

The  immediate  effects  of  inhalation  of  impure  air  are  discomfort  and 
oppression,  which  may  amount  to  headache,  dizziness,  faintness,  and 
even  nausea.  Continued  exposure  is  likely  to  bring  about  a  gradual 
impairment  of  health,  shown  by  pallor,  languor,  anaemia,  skin  troubles, 
loss  of  appetite,  and  diminished  power  of  resistance  to  the  exciting 
causes  of  disease,  and  this  is  especially  true  of  those  whose  daily  work 
is  carried  on  in  crowded  sj)aces. 

It  is  customary  to  cite  as  extreme  cases  of  overcrowding  and  its 
effects,  the  Black  Hole  of  Calcutta,  the  ship  Londonderry,  and  the 
prison  at  Austerlitz ;  but  the  conditions  that  obtained  in  each  of  these 
instances  were  most  unusual,  and  the  cases  are  of  historical  rather  than 
sanitary  interest,  since  the  confining  of  a  number  of  persons  in  a  space 
from  M^hich  air  is  practically  excluded  can  have  but  one  outcome. 

The  Black  Hole  of  Calcutta  is  the  name  applied  to  the  military 
prison  of  Fort  William,  where,  in  June,  1756,  Surajah  Dowlah  con- 
fined 146  persons  over  night  in  a  space  of  less  than  5,900  cubic  feet, 
with  two  small  windows  in  one  side.  Within  an  hour,  all  broke  out 
in  a  profuse  sweat,  and  were  tortured  with  thirst  and  difficult  breathing ; 
in  three  and  a  half  hours,  a  majority  were  delirious,  and  when  the  place 
was  opened  in  the  morning,  123  of  the  prisoners  were  found  dead. 

In  the  case  of  the  Londonderry,  which,  in  December,  1848,  left  Sligo 
for  Liverpool  and  ran  into  a  storm,  200  steerage  passengers  were  con- 
fined over  night  in  a  space  18  by  11  by  7  feet,  with  no  means  of  ven- 
tilation. In  the  morning,  when  they  were  released,  it  was  found  that 
over  70  had  expired. 

In  the  other  extreme  case,  that  at  Austerlitz,  300  captured  soldiers 
were  confined  in  a  small  cellar,  and  within  a  few  hours  all  but  40  were 
dead. 

To  what  one  or  more  conditions  of  impure  air  are  the  ordinary 
effects  due  ?  We  have  seen  that  COj  is  in  itself  not  an  active  poison, 
and  that  its  action  is  to  interfere  with  the  proper  oxygenation  of  the 
blood  within  the  lungs.  The  aqueous  vapor  of  respiration  and  from 
the  skin,  and  that  produced  in  the  combustion  of  illuminating  material, 
constitutes  an  important  part  of  a  vitiated  atmosphere,  and  is  respon- 
sible for  at  least  a  part  of  the  discomfort  produced  ;  but  it  is  also  true 
that  a  deficiency  in  watery  vapor  in  the  air  of  well-ventilated  rooms 
has  equal  or  greater  disadvantages,  as  will  appear  in  the  consideration 
of  Ventilation, 
ifi 


242 


AIR. 


Concerning  the  effect  of  usual  amounts  of  ordinary  dust  in  in- 
habited rooms,  there  is  little  to  be  said.  The  micro-organisms,  most 
of  which  are  non-pathogenic,  vary  in  number  with  efficiency  of  ven- 
tilation. In  pure  air,  the  bacteria  and  moulds  approximate  each  other 
in  number ;  but  in  vitiated  air,  the  bacteria  increase  in  number,  while 
the  moulds  are  much  less  affected.  The  experiments  of  Carnelly, 
Haldane,  and  Anderson  showed  a  progressive  increase  in  both  bacteria 
and  moulds  with  diminished  ventilation.     Thus, 


Character  of  air  space. 

Number  organisms  in  10  L.  air. 

Ratio  of 
moulds  to 

Moulds. 

Bacteria. 

bacteria. 

External  air 

2 

4 

22 

12 

6 

85 
430 

580 

1  •  3 

4-roorued  houses 

1  •  21 

2-i'oonied  houses 

1:20 
1  •  48 

1-roomed  houses 

The  increase  in  bacteria  is  not  due  to  respiration,  though  a  diminu- 
tion in  their  number  might  be  thus  explained  ;  for  the  great  majority 
of  inhaled  bacteria  are  filtered  out  by  the  nose,  and  the  expired  air  is 
almost  completely  free  from  germs,  although  they  may  be  thrown  out 
in  the  act  of  coughing  or  sneezing. 

Investigation  thus  far  has  not  proved  that  the  bacteria  of  infection 
are  commonly  introduced  into  the  system  through  the  medium  of  re- 
spired air. 

As  has  been  mentioned,  it  is  held  by  many  that  the  effects  of  vitiated 
air  are  not  due  to  carbon  dioxide,  but  to  the  organic  matters  and  aqueous 
vapor  given  off  by  the  lungs  and  skin,  and  that  these  are  estimated 
conveniently  by  determining  the  amount  of  carbon  dioxide  with  which 
they  are  discharged.  It  is  said  also  that,  while  considerable  carbon 
dioxide  escapes  even  under  the  most  imperfect  system  of  ventilation,  the 
organic  matters  and  watery  vapor  do  not  so  readily  pass  out,  but  are 
deposited  on  walls,  furniture,  hangings,  and  clothing,  where  they  putrefy 
and  become  offensive.  As  proof  of  this,  is  cited  the  fact  that  a  room  in 
which  a  person  has  slept  without  adequate  ventilation  has  an  unpleasant 
smell  in  the  morning,  and  that  this  persists  even  after  prolonged 
airing. 

Brown-Sequard  and  d' Arson val,  in  1888,  obtained  from  condensa- 
tion of  the  aqueous  vapor  of  men  and  animals  a  liquid  which,  injected 
into  rabbits,  caused  death  with  greater  or  less  rapidity,  according  to  the 
size  of  the  dose.  They  believed  the  toxic  element  to  be  of  the  nature 
of  a  volatile  alkaloid,  and  that  it  was  exhaled  dissolved  in  the  aqueous 
vapor  of  the  breath.  In  the  same  year,  Wurtz,  reporting  a  similar 
research,  claimed  to  have  found  a  toxic  substance. 

Merkel,^  in  1892,  claimed  to  have  obtained  positive  results,  and  con- 
cluded that  respired  air  from  persons  in  health  contains  a  minute  quan- 
tity of  a  volatile  organic  base,  which  is  poisonous  when  free,  but  innoc- 
^  Archiv  fiir  Hygiene,  XV.,  p.  1. 


EFFECTS  OF   VITIATED  AIR.  243 

uoiis  after  contact  with  an  acid.  Dr.  Sivierato  ^  collected  the  aqueous 
vapor  of  the  breath  of  persons  suffering  fr(jm  diseases  of  respiration, 
both  with  and  without  fever,  of  persons  with  no  respiratory  disease,  but 
with  fever,  and  of  persons  in  health,  and  injected  it  into  rabbits.  That 
from  those  with  respiratory  diseases  produced  fever  and  diminished 
reflexes  lasting  three  to  six  days  ;  that  from  cases  of  fever  with  no  res- 
piratory disease  caused  little  or  no  disturbance ;  and  that  from  persona 
in  health  produced  no  results  whatever. 

Formanek  ^  concluded,  after  much  study,  that  nO  poisonous  substance 
originates  in  the  limgs ;  that  the  ammonia  sometimes  found  is  not  a 
product  of  metabolism,  but  of  decomposition  in  the  mouth  cavity  (cari- 
ous teeth,  etc.)  and  in  the  trachea  and  lungs  after  tracheotomy,  and  in 
pulmonary  tuberculosis ;  that,  in  the  experiments  which  led  to  the 
theory  of  an  unknown  alkaloid,  ammonia  was  used,  and  might  have 
caused  the  observed  effects ;  and  that  the  results  of  overcrowding  can- 
not be  due  to  any  one  cause. 

Many  other  experimenters,  French,  German,  Italian,  American,  and 
English,  w^orking  along  the  same  lines,  but  with  extra  precautions  to- 
exclude  matters  from  the  nose  and  mouth,  have  failed  to  obtain  toxic 
effects  from  the  condensed  vapor ;  others  have  demonstrated  that  the- 
lungs  exhale  no  organic  matter  except  in  minute  amounts,  and  that 
these  have  no  poisonous  influence. 

Arloing  pursued  the  subject  further,  in  the  belief  that  the  constitu- 
ents of  the  sweat  are  concerned  in  the  harmful  effects.  He  soaked 
the  underclothes  of  a  man  who  had  spent  a  long  evening  in  dancing, 
and  injected  the  watery  extract  into  dogs  and  rabbits.  From  the  fact 
that  the  animals  showed  various  evidence  of  intoxication  and  died  he 
concluded  that  sweat  is  toxic.  Experiments  in  the  author's  laboratory,, 
however,  with  sweat  obtained  directly  from  well-scrubbed  forearms 
and  injected  in  considerable  amounts  into  rabbits  and  other  animals 
yielded  negative  results.  Sweat  vaporized  in  small  confined  spaces 
was  equally  innocent  of  harmful  results  to  men  and  animals  exposed 
thereto.  At  present  the  weight  of  evidence  leads  to  the  con- 
clusion that  the  injurious  action  of  vitiated  air  is  due  to  the  dimi- 
nution of  oxygen  and  to  the  increase  of  carbon  dioxide,  both  of  which 
factors,  alone  or  together,  interfere  ^^'ith  the  intake  of  oxygen  and  the 
excretion  of  carbon  dioxide  from  the  lungs.  Yet,  diminution  in 
oxygen,  which  even  in  very  crowded  rooms  does  not  proceed  very 
far,  is  met  by  increase  in  the  respiratory  function,  which,  however, 
cannot  increase  the  difference  between  the  tension  of  the  carbon  dioxide 
of  the  air  and  of  the  blood.  Not  even  in  very  imperfectly  ventilated 
mines  does  the  oxygen  fall  much  below  20  per  cent,  by  volume,  and 
thus  we  see  that  the  whole  range  of  fluctuation  in  the  oxygen  of  pure 
and  of  very  foul  air  is  but  little  more  than  1  volume  per  cent. 

Smith  and  Haldane^  have  shown  tliat  in  a  leaden  chamber  containing 

^  Arohives  Ttaliennes  dc  Jiiolooie,  1895. 

f  Archiv  fiir  Hygiene,  XXXVill.  (1<)00),  p.  ]. 

"  Journal  of  Patliology  and  Jjiictei'iology,  I.,  1892. 


244  AIB. 

air  which  had  suffered  but  slight  diminution  in  oxygen,  but  which 
(•(mtained  384  parts  of  carbon  dioxide  in  10,000,  two  men  suffered  from 
headache  immediately  on  entering. 

As  a  rule,  vitiated  air  is  associated  with  high  temperature  and  satu- 
ration with  aqueous  vapor,  which  latter  interferes  with  evaporation 
from  the  skin.  Less  often  it  is  associated  with  low  temperature,  and 
with  this  condition  comes  an  increased  demand  for  oxygen  to  meet 
the  requirements  of  the  oxidation  processes. 

It  seems  j)i'obable  that  where  the  carbon  dioxide  is  not  present  in  any 
great  excess,  and  the  oxygen  is  not  markedly  deficient,  the  conclusion 
arrived  at  by  Drs.  Weir  Mitchell,  Billings,  and  Bergey  is  true  ;  namely, 
that  the  discomfort  suffered  is  due  largely  and  chiefly  to  heat  and  dis- 
agreeable odors  arising  from  the  occupants  in  various  ways  :  from  bad 
breath,  unclean  skin,  unclean  clothes,  sweat,  and  gases  from  the  bowels. 
Such  may  induce  very  disagreeable  sensations,  amounting  even  to 
nausea,  in  those  who  are  not  habituated  to  such  influences  ;  but,  on  the 
other  hand,  those  who  are  accustomed  to  such  air  notice  no  discomfort. 

Disagreeable  smells  do  not  act  directly  as  a  cause  of  specific  disease, 
but  appear  to  have  an  influence  on  the  appetite,  and  hence  on  the  gen- 
eral well-being  of  persons  not  accustomed  to  them.  Much  is  due  also 
to  the  imagination  ;  a  disagreeable  smell  from  a  source  known  to  be 
clean  (chemicals,  for  instance)  has  not  ordinarily  as  much  influence 
as  another  of  equally  offensive  character  supposed  to  be  from  filth.  It 
seems  probable  also  that  there  is  much  to  learn  concerning  the  real 
effects  of  disagreeable  smells,  and  that  they  may  be  more  extensive  than 
we  now  commonly  believe  ;  but  in  order  to  determine  this,  we  shall 
need  methods  which  will  reveal  the  nature  of  the  odoriferous  substances 
and  make  their  isolation  possible. 

Other  causes  of  discomfort  may  be  sought  for  in  the  presence  of 
traces  of  carbon  monoxide  from  heating  apparatus  or  incomplete  com- 
bustion of  illuminating  gas,  and  in  excessive  diyness  of  the  air  due  to 
furnace  or  steam  heat. 

It  should  not  be  overlooked  that  impure  air  may  affect  the  vitality 
and  bactericidal  power  of  the  cells  of  the  air-passages  and  of  the  ali- 
mentary tract,  and  thus  lessen  the  power  to  resist  the  action  of  infective 
material. 

The  Air  as  a  Carrier  of  Infection. 

On  the  agency  of  air  in  spreading  infectious  matter,  much  has  been 
said  and  written,  and  much  careful  research  has  been  conducted,  but 
the  conclusions  reached  are  by  no  means  in  agreement  or  conclusive. 
It  is  conceded  generally  that  pathogenic  organisms  in  the  air  are  ad- 
herent to  particles  of  dust  of  various  kinds,  and  that  their  retention  of 
virulence  depends  upon  the  amount  of  hygroscopic  moisture  with  which 
they  are  associated.  The  conditions  favorable  to  their  continuance  as 
living  organisms  are  naturally  more  likely  to  obtain  in  indoor  air,  with 
imperfect  ventilation,  than  in  the  outer  air,  where  they  are  diluted 
and  blown  about  and  exposed  to  the  disinfectant  action  of  the  direct 


THE  A  IE  AS  A   CARRIER   OF  INFECTION.  245 

rays  of  the  sun.  Indoors  or  outdoors,  the  more  they  are  protected  by 
hygroscopic  dust  particles,  the  longer  they  will  retain  the  moisture 
which  is  essential  to  their  viability.  It  appears,  too,  that,  conditions 
being  equal,  certain  micro-organisms  retain  vitality  longer  than  others, 
some  being  but  slightly,  others  very  tenacious  of  life. 

With  regard  to  the  transmission  of  pulmonary  tuberculosis  through 
the  air,  it  should  be  said  that  while  there  can  be  no  doubt  that  this  dis- 
ease is  connected  preeminently  with  overcrowding  and  vitiated  air, 
there  is  a  very  decided  difference  of  opinion  as  to  the  method  of  con- 
veyance, some  contending  that  dust,  and  others  that  tuberculous 
material,  thrown  into  the  air  in  coughing,  speaking,  and  sneezing,  is 
the  vehicle. 

Buchner  has  found  B.  tuberculosis  in  an  active  state  in  the  dust  of 
a  room  a  year  after  the  death  of  its  occupant  from  the  disease.  G. 
Cornet^  demonstrated  its  presence  in  more  than  a  third  of  147  samples 
of  dust  collected  in  hospitals  and  other  public  institutions,  and  in  private 
houses  inhabited  by  phthisical  persons,  and  succeeded  later  in  producing 
the  disease  in  46  out  of  48  guinea-pigs  exposed  to  air  containing  dust 
from  dried  tuberculous  sputum.  Some  of  the  animals  were  placed  8 
inches  from  a  glass  vessel  containing  dried  pulverized  sputum  from  an 
advanced  case ;  others  were  placed  on  shelves  8  to  28  inches  from  the 
floor  of  a  room,  on  the  carpet  of  which,  sputum,  mixed  with  dust,  had 
been  spread  and  dried  and,  at  the  end  of  two  days,  stirred  up  by 
sweeping  ;  others  were  allowed  to  stay  in  the  room  without  disturbance 
of  the  dust. 

Klein  obtained  positive  results  with  guinea-pigs  placed  in  the  venti- 
lating shaft  of  a  consumptives'  hospital ;  but  Heron  ^  obtained  but  2.7 
per  cent,  of  positive  results  in  74  guinea-pigs  inoculated  with  dust  from 
the  ventilating  shaft  of  the  London  Hospital  for  Diseases  of  the  Chest ; 
and  Kirchner^  got  but  1  positive  result  out  of  16  pigs  inoculated  with 
the  dust  from  a  military  hospital.  Fliigge,  on  the  other  hand,  was 
wholly  unsuccessful  in  inducing  the  disease  in  guinea-pigs  exposed  to 
such  dust ;  and  concluded  that  the  transmission  from  one  person  to 
another  is  chiefly  by  means  of  the  finest  droplets  thrown  into  the  air  in 
speaking,  coughing,  and  sneezing.  From  later  experiments,  conducted 
under  his  supervision  by  Laschtschenko,  Heymann,  Sticher,  and 
Beninde,^  he  concluded  that  in  rooms  in  which  tuberculous  sputum  is 
dried  on  the  floor  or  other  places,  and  where  the  air  is  filled  with  coarse 
dust  through  dry  cleaning  and  air  currents,  or,  as  in  railway  cars,  by 
continual  mechanical  jarring,  infection  may  arise  ;  and  that,  under  these 
conditions,  long-continued  exposure  offers  a  certain  degree  of  probability 
of  infection.  Therefore,  dry  cleaning  is  to  be  avoided  in  rooms  in 
which  consumptives  are  employed  with  others,  and  the  rooms  should 
not  be  occupied  so  long  as  the  air  is  percejitibly  dusty.  The  great  pos- 
sibility of  infection  through  matters  thrown  off  in  coughing  and  sneez- 

•  Z(;itschrift  fiir  Ilygeine,  V.,  p.  191.  ''  The  Lancet,  .Januaiy  6,  1894. 
^  Zeitschrift  fiir  IIv>(iene  und  Infectionskrankheiten,  XIX.,  p.  lo3. 

*  Ibidem,  XXX.,  p.  107. 


246  AIR. 

ing  is  insisted  upon  as  of  paramount  importance.  This  danger  is  to 
he  prevented  by  requiring  the  person  coughing  to  hold  a  handkerchief 
or  the  hand  before  the  mouth  during  the  act,  and  by  the  avoidance  on 
the  part  of  others  of  approaching  within  a  meter. 

Answering:  Fliig^o^e,  Cornet  ^  contends  that  the  number  of  bacilli 
throAvn  into  the  air  during  the  act  of  coughing  must  be  extremely 
small.  He  caused  18  consumptives  to  hold  dishes  before  the  mouth 
while  coughing,  and  obtained  2  positive  results  therefrom  on  inoculation 
into  guinea-pigs ;  repeating  the  test  with  1 5  others,  he  got  none ;  but 
Heymann  ^  was  more  successful,  for  glass  plates  exposed  in  the  imme- 
<iiate  vicinity  of  coughing  consumptives,  confined  for  an  hour  and 
a  half  in  a  glass  cabinet  of  three  cubic  meters'  capacity,  were  proved 
to  have  become  contaminated  ^by  the  specific  organism.  The  plates 
were  rubbed  up  with  small  amounts  of  broth,  which  was  then  injected 
intraperitoneally  into  guinea-pigs,  mostly  with  positive  results. 

Experiments  conducted  by  Kdniger^  confirm  Fliigge  in  his  estimate 
of  the  danger  of  transmission  by  droplets.  In  order  to  give  the  ex- 
pelled droplets  a  character  which  would  admit  of  their  being  traced,  he 
rinsed  his  mouth  with  liquid  rich  in  B.  prodigiosus  or  B.  mycoides,  or 
with  very  dilute  caustic  soda,  and,  in  order  to  trace  them,  he  exposed 
Petri  dishes  and  glass  plates  coated  with  phenolphthalein,  which  agent, 
turning  pink  in  contact  with  an  alkali,  would  show  not  only  the 
number  of  droplets,  but  their  size  as  well.  It  was  found  that  no  drop- 
lets are  thrown  out  in  ordinary  exhalation  nor  in  vowel  formation,  but 
with  consonants,  as  t,  k,  and  p,  the  number  is  very  great,  and  is  largely 
dependent  upon  the  amount  of  force  with  which  the  air  under  pressure 
in  the  mouth  cavity  is  released  in  their  formation,  and,  therefore,  upon 
the  manner  of  pronouncing.  Loudness  and  rapidity  of  speech  have 
but  little  influence ;  whispering  may,  indeed,  under  some  conditions, 
cause  a  greater  number  of  droplets  tlian  loud  speech.  Even  with  sub- 
dued speech  and  a  quiet  atmosphere,  it  was  found  that  the  organisms 
expelled  reached  the  most  distant  parts  of  the  room,  which  was  more 
than  20  feet  in  width,  and  in  all  directions.  They  were  found  to 
remain  in  suspension  in  the  air  not  longer  than  an  hour,  and  it  was 
Doticed  that  they  fell  upon  the  plates  in  groups,  sometimes  as  many  as 
40  close  together,  which  suggests  that  they  fall  not  as  dry  dust  particles, 
but  that  the  droplets  themselves,  with  their  contained  or  adherent 
organisms,  are  deposited.  In  coughing  and  sneezing,  more  droplets 
are  expelled  than  in  speaking,  and  they  are  projected  to  a  greater  dis- 
tance, because  of  the  greater  force  engaged.  The  precautions  recom- 
mended apply  not  alone  in  tul^erculosis,  but  also  in  diphtheria,  w^hoop- 
ing-cough,  and  other  diseases  in  which  the  respective  specific  organisms 
are  found  in  the  air-passages. 

Hutchison*  found  that  bacteria,  sprayed  in  minute   droplets  upon 

^  Berliner  klinLsche  Wochenschrift,  May  13,  1899. 

^  Zeitschrift  fiir  Hvgiene  und  Infectionskiankheiten,  XXXVIII.  (1901),  p.  21. 

^  Ibidem,  XXXIV".  (1900),  p.  119. 

^  Ibidem,  XXXVI.  (1901),  p.  223. 


THE  AIR  AS  A   CARRIER   OF  INFECTION.  247 

objects,  perish  in  a  short  time,  the  main  factor  in  their  destruction  being 
the  influence  of  sunlight.  Sprayed  directly  into  the  air,  most  of  them 
were  found  to  have  become  deposited  within  a  half  hour,  when  the  air 
of  the  room  was  allowed  to  remain  undisturbed,  but  numbers  of  them 
were  kept  in  suspension  for  considerable  periods  by  slight  unavoidable 
air  currents  in  the  lower  strata.  He  showed  that,  with  favoring  air 
currents,  the  suspended  bacteria  may  be  conducted  through  very  nar- 
row crevices,  as  into  closed  bureau  drawers,  and  from  one  room  to 
another  through  keyholes  and  cracks.  While  the  danger  of  dissemi- 
nating bacteria  by  walking  over  an  infected  floor  was  found  to  be 
slight,  those  thrown  up  by  the  elastic  rebound  of  the  boards  failing  to 
infect  plates  suspended  4  inches  above  them,  ordinary  sweeping  was 
found  to  contaminate  the  atmosphere  throughout  its  whole  extent,  even 
to  the  ceiling,  thus  confirming  Fliigge's  statement  as  to  the  undesira- 
bility  of  dry  cleaning. 

Closely  similar  results  were  obtained  by  Kirstein,^  who  concludes 
that  ordinary  air  currents  cannot  detach  living  organisms  from  surfaces 
upon  which  they  have  been  deposited  and  become  dried,  but  concedes 
that,  when  the  bacteria  are  sprayed  upon  fine  dust  particles,  they  may 
easily  be  borne  about  in  the  air.  Yet  how  slight  the  danger  of  this 
method  of  infection  is,  so  far  at  least  as  typhoid  fever  is  concerned,  is 
shown  by  the  marked  rapidity  with  which  the  typhoid  organisms  die 
when  sent  forth  in  the  form  of  spray.  Other  non-spore-builders, 
sprayed  into  the  air,  retained  their  vitality  for  only  a  comparatively 
short  time,  because  of  the  influence  of  light  and  air  ;  and  he  believes 
that  the  marked  sensitiveness  of  the  tubercle  bacillus  to  the  influence 
of  light  makes  early  destruction  of  this  organism  most  probable  when 
it  is  thrown  into  the  air  in  minute  droplets,  and  that  thus  may  be  ex- 
plained the  fact  that,  even  in  consumptive  wards,  in  which  there  is, 
without  doubt,  a  constant  discharge  of  bacilli  into  the  air,  attempts  to 
detect  living  organisms  in  the  dust,  etc.,  fail,  excepting  in  those  cases 
in  which  the  sputum  itself  has,  through  lack  of  care,  become  dis- 
seminated. 

Positive  results  of  examination  of  droplets  expelled  by  consumptive 
patients  during  coughing  have  been  recorded  by  Curry,^  Boston,^  and 
others.  Curry  experimented  with  12  patients,  who  coughed  toward 
plates  suspended  from  1  to  3  feet  distant ;  he  found  the  bacilli  in  the 
larger  droplets  expelled  by  half  the  subjects.  Boston,  observing  fine 
droplets  being  ejected  from  the  mouth  of  a  patient  with  advanced 
disease  in  each  act  of  coughing,  concluded  that  such  constant  spraying 
at  the  table  and  elsewhere  might  afford  an  explanation  why  patients 
in  the  early  stage  of  the  disease  did  not  do  well  in  the  institution  where 
his  observations  were  made,  in  which  every  possible  attention  is  given 
to  ventihition,  light,  and  disinfection  of  sputum.  By  means  of  a  simple 
device,  the  spray  sent  out  by  oO  patients  was  collected,  and  then  sub- 

'  ZoitHchrifl  fiir  Hyf^iene  und  Infectionskrankheiten,  XXV.  (1900),  p.  123. 

^  BoHton  Mf'dioal  n'nd  Siirfiicjil  .Journal,  October  13,1898. 

^  Journal  of  the  American  Medical  AHSociation,  >Sept.,  14,  1901. 


248  AIR. 

jected  to  examination  for  the  specific  organism,  which  was  found  in  76 
per  cent,  of  the  cases.  The  smallest  number  found  in  any  specimen 
was  4,  and  in  fully  a  third  the  bacilli  were  very  numerous. 

Ravenel's  ^  experiments  with  tuberculous  cows  have  proved  that 
they,  too,  send  forth  the  bacilli  iu  great  numbers  in  the  act  of 
coughing. 

Experiments  conducted  at  the  Adirondack  Cottage  Sanitarium  by 
Dr.  I.  H.  Hance,^  for  the  purpose  of  determining  the  degree  of  danger 
of  infection  when  all  possible  sanitary  measures  for  disinfection  of 
sputum  are  enforced,  support  the  view  that  dust  in  the  air  is  of 
secondary  importance,  but  that,  where  carelessness  in  this  regard  ob- 
tains, the  danger  is  a  real  one.  A  complete  examination  was  made  of 
the  group  of  buildings,  some  of  which  had  been  occupied  by  consump- 
tives for  eleven  years.  Dust  was  collected  from  places  most  likely  to 
be  infected,  and  with  it  81  guinea-pigs  were  inoculated.  Four  inocu- 
lated with  dust  from  the  infirmary  (a  building  where  all  the  acutely 
sick  are  sent),  and  from  the  main  building  (in  which  are  a  parlor,  sit- 
ting-room and  library),  died  of  other  infections  on  the  third  to  the 
sixth  day.  Five  of  the  ten  inoculated  with  dust  from  the  oldest  cot- 
tage, which  was  occupied  by  a  man  Avho  had  been  complained  of  for 
promiscuous  spitting,  became  tuberculous.  Those  inoculated  with  the 
dust  from  the  other  buildings  gave  negative  results.  During  eleven 
years,  not  one  of  the  20  to  25  attendants  employed  had  developed  the 
disease. 

As  to  typhoid  fever,  too,  opinions  are  at  variance.  Dr.  John 
Brownlee  reported  before  the  Glasgow  Philosophical  Society  an  ex- 
periment proving  that  the  specific  bacilli  can  live  in  ordinary  dust. 
Buchner  is  of  the  opinion  that  neither  typhoid  nor  other  fevers  can 
thus  be  spread. 

Perhaps  the  most  extensive  research  on  the  subject  of  transmission 
of  this  and  other  diseases  is  that  conducted  by  Dr.  Eduardo  Germauo.^ 
In  his  experiments,  he  used  various  kinds  of  dust  and  dirt,  and  from 
his  results,  he  concludes  that  the  typhoid  germ  is  unable  to  withstand 
complete  drying,  and  hence  cannot  be  transmitted  to  man  through  dust 
sufficiently  dry  to  be  disseminated  by  air  currents.  Experiment  showed 
that  the  germ  can  live  for  a  long  time  in  moist  surroundings,  even  in 
an  apparently  dry  condition,  that  is,  when  adherent  to  or  encompassed 
by  matters  which  contain  a  certain  amount  of  moisture,  such  as  cloth- 
ing, particles  of  dirt,  and  fecal  filth.  Most  of  the  bacilli  die  as  drying 
progresses,  but  some  are  more  or  less  resistant,  though  not  necessarily 
dangerous  on  admission  to  air  currents,  since  then  complete  drying  and 
consequent  death  occur.  They  are  dangerous  only  in  case  of  intro- 
duction into  the  system  through  contact  with  the  fingers,  food,  or 
eating  utensils. 

^  University  Medical  Magazine,  November,  1 900. 

2  Medical  Eecord,  December  28,  1895. 

3  Zeitscbrift  fiir  Hvgiene  und  Infectionskrankheiten,  XXIV.,  p.  403  ;  XXV.,  p.  439  ; 
XXVI.,  pp.  66  and  273. 


THE  AIR  AS  A    CARRIER    OF  INFECTION.  249 

With  regard  to  diphtheria,  Germano  found  that  the  bacillus  with- 
stands long  drying  in  membranes,  tissues,  and  dust,  even  when  the 
drying  process  is  assisted  by  sulphuric  acid  ;  and  that  its  resistance  is 
greater  according  to  the  amount  of  enveloping  material  which  retards 
oxidation.  AVhen  completely  dry,  it  preserves  its  virulence  up  to  the 
time  it  dies.  Hence  his  belief  that  this  disease  may  be  disseminated  by 
air  currents. 

With  regard  to  pneumonia,  erysipelas,  and  other  streptococcus  infec- 
tions, Germano  finds  that  the  resistance  of  the  organism  to  the  drying 
process  is  always  high,  though  it  varies  with  the  method  followed  and 
the  nature  of  the  enveloping  material,  and  may  persist  a  number  of 
months.  Transmission  through  the  air  is  extremely  probable.  The 
diplococci,  in  general,  bear  drying  for  a  long  time ;  some  varieties  live 
longer  when  dried  than  if  moist,  and  some  possess  but  little  resistance  ; 
but  the  rapidity  of  the  drying  process  with  medium  temperature  does 
not  affect  the  result.  He  found  that  the  cholera  organism  retains  its 
virulence  only  so  long  as  it  remains  moist,  and  dies  quickly  on  drying, 
particularly  if  the  process  is  hastened.  He  concluded  that  dissemina- 
tion by  air  is  most  highly  improbable. 

Germano's  work  with  the  plague  bacillus  confirms  the  results  an- 
nounced by  Kitasato  and  Wilm.  This  organism  does  not  withstand 
drying,  but  lives  a  long  time  in  a  moist  condition.  It  remains  active 
fairly  long  when  dried  on  cloth,  because  then  complete  drying  requires 
a  long  time,  and  thus  may  be  explained  the  danger  of  infection  recog- 
nized to  exist  in  infected  clothing. 

Germano's  experiments  with  the  diplococcus  of  epidemic  cerebro- 
spinal meningitis  agree  in  results  with  those  of  Jager,  who  found  the 
organism  in  an  active  condition  in  a  handkerchief  six  weeks  after  use 
by  a  patient  sick  with  the  disease.  Germano  shows  that  it  belongs  to 
the  class  of  bacteria  which  oppose  the  greatest  possible  resistance  to 
drying,  whether  the  process  is  slow  or  quick,  and  whether  assisted  by 
the  action  of  sulphuric  acid ;  and  concludes  that  it  may  without  diffi- 
culty enter  the  air  in  the  form  of  dust,  and  thus  spread  the  infection. 
This  view  is  supported  by  Buchanan,^  who  argues  from  the  fact  that, 
of  60  cases  which  came  under  his  observation,  57  were  in  men  who 
followed  occupations  in  which  they  were  exposed  to  dust,  the  specific 
organisms  are  thus  conveyed. 

Dr.  Max  Neisser,^  working  in  the  same  line  as  Germano,  with  an 
apparatus  of  his  own  design,  which  maintains  a  constant  aspiration 
current  of  dusty  infected  air,  disagrees  as  to  the  pneumocoecus,  inas- 
much as,  while  mice,  inoculated  with  infected  dust,  died  from  the  in- 
fection without  exception,  24  others,  inoculated  with  the  dust  after 
it  had  been  sent  through  the  apparatus  in  a  current  of  air,  gave  abso- 
lutely negative  results.  His  experiments  with  various  organisms  led 
him  to  the  conclusion  that  dust  infection  is  impossible  with  the  organ- 
isms of  diphtheria,  typhoid  fever,  cholera,  plague,  and  pneumonia,  but 

'  Britisli  Medifjil  .loiirnal,  September  14,  ]'.»01. 

''  Zfeitscbrift  fiir  Hygiene  und  Infectionskiankheiten,  XXVI.,  p.  175. 


250 


AIR. 


possible  with  Staphylococcus  pyogenes  aureus,  B.  pyocyaneus,  B.  an- 
thracis,  B.  tuberculosis,  and  meningococcus. 

Neisser's  conclusions,  so  far  as  they  relate  to  diphtheria,  are  opposed 
to  the  results  obtained  by  Richardiere  and  Tollemer,^  who  made  a  series 
of  examinations  of  the  air  of  diphtheria  wards  of  the  Hopital  Trous- 
seau. In  one  set  of  experiments,  the  wards  had  not  been  disinfected 
for  several  Aveeks ;  and  in  another,  the  examinations  were  made  after 
disinfection  had  been  carried  out.  The  results  showed  that  active 
diphtheria  bacilli  were  present  in  the  air  which  had  not  undergone 
disinfection.  The  bacteriological  tests  were  controlled  by  inoculation 
experiments  with  animals. 

AVith  regard  to  the  possibility  of  spreading  cholem  germs  through 
the  agency  of  moving  air,  Dr.  N.  William  ^  has  reported  that,  while 
that  means  has  been  regarded  as  most  favorable,  in  actual  experiment 
it  fails.  JVIixed  with  dry  dust,  the  germs  live  but  a  short  time,  and 
perish  more  quickly  when  a  current  of  air  is  conducted  through  the 
dust.  When  the  dust  is  distributed  through  large  volumes  of  air,  the 
germs  die  rapidly,  and  when  the  impregnated  dust  is  let  fall  upon  a 
suitable  culture,  only  a  veiy  small  proportion  of  living  organisms  can 
be  found.  In  other  words,  cholera  germs,  adherent  to  dust  particles 
floating  in  and  moved  about  by  air,  do  not  retain  their  activity  for  any 
length  of  time  ncor  through  any  considerable  distance. 

The  experiments  of  Honsell  ^  indicate  that  the  cholera  organism  finds 
uo  favoring  conditions  for  its  passage  into  the  air  from  its  situation  in 
privy  vaults. 

The  subject  of  danger  of  cholera  infection  by  dust  from  baled  rags 
was  considered  thoroughly  at  the  Dresden  Cholera  Conference,  and  it 
was  found  impossible  then  to  quote  a  single  case  in  which  infection 
could  be  traced  to  this  source. 

According  to  Dr.  E.  W.  Hope,*  atmospheric  dust  is  largely  respon- 
sible for  the  spread  of  infantile  diarrhoea  in  cities  and  large  towns, 
where,  from  unavoidable  causes,  the  air  becomes  more  or  less  laden 
with  filth.  He  presents  evidence  of  the  association  of  rainfall  and 
its  attendant  cleansing  of  the  atmosphere  with  diminished  mortality 
from  choleraic  diarrhoea,  as  follo^vs  : 


Period. 

Average  rainfall 

June  to 

September. 

Conditions. 

Annual  average  of  deaths 
from  diarrhwa  during 
third  quarter  of  year. 

6  years 

13.8  inches 

Average  wet  sum- 

373 

14      " 

10.9      " 

mers. 
Average  dry  sum- 
mers. 

573 

Extreme  years. 
1891 
1895 

16.0      " 

7.7      " 

Wettest  summer. 
Driest  summer. 

203 

819 

'■  Gazette  des  Maladies  infantiles,  No.  10,  1899. 

^  Zeitschrift  fiir  Hygiene  und  Infectionskrankbeiten,  XV.  (1893),  p.  166. 
^  Arbeiten  aus  dem  patholog-anatomiscben  Institut  zu  Tubingen,  1896. 
*  Public  Health,  July,  1899. 


EXAMINATION  OF  AIR.  251 


Influence  of  Fog. 


Dust  and  moisture  together  in  the  form  of  fog  affect  the  health  of 
large  communities  in  a  marked  degree.  In  a  still  air  nearly  or  com- 
pletely saturated  with  aqueous  vapor  and  containing  ordinary  dust  and 
smoke,  a  fall  in  temperature  causes  each  particle  of  dust  and  soot  to 
become  the  nucleus  of  a  minute  droplet  of  condensed  moisture.  These 
countless  droplets  in  a  state  of  suspension  form  a  more  or  less  dense 
blanket  of  fog,  which  impedes  dispersion  of  the  impurities  given  off 
by  natural  processes  and  as  products  of  combustion.  While  ordinary 
country  and  seashore  fogs  are  not  known  to  exert  deleterious  effects, 
in  smoky  cities,  like  London,   the  case  is  quite  different. 

It  is  a  well-recognized  fact  that,  during  periods  of  heavy  fogs  in 
manufacturing  centers,  the  morbidity  and  mortality  from  respiratory 
disease  are  increased  very  greatly,  and  that,  as  the  atmosphere  clears,  a 
sharp  decline  follows.  In  London,  for  example,  the  usual  death-rate 
from  all  causes  has  been  known  to  become  almost  doubled  during  a 
fortnight  of  continued  dense,  smoky  fog,  and  then  to  return  to  its 
normal  figure  with  the  advent  of  clear  weather,  the  increase  being  due 
particularly  to  bronchitis  and  other  affections  of  the  respiratory  tract, 
attributed  to  the  irritating  influence  of  the  finely  divided  particles  of 
soot  and  the  acids  which  accompany  them. 

During  the  prevalence  of  thick  fogs,  the  air  being  necessarily  in  a 
stagnant  condition,  it  has  been  observed  that  the  carbon  dioxide  content 
increases  progressively.  During  one  such  period  following  bright 
weather,  the  air  of  London  acquired,  in  four  days,  three  and  a  half 
times  its  normal  content  of  this  gas. 

The  importance  of  smoke,  both  as  a  promoter  of  disease  and  on  ac- 
count of  its  corrosive  and  disfiguring  action  on  buildings,  and  also  on 
account  of  the  obstruction  of  liglit,  has  led  to  much  legislation  and  to 
the  exercise  of  inventive  genius  for  devising  means  for  the  prevention 
of  its  discharge  in  objectionable  amounts  into  the  atmosphere  of  cities. 
Many  patents  have  been  granted  for  smoke-consuming  devices,  the 
majority  of  which  have  been  found  to  work  unsatisfactorily.  The 
most  effective  invention,  which  gives  promise  of  solving  the  problem 
most  completely,  is  one  which  has  been  brought  to  the  attention  of  the 
Department  of  State  by  Consul  General  Mason.^  This  process  consists 
in  distributing  heated  and  slightly  compressed  air  through  hollow  grate 
bars  to  the- whole  lower  surface  of  the  furnace.  Not  only  is  practically 
perfect  combustion  attained,  but  immense  saving  of  expense  is  possible, 
.since  what  are  ordinarily  unsalable  low-grade  coals  can  be  employed  to 
greatest  advantage. 

Examination  of  Air. 

For  all  practical  purposes,  the  examination  of  air  may  be  restricted 
to  the   determination   of  the  amounts  of  aqueous  vapor  and   carbon 
dioxide.     The  essential  element,  oxygen,  fluctuates   within   such  very 
'  Consular  Keports,  1899,  p.  491. 


252 


AIR. 


narrow  limits  that  its  estimation  is  a  matter  of  purely  scientific  interest, 
and,  moreover,  the  process  is  one  which  demands  a  much  higher 
degree  of  manipulative  skill  than  is  possessed  by  those  to  whom  the 
task  of  making  sanitary  examinations  ordinarily  falls.  The  chief  con- 
stituent, nitrogen,  is  practically  constant  in  amount,  and  its  determina- 
tion would  serve  no  useful  purpose.  Whatever  is  the  cause  of  the 
deleterious  effects  of  an  atmosphere  vitiated  by  respiration,  whether  it 
be  carbon  dioxide  or  the  organic  matters  given  off  by  the  body,  this  at 
least  is  certain,  that  the  amount  of  carbon  dioxide  serves  as  an  index 
of  impurity,  and  that  the  amount  of  aqueous  vapor  is  of  considerable 
sanitary  importance.  In  special  cases,  it  is  important  to  look  for  that 
most  dangerous  contamination,  carbon  monoxide,  which,  coming  even 
in  very  small  amounts  from  leaking  gas  pipes  and  other  sources,  exerts 
a  decidedly  deleterious  influence.  In  the  minds  of  many,  the  test  for 
ozone  is  also  of  importance. 

In  addition  to  chemical  analysis,  the  determination  of  the  amount 
of  dust  and  the  number  and  varieties  of  micro-organisms  present  may 
be  of  interest  and  importance. 

Determination  of  Aqueous  Vapor. — As  has  been  stated  above,  a 
volume  of  air  at  a  given  temperature  can  hold  a  definite  amount  of 
moisture,  and  no  more,  and  when  this  amount  is  present  the  air  is  said 

Fig.  9. 


Apparatus  for  direct  determination  of  moisture. 

to  be  saturated.  The  amount  which  a  volume  of  air  contains  consti- 
tutes its  absolute  humidity,  and  the  difference  between  this  and  the 
amount  which  it  is  possible  for  it  to  hold  is  known  as  its  saturation 
deficiency.  The  ratio  which  its  absolute  humidity  bears  to  its  possible 
content  is  known  as  its  relative  humidity. 

Direct  Determination  of  Moisture  by  Weighing. — Prepare  two  wide- 
mouthed  flasks  of  about  150  cc.  capacity  in  the  following  manner: 


EXAMINATION   OF  AIR. 


253 


Provide  each  with  a  tightly  fitting  rubber  stopper  with  two  perforations, 
through  which  are  inserted  two  pieces  of  glass  tubing  bent  at  a  right 
angle.  One  of  these  reaches  to  the  bottom  of  the  flask,  and  serves  as 
an  inlet ;  the  other  extends  only  a  short  distance  below  the  stopper, 
and  serves  as  an  outlet.  Fill  the  flasks  with  small  pieces  of  pumice 
which  have  been  heated  to  a  high  temperature  over  a  Bunsen  burner, 
dropped  while  hot  into  concentrated  sulphuric  acid,  removed  therefrom, 
and  quickly  drained.  The  two  flasks  thus  filled,  and  with  stoppers 
tightly  inserted,  are  then  to  be  connected  by  means  of  a  short  piece  of 
rubber  tubing,  the  inlet  of  one  joining  the  outlet  of  the  other.  They 
are  then  weighed.  The  flask  with  the  free  outlet  tube  is  now  to  be 
connected  with  an  aspirator,  by  means  of  which  from  20  to  50  liters 
of  air  are  drawn  through.  As  the  air  comes  in  contact  with  the  pumice 
saturated  with  sulphuric  acid,  its  moisture  is  absorbed  and  retained.  At 
the  expiration  of  the  aspirating  process,  the  flasks  are  disconnected  from 
fhe  aspirator  and  again  weighed.  The  increase  in  weight  represents 
the  amount  of  moisture  in  the  volume  of  air 
used.  The  apparatus  is  shown  in  Fig.  9.  Know-  ^^^-  ^^^ 

ing  the  temperature  of  the  air,  one  can  then 
easily  determine  the  relative  humidity  by  refer- 
ence to  the  table  below,  which  shows  the  maxi- 
mum humidity  possible  at  different  temperatures. 

TABLE  OF  MAXIMUM  WATER  CAPACITY  FOR 
TEN  LITERS  OF  AIR. 


Tempera- 

Corre- 

Tempera- 

Corre- 

ture centi- 

sponding 

Grams. 

ture  centi- 

sponding 

Grams. 

grade. 

degrees  F. 

grade. 

degrees  F. 

—10 

14.0 

0.021 

13 

55.4 

0.113 

—  8 

17.6 

0.027 

14 

57.2 

0.120 

—  6 

21.2 

0.032 

15 

59.0 

0.128 

—  4 

24.8 

0.038 

16 

60.8 

0.136 

—  2 

28.4 

0.044 

17 

62.6 

0.145 

0 

32.0 

0.049 

18 

64.4 

0.151 

1 

33.8 

0.052 

19 

66.2 

0.162 

2 

35.6 

0.056 

20 

68.0 

0.172 

3 

37.4 

0.060 

21 

69.8 

0.182 

4 

39.2 

0.064 

22 

71.6 

0.193 

5 

41.0 

0.068 

23 

73.4 

0.204 

6 

42.8 

0.073 

24 

75.2 

0.215 

7 

44.6 

0.077 

25 

77.0 

0.229 

8 

46.4 

0.081 

26 

78.8 

0.242 

9 

48.2 

0.088 

27 

80.6 

0.256 

10 

50.0 

0.094 

28 

82.4 

0.270 

11 

51.8 

0.100 

29 

84.2 

0.286 

12 

53.6 

0.106 

30 

86.0 

0.301 

Determination  of  Relative  Humidity  by  the 
wet  and  dry  Thermometer  Bulbs.  This  instru- 
ment, which  is  known  also  as  the  psychrom- 
eter,  consists  of  a  pair  of  accurate  thermom- 
eters on  an  npn'ght  support.  The  bulb  of  one 
is  free ;  that  of   the  other  is  covered  with    a 


l's}(:hr(jniutt;r. 


254 


AIR. 


layer  of  muslin  kept  moistened  by  means  of  a  piece  of  wicking  which, 
dips  into  a  small  vessel  of  water  beneath.  (See  Fig.  10.)  In  a  satu- 
rated atmosphere,  no  evaporation  can  occur  from  the  wet  muslin ;  but 
in  one  not  saturated,  the  process  goes  on  with  varying  rapidity.  Evap- 
oration is  a  process  which  requires  heat  and  causes  a  lowering  of  the 
temperature  of  the  moist  surface ;  the  more  rapid  its  rate,  the  greater 
the  abstraction  of  heat.  The  drier  the  atmosphere,  the  greater  the  rate 
of  evaporation,  and,  therefore,  the  greater  the  fall  in  temperature.  If 
the  instrument  is  placed  in  a  saturated  atmosphere,  the  two  thermom- 
eters will  give  the  same  readings ;  but  in  one  not  saturated,  the  wet. 
thermometer  wall  fall  gradually  until  the  temperature  of  the  surface  of 
its  bulb  is  nearly  as  low  as  that  of  the  dew-point ;  that  is,  falls  to  that, 
point  at  which  air  at  the  indicated  temperature  is  so  saturated  that  a 
farther  lowering  would  be  followed  by  condensation  of  moisture.  A& 
a  matter  of  fact,  the  wet  thermometer  does  not  fall  so  far  in  a  quiet 
air,  since  its  bulb  becomes  surrounded  by  a  layer  of  stagnant  saturated 
air,  and  receives  more  or  less  heat  from  the  surrounding  warmer 
atmosphere.  Again,  in  a  saturated  atmosphere,  the  wet  thermometer 
may  stand  slightly  higher  than  the  dry  one,  owing  to  the  fact  that  its 
covering  protects  it  from  loss  of  heat  by  radiation. 


GLAISHER'S  TABLE. 

Heading  of 

Reading  of 

Reading  of 

dry  bulb 

Factor. 

dry  bulb 

Factor. 

dry  bulb 

Factor. 

thermometer. 

thermometer. 

thermometer. 

10 

8.78 

41 

2.26 

71 

1.76 

11 

8.78 

42 

2.23 

72 

1.75 

12 

8.78 

43 

2.20 

73 

1.74 

13 

8.77 

44 

2.18 

74 

1.73 

14 

8.76 

45 

2.16 

75 

1.72 

15 

8.75 

46 

2.14 

76 

1.71 

16 

8.70 

47 

2.12 

77 

1.70 

17 

8.62 

48 

2.10 

78 

1.69 

18 

8.50 

49 

2.08 

79 

1.69 

19 

8.34 

50 

2.06 

80 

1.68 

20 

8.14 

51 

2.04 

81 

1.68- 

21 

7.88 

52 

2.02 

82 

1.67 

22 

7.60 

53 

2.00 

83 

1.67 

23 

7.28 

54 

1.98 

84 

1.66 

24 

6.92 

55 

1.96 

85 

1.65 

25 

6.53 

56 

1.94 

86 

1.65 

26 

6.08 

57 

1.92 

87 

1.64 

27 

5.61 

58 

1.90 

88 

1.64 

28 

5.12 

59 

1.89 

89 

1.63 

29 

4.63 

60 

1.88 

90 

1.63 

30 

4.15 

61 

1.87 

91 

1.62 

31 

3.60 

62 

1.86  . 

92 

1.62 

32 

3.32 

63 

1.85 

93 

1.61 

33 

3.01 

64 

1.83 

94 

1.60 

34 

2.77 

65 

1.82 

95 

1.60 

35 

2.60 

66 

1.81 

96 

1.59 

36 

2.50 

67 

1.80 

97 

1.59 

37 

2.42 

68 

1.79 

98 

1.58 

38 

2^36 

69 

1.78 

99 

1.58 

39 

2.32 

70 

1.77 

100 

1.57 

40 

2.29 

EXAMINATION   OF  AIR. 


255 


For  the  purpose  for  which  it  is  intended,  the  instrument  is  exposed 
until  the  wet  thermometer  ceases  to  fall,  and  then  the  reading  of  both 
is  noted.  From  these  data,  with  the  assistance  of  Glaisher's  factors 
(see  table  on  page  254),  the  dew-point  is  easily  calculated  in  the  follow- 
ing manner  :  Multiply  the  difference  in  the  two  readings  by  the  factor 
opposite  the  figure  in  the  table  corresponding  to  the  temperature  of  the 
dry  bulb,  and  subtract  the  product  from  this  temperature. 

TABLE  OF  TENSIONS. 


Tempera- 
ture. 

Corre- 
sponding 

Tension 
in  inches  of 

Tension 

Tempera- 
ture. 

Corre- 
sponding 

Tension 
in  inches  of 

Tension 

Fahrenheit. 

degrees  C. 

mercury. 

in  mm. 

Fahrenheit. 

degrees  C. 

mercury. 

in  mm. 

1° 

—17.2° 

0.046 

1.17 

51° 

10.6° 

0.374 

9.50 

2 

—16.7 

0.048 

1.22 

52 

11.1 

0.388 

9.86 

3 

—16.1 

0.05 

1.27 

53 

11.7 

0.403 

10.24 

4 

-15.6 

0.052 

1.32 

54 

12.2 

0.418 

10.62 

5 

—15.0 

0.054 

1.37 

55 

12.'8 

0.433 

11.00 

6 

—14.4 

0.057 

1.45 

56 

13.3 

0.449 

11.40 

7 

—13.9 

0.060 

1.52 

57 

13.9 

0.465 

11.81 

8 

—13.3 

0.062 

1.57 

58 

14.4 

0.482 

12.24 

9 

—12.8 

0.065 

1.65 

59 

15.0 

0.500 

12.70 

10 

12.2 

0.068 

1.73 

60 

15.6 

0.518 

13.16 

11 

— 1L7 

0.071 

1.80 

61 

16.1 

0.537 

13.64 

12 

—11.1 

0.074 

1.88 

62 

16.7 

0.556 

14.12 

13 

—10.6 

0.078 

1.98 

63 

17.2 

0.576 

14.63 

14 

—10.0 

0.082 

2.08 

64 

17.8 

0.596 

15.14 

15 

—  9.4 

0.086 

2.18 

65 

18.3 

0.617 

15.67 

16 

—  8.9 

0.090 

2.28 

m 

18.9 

0.639 

16.23 

17 

—  8.3 

0.094 

2.38 

67 

19.4 

0.661 

16.79 

18 

—  7.8 

0.098 

2.49 

68 

20.0 

0.684 

17.37 

19 

—  7.2 

0.103 

2.62 

69 

20.6 

0.708 

17.98 

20 

—  6.7 

0.108 

2.74 

70 

21.1 

0.733 

18.62 

21 

—  6.1 

0.113 

2.87 

71 

21.7 

0.759 

19.28 

22 

—  5.6 

0.118 

3.00 

72 

22.2 

0.785 

19.94 

23 

—  5.0 

0.123 

3.12 

73 

22.8 

0.812 

20.62 

24 

—  4.4 

0.129 

3.28 

74 

23.3 

0.840 

21.34 

25 

—  3.9 

0.135 

3.43 

75 

23.9 

0.868 

22.05 

26 

—  3.3 

0.141 

3.58 

76 

24.4 

0.897 

22.78 

27 

—  2.8 

0.147 

3.73 

77 

25.0 

0.927 

23.55 

28 

—  2.2 

0.153 

3.89 

78 

25.6 

0.958 

24.33. 

29 

—  1.7 

0.160 

4.06 

79 

26.1 

0.990 

25.15 

30 

—  1.1 

0.167 

4.24 

80 

26.7 

1.023 

25.98; 

31 

—  0.6 

0.174 

4.41 

81 

27.2 

1.057 

26.85 

32 

—  0.0 

0.181 

4.60 

82 

27.8 

1.092 

27.74 

33 

+   0.6 

0.188 

4.78 

83 

28.3 

1.128 

28.65 

34 

1.1 

0.196 

4.98 

84 

28.9 

1.165 

29.59 

35 

1.7 

0.204 

5.18 

85 

29.4 

1.203 

30.55 

36 

2.2 

0.212 

5.38 

86 

30.0 

1.242 

31.55 

37 

2.8 

0.220 

5.58 

87 

30.6 

1.282 

33.56 

38 

3.3 

0.229 

5.82 

88 

31.1 

1.323 

33.60 

39 

3.9 

0.238 

6.04 

89 

31.7 

1.366 

34.69 

40 

4.4 

0.247 

6.27 

90 

32.2 

1.410 

35.81 

41 

5.0 

0.257 

6.53 

91 

32.8 

1.455 

36.95 

42 

5.6 

0.267 

6.78 

92 

33.3 

1.501 

38.12 

43 

6.1 

0.277 

7.04 

93 

33.9 

1.548 

39.31 

44 

6.7 

0.288 

7.32 

94 

34.4 

1.596 

40.53 

45 

7.2 

0.299 

7.59 

95 

35.0 

1.646 

41. SO 

46 

7.8 

0.311 

7.90 

96 

35.6 

1.697 

43.09 

47 

8.3 

0.323 

8.20 

97 

36.1 

1.749 

44.42 

48 

8.9 

0.335 

8.51 

98 

36.7 

1.802 

45.77 

49 

9.4 

0.348 

8.84 

99 

37.2 

1.856 

47.14 

50 

10.0 

0.361 

9.17 

100 

37.8 

1.911 

48.54 

256 


AIR 


Fig.  11. 


Having  now  determined  the  dew-point,  the  next  step  is  to  ascertain 
the  elastic  tension  of  the  vapor  present  in  the  air,  that  is,  the  tension 
of  the  dew-point,  and  the  tension  of  that  necessary  for  saturation  at  the 
temperature  of  the  dry  bulb,  which  data  can  be  obtained  by  reference 
to  the  table  on  page  255. 

From  these  several  data  the  relative  humidity  is  calculated  as  fol- 
lows :  Divide  the  tension  of  the  dew-point  by  that  of  saturation  at  the 
actual  temperature,  and  multiply  by  100. 

Example  : 

Beading  of  dry  bulb  =  67° 
Heading  of  we"t.  bulb  =  62° 
Dew  point  =  67— (5X1-80)  =  67—9  =  58° 

Kelative  humidity      =  ^-^  X  100  =  72.92  per  cent. 
^  0.661  ^ 

More  accurate  determination  may  be  made  by  employing  the 
"  whirled  "  or  "  sling  "  thermometers.  These  are  fastened  to  a  string 
of  such  a  length  that  the  distance  from  the  bulbs  to  the  held  end  is 
exactly  a  meter.  In  use,  they  are  whirled  in  a  horizontal  plane  100 
times  at  the  rate  of  one   revolution   ])er  second.     By  their  use,  the 

errors  mentioned  as  likely  to  occur  when  the 
observations  are  made  in  still  air  are  elimi- 
nated. For  all  practical  purposes,  the  use  of 
the  thermometers  in  the  ordinary  way  gives 
sufficiently  accurate  results. 

In  making  determinations  out  of  doors 
when  the  temperature  is  below  the  freezing- 
point,  the  wick  may  be  dispensed  with,  and 
the  bulb  is  then  wetted  by  dipping  it  into 
water,  the  excess  being  removed  by  means 
of  filter-paper  or  common  blotting-paper,  or 
water  may  be  applied  with  a  camel's-hair 
pencil.  Below  the  freezing-point,  however, 
the  relative  humidity  is  of  little  hygienic 
interest,  since  the  amount  of  moisture  which 
air  then  can  contain  is  but  slight. 

A  very  convenient  instrument  for  quick 
approximate  determinations  without  the 
necessity  of  tables  and  computation  is 
knoAvu  as  the  hygrophant  of  Winlock  and 
Huddleston.  It  consists  of  a  pair  of  ther- 
mometers and  a  cylinder,  upon  which  is 
inscribed  a  series  of  22  columns  of  figures 
numbered  from  1  to  22,  any  one  of  which 
may,  by  a  turn  of  a  knob,  be  brought  into 
apposition  with  a  fixed  scale  on  the  casing.  (See  Fig.  11.)  To  ascer- 
tain the  relative  humidity,  note  the  difference  in  the  readings  of  the 
thermometers,  turn  the  cylinder,  until  the  column  having  at  its  top 
the  number  corresponding  to  the  difference  appears  opposite  the  scale, 


Hygrophant. 


EXAMINATION  OF  AIR. 


257 


and  read  the  figures  opposite  the  number  corresponding  to  the  tem- 
perature of  the  wet  bulb. 
Example  : 

Eeading  of  dry  bulb  =  72° 
Beading  of  wet  bulb  =  60° 
Diflerence  =  12° 

The  cylinder  is  turned  until  column  12  appears.  Opposite  60  of  the 
scale,  the  reading  is  46  ;  and  this  is  approximately  the  percentage  of 
saturation  present. 

Determination  of  Carbon  Dioxide. — For  the  collection  of  samples 
of  air  for  this  determination,  it  is  well  to  provide  a  number  of  bottles 
of  about  a  gallon  capacity.  These  should,  first  of  all,  be  measured 
very  carefully.  This  may  be  done  by  filling  them  with  ice  water  and 
noting  the  number  of  cc.  required,  or  by  determining  by  means  of  plat- 
form scales  sensitive  to  5  grams  the  difference  between  their  weights 
empty  and  filled.  It  is  well  to  place  a  distinguishing  number  and  the 
figures  denoting  its  capacity  on  each  bottle,  either  on  a  label,  or,  better, 
by  means  of  a  writing  diamond.  When  used,  the  bottle  should  be 
perfectly  clean  and  dry. 

When  it  is  necessary  to  employ  the  same  bottle  again,  time  being  an 
object,  the  drying  process  is  hastened  very  much  by  washing  first  with 
water,  then  with  a  little  alcohol  to  remove  the  small  amount  of  water 
which  will  not  drain  away,  and,  finally,  with  a  little  ether  for  the  re- 
moval of  the  residuum  of  alcohol.  The  small  amount  of  adherent  ether 
may  then  be  removed  by  blowing  a  current  of  air 
into  the  bottle  by  means  of  a  bellows.  A  number 
of  tightly  fitting  rubber  caps  should  be  provided 
in  place  of  corks  or  rubber  stoj)pers,  though  if 
these  are  not  at  hand,  the  latter  may  be  used ;  but 
note  should  be  made  of  the  volume  of  air  which 
they  displace  when  they  are  inserted. 

Solutions  Required. — 1.  Solution  of  Baeium 
Hydrate. — Dissolve  about  4.5  grams  of  barium 
hydrate  and  0.5  of  barium  chloride  in  a  liter  of 
distilled  water  which  previously  has  been  boiled, 
in  order  to  expel  any  carbon  dioxide  which  it  may 
contain.  It  is  well  to  prepare  an  amount  suf- 
ficient for  future  needs,  say  4  liters,  and  to  keep 
it  in  a  bottle  such  as  is  shown  in  Fig.  12.  This 
is  provided  with  a  rubber  sto]:>per  with  two  per- 
forations, through  one  of  which  a  bent  tube,  reach- 
ing to  tlie  bottom,  and  intended  for  withdrawal 
of  the  reagent,  is  inserted.  Through  the  other 
is  carried  a  tube  extending  only  into  the  neck, 
and  communicating  at  its  outer  extremity  with 
a  U-tube  filled  with  ])iec('S  of  pumice  soaked  while  hot  in  a  strong 
solution  of  caustic  potash.       The   delivery   tube  carries  at  its  outer 

17 


Fig.  12. 


Bottle   for  barium 
hydrate. 


258  AIB. 

end  a  piece  of  closely  fitting  rubber  tubing,  which  is  kept  closed  by 
means  of  a  pinchcock. 

In  withdrawing  the  reagent  for  use,  a  100  cc.  pipette  is  inserted 
into  the  free  end  of  the  rubber  tube,  suction  is  applied,  and  the 
pinchcock  is  opened.  When  the  pipette  is  filled  to  the  mark,  the 
pressure  is  removed  from  the  pinchcock  and  the  pipette  released.  As 
the  reagent  is  withdrawn,  air  flows  in  through  the  other  opening,  and 
is  robbed  of  its  carbon  dioxide  by  contact  with  the  caustic  potash  with 
which  the  pumice  has  been  charged.  This  reagent  is  used  for  the 
absorption  of  the  carbon  dioxide  contained  in  the  sample  of  air  under 
examination.     The  reaction  is  expressed  by  the  following  formula  : 

Ba02H2+CO,=BaC03+H20. 

The  function  of  the  barium  chloride  is  explained  below. 

2.  Staxdaed  Solution  of  Oxalic  Acid. — Dissolve  2.808  grams 
of  pure  oxalic  acid  in  a  liter  of  distilled  water.     One  cc.  of  this  solu- 
tion is  equivalent  to  0.5  cc.  of  carbon  dioxide;  that  is  to  say,  will 
neutralize  the  same  amount  of  barium  hydrate  as  will  combine  with 
carbon  dioxide  to  form  barium  carbonate. 

3.  Solution  of  Phenolphthaleix. — Dissolve  0.5  gram  of 
phenolphthalein  in  100  cc.  of  alcohol.  This  solution  is  used  as  an 
"  indicator  "  of  alkalinity. 

Process  of  Analysis. — The  process  of  analysis  depends  upon  the  fact 
that  when  a  volume  of  the  barium  hydrate  solution  is  brought  into 
contact  with  carbon  dioxide,  its  alkalinity  is  diminished  by  the  forma- 
tion of  barium  carbonate,  which  is  a  neutral  body.  The  greater  the 
amount  of  carbon  dioxide  to  which  it  is  exposed,  the  greater  will  be  the 
reduction  of  its  alkaline  strength.  A  preliminary  determination  of 
the  amount  of  oxalic  acid  solution  Avhich  100  cc.  of  the  reagent  will 
neutralize  is  made  by  titrating  25  cc.  contained  in  an  Erlenmeyer  flask 
and  colored  by  means  of  a  few  drops  of  the  phenolphthalein  solution, 
and  multiplying  the  result  by  4.  After  the  reagent  has  been  sub- 
jected to  the  influence  of  the  gas  in  the  air  sample,  a  similar  determin- 
ation is  made.  The  difference  between  the  two  results,  divided  by  2, 
indicates  the  number  of  cc.  of  carbon  dioxide  present  in  the  amount 
of  air  employed. 

The  sample  of  air  is  obtained  in  the  following  manner  :  One  of  the 
bottles  above  mentioned  is  placed  in  the  situation  from  which  the  air 
is  to  be  obtained,  and  its  air  content  is  displaced  by  means  of  a  bellows 
provided  at  its  outlet  with  a  rubber  tube  of  sufficient  length  to  reach 
nearly  or  quite  to  the  bottom.  A  half  minute's  pumping  is  sufficient 
to  insure  that  the  original  air  is  replaced  by  that  under  observation. 
One  is  sometimes  admonished  to  be  careful  not  to  breathe  in  the  direc- 
tion of  the  mouth  of  the  bottle,  but  this  is  an  unnecessary  precaution, 
since  the  current  issuing  from  the  bottle  is  much  too  powerful  to  admit 
of  the  entrance  of  any  air  except  that  propelled  by  the  bellows.  A 
much  more  and  very  necessary  precaution  to  be  observed  is  that  the 
operator  shall  not  allow  his  breath  to  reach  the  inlet  holes  of  the  bel- 


EXAMINATION  OF  AIR.  259 

lows.  After  a  half  minute's  pumping,  the  rubber  cap  is  affixed,  and 
the  bottle  may  then  be  carried  to  the  laboratory,  or,  better,  the  treat- 
ment of  the  contained  air  may  be  proceeded  with  on  the  spot.  An- 
other method  of  collecting  the  sample  is  often  recommended  in  place 
of  the  one  described.  It  consists  in  filling  the  Vjottle  with  water  and 
emptying  it  where  the  air  is  to  be  taken.  By  this  process,  the  space 
originally  occupied  by  water  is  filled  with  air,  but  the  method  is  objec- 
tionable in  that  the  water  cannot  drain  away  completely,  and  that  that 
which  remains  serves  to  dilute,  slightly  it  is  true,  the  charge  of  barium 
hydrate  next  to  be  introduced,  and  thus  brings  in  an  error  at  the  very 
outset. 

J^ext,  100  cc.  of  the  barium  hydrate  solution  are  introduced  by 
drawing  aside  the  edge  of  the  rubber  cap  and  inserting,  into  the  opening 
so  made,  the  point  of  the  filled  pipette,  and  allowing  its  contents  to 
flow  unaided  into  the  bottle.  The  beginner  will  often  incline  inadver- 
tently to  gain  time,  and  assist  the  emptying  of  the  pipette,  by  blowing 
into  it,  thereby  vitiating  his  results  with  the  impurities  of  his  own 
respiration.  As  soon  as  the  pipette  is  emptied,  it  is  withdrawn  and  the 
edge  of  the  cap  is  replaced.  The  bottle  is  then  shaken  thoroughly  for 
about  ten  minutes,  care  being  observed  not  to  wet  the  cap,  since  in  that 
event  some  of  the  reagent  may  escape  by  capillary  attraction.  At  the 
end  of  that  time  it  may  be  assumed  that  all  of  the  contained  carbon 
dioxide  has  been  brought  into  contact  with  and  absorbed  by  the  barium 
hydrate,  which  is  then  to  be  poured  quickly  from  the  bottle  through  a 
fairly  large  funnel  into  a  glass-stoppered  bottle  of  rather  more  than 
100  cc.  capacity.  The  solution,  w^hich  is  now  more  or  less  turbid  from 
the  presence  of  barium  carbonate,  is  allowed  to  stand  until,  through 
settling  of  this  substance,  the  supernatant  liquid  is  clear.  Three 
successive  portions  of  25  cc.  each  are  next  to  be  withdrawn  by  means 
of  a  pipette  of  the  proper  size,  and,  after  addition  of  the  indicator, 
titrated  in  Erlenmeyer  flasks  with  the  standard  oxalic  acid  solution 
until  the  pink  color  caused  by  the  former  is  made  to  disappear.  So 
long  as  any  color  remains,  one  knows  that  barium  still  exists  in  the 
form  of  hydrate,  and  that  the  contents  of  the  flask  are  still  alkaline, 
for  phenolphthalein  gives  a  pink  tinge  only  in  the  presence  of  the 
alkalies.  When  the  pink  color  disappears,  the  process  is  finished,  and 
the  reading  of  the  burette  is  noted.  The  three  portions  of  25  cc.  each  are 
titrated  in  turn,  and  the  mean  of  the  results  is  multiplied  by  4.  The 
difference  between  this  product  and  the  figure  obtained  in  the  pre- 
liminary test  of  the  strength  of  the  reagent,  divided  by  2,  indicates 
the  number  of  cc.  of  carbon  dioxide  in  the  volume  of  air  taken  for 
analysis. 

In  filling  the  25  cc.  pipette  from  the  bottle  containing  the  used 
reagent,  great  care  should  be  observed  not  to  stir  up  the  sediment  of 
barium  carbonate.  To  perform  the  operation  properly,  it  is  necessary 
to  insert  the  point  of  the  pipette  well  below  the  surface,  and  to  fill  it 
up  to  the  mark,  or  just  beyond  it,  l)y  one  uninterrupted  act  of  suction. 
If  one  stops  to  regain   breath,  part  of  the  liquid   already  within   the 


^60  AIB. 

pipette  will  escape  downward  during  the  interval  with  sufficient  force 
to  stir  up  the  sediment.  When  the  pipette  is  filled,  the  point  of  the 
tongue  should  be  applied  to  its  upper  end,  and  the  tip  should  then  be 
Avithdrawn  from  the  bottle.  Then  by  placing  the  end  of  the  forefinger 
over  the  opening  of  the  tip  of  the  pipette,  the  escape  of  its  contents  is 
prevented,  while  the  forefinger  of  the  other  hand  is  replacing  the  point 
of  the  tongue.  The  reason  for  such  careful  avoidance  of  stirring  up 
the  sediment  is  that  the  presence  of  barium  carbonate  introduces  a 
slight  error  in  the  titration.  The  slight  excess  of  oxalic  acid  present 
when  the  color  of  the  phenolphthalein  is  discharged  attacks  the  sus- 
pended barium  carbonate,  forming  barium  oxalate  and  setting  free  the 
combined  carbon  dioxide.     Thus  : 

H2C2O4  +  BaCOg  =  BaCjO^  +  HoO  +  COj. 

The  free  carbon  dioxide  then  attacks  more  of  the  carbonate  and  forms 
barium  bicarbonate,  which,  being  soluble  and  of  alkaline  reaction, 
causes  the  pink  color  to  reappear. 

/OH 

/>Ba  =BaH2(C03)2. 
CO/ 
^OH 

The  reason  for  adding  barium  chloride  in  making  the  barium 
hydrate  solution  is  that  most  barium  hydrate  contains,  in  addition  to 
small  amounts  of  carbonate,  traces  either  of  caustic  soda  or  of  caustic 
potash.  When  either  of  these  substances  is  brought  into  contact  with 
barium  chloride,  mutual  decomposition  occurs,  and  we  have  as  results 
barium  hydrate  and  sodiimi  (or  potassium)  chloride.  If  the  impurity 
were  disregarded,  it  would  cause  errors,  as  shown  below.  The  barium 
hydrate  solution  when  titrated  with  oxalic  acid  would  behave  according 
to  the  following  formula: 

BaO^H^  +  BaCOs  +  2NaOH  +  2H,C,0,  =  BaC,0,  +  BaCOg  +  Na^C^O,  +  4HjO 
(Barium         (Barium  (Sodium  (Oxalic  (Bariiam  (Sodium 

hydrate)       carbonate)      hydrate)  acid)  oxalate)  oxalate) 

In  practice  a  very  slight  excess  of  oxalic  acid  is  also  present,  and 
the  reaction  then  proceeds  still  farther.  The  sodium  oxalate  attacks 
the  barium  carbonate,  forming  barium  oxalate  and  sodium  carbonate. 
Thus 

Na^CsO,  +  BaCOg  =  BaCA  +  Na^COj. 

!N"ext,  the  sodium  carbonate  neutralizes  the  traces  of  free  oxalic  acid, 
and  any  surplus  causes  a  reappearance  of  the  pink  color  and  neces- 
sitates farther  addition  of  oxalic  acid.  This  causes  the  formation  of 
more  sodium  oxalate,  which  in  its  turn  attacks  another  portion  of  the 
barium  carbonate,  with  the  same  results  as  before ;  and  so  the  cycle 
continues  until  the  last  trace  of  suspended  carbonate  is  decomposed. 
If  the  hydrate  contains  no  impurities,  the  addition  of  chloride  is 
unnecessary. 


EXAMINATION  OF  AIR.  261 

Corrections. — In  figuring  the  results  of  the  determination,  certain 
corrections  are  necessary.  First,  the  volume  of  the  barium  hydrate 
used  (100  cc.)  must  be  subtracted  from  the  capacity  of  the  bottle,  since 
its  introduction  displaces  an  equal  volume  of  air  ;  and  next,  allowances 
must  be  made  for  any  departure  from  standard  temperature  and  baro- 
metric pressure,  since  the  capacity  of  the  sample  bottle  is  reckoned  for 
air  at  0°  C.  and  760  mm.  pressure.  In  order  to  make  the  necessary 
corrections  for  temperature  and  pressure,  the  thermometer  and  barom- 
eter should  be  noted  at  the  time  of  taking  the  sample. 

In  determining  the  amount  of  correction,  we  are  guided  by  two 
physical  laws  :  that  for  each  degree  of  temperature,  air  expands  a  con- 
stant fraction  of  its  own  volume  (Law  of  Charles) ;  and  that  the  vol- 
ume of  a  gas  is  inversely  proportionate  to  the  pressure  (Law  of  Boyle).. 
For  each  degree  centigrade  above  or  below  0°  C,  air  expands  or  con- 
tracts 0.0036648  of  its  volume ;  and  this  figure  is  known  as  the  co- 
efficient of  expansion  for  centigrade  degrees.  For  each  degree  Fahren- 
heit above  or  below  32°,  air  expands  or  contracts  0.002036  of  its- 
volume  ;  and  this  is  known  as  the  coefficient  of  expansion  for  Fahren- 
heit degrees.  Thus,  1  liter  of  air,  heated  to  40°  C,  will  expand  to- 
1  +  (40  X  0.0036648),  which  equals  1.146592  liters;  or  heated  to 
104°  F.  (104°  F.  =  40°  C),  it  will  expand  to  1  +  (72  X  0.002036),, 
which  equals  1.146492,  as  before.  Again,  the  same  volume  cooled  tO' 
— 15°  C,  will  contract  to  1  —  (15  X  0^0036648),  or  945  cc. ;  or  cooled 
to  5°  F.  (5°  F.  =  15°C.),  it  will  become  1  —(27  X  0.002036)  or  945 
cc,  as  before.  So  an  apparent  volume  of  1,000  cc.  at  any  temperature 
above  freezing  is  in  reality  a  smaller  volume  expanded  to  that  size ; 
and  at  any  temperature  below,  is  a  larger  volume  brought  to  that  size 
by  contraction. 

To  correct  volume  for  temperature,  we  must  divide  the  apparent 
volume  by  1  plus  the  product  of  0.0036648  times  the  number  of 
degrees  away  from  0°  C,  or  in  case  of  temperatures  below  freezing, 
by  1  minus  that  amount.  If  the  Fahrenheit  scale  is  used,  the  appro- 
priate coefficient  and  factors  must  be  substituted.  Thus  we  may  employ 
a  set  of  formulae  as  follows  : 

For  temperatures  above  0°  C V= 


For  temperatures  below  0°  C V^ 


1  +  0.0036648.«°  C. 


For  temperatures  above  32°  F.   .    .    .  F"  = 


1  —  0.0036648.<°  C. 


1  +  0.002036  (<°  F.  — 32) 


For  temperatures  below  32°  F.   .    .    .  F^ 


1  —  0.002036  (32  — <°F.) 

In  the  above,  F=  correct  volume. 
V':^  apparent  volume. 

Inasmuch  as  volume  is  inversely  proportionate  to  pressure,  the  true 
volume  at  any  observed  pressure  is  obtained  by  miilti])lying  the 
apparent  volume  by  the  barometric  pressure  expressed  in  millinieters 


262  AIB. 

or  inches,  and  dividing  the  product  by  760  or  by  29.92,  as  the  case 
may  be.     We  may  use,  then,  this  formula  : 

760 

Applying  it,  we  find  that  an  apparent  volume  of  1,000  cc.  at  750  mm. 
becomes 

760 

or  using  the  other  scale,  the  barometer  standing  at  29.53  inches  (29.53 
in.,  750  mm.),  it  becomes 

1,000  X  29.53  ^Q87cc. 
29.92 

If  the  barometer  reads  higher  than  the  standard  pressure,  the  true 
volume  will  be  greater  than  the  apparent.  Thus,  suppose  the  pressure 
to  be  30.22  inches,  then  1,000  cc.  will  represent 

iOOOX  3022^1  010  cc. 

29.92 

Instead  of  going  through  two  separate  calculations,  we  may  make 
both  corrections  at  once  by  means  of  one  formula  which  is  a  combina- 
tion of  the  two  kinds  already  used.  For  temperatures  above  0°  C. 
the  correct  volume  is  obtained  by  means  of  the  following : 


(l  +  0.0036648.<°)  760 

By  changing  the  plus  sign  to  minus,  the  formula  is  adapted  to  tem- 
peratures below  freezing.  If  the  Fahrenheit  thermometer  is  used,  and 
the  barometric  pressure  is  expressed  in  inches,  the  formula  is  as  fol- 
lows : 

v= E^-X^ 

[1  +  0.002036  {t°F.  -  32)]  29.92 
and  if  the  temperature  is  below  32°,  it  must  be  changed  to 
V= YLXA 

[1  —  0.002036  (32  —  <°  F.)]  29.92 
In  these  formulae : 

V  =  correct  volume. 

V  =  apparent  volume. 

B    =  barometric  pressure. 
t°    =  temperature. 

In  order  to  avoid  the  tedious  process  of  multiplication  and  division 
which  the  working  of  these  formula  involves,  recourse  may  be  had  to 
the  admirable  tables  of  Dr.  AValter  Hesse,^  wherein  can  be  found  the 
correction  to  be  made  for  all  temperatures  between  —  2°  and  30°  C. 
and  for  all  pressures  between  680  and  770  mm.,  by  simple  reference 
to  the  proper  column. 

1  Tabellen  zur  Eeduction  eines  Gasvolumens  auf  0°  und  760  mm.    Brunswick,  1879. 


EXAMINATION  OF  AIR.  263 

For  all  practical  purposes,  the  coefficients  of  expansion  may  be 
shortened  to  0.00366  and  0.002,  thus  avoiding  much  figuring  which 
has  very  little  influence  on  the  end  results. 

Example  of  Method  of  Reckoning  COj. — Capacity  of  sample  bottle, 
3,885  cc.  25  cc.  of  barium  hydrate  solution  require  21  cc.  of  standard 
solution  of  oxalic  acid,  hence  100  cc.  =  84  cc.  After  contact,  25  cc. 
require  17.2  cc. ;   100  cc.  require  68.8  cc. 

Difference  in  oxalic  acid  required  ^=  84  —  68.8  =  15.2  cc. 

1  cc.  of  oxalic  acid  solution  =  0.5  cc.  of  CO2 ;  hence,  15.2  cc.=  7.6 
cc.  of  CO2. 

The  air  in  the  bottle  contained,  therefore,  7.6  cc.  of  CO2. 

Determination  of  volume  of  air  taken  : 

Capacity  of  bottle  =  3,885 

Amount  of  barium  solution      =     100 
Apparent  volume  of  air  =  3,785 

Observed  barometric  pressure  =  29.60  inches. 
Observed  temperature  =  65°  F. 

y 3,785  X  29.60 112,036         _  112,036 

"~  [1  +  (0.002036  X  33)]  X  29.92  ^  1.067188  X  29.92  ~    31.93  ~~ 
3,509  cc.  =^  actual  air  volume  examined. 

Then  3,509  cc.  of  air  contain  7.6  cc.  of  COg.     It  being  customary  to 
express  results  in  parts  per  10,000,  this  rate  is  determined  as  follows  : 

3,509  :  7.6  =  10,000  -.x    x^ 21.66. 

Hence  the  air  contains  21.66  volumes  of  CO2  in  10,000. 

Determination  of  CO2  by  Wolpert's  Method. — This  process  is  designed 
for  what  may  be  called  roughly  approximate  work  in  testing  the  air 
of  school  rooms  and  similarly  crowded  spaces.  It  requires  no  chemical 
training  on  the  part  of  the  operator,  and  for  practical  purposes  gives 
fairly  satisfactory  results,  indicating  that  the  air  is  good,  fair,  poor,  or 
very  bad.  The  apparatus  consists  of  a  graduated  glass  cylinder 
with  a  movable  piston  reaching  to  the  bottom  and  kept  in  proper 
position  by  a  metallic  cap,  through  the  center  of  which  the  shaft  pro- 
trudes. The  shaft  is  a  glass  tube  of  narrow  caliber,  open  at  both  ends. 
The  reagent  used  is  a  standard  solution  of  alkali,  colored  with  phenol- 
phthalein. 

In  making  a  test,  the  piston  is  removed  and  2  cc.  of  the  solution  are 
introduced  into  the  cylinder  by  means  of  a  pipette.  The  piston  is  re- 
placed and  pressed  down  until  all  air  is  expelled  through  the  shaft  and 
the  liquid  appears  within  the  bore.  The  piston  is  then  drawn  up  until 
its  lower  edge  is  opposite  the  first  mark,  and  in  the  process  the  space 
so  made  is  filled  with  air  which  enters  through  the  shaft.  The  appara- 
tus is  now  shaken  vigorously  for  one  minute.  If  the  liquid  becomes 
colorless,  it  is  proof  that  the  air  of  the  room  is  bad.  If,  on  the  other 
hand,  the  color  jiersists,  the  piston  is  raised  to  the  next  graduation, 
and  the  shaking  is  renewed  for  another  minute.  If  the  reagent  still 
retains  color,  the  ])iston  is  raised  further  and  more  air  is  admitted. 
The  [)rocess  is  continued  until  repeated  additions  of  air  and  renewed 


264 


AIB. 


shakings  cause  the  color  to  be  discharged.  At  this  point,  the  reading 
of  the  scale  indicates  the  character  of  the  air.  The  greater  the  amount 
of  air  required  for  complete  decolorization,  the  less  the  relative  amount 
of  impurity.     The  apparatus  is  shown  in  Fig.  13. 

Determination  by  Fitz's  Method. — A  modification  of  this  process,  giv- 
ing results  which  are  in  close  agreement  with  parallel  analyses  by  the 
Pettenkofer  method  above  described,  has  been  devised  by  Dr.  G.  W. 
Fitz.^     The  apparatus  is  very  simple,  and  consists  of  a  small  cylinder 
of  glass  with  a  rounded  bottom,  and  a  smaller  open  one 
Fig.  13.         which  slips  into  the  other  through  a  collar  of  rubber  tubing 
which  makes  a  tight  joint.     As   the   inner  cylinder    is 
drawn   out,  air   enters   through   its   upper   end,  and  its 
amount   is  measured   by  the  graduations  on    the    outer 
tube,  the  lower  margin   of  the  inner  tube  serving  as  an 
index.      (See  Fig.  14.) 

The  reagent  used   is   a  1   per  cent,    solution   of  lime 
water  made  in  the  following  manner.     About  95  cc.  of 
water  containing  a  few  drops  of  phenolphthalein  solu- 
tion are  neutralized    by  the  addition,  drop  by  drop,  of 
lime  w-ater,  which  causes  a  pink  color  that  at  first  dis- 
appears on  shaking.     As  soon  as  a  faint  tinge  persists^ 
the  complete  neutralization  of  the  carbon  dioxide  of  the 
water  is  evident.    One  cc.  of  saturated  lime  water  is  next 
added,  and  the  whole  is  then  made  up  to 
100  cc.     The  solution  should  be  made  as 
needed,  since   it  retains  its  full   strength 
but  about  twelve  hours. 

In  making  a  test,  10  cc.  are  introduced 
into  the  outer  cylinder ;  the  inner  one  is 
inserted  as  far  as  it  Mill  go  and  then 
raised  to  the  10  cc.  mark  on  the  scale, 
which  means  the  presence  of  20  cc.  of 
air,  since  the  tube  itself  contains  10  cc. 
The  apparatus  is  then  closed  by  applying 
the  end  of  the  forefinger,  and  shaken 
vigorously  thirty  times.  If  the  pink 
color  persists,  the  inner  cylinder  is  pushed 
to  the  bottom  and  then  drawn  up  again, 
and  the  operation  is  repeated  until  the 
color  disappears.  At  this  point,  the 
amount  of  air  used  is  noted,  and  by 
reference  to  a  table,  the  number  of  parts 
Fitzs  air  tester,  p^j,  10,000  is  ascertained.^  Dr.  Fitz 
asserts  that,  in  the  hands  of  an  ordinarily 
careful  man,  the  process  is  accurate  within  1  part  of  CO2  in  1 0,000 » 


^il^ 


^1^ 


Fig.  14. 


Wolpert's  air 
tester. 


^  Journal  of  the  Massachusetts  Association  of  Boards  of  Health  IX.,  p.  5. 
^  The  apparatus  and  complete  directions  for  use  are  obtainable  of  the  Knott  Appa- 
ratus Company,  Boston. 


EXAMINATION  OF  AIR.  265- 

This  is  substantiated  by  Professor  L.  P.  Kinnicutt/  of  the  Worcester 
Polytechnic  Institute,  who  has  employed  the  process  himself  and 
controlled  its  use  by  others  with  parallel  analyses  by  the  Pettenkofer 
method. 

Determination  of  Carbon  Monoxide. — While  a  number  of  proc- 
esses have  been  devised  for  the  detection  and  determination  of  carbon 
monoxide,  none  has  been  discovered  as  yet  that  is  wholly  satisfactory 
for  other  than  qualitative  work.  The  gas  may  be  detected  qualita- 
tively by  exposing  water  containing  a  small  amount  of  fresh  normal 
blood  to  the  air  under  examination,  and  then  examining  the  same 
with  the  spectroscope.  If  no  carbon  monoxide  is  present  in  the  air, 
the  characteristic  absorption  bands  of  oxyhsemoglobiu,  shown  by  the 
spectroscope,  are  changed  to  a  single  band  in  the  space  between  on  the 
addition  of  a  reducing  agent,  such  as  ammonium  sulphide.  If,  how- 
ever, the  gas  is  present,  no  change  occurs. 

The  test  is  applied  in  the  following  manner  :  A  few  drops  of  blood 
well  diluted  with  water  are  exposed  to  the  air  in  a  jar,  and  brought 
into  intimate  contact  by  vigorous  shaking.  A  few  drops  of  ammonium 
sulphide  are  next  added,  and  the  mixture  is  again  well  shaken.  If  on 
spectroscopic  examination  but  a  single  band  is  observed,  the  absence 
of  the  gas  in  amount  equal  to  3  parts  per  10,000  may  be  inferred,  for 
this  is  the  limit  of  delicacy  claimed.  If,  however,  the  characteristic 
two  bands  of  oxyhsemoglobin  appear,  the  presence  of  the  impurity  to 
that  extent  is  proved,  since  otherwise  the  reagent  would  have  exerted 
its  normal  effect. 

The  following  process,  devised  by  Fodor,^  is  said  to  be  of  sufficient 
delicacy  to  detect  1  part  in  20,000.  Fresh  defibrinated  blood  is  mixed 
with  10  volumes  of  water  and  introduced  into  a  large  jar  containing 
the  suspected  air.  After  being  allowed  to  stand  for  about  an  hour 
without  shaking,  it  is  transferred  to  a  small  flask  provided  with  a  rub- 
ber stopper  carrying  two  glass  tubes,  one  of  which  dips  beneath  the 
surface  and  connects  at  its  outer  end  with  a  potash  bulb  containing 
palladium  chloride  solution.  The  other  tube  serves  as  an  outlet,  and 
is  connected  with  a  series  of  three  potash  bulbs  containing  respectively 
lead  acetate  solution,  dilute  sulphuric  acid,  and  palladium  chloride  so 
diluted  that  it  has  a  bright-yellow  color.  The  terminal  bulb  is  con- 
nected with  an  aspirator,  which,  when  set  in  action,  draws  a  current 
of  air  through  the  five  different  pieces.  The  flask  containing  the  blood 
is  heated  on  a  water-bath  for  fifteen  to  thirty  minutes  with  occasional 
shaking,  and  meanwhile  a  slow  current  of  air  is  drawn  through  the 
apparatus.  When  the  blood  begins  to  change  color,  the  carboxyhsemo- 
globin  decomposes  and  yields  its  CO,  which  reduces  the  palladium 
contained  in  the  terminal  bulb.  The  chloride  of  palladium  in  the  first 
bulb  is  used  for  removing  any  traces  of  the  gas  and  of  other  reduciug 
agents  in  the  aspirated  air.  At  the  close  of  the  operation,  if  the 
blood  contained  CO,  the  palladium  cliloride  in  the  terminal  bulb  shows 

'  Loco  citato,  p.  8. 

^  Deutsche  Vierteljahrsschrit't  lur  olH'iillicliL'  ( icsiindiicitspfiege,  Vol.  12. 


266  ~  A  IB. 

a  precipitate  of  reduced  palladium  and  the  liquid  has  a  somewhat 
darker  tint.  The  lead  acetate  and  dilute  sulphuric  acid  serve  to  remove 
any  traces  of  sulphuretted  hydrogen  and  ammonia,  both  of  which  sub- 
stances will  cause  precij^itatiou  of  the  palladium. 

Other  qualitative  tests  of  greater  or  less  delicacy  include  the  following  : 

1.  Mix  5  cc.  of  exposed  blood  solution  and  15  cc.  of  a  1  per  cent, 
solution  of  tannic  acid.  The  resulting  precipitate,  which  settles  very 
slowly,  has  a  brownish-red  color,  if  CO  was  present  in  the  air ;  other- 
wise it  is  grayish-brown. 

2.  Mix  10  cc.  of  the  blood  solution  with  5  cc.  of  a  20  per  cent, 
solution  of  potassium  ferrocyanide  and  1  cc.  of  acetic  acid  (1  part  of 
glacial  acetic  acid  to  2  of  water).  A  reddish-brown  precipitate  is  in- 
dicative of  the  presence  of  the  gas,  and  one  of  grayish-brown  shows  its 
absence. 

3.  Bring  together  on  a  porcelain  plate  1  drop  each  of  exposed  defi- 
brinated  blood  and  sodium  hydrate  solution  of  a  specific  gravity  of 
1.300.  With  CO  blood,  the  color  is  bright  red,  while  with  normal 
blood  it  is  brownish  or  blackish. 

4.  In  place  of  the  above  reagent,  use  a  mixture  of  1  part  of  the  same 
with  3  of  calcium  chloride  solution.  CO  blood  gives  a  carmine,  and 
normal  blood  a  light-brown  or  bro'svnish-red,  color. 

5.  Draw  air  through  a  tube  containing  a  solution  of  cuprous  chlo- 
ride, which,  in  the  presence  of  CO,  deposits  a  characteristic  precipitate, 
which,  according  Berthelot,  is  Cu.ClCO. 211^0. 

Quantitative  Determination. — Xicloux  ^  has  devised  a  colorimetric 
method  for  which  he  claims  great  accuracy.  It  is  based  upon  the  fact 
that,  by  the  action  of  carbon  monoxide  on  iodic  acid,  definite  amounts 
of  iodine  are  set  free.  He  combines  this  with  an  alkali,  acidulates  and 
shakes  out  with  chlorform  or  carbon  disulphide,  and  then  compares 
the  color  with  solutions  containing  known  amounts  of  iodine.  From 
the  amount  of  iodine,  the  amount  of  CO  which  caused  its  liberation 
may  be  reckoned. 

Gautier^  allows  the  liberated  iodine  to  act  upon  copper  foil,  and 
determines  the  amount  of  CO  from  the  increase  in  weight.  He  also 
determines  the  COj  produced  by  the  action  of  iodine  pentoxide  on 
CO ;  the  result  indicates  volume  for  volume.  Potain  and  Drouin  ^ 
recommend  a  colorimetric  method  by  means  of  dilute  palladium 
chloride  solution. 

Determination  of  Ozone. — The  allotropic  form  of  oxygen  acts 
upon  potassium  iodide  in  the  presence  of  moisture  and  converts  it  to 
hydrate,  with  liberation  of  iodine,  according  to  the  following  formula : 

2KI  +  H,0  +  O3  =  2K0H  +  O^  +  I^. 

This  reaction  is  the  basis  of  most  of  the  processes  which  have  been 
proposed  for  qualitative  and  quantitative  determination,  none  of  which 
may  be  regarded  as  of  value,  since  there  are  many  sources  of  error  to 

^  Coraptes  rendus,  CXXVI.,  p.  746. 

2  Ibidem,  CXXVI,.  pp.  871,  931,  973.  3  Ibidem,  p.  938. 


EXAMINATION  OF  AIR.  267 

be  taken  into  account,  sources  impossible  to  eliminate  and  of  impor- 
tance impossible  to  compute. 

The  presence  of  ozone  in  the  air  is  supposed  to  be  demonstrated 
when,  on  exposure  of  paper  saturated  with  starch  paste  containing 
potassium  iodide,  a  blue  color  gradually  develops,  owing  to  the  action 
of  the  liberated  iodine  on  the  starch.  Quantitative  determinations  are 
made  by  comparing  the  tint  with  a  standard  scale,  the  depth  of  color 
being  dependent  upon  the  amount  of  iodine  liberated,  and  this  upon 
the  amount  of  ozone  present.  The  papers  are  prepared  in  the  follow- 
ing manner  :  From  2.5  to  10  grams  of  starch  are  taken,  according  to 
the  recommendations  followed,  and,  after  trituration  with  a  small 
amount  of  cold  water,  are  boiled  for  about  ten  minutes  in  about 
200  cc.  of  water,  and  filtered.  One  gram  of  potassium  iodide  in  solu- 
tion is  next  added  gradually  with  constant  stirring.  Strips  of  stout 
filter-paper,  wet  with  distilled  water,  are  soaked  in  the  starch  prepa- 
ration until  they  are  thoroughly  impregnated  (about  two  to  four 
hours),  then  removed  with  the  aid  of  forceps,  spread  flat,  and  dried 
in  the  dark.  When  used,  they  are  hung  up  out  of  the  direct  sun- 
light and  exposed  for  a  definite  time,  then  removed,  moistened  with 
water,  and  compared  with  the  scale.  The  objections  to  the  process 
are  that  a  number  of  other  substances  which  may  be  in  the  air, 
such  as  certain  volatile  organic  acids,  chlorine,  nitrous  acid,  and  hydro- 
gen peroxide,  cause  this  same  chemical  reaction ;  that  the  blue  color  is 
destroyed  by  other  substances,  as  sulphuretted  hydrogen  and  sulphur- 
ous acid  ;  and  that  light,  moisture,  heat,  and  wind  exert  very  decided 
modifying  influences.  Thus,  wind  brings  more  air  into  contact,  sun- 
light bleaches  the  color,  moisture  hastens  the  bluing,  and  heat  dissi- 
pates the  free  iodine. 

In  order  to  diflerentiate  between  ozone  and  nitrous  acid,  it  has 
been  proposed  to  use  neutral  litmus  (violet)  paper  instead  of  ordi- 
nary filter-paper  in  making  the  strips.  The  KOH  formed  in  the 
reaction  will  change  the  violet  to  blue,  while  nitrous  acid,  chlorine, 
and  organic  aoids  will  convert  it  to  red,  or  bleach  it,  or  leave  it 
unchanged. 

In  spite  of  the  fallacies  mentioned,  the  weight  of  evidence  thus  far 
obtained  in  ozonimetry  shows  that  the  reaction  with  starch  is  most 
marked  in  pure  air  at  the  seashore  and  at  great  heights,  and  that  but 
little  reaction  occurs  indoors. 

Determination  of  Dust. — Dust  is  determined  quantitatively  in 
two  ways,  and  the  results  are  expressed  in  terms  of  weight  or  of 
number.  In  order  to  ascertain  the  weight  of  the  dust  contained  in 
a  given  volume  of  air,  a  chloride  of  calcium  tube,  containing  per- 
fectly dry  absorbent  cotton  or  glass  wool,  is  weighed  accurately, 
and  then  attached  to  a  water  suction-pump  with  an  air-meter  between. 
A  large  amount  of  air,  say  500  liters,  is  then  drawn  through  as 
quickly  as  possible.  AVhen  a  sufficient  amount  has  passed,  the  tube  is 
detached  and  placed  either  in  a  drying-oven  or  in  a  desiccator  over 
sulphuric  acid,  and  kept  until  it  ceases  to  lose  weight  (moisture).    The 


268  AIR. 

net  increase  in  weight  represents  the  amount  of  dust  in  the  volume  of 
air  aspirated. 

To  determine  the  number  of  dust  particles  in  a  given  volume,  the 
method  of  Aitkin  is  employed.  The  apparatus  includes  a  shallow 
metallic  box  with  glass  top  and  bottom  etched  in  squares.  Into  this 
box,  containing  air  which  has  been  freed  from  dust  by  filtration  through 
cotton,  and  is  kept  saturated  with  moisture  by  means  of  wet  filter- 
paper,  a  small  measured  amount  of  the  air  under  examination  is  in- 
troduced. By  causing  the  formation  of  a  partial  vacuum,  each  par- 
ticle of  dust  becomes  coated  with  condensed  moisture  and  hence  tends 
to  fall  upon  the  etched  squares  of  the  bottom.  The  number  deposited 
is  counted  with  the  aid  of  a  magnifying  glass.  The  number  of  par- 
ticles varies,  according  to  Aitkin's  observations,  from  8,000  to  100,000 
per  cubic  inch  in  the  country,  and  from  1,000,000  to  50,000,000  in 
cities. 

Bacteriological  Examination. — The  method  which  involves  the 
least  trouble  and  requires  a  minimum  of  apparatus,  and  which  for  all 
practical  purposes  gives  greatest  satisfaction,  consists  in  exposing 
gelatin  plates  or  Petri  dishes  for  a  definite  period,  and  then  covering 
them  and  letting  the  colonies  develop.  After  the  proper  interval,  the 
number  of  growths  may  be  counted,  and  the  individual  species  isolated 
and  studied.  This  method  is  very  useful  for  comparative  work,  the 
results  being  given  as  the  number  of  colonies  which  develop  after  a 
given  exposure. 

For  more  accurate  quantitative  Avork,  Petri  ^  devised  a  process  of  sand 
filtration.  A  glass  tube,  9  by  1.6  cm,,  serves  to  carry  two  small  filters, 
which  are  arranged  in  the  following  manner :  Two  small  tightly 
fitting  diaphragms  of  fine  wire  gauze  are  inserted  into  the  tube  at  a 
point  midAvay  between  the  ends.  Into  one  side,  a  quantity  of  fine 
quartz  sand  is  packed,  and  upon  it,  to  keep  it  in  place,  another  dia- 
phragm is  driven.  Above  this,  the  space  is  filled  with  a  cotton  ping. 
The  tube  is  now  reversed  and  a  second  filter  of  sand  is  made  in  the 
same  way.  After  complete  sterilization,  the  cotton  plug  in  one  end  gives 
way  to  a  rubber  stopper  with  a  single  perforation,  through  which  passes 
a  glass  tube  connected  with  an  aspirating  pump.  The  other  cotton 
plug  is  removed  and  the  process  of  suction  begun.  When  a  sufficient 
amount  has  been  drawn  through,  the  two  filters  are  removed,  each  by 
itself,  and  mixed  with  the  nutrient  gelatin  from  Avhich  plates  are  next 
to  be  made.  The  first  filter  should  contain  all  of  the  organisms,  the 
second  serving  as  a  control. 

Ficker  suggested  an  improvement  in  the  construction  of  the 
filters,  substituting  for  sand,  which  to  a  certain  extent,  masks  the 
colonies,  powdered  glass,  which  has  not  this  disadvantage.  A  still 
better  material  is  fine  sugar,  the  use  of  which  was  suggested  first 
by  Sedgwick.  The  advantage  of  this  is  that  it  is  dissolved  in  the 
liquefied  gelatin,  and  thus  disappears  from  view,  and,  therefore, 
neither  masks  the  colonies  nor  can  be  mistaken  for  them  in  counting. 
^  Zeitschrift  fiir  Hygiene,  III.,  p.  1. 


EXAMINATION  OF  AIR.  269 

Sedgwick's  method  of  collecting  organisms  and  obtaining  cultures  is 
one  which,  on  the  whole,  is  preferable  to  any  other  that  has  been  sug- 
gested. His  apparatus,  known  as  the  aerobioscope,  is  a  glass  tube  about 
14  inches  in  length,  shaped  like  a  hydrometer  and  open  at  both  ends. 
The  narrow  portion,  which  is  rather  less  than  half  the  length  of 
the  tube,  has  an  internal  diameter  of  0.2  inch  ;  the  broader  portion  has 
an  internal  diameter  of  1.8  inches,  and  at  its  free  end  is  constricted  for 
an  inch  to  about  half  its  size.  Into  the  outer  end  of  the  narrow  por- 
tion, a  diaphragm  consisting  of  a  roll  of  fine  wire  gauze  is  inserted  to 
act  as  a  plug  for  the  sugar  filter.  The  two  open  ends  are  stopped  with 
cotton,  and  the  apparatus  is  then  sterilized.  The  plug  at  the  larger 
end  is  next  removed  and  the  sugar,  sufficient  in  amouut  to  fill  the  small 
tube  above  its  contained  diaphragm,  is  introduced.  The  plug  is  replaced, 
and  then  the  whole  is  sterilized  at  120°  C.  for  several  hours.  In  use,  the 
apparatus  is  held  in  a  vertical  position  with  the  narrow  portion  down, 
the  plugs  are  removed,  and  a  measured  volume  of  air  is  drawn  through 
by  means  of  an  aspirating  apparatus  connected  by  a  rubber  tube  to  the 
lower  end.  When  the  desired  amount  of  air  has  been  aspirated,  the 
sugar  with  the  bacteria  which  it  has  arrested  is  brought,  by  proper 
manipulation,  into  the  broad  part,  into  which,  by  means  of  a  bent 
funnel,  a  sufficient  amount  of  liquefied  nutrient  gelatin  is  introduced. 
The  plug  is  replaced,  and  the  tube  is  then  rolled  and  chilled  on  ice,  and 
set  aside  for  the  development  of  colonies.  After  the  proper  interval, 
the  count  is  made  in  the  usual  manner. 

The  methods  above  given  have  generally  superseded  that  of  Hesse, 
who  was  a  pioneer  in  this  branch  of  investigation.  His  apparatus  con- 
sists of  a  glass  tube,  28  inches  long  and  about  IJ  wide,  supported  in  a 
horizontal  position  upon  a  wooden  tripod.  One  end  is  covered  with  two 
rubber  caps,  the  inner  of  which  has  a  single  perforation ;  the  other  end 
is  closed  with  a  rubber  stopper  with  an  outlet  tube  of  glass  plugged  at 
each  end  with  cotton  and  connected  with  a  pair  of  aspirating  flasks  of 
a  liter  capacity.  The  tube  is  sterilized  and  charged  with  50  cc.  of 
gelatin,  which  is  allowed  to  solidify  before  use.  In  conducting  the 
operation,  the  outer  cap  is  removed,  thus  exposing  the  inner  perforated 
one,  and  a  current  of  air  is  drawn  slowly  through  by  the  action  of  the 
aspirating  flask,  which,  filled  with  water,  empties  itself  into  the  other. 
By  reversing  the  flasks,  any  number  of  liters  of  air  may  be  drawn 
through.  In  its  passage,  the  air  deposits  its  bacteria  on  the  gelatin. 
The  process  has  many  disadvantages,  and  can  make  no  great  claim  to 
accuracy. 


CHAPTEE    III. 
THE   SOIL. 

Notwithstanding  the  constant  and  necessarily  intimate  relation 
of  all  life  to  the  soil  upon  which  we  build  our  habitations,  from 
which  we  derive  in  such  great  part  our  supply  of  drinking-water, 
into  which  Ave  cast  vast  quantities  of  organic  filth,  and  to  which  we 
consign  our  dead,  the  subject  of  the  sanitary  importance  of  the  soil 
has  not  until  within  comparatively  recent  years  received  the  attention 
which  it  merits.  That  the  soil  exerts  important  influences  on  the 
public  health,  was  recognized  long  before  the  time  of  Hippocrates, 
and  extensive  researches  on  the  subject  figure  among  the  earliest 
investigations  of  the  modern  hygienist,  but  by  for  the  greatest  part 
of  the  attention  paid  to  the  study  of  the  soil  has  been  due  to  con- 
siderations of  public  wealth  rather  than  of  public  health.  With 
the  gradual  development,  however,  of  a  more  accurate  knowledge 
of  the  causes  of  disease,  has  come  an  increasing  interest  in  the  rela- 
tions of  the  soil  to  those  causes,  and  what  has  hitherto  been  a 
rather  neglected  field  of  exploration  now  bids  fair  to  be  well  and 
thoroughly  tilled. 

That  portion  of  the  earth's  ciiTst  in  which  we  as  hygienists  are 
interested  includes  the  superficial  layer,  known  as  tilth  or  arable  soil, 
which  is  the  result  of  the  disintegration  of  rocks  and  decay  of  animal 
and  vegetable  life,  and  the  subsoil,  which  lies  directly  beneath.  The 
former  varies  from  a  few  inches  to  several  feet  in  depth  ;  the  latter 
extends  few  or  many  feet  downward  to  the  hardjjan  or  other  imper- 
meable stratum. 

Soil  is  a  mixture  of  sand,  clay,  and  other  mineral  substances,  with 
humus,  or  organic  matter,  and  living  organisms ;  and  it  is  classified 
according  as  one  or  another  of  its  constituents  predominates.  The 
usual  classification  of  soils  includes  sands,  clays,  loams,  marls,  humus, 
and  peats. 

Sandy  soils  consist  almost  wholly,  or  at  least  more  than  four-fifths, 
of  pure  sand  of  any  kind. 

Clays  are  stiff  soils  consisting  chiefly  of  silicate  of  aluminum  and 
other  very  finely  divided  mineral  matters.  Clay  exists  in  particles  of 
the  smallest  possible  size,  is  very  cohesive,  possesses  a  high  degree  of 
plasticity,  and  plays  a  very  important  part  in  determining  the  fertility 
of  soils,  their  texture,  and  their  capacity  for  holding  water.  Its  plas- 
ticity is  due  to  the  presence  of  a  small  proportion  of  hyclrated  silicate, 
and  is  modified  very  greatly  by  the  addition  of  less  than  a  hundredth 
part  of  caustic  lime.  It  is  exceedingly  impermeable  to  water,  and 
when  wet  dries   with  great  slowness. 

270 


THE  SOIL.  271 

Loams  are  mixtures  of  sand,  clay,  and  humus  ;  hence  their  proper- 
ties partake  of  the  characteristics  of  these  substances  according  to  the 
extent  to  which  each  is  present.  When  sand  predominates,  they  are 
designated  as  light ;  and  when  clay  prevails,  they  are  known  as  heavy. 
These  terms,  however,  have  no  reference  to  weight,  but  to  the  ease  or 
difficulty  with  which  they  are  worked  in  the  processes  of  agriculture ; 
and,  indeed,  those  soils  which  are  the  lightest  in  this  sense  are  the 
heaviest  in  actual  weight.  Since  loams  consist  of  varying  proportions 
of  the  chief  constituents,  it  is  obvious  that  the  word  loam  may  have 
but  little  significance  without  some  qualifying  term,  and  they  are,  there- 
fore, divided  into  five  classes,  as  follows  : 

1.  Heavy  clay  loam,  containing 10-25  per  cent,  of  sand. 

2.  Clay  loam,  containing 25-40         "  " 

3.  Loam,  containing 40-60         "  " 

4.  Sandy  loam,  containing 60-75         "  " 

5.  Light  sandy  loam,  containing 75-90        "  " 

Mixtures  containing  less  than  10  or  more  than  90  per  cent,  of  sand  are 
classed,  respectively,  as  clay  or  sand. 

3Iarls  are  mixtures  of  clay,  sand,  and  amorphous  calcium  carbonate 
in  various  proportions,  and  contain,  often,  potash  or  phosphates  from 
the  fauna  and  flora  of  the  sea.  From  their  content  of  carbonate  of 
calcium  they  are  known  often  as  lime  soils,  and  according  as  one  or 
another  constituent  predominates  they  are  designated  as  clay  marl,  sand 
marl,  and  shell  marl.     All  contain  varying  amounts  of  humus. 

Humus  is  a  term  used  to  designate  the  entire  product  of  vegetable 
decomposition  in  the  various  intermediate  stages  of  the  process.  It  is 
the  essential  element  of  vegetable  mould,  and  is  necessarily  of  most 
complex  composition — so  complex,  indeed,  that  it  cannot  definitely  be 
determined.  It  is  composed  of  a  great  number  of  closely  related 
definite  chemical  compounds,  chief  among  which  are  ulmin  and  ulmic 
acid,  which  are  supposed  to  characterize  brown  humus ;  humiu,  and 
humic  acid,  which  dominate  dark,  or  black  humus ;  and  crenic  and 
apocrenic  acids.  Its  principal  characteristic  is  its  high  percentage 
of  nitrogen,  especially  marked  in  some  of  our  prairie  soils  and  in  the 
"  black  soil "  found  in  the  provinces  of  the  Ural  Mountains,  which, 
accorduig  to  Von  Hensen,^  contains  as  much  as  from  5  to  12  per  cent, 
of  organic  matter.  Its  complete  decay  is  most  rapid  in  warm  well- 
drained  soils  permeable  to  air,  and  in  such  soils  the  amount  of  humus 
present  at  any  one  time  will  be  relatively  small,  while  in  soils  which 
are  damp,  not  well  ventilated,  and,  for  months  at  a  time,  frozen,  its 
accumulation  is  favored.  While  its  ultimate  products  of  decay  are  of 
the  greatest  importance  U)  vegetable  growth,  it  does  not  follow  that  its 
complete  absence  renders  a  soil  necessarily  sterile,  or  even  poor, 
provided  the  necessary  nitrogen  is  supplied  in  the  form  of  nitrates. 
But  its  presence  is  necessary  to  the  growth  and  life  processes  of  the  soil 
bacteria,  without  whose  assistance  many  plants  would  fail  to  thrive. 

Peat,  muck,  and  humus  soils  contain  large  amounts  of  luunus,  but  differ 
'  Zeitschrift  fiir  wiasenschaftliche  Zoologie,  XXVIIL,  p.  360. 


272  THE  SOIL. 

according  to  the  conditions  under  which  they  are  formed.  Peat  and 
muck  result  from  the  incomplete  decay  of  vegetable  matter  under  water  ; 
the  former  term  applies  to  that  which  is  compact  and  fibrous  ;  the  latter 
is  less  compact,  not  fibrous,  and,  when  dry,  easily  reduced  to  powder. 
They  contain  but  a  small  amount  of  mineral  matter.  Humus  soils  are 
soils  which  contain  large  percentages  of  vegetable  mould  with  ordinary 
soil  constituents. 

The  expression  rocky  soil  applies  to  any  kind  of  soil  containing 
masses  of  rock. 

Gravelly  soils  are  those  which  contain  notable  amounts  of  gravel, 
which  consists  of  small  fragments  of  rock  more  or  less  worn  by  the 
action  of  water,  and  larger  and  coarser  than  sand. 

Alkaline  or  salt  soils  are  soils  which  contain  considerable  amounts 
of  soluble  salts,  especially  carbonate  and  sulphate  of  sodium  and  salts 
of  calcium. 

Constituents  of  the  Soil. — The  chief  constituent  of  the  soil  is  silica, 
which,  it  is  estimated,  forms  about  two-thirds  of  the  entire  earth's  crust. 
JS^ext  in  abundance  is  aluminum,  chiefly  in  the  form  of  clay  (silicate  of 
aluminum).  Lime  and  magnesia  are  large  constituents,  existing  chiefly 
as  carbonates  in  the  form  of  limestone.  Both  are  indispensable  to  the 
growth  of  plants,  and  lime  exerts  a  marked  influence  on  the  physical 
condition  of  the  soil  and  upon  the  processes  of  nitrification.  Although 
its  principal  combination  is  carbonate,  it  exists  also  largely  as  phos- 
phate and  sulphate. 

Iron  is  universally  present,  and  is  of  ver\'  great  importance  to  vege- 
tation, although  but  a  small  amount  is  needed.  The  red  and  yellow- 
colors  of  soils  are  due  to  the  presence  of  iron  compounds.  Manganese 
stands  second  to  iron  in  abundance  among  the  heavy  metals,  but  is  of 
much  less  importance.  It  is  a  constituent  of  many  plants,  notably  of 
tea.  Chlorine  is  not  a  large  constituent ;  it  occurs  chiefly  in  combina- 
tion with  sodium,  potassium,  and  magnesium.  Its  total  amount  in 
ordinary  unpolluted  soil  seldom  exceeds  ^  ^  ^  ^  ^  part  of  the  whole.  Sul- 
phur occurs  as  sulphides  and  sulijhates,  the  latter  usually  in  combina- 
tion with  calcium.  It  is  very  necessary  to  vegetable  growth,  as  it  is  an 
essential  element  of  vegetable  albumin.  Ph®sphorus  in  the  form  of 
phosphates  of  lime,  magnesia,  iron,  and  alumina,  is  another  essential 
element,  widely  distributed  in  small  amounts.  Sodium  and  potassium 
are  present,  chiefly  in  the  form  of  insoluble  silicates  and  partly  as 
chlorides.     Their  total  in  combination  seldom  exceeds  4  per  cent. 

Xitrogen  exists  in  soils  in  three  distinct  forms  :  proteids,  ammonia 
and  its  salts,  and  nitric  acid  and  nitrates.  In  average  soils,  the  total 
nitrogen  is  not  large  in  amount — considerably  less  than  1  per  cent. — 
but  in  some  exceptionally  rich  humus  soils  4,  5,  and  even  6  per  cent, 
are  found.  In  the  organic  combinations  (proteids)  it  is  not  available  as 
plant  food,  consequently  these  must  be  broken  up  into  simpler  forms 
in  order  to  be  of  direct  use.  In  their  decomposition,  the  second  form, 
amimonia,  is  produced,  but  not  all  the  ammonia  of  the  soil  is  from  this 
source,  for  some  is  brought  into  it  from  the  air  bv  rain.     And  in  the 


THE  SOIL.  273 

second  form,  also,  it  appears,  to  be  not  available  as  plant  food,  but  even, 
according  to  Bouchardat  and  Cloez,'  seems  to  act  as  an  energetic  poison 
when  absorbed  by  plant  roots  from  solutions  of  0.1  to  0.01  per  cent, 
strength.  So  it  is  probable  that  complete  oxidation  to  the  third  form 
is  necessary  for  the  absorption  of  any  form  of  nitrogen.  As  soon  as 
the  ammonia  is  oxidized  in  its  turn  to  nitric  acid,  this  latter  combines 
with  sodium,  potassium,  or  calcium,  and  the  resulting  nitrates  are  then 
ready  for  absorption. 

All  of  these  changes  from  the  complex  proteid  to  the  simple  nitrate 
are  carried  along  by  different  groups  of  micro-organisms,  but  no  great 
accumulation  of  the  end  products  occurs,  because,  while  vegetation  is 
flourishing,  they  are  removed  as  fast  as  formed,  and  when  it  has  ceased, 
they  are  washed  down  into  the  subsoil  by  the  rain  and  melting  snow. 

The  amount  of  organic  matter  in  soils  varies  widely  according  to 
circumstances,  but  the  amount  necessary  for  vegetation  is  quite  small, 
although  certain  crops,  as  tobacco  and  wheat,  require  much  more  than 
others,  as  oats  and  rye.  The  soils  richest  in  organic  matter  are  the 
peats  and  mucks ;  next  come  the  very  rich  humus  soils,  which  may 
yield  more  than  a  fourth  of  their  weight.  From  10  to  15  per  cent, 
denotes  unusual  richness,  and  about  6  per  cent,  may  be  regarded  as  a 
fair  amount  for  a  productive  soil. 

Physical  Properties  of  Soils. — Pore-volume. — In  all  soils,  no  mat- 
ter how  closely  the  individual  particles  are  packed,  there  must  exist  a 
greater  or  less  amount  of  interstitial  space,  which  may  be  filled  with 
water  or  air,  or  both  together.  The  sum  total  of  these  interstitial 
spaces  is  known  as  the  porosity  or  j)ore-volume,  and  is  expressed  in  per- 
centage of  the  volume  of  the  soil.  Its  amount  depends  not  upon  the 
size  of  the  soil  particles,  but  upon  their  uniformity  or  lack  of  uniform- 
ity of  size,  and  upon  their  arrangement.      If.  we  have,  for  instance,  a 

Fig.  15.  Fig.  16. 


very  coarse  soil,  consisting  of  particles  of  uniform  size  as  large  as  peas, 
and  another  of  uniform  particles  the  size  of  small  shot,  we  shall  find, 
on  determining  their  pore-volume,  that  it  is  practically  the  same  in 
each  case,  and  is  probably  not  far  from  a  third  of  the  whole.  Packed 
in  the  most  solid  manner  possible,  which  is  that  in  which  each  sphere 
rests  on  three  beneath  it  (arranged  like  the  familiar  pyramid  of  mar- 
bles), helps  support  three  in  the  layer  above  it,  and  comes  in  contact 
with  others  at  six  equidistant  points  along  its  equator,  as  in  Fig.  15, 
the  volume  of  interstitial  si^ice  will  c({ual  25.95  per  cent,  of  the  whole. 
Packed  as  loosely  as  possible,  so  that  each  rests  upon  but  one,  sup- 
'  DeutHche  medicinische  Wochenschrift,  188G. 
18 


274  THE  SOIL. 

ports  another,  and  comes  in  contact  with  but  four  of  its  neighbors  in 
the  same  layer  as  itself,  as  in  Fig.  16,  the  volume  of  the  interstices 
will  be  47.64  per  cent.^  Thus  a  soil  composed  of  spherical  grains  of 
uniform  size  would  have,  regardless  of  the  coarseness  of  the  grains, 
a  pore-volume  of  not  less  than  25.95  per  cent. 

That  the  size  of  the  individual  grains  makes  no  difference,  may  easily 
be  demonstrated  in  a  practical  manner.  If  we  take  two  cylindrical 
glass  vessels  of  the  same  size,  fill  them  to  the  same  height  with  water, 
and  then  add  to  the  one  a  measure  of  large  shot  and  to  the  other  an 
equal  measure  of  much  finer  shot,  and  secure  as  solid  packing  as  pos- 
sible by  gentle  tapping,  it  will  be  found  that  the  water  in  each  cylin- 
der has  risen  to  practically  the  same  height ;  that  is,  that  the  actual 
volume  of  each  is  about  the  same.  There  will  be,  perhaps,  some  slight 
difference  one  way  or  the  other,  owing  to  the  impossibility  of  securing 
absolute  uniformity  of  packing,  and  to  the  error  due  to  the  inequality 
of  the  spaces  along  the  circumference  of  the  cylinders.  But  in  nature 
we  do  not  deal  with  perfect  spheres  or  with  soils  made  up  of  particles 
all  of  the  same  size,  but  with  soils  composed  of  angular  pieces  of 
varying  size.  The  greater  the  variation  in  size  of  the  particles,  the 
greater  the  possibility  of  variation  from  the  limits  of  pore-volume  as 
given  above.  With  varying  size,  the  small  particles  may  fall  into  the 
spaces  made  by  the  larger  ones,  and  the  spaces  between  the  new  comers 
may  be  trespassed  upon  by  still  smaller  grains,  and  so  on  until  the 
interstitial  space  has  been  reduced  to  a  minimum. 

To  illustrate  this  diminution  in  a  practical  way,  fill  a  large  beaker 
with  marbles,  then  pour  into  it,  from  a  graduate,  sufficient  water  to 
displace  all  of  the  air  in  the  interstices,  and  note  the  amount  of  water 
required,  which  is  the  pore-volume  of  the  mass.  Next,  pour  out  the 
water  as  completely  as  possible  and  run  on  to  the  surface  of  the 
marbles  a  quantity  of  coarse  sand  or  shot,  and  shake  the  vessel  gently 
in  all  directions  so  as  to  favor  their  descent  into  the  spaces  below. 
When  all  have  penetrated  that  can,  pour  in  ^vater  again  until  it  ap- 
pears at  the  surface,  and  note  the  amount  required ;  this  is  smaller 
than  before,  on  account  of  diminished  air  spaces.  Now  pour  off  the 
water  a  second  time,  add  still  finer  shot,  and  repeat  the  operation  as 
before.  So  long  as  new  matter  can  be  added,  so  long  will  the  pore- 
volume  show  a  diminution. 

Irregularity  of  size  and  shape  of  the  particles  may  also  have  an  in- 
fluence in  the  other  direction,  and  cause  the  formation  of  large  spaces 
and  increased  poi'e-volume. 

All  soils,  even  the  most  compact  rocks,  have  a  certain  amount  of 
pore-volume,  and  some  apparently  compact  masses,  such  as  sandstone, 
have  as  much  as  30  per  cent.  In  soils  which  are  cemented  into  homo- 
geneous masses,  the  pore-volume  sinks  to  a  minimum,  but  in  ordinary 
soils  it  amounts  to  about  40  per  cent. 

Permeability  of  Soils. — The  permeability  of  a  soil  to  air  depends 
not,  as  it  might  appear,  upon  the  amount  of  its  pore-volume,  but  upon 
'  Soyka,  Der  Boden,  Leipzig,  1887. 


THE  SOIL. 


275 


the  size  of  the  individual  spaces.  In  fact,  a  soil  of  high  pore-volume 
may  be  almost  impermeable  to  air  in  comparison  with  one  of  less  pore- 
volume,  as  will  be  shown  ;  and  the  pore-volume  is  of  itself  no  measure 
whatever  of  permeability,  which  diminishes  in  an  extraordinary  degree 
with  diminution  in  the  size  of  the  soil  particles.  The  greater  the  num- 
ber of  the  individual  spaces,  the  greater  the  number  of  angles  and  the 
greater  the  friction  of  the  entering  air ;  and,  conversely,  the  less  the 
number,  and  consequently  the  hirger  the  size  of  the  spaces,  the  less  the 
number  of  angles  and  the  less  the  obstruction.  A  series  of  experiments 
conducted  very  carefully  by  Reuk  ^  with  different  kinds  of  soil  in 
cylinders  of  equal  height,  through  which  air  was  forced  under  the  same 
degree  of  pressure,  yielded  the  following  interesting  results  : 


Nature  of  soil. 

Diameter  of  grains. 

Pore- 
Tolume  fo. 

Pressure 

in  mm.  of 

water. 

Amount  of 

air  in 
liters  per 
minute. 

Ratio. 

Fine  sand 

Medium  sand     .    .    . 
Coarse  sand     .... 
Fine  gravel     .... 
Medium  gravel  .    .    . 

Less  than  J  mm. 
^  to  1  mm. 

1  to  2  mm. 

2  to  4  mm. 
4  to  7  mm. 

55.5 
55.5 
37.9 
37.9 
37.9 

20 
20 
20 
20 
20 

0.00133 
0.112 
1.280 
6.910 
15.540 

1 

84 

961 

5,195. 

11,684 

Thus  it  is  seen  that  a  fine  sand  with  a  pore-volume  of  55.5  per  cent, 
permitted  the  passage  of  but  1  volume  of  air,  while  a  gravel  of 
medium  coarseness  with  much  lower  porosity  permitted  the  passage  of 
11,684  times  as  much  in  the  same  unit  of  time.  Renk  showed,  farther, 
that  with  soils  of  the  finer  textures,  permeability  to  air  is  directly  pro- 
portionate to  pressure,  but  that  this  is  not  true  of  those  of  coarser  grain. 


Nature  of  soil. 

Size  of  grain. 

Height 

of 
column. 

Units 

of 

pressure. 

Ratio  of 

volume  of  air 

passed. 

Fine  sand    ........ 

Medium  sand 

Coarse  sand 

Fine  gravel 

Medium  gravel 

Less  than  J  mm. 
J  to  1  mm. 

1  to  2  mm. 

2  to  4  mm. 
4  to  7  mm. 

0.50  m. 
0.50  m. 

2.00  m. 

0.50  m. 

2.00  m. 

0.50  m. 

2.00  m. 

2.00  m. 

1 

1.5 

1 

2 

3 

1 

2 

3.6 

1 

2 

3 
1 

2   ■ 

3 

1 

2 

4 

1 

2 

3 

1 

2 

3 

1 

1.5 
1 

2 

3 

1 

2 

3.6 

1 

1.91 

2.78 

1 

2 

2.9 

1 

1.67 

2.30 

1 

1.77 

2.42 

1 

1.65 

2.19 

Zeitschrift  fur  Biologie,  XV,,  p.  205. 


276 


THE  SOIL. 


The  absence  of  any  connection  between  pore-volume  and  permeabil- 
ity has  been  shown  also  by  von  Welitschkowsky/  from  whose  results 
the  following  table  has  been  constructed  : 


Nature  of  soil. 


Pore-volume  Jb. 


Pressure 
in  mm. 
of  water. 


Amount  of  air 

in  liters 
per  minute. 


Ratio. 


Fine  sand     . 
Medium  sand 
Coarse  sand . 
Fine  gravel  . 


41.87 
40.64 
37.38 
35.47 


50 
50 
50 
50 


0.0058 

0.8990 

7.399 

33.651 2 


1 

155 

1,276 

5,802 


Since  permeability  duninishes  with  fineness  of  texture,  it  follows  that 
clay  and  similar  soils  possess  this  property  in  the  smallest  degree,  and 
that  when  these  are  mixed  with  sand}^  soils  they  must  necessarily  lessen 
it  to  a  very  marked  extent.  But  clays  and  loams  may  occur  in  very 
open  crumbly  form,  that  is,  in  loose  fragments  of  varying  size,  each 
consisting  of  myriads  of  small  particles  held  together  by  the  aid  of 
moisture ;  and  such  soils  show  a  high  permeability,  due  to  their  large 
interstitial  spaces. 

The  degree  of  permeability  to  air  is  influenced  very  greatly  by  the 
amount  of  contained  moisture,  the  maximum  influence  being  exerted 
by  decided  wetness.  This  is  due  to  the  fact  that  the  greater  the 
amount  of  water  present  in  the  mterstices,  the  greater  the  diminution 
in  the  space  available  for  the  passage  of  air  and  the  greater  the 
obstruction  to  its  movement.  Thus  the  complete  occlusion  of  the 
interstices  by  water  is  equivalent  to  absolute  impemieability,  except 
when  the  pressure  of  air  is  sufficient  to  displace  the  water  and  move  it 
along. 

In  the  case  of  soils  that  are  only  partially  wet,  the  diminution  in 
permeability  varies  accordmg  as  the  moisture  enters  from  above  by 
rain  or  from  below  by  capillary  attraction  from  the  water  in  the  sub- 
soil. This  is  owing  to  the  fact  that  when  the  soil  is  wetted  from 
above  by  rain,  the  superficial  interstices  are  occluded  more  or  less 
completely,  and  the  air  in  those  below  is  restrained  in  its  movement ; 
while  when  the  moisture  is  derived  by  capillary  attraction,  the  air  is 
displaced  upward,  and  the  superficial  interstices  are  more  or  less  com- 
pletely open.  The  action  of  downward  and  upward  moistening  has 
been  investigated  by  Renk,^  whose  results,  in  part,  are  given  in  the 
following  table  : 

1  Beitrag  zur  Kenntniss  der  Permeabilitiit  des  Bodens  fiir  Liift :  Archiv  fiir  Hj-giene, 
II.,  p.  483. 

''  The  height  of  the  column  of  material  in  this  experiment  was  three-fourths  of  a 
meter,  instead  of  a  half,  as  in  the  case  of  the  three  others.  With  an  equal  height  the 
result  would  have  been  much  larger. 

^  Loco  citato. 


THE  SOIL. 


277 


Nature  of  soil. 


Pore- 
volume  '/o. 


Moisture. 


Pressure. 


Ratio  of  air 
passed. 


Medium  gravel 
Fine  gravel     . 
Coarse  sand 
Medium  sand  . 


Fine  sand 


37.9 
37.9 
37.9 
41.5 
55.5 
55.5 


absent 
from  above 
from  below 
absent 
from  above 
from  below 
absent 
from  above 
from  below 
absent 
from  above 
from  below 
absent 
from  above 
from  below 
absent 
from  above 
from  below 


20 

20 

20 

40 

40 

40 

40 

40 

40 

150 

150 

150 

150 

150 

150 

150 

150 

150 


15.54 

14.63 

13.70 

14.04 

13.16 

12.55 

2.33 

1.91 

1.71 

0.57 

0.11 

0.00 

0.04 

0.03 

0.00 

0.01 

0.00 

0.00 


Permeability  is  lessened  also  by  freezing  temperatures,  by  reason  of 
the  fact  that  the  contained  moisture  expands  about  one-eleventh  of  its 
volume  as  it  freezes,  and  so  occupies  that  much  more  space  in  the  inter- 
stices. Moreover,  when  frozen,  the  moisture  is  in  a  fixed  rather  than 
a  movable  condition,  and  causes  the  production  of  a  compact  mass 
more  or  less  resembling  stone.  The  finer  the  grain,  the  more  solid  the 
product,  and  the  greater  the  diminution  of  permeability.  Renk  '^  deter- 
mined the  diminution  in  the  permeability  of  soils  of  different  grain  size 
due  to  freezing,  as  follows  : 


Nature  of  soil. 


Medium  gravel 
Fine  gravel  .    . 

it  a 

Coarse  sand  .    . 
Medium  sand  . 


Source 
of  moisture. 


from  above 

"  below 

"  above 

"  below 

"  above 

"  below 

"  above 

"  below 

"  above 

"  below 


Permeability. 

iSioist. 

Frozen. 

14.63 

13.87 

13.70 

12.20 

13.16 

12.54 

12.55 

10.18 

1.91 

1.64 

1.71 

1.27 

0.11 

0.07 

0.00 

0.00 

0.23 

0.00 

0.00 

0.00 

Diminution. 


The  degree  of  permeability  of  soil  to  water,  like  that  of  permeability 
to  air,  is  governed  by  the  texture  rather  than  by  pore- volume,  as  is 
shown  by  the  following  results  obtained  by  von  Welitschkowsky,^  who 
determined  the  rates  at  which  water  would  pass  through  columns  of 
soil  of  differing  fineness  packed  in  cylinders  of  equal  diameter.     Each 

^  Beitrag  zur  Kenntniss  der  Permeabilitilt  des  Bodens  fUr  Luft :  Archiv  fiir  Hygiene, 
H.,  p.  483. 

^  Kxpurimentelle  Untersufiliung  iiber  die  Permeabilitilt  des  Bodens  fiir  Wasser, 
Arfliiv  nil-  Hygiene,  II.,  p.  499. 


278 


THE  SOIL. 


specimen  was  first  completely  saturated  and  then  kept  so  during  each 
experiment,  the  water  supplied  heing  kept  at  constant  level. 


Height  of  column  of  soil. 

25  cm. 

50  cm. 

Height  of  water  column  above  soil  surface. 

20  cm.      1      50  cm. 

20  cm.       1       50  cm. 

Nature  of  soil  and  size  of  grain. 

Amount  of  water  discharged  in  liters  per  min. 

Fine  sand,  less  than  J  mm 

Medium  sand   3  to  1  mm 

0.00024 
0.175 

0.00059 
0.435 
4.014 
16.190 

0.00014 
0.123 
1.351 
7.465 

12.872 

0.00028 
0.237 

1.767 

8.570 

14.909 

2.422 

11.705 

Medium  gravel,  4  to  7  mm 

Comparing  these  results  with  those  obtained  by  the  same  investi- 
gator in  his  experiments  on  permeability  to  air,  it  will  be  noticed  that 
the  total  pore-volume  has  here  even  less  significance. 


Nature  of  soil. 


Height. 


Pressure. 


Pore- 
volume  ! 


Ratio  of  permeability. 


To  air. 


To  water. 


Fine  sand 50  cm. 

Medium  sand 50  cm. 

Coarse  sand I    50  cm. 


50  cm. 
50  cm. 
50  cm. 


41.87 
40.64 
37.38 


1 
155 

1,276 


1 

846 

8,650 


Capacity  for  Water,  and  Water-retaining  Capacity. 

If  to  a  volume  of  any  soil  packed  into  a  cylinder  of  glass  or  metal 
we  add  water  in  such  a  way  that  all  of  the  air  in  the  interstices  is  dis- 
placed, the  soil  is  then  saturated  and  the  amount  of  the  contained 
"water  represents  the  total  "  water  capacity,"  which,  it  is  seen,  equals 
the  pore-volume.  The  "  water-retaining  capacity,"  is  quite  another 
thing,  and  depends  upon  the  structure  and  composition  of  the  soil, 
and,  in  a  minor  degree,  upon  other  considerations.  If  for  the  imper- 
vious bottom  we  substitute  one  of  wire  gauze  or  coarse  cloth,  the  con- 
tained water  will  begin  to  drain  away,  owing  to  the  force  of  gravity, 
and  the  flow  will  by  degrees  become  less  and  less,  and  finally  cease. 
Then  the  interstices,  w^hich  originally  were  filled  with  air  alone  and 
next  with  water,  are  filled  in  part  with  the  one  and  in  part  with  the 
other. 

By  comparing  the  original  weight  of  the  volume  of  soil  with  its 
weight  in  its  now  wet  condition,  its  poAver  to  retain  water  is  easily  de- 
termined. This  power  is  the  result  of  two  forces  acting  in  opposition 
to  the  force  of  gravity  ;  namely,  surface  attraction  of  solids  for  liquids, 
and  capillary  attraction.  The  water  which  is  simply  adherent  to  the 
surfaces  of  the  soil  grains  is  known  as  hygroscopic  water,  while  that 
which  is  held  in  the  capillary  spaces  is  called  capillary  water ;  and  it  is 
the  latter  which,  in  any  but  the  coarsest  soils,  constitutes  by  far  the 
larger  part  of  the  retained  moisture. 

Not  all  of  the  interstices  of  a  soil  form  capillary  spaces,  but  only 
those  of   which  the  boundary  walls  are   separated  only  by  intervals 


CAPACITY  FOR    WATER,   AND    WATER-RETAINING    CAPACITY.    279 

which  come  within  the  limits  of  capillary  magnitude.  Thus,  a  coarse 
soil  may  contain  comparatively  few  such  spaces,  while  one  of  a  fine 
texture  may  have  its  particles  so  closely  approximated  that  all  of  its 
interstitial  spaces  are  capillary.  It  follows,  therefore,  that  compact 
soils  possess  greater  retaining  power  than  those  with  large  inter- 
stices which  permit  rapid  percolation,  and  that  when  the  texture  is  so 
line  that  all  the  spaces  are  capillary,  the  maximum  retaining  power  is 
attained. 

The  influence  of  soil  texture  on  capacity  for  holding  water  may  be 
seen  in  the  following  table  of  some  of  the  results  obtained  by  Hof- 
mann  :  ^ 


Diameter  of  grain 

Pore-volume  per 

Amount  of  con- 

Amount of  con- 

Per cent,  of  pore- 

in  mm. 

1,000  CO. 

tained  water  in  cc. 

tained  air  in  cc. 

water. 

5 

434 

55 

379 

12.7 

3 

418 

77 

341 

18.4 

2 

410 

98 

312 

23.9 

1 

400 

150 

250 

37.5 

0.5 

413 

270 

143 

65.4 

less  than  0.5 

413 

347 

66 

84.0 

The  water-retaining  capacity  of  soils  is  determined  very  largely  also 
by  the  amounts  of  organic  matter  present ;  a  soil  rich  in  organic  matter 
will,  other  conditions  being  the  same,  show  more  water  than  another 
of  less  richness.  The  extreme  influence  is  observed  in  the  case  of 
humus,  which  can  hold  ten  times  its  weight  of  water.  In  view  of  this 
influence  of  organic  matter,  it  is  very  clear  that  one  way  to  help  keep 
a  soil  dry  is  to  avoid  discharging  filth  into  it,  and  thus  keep  it  clean. 

For  the  purpose  of  illustrating  the  influence  of  very  fine  soil  par- 
ticles (clay)  and  of  organic  matter  (humus),  the  following  results  of  an 
investigation  by  Wolif  ^  may  be  quoted.  He  packed  soils  of  varying 
clay  and  humus  content  into  a  metallic  vessel  with  a  permeable  bottom, 
saturated  them  completely  with  water,  then  superimposed  a  column  of 
water  of  equal  cross-section  and  8  cm.  high,  and  observed  the  time 
required  for  the  added  water  to  be  delivered  below  : 


Nature  of  soil. 

Percentage  of  clay. 

Percentage 

of 

humus. 

Time  required. 

Per  cent. 

Eatio. 

Hours. 

Eatio. 

Very  fine  sandy  loam     .... 
Very  fine  sandy  loam      .... 
Black,  rich,  chalky  loam    . 
Very  fine  sandy  loam      .... 

Very  clayey  soil 

Soil  with  considerable  clay    .    . 

15.74 
15.96 
18.17 
25.93 
42.56 
29.76 

1. 

1.+ 
1.15 
1.64 
2.70 
1.89 

0.88 
1.40 
6.87 
0.92 
0.66 
2.19 

20.3 

25.8 

31.0 

75.8 

133.0 

188.0 

1. 
1.27 

1.52 
3.73 
6.55 
9.26 

It  will  be  observed  that  the  soil  which  permitted  the  passage  of  the 
water  in  the  shortest  time  was  poorest  in  clay  and  almost  so  in  humus, 


An-liiv  fiir  Hygiene,  T.,    p.  273. 
Anleitunj'  zur  chemischen  Untei'siiclnni' 


andwirtlischnftlich  wichtiger  Stofle,  1875. 


280  THE  SOIL. 

and  that  the  one  which  required  the  longest  time  combined  a  consid- 
erable amount  of  clay,  not  the  highest,  with  a  high  percentage  of  humus, 
also  not  the  highest.  The  highest  percentage  of  clay  was  associated 
with  the  lowest  amount  of  humus,  and  the  highest  of  humus  with  a  low 
content  of  clay ;  but  these  two  soils  (Nos.  5  and  3)  were  both  less 
impermeable  than  that  (No.  6)  w^hich  contained  less  clay  than  the  one 
and  less  humus  than  the  other.  It  is  to  be  noted,  however,  in  the  case 
of  the  soil  with  the  highest  proportion  of  clay  and  lowest  of  humus, 
that  it  contained  12.8  per  cent,  of  chalk  as  against  2.28  per  cent,  in 
the  most  impermeable,  and  that  this  substance,  as  has  been  mentioned, 
has  a  very  great  influence  in  diminishing  the  degree  of  plasticity  of 
clays. 

Soil  Temperature. 

The  sources  of  heat  in  the  soil  are  three  in  number ;  namely,  the 
sun's  rays,  chemical  changes,  and  the  original  heat  of  the  earth's  inte- 
rior. The  principal  source  is  the  sun.  The  heat  derived  from  chemical 
changes  is  not  great,  and,  indeed,  is  not  even  worthy  of  consideration, 
except  in  soils  very  rich  in  organic  matter  ;  and  here  the  changes 
occur  only  in  the  presence  of  comparatively  high  temperature  due 
to  the  action  of  the  sun.  The  third  source  is  constant  and  of  much 
importance. 

The  soil  temperature  is  influenced  by  a  number  of  conditions, 
including  exposure,  atmospheric  temperature,  color,  compactness,  com- 
position, and  moisture.  Naturally,  the  surfaces  exposed  to  the  greatest 
amount  of  sunshine  get  more  heat  than  others.  The  nearer  the  angle 
of  incidence  of  the  sun's  rays  approaches  a  right  angle,  that  is,  the 
more  perpendicularly  the  rays  strike,  the  greater  the  amount  of  heat 
received. 

The  rapidity  with  which  soils  are  affected  in  either  direction  by 
changes  in  atmospheric  temperature  varies  widely,  but  with  any  soil  it 
is  only  in  the  very  uppermost  layers,  the  very  surface  in  fact,  that  any 
immediate  corresponding  rise  or  fall  is  observ^ed.  Great  sudden  changes 
aifect  the  soil  below  the  surface  very  slowly,  and  in  the  deeper  layers 
the  maxunum  and  minimum  temperatures  occur  much  later  than  in  the 
atmosphere  above.  The  annual  variation  diminishes  as  the  distance 
from  the  surface  increases ;  at  fifteen  feet  the  amplitude  is,  as  a  rule, 
less  than  10  degrees  F.,  and  between  fifty  and  eighty  feet  the  tempera- 
ture is  constant  the  year  round. 

The  color  of  a  soil  exerts  an  important  influence  in  the  determination 
of  its  temperature.  As  is  well  known,  a  black  surface  exposed  to 
the  sun  absorbs  the  heat  rays  more  than  a  white  one.  A  common 
illustration  of  this  fact  is  the  greater  rapidity  with  which  snow  melts 
when  its  surface  is  dotted  over  with  dirt  and  soot  than  when  it  is 
clean  and  white,  owing  to  the  absorption  of  heat  by  the  dark  particles 
and  its  communication  by  conduction  to  the  snow  beneath  and  about. 
In  the  same  way,  soot  and  cinders  w^ork  their  way  downward  into  the 
ice    on    a    pond.      Another    illustration    is    the    greater    feeling    of 


SOIL   TEMPERATURE.  281 

warmth  conferred  by  black  clothes  than  by  white  in  the  bright  sun- 
shine. 

So,  other  conditions  being  the  same,  a  dark  soil  is  warmer  than  a 
light  one,  which  reflects  the  heat  rays  instead  of  absorbing  them. 
Observation  has  shown  a  difference  of  more  than  25  degrees  F.  in  the 
temperature  of  black  and  white  sands  exposed  side  by  side  to  tlie 
direct  rays  of  the  sun,  but  the  white  sand  by  reason  of  reflecting  the 
heat  rays  will  appear  to  be  much  hotter  than  it  really  is. 

The  influence  of  compactness  on  soil  temperature  varies  with  the 
season.  According  to  King,^  the  general  tendency  of  rolling  the  land 
is  to  make  it  warmer  during  bright,  sunny  weather,  but  in  cloudy  or 
cold  weather  it  tends  to  promote  cooling.  He  has  observed  that,  at 
the  depth  of  1.5  inches  below  the  surface,  a  rolled  field  may  have  a 
temperature  10  degrees  F.  higher  than  a  similar  soil  not  rolled,  and  at 
double  the  distance  he  has  noted  a  diffei'euce  of  6.5  degrees.  This  is 
due  chiefly  to  the  fact  that  a  compact  soil  is  a  better  conductor  of  heat 
than  one  containing  large  interstices  filled  with  air. 

The  character  of  the  mineral  and  organic  constituents  of  the  soil  and 
the  amount  of  its  content  of  water  exert  the  very  greatest  influence 
upon  its  temperature.  Rocks,  sands,  and  mineral  substances  in  gen- 
eral are  better  heat  conductors  than  water,  organic  matter,  and  air,  and 
they  differ  also  one  from  another  in  conductivity.  Organic  matter  is 
a  particularly  poor  conductor  of  heat,  and  hence  the  greater  the  amount 
of  humus  a  soil  contains,  the  slower  its  response  to  the  action  of 
the  sun. 

The  great  influence  of  moisture  on  soil  temperature  is  due  to  the 
high  specific  heat  of  water,  and  to  the  loss  of  heat  which  accompanies 
the  process  of  evaporation.  The  specific  heat  of  ordinary  dry  soils 
varies  from  a  fifth  to  a  fourth  of  that  of  water,  although  in  exceptional 
cases  it  may  amount  to  nearly  a  half;  and  the  wetter  the  soil  is,  the 
higher  will  be  the  specific  heat  of  the  mass,  that  is,  the  greater  the 
number  of  heat  units  necessary  to  warm  a  given  weight  1  degree. 
Thus  it  happens  that  a  light-colored  dry  soil  may,  in  spite  of  the  great 
influence  of  color,  attain  a  much  greater  degree  of  warmth  than  a  dark 
one  which  is  damp.  The  different  soil  constituents  have  different 
specific  heats,  ranging  from  about  0.16  for  certain  sands  and  clays,  to 
about  0.44  for  dry  humus,  that  of  water  being  unity.  Thus,  to  raise 
the  temperature  of  100  pounds  of  water  1  degree  will  require  100 
units  of  heat,  while  to  perform  the  same  office  for  equal  weights  of  dry 
sand,  weathered  porphyry,  weathered  granite,  and  humus,  will  require 
respectively  16,  20,  30,  and  44  units.  Therefore,  the  sarne  amount  of 
heat  necessary  to  raise  a  given  weight  of  water  1  degree  will  raise  the 
equivalent  weights  of  these  substances  respectively  6.67,  5.00,  3.33, 
and  2.27  degrees. 

But  although  the  high  specific  heat  of  water  is  of  importance  in 
determining  soil  temperatures,  the  chief  influence  of  moisture  in  this 
direction  is  due  to  the  groat  loss  of  heat  which  accompanies  the  process 
'  The  Soil,  New  York,  1898. 


282  THE  SOIL. 

of  evaporation,  for  the  change  from  the  liquid  to  the  gaseous  form  is 
accomplished  only  at  the  expense  of  heat.  The  greater  the  amount  of 
^v•ater  evaporated  from  a  given  soil,  therefore,  the  greater  the  expendi- 
ture of  heat  and  the  greater  the  lowering  of  the  soil  temperature. 
Conversely,  the  drier  the  soil,  the  less  the  evaporation,  and  the  greater 
its  warmth.  Water  does  not,  however,  always  tend  to  produce  lower- 
ing of  the  temperature,  for,  in  point  of  fact,  it  may  and  often  does 
have  the  opposite  effect.  In  the  spring,  for  instance,  when  the  frost 
is  not  yet  out  of  the  ground  and  when  the  interstices  are  filled  with 
cold  water  derived  from  the  melting  ice  and  snow,  the  warmer  rain 
hastens  the  removal  of  frost,  and,  as  it  sinks  into  the  soil,  displaces 
downward  the  colder  water  and  consequently  raises  the  temperature. 

Changes  in  the  Character  of  Soils  Due  to  Chemical  and 
Biological  Agencies. 

Chemical  action  is  constantly  at  work  in  the  soil,  not  alone  on  the 
organic  constituents,  but  upon  the  mineral  matters  as  well.  The 
changes  which  occur  in  the  latter  are  of  importance  to  the  hygienist 
almost  solely  in  so  far  as  they  affect  the  quality  of  the  drinking-water. 
Complicated  processes  involving  the  decomposition  of  organic  matters 
give  rise  to  quantities  of  carbon  dioxide  which,  being  taken  into  solu- 
tion by  the  water  in  the  interstices,  assists  in  the  production  of  still 
more  complicated  pi^ocesses  which  engage  the  mineral  constituents. 

The  changes  which,  from  a  public  health  point  of  view,  are  of  the 
greatest  interest  are  those  which  are  in  progress  in  the  process  known 
as  the  "  self-purification  "  of  soils,  in  which  the  complex  organic  mat- 
ters are  broken  up  and  reduced  to  simple  chemical  substances  through 
the  intervention  of  bacterial  life.  In  the  end,  the  carbon  is  oxidized 
to  CO2,  and  the  nitrogen  either  is  set  free,  or  is  combined  with  hydro- 
gen in  the  form  of  ammonia,  or  is  oxidized  to  nitric  acid  and  nitrates. 

The  process  requires  the  presence  of  atmospheric  air  and  of  moist- 
ure not  in  excess,  and  is  favored  by  temperatures  between  53°  and  131  ° 
F.,  the  most  favorable  being  98°.  It  proceeds  most  vigorously  and 
perfectly  nearest  the  surface,  and  virtually  ceases  at  a  depth  of  more 
than  three  feet,  little  or  no  action  occurring  in  the  subsoil  beyond  that 
depth.  If  too  much  organic  filth  and  its  attendant  moisture^  are  pres- 
ent, the  soil  becomes  boggy  and  the  changes  cannot  proceed. 

An  influence  of  very  great  importance  in  its  effects  on  the  physical 
and  chemical  characteristics  of  soils  is  that  exerted  by  earth  worms, 
which  live  chiefly  on  half-decayed  leaves,  which  they  drag  into ,  their 
burrows  to  be  used  as  food  and  as  linings  and  plugs  for  the  burrows  as 
well.  According  to  Charles  Darwin,^  their  castings  contain  0.018  per 
cent,  of  ammonia,  and  the  humus  acids,  which  have  been  proved  to 
play  a  very  important  part  in  the  disintegration  of  various  kinds  of 
rocks,  appear  to  be  generated  ^vithin  their  bodies.  They  swallow 
earth  both  in  the  process  of  excavating  their  burrows  and  for  the 
^  The  Formation  of  Vegetable  Mould  through  the  Action  of  Woims. 


SOIL- AIR. 


283 


nutriment  which  it  may  contain,  and  exert  an  important  mechanical 
:action  on  the  soil  grains,  reducing  their  size  by  attrition  within  their 
gizzards.  After  filling  themselves  with  earth,  they  soon  come  to  the 
surface  for  the  purpose  of  emptying  themselves. 

"  In  many  parts  of  England  a  weight  of  more  than  10  tons  of  dry 
'•earth  annually  passes  through  the  bodies  of  worms,  and  is  brought  to 
the  surface  on  each  acre  of  land,  so  that  the  whole  superficial  bed  of 
vegetable  mould  passes  through  their  bodies  in  the  course  of  every  few 
years."  From  various  data,  Darwin  calculated  that  the  castings, 
spread  out  uniformly,  would  form,  in  the  course  of  ten  years,  a  layer 
varying  from  0.83,  in  the  case  of  a  very  poor  soil,  to  2.2  inches  in 
ordinarily  rich  soils.  Their  mechanical  action  and  that  of  ants,  moles, 
and  other  burrowing  animals  have  much  to  do  with  keeping  soils  open 
and  friable. 

Soil-air. 

The  air  in  the  interstices  of  the  soil  differs  from  that  of  the  atmos- 
phere mainly  in  its  richness  in  carbon  dioxide,  which  arises  from  the 
decomposition  of  organic  matters.  It  is  also  poorer  in  oxygen,  but  by 
no  means  always  in  a  corresponding  degree,  and  it  is  usually  quite 
humid  by  reason  of  the  presence  of  soil  moisture. 

The  amount  of  carbon  dioxide  varies  very  widely  in  different  soils 
and  at  different  depths  of  the  same  soil,  and  it  fluctuates  very  consider- 
ably also  under  differing  conditions  at  any  given  point  in  the  same  soil. 
Other  conditions  being  the  same,  the  amount  is  most  marked  in  soils 
rich  in  organic  matter  undergoing  decomposition-changes.  In  soils 
poor  in  this  respect,  the  amount  may  be  no  greater  than  in  the  atmos- 
phere. Pettenkofer,  for  instance,  found  in  the  air;  of  desert  sand, 
which  was  devoid  of  organic  matter,  the  same  amount  as  was  present 
in  the  air  immediately  above  it. 

In  ordinary  soils,  the  amount  increases  with  the  distance  from  the 
surface,  as  has  been  shown  by  Fodor,^who  made  a  great  number  of 
analyses  of  air  at  different  depths  at  a  number  of  places,  the  observa- 
tions extending  over  several  years.  The  average  amounts  found  at 
depths  of  1,  2,  3,  and  4  meters,  expressed  in  parts  per  1,000,  were 
as  follows  : 


Depth  in  meters. 

1 

2 

.3 

4 

Station  1 

4.8 
13.7 
18.1 

6.6 
14.3 

28.4 

20.1 

28.7 

Station  2 

Station  3 

36.5 

Th(.'  influence  of  season  also  was  shown  by  him  to  be  very  considerable, 
the  liighe.st  amounts  occurring  during  the  hot  months,  and  the  lowest 
in  winter.  The  averages  by  months  are  presented  in  the  following 
table  : 

'  Bodcn  und  Wasser,  Braunschweig,  1882. 


284 


THE  SOIL. 


Month. 


January  . 
February  . 
March  .  . 
April  .  . 
May  .  .  . 
June .  .  . 
July  .  .  . 
August .  . 
September 
October  . 
November 
December 


Depth  in  meters. 


12.6 
12.2 
11.8 
14.9 
16.1 
21.5 
22.8 
20.7 
19.3 
15.0 
13.8 
12.6 


25.0 
24.8 
24.7 
25.2 
27.2 
29.2 
35.9 
32.6 
31.4 
29.4 
26.5 
25.8 


Fig.  17. 


These  results  are  only  such  as  might  be  expected  when  we  consider 
that  decomposition  of  organic  matters  proceeds  most  vigorously  within 
certain  limits  of  high  temperature. 

Fluctuations  in  the  amount  present  at  any  given  point  are  due  to  a 
number  of  conditions  which  include  rainfall,  the  action  of  the  wind, 
the  rise  and  fall  of  the  subsoil-water,  and  differences  in  atmospheric 
pressure  and  temperature. 

Rainfall,  by  filling  the  superficial  interstices  of  the  soil  with  water, 
interferes  with  the  natural  process  of  soil  ventilation  and  causes  an 
immediate  accumulation  of  carbon  dioxide,  which, 
however,  is  shortly  followed  by  a  diminution  due 
to  absorption  of  the  gas  by  the  water,  w'hich 
thus  acquires  an  increase  in  its  power  of  attacking 
and  dissolving  the  mineral  constituents  of  the  soil. 
Inasmuch  as  the  bulk  of  the  absorbed  rainfall  is 
held  by  the  upper  strata  of  the  soil,  its  influence  is 
more  marked  there  than  at  greater  depths.  As  it 
sinks  downward,  however,  in  very  wet  weather,  it 
drives  the  air  before  it,  and  causes  its  escape  at 
points  where  its  egress  is  not  obstructed. 

The  action  of  wind  is  exerted  in  two  ways:  by 
perflation  and  by  aspiration.  By  blowing  strongly 
across  the  surface  of  the  soil,  it  aspirates  the  air  in 
the  upper  layers  and  causes  an  upward  movement 
in  the  air  below,  or  it  may  suck  it  out  at  one  mo- 
ment and  take  its  place  the  next.  Again,  it  may 
blow  with  such  force  against  the  surface  as  to  drive 
the  contained  air  downward  before  it,  so  that  the 
interstices  become  filled  with  ordinary  atmospheric 
air.  The  action  is  more  marked  in  soils  of  ordi- 
nary coarseness  of  texture  than  in  very  open  soils 
with  large  interstices,  which  permit  freer  movement 
in  the  upper  strata.  This  may  readily  be  demonstrated  by  means  of  a 
simple  experiment  with  the  apparatus  shown  in  Fig.  17.  Here  we  have 
a  glass  cylinder,  inside  which  is  a  glass  tube  extending  from  the  bottom 


Apparatus  to  show  action 
of  wind  on  soil  air. 


SOIL- AIR.  285 

and  bent  over  at  the  top  so  as  to  form  a  U,  into  which  an  amount  of 
water  sufficient  to  form  a  seal  may  be  introduced.  If  now  we  fill  the 
intervening  space  up  to  the  top  with  sand,  and  then  direct  against  the 
surface  of  the  latter  a  current  of  air  by  means  of  a  bellows  or  by  blow- 
ing sharply  through  a  tube  of  glass  or  other  material,  the  whole  volume 
of  air  in  the  interstices  is  set  in  motion,  which  is  communicated  to  the 
air  within  the  enclosed  tube,  so  that  the  water  in  the  U-shaped  depres- 
sion is  caused  to  oscillate.  If  the  water  completely  fills  the  short  leg 
of  the  U,  it  may  be  forced  over  and  caused  to  drip.  If,  however, 
instead  of  employing  sand,  we  fill  the  cylinder  with  coarse  gravel, 
the  oscillation  of  the  water  will  be  either  less  noticeable  or  entirely 
absent,  the  air  which  enters  at  one  point  on  the  surface  communi- 
cating its  motion  only  to  that  immediately  adjacent  in  the  upper  part. 

The  rise  and  fall  of  the  water  in  the  subsoil  assist  in  the  production 
of  variations  in  the  amount  of  carbon  dioxide ;  on  the  one  hand,  by 
its  rise,  forcing  the  rich  soil  air  upward  and  outward,  and,  on  the 
other  hand,  by  its  fall,  drawing  the  soil-air  downward  and  causing 
its  place  in  the  upper  strata  to  be  filled  with  atmospheric  air  with 
low  content  of  the  gas. 

Differences  in  temperature  and  barometric  pressure  have  also  been 
mentioned  as  exerting  influence  on  the  motion  of  the  ground  air.  In 
spring  and  summer,  the  ground  air  is  colder  and  denser;  and  in 
autumn  and  winter,  it  is  warmer  and  lighter  than  the  air  above.  Hence 
in  the  former,  it  tends  to  remain  stationary  or  to  sink ;  while  in  the 
latter,  it  rises  and  mingles  with  the  atmosphere,  which,  under  proper 
conditions,  replaces  it.  Again,  these  changes  may  occur  in  both 
directions  within  the  same  space  in  twenty-four  hours.  For  instance, 
at  evening  and  at  night  the  atmospheric  air,  being  colder,  enters  the 
soil ;  while  by  day,  being  warmer,  its  direction  is  reversed,  and  air  is 
drawn  up  from  below. 

Movement  due  to  temperature  differences  is  almost  constant,  since  it 
is  only  rarely  that  the  temperatures  of  the  air  and  soil  are  in  agree- 
ment. The  influence  of  barometric  pressure-changes  is  not  very  great ; 
with  fall  in  pressure,  the  tendency  is  toward  upward  movement,  and 
with  rise,  toward  downward  movement ;  but  Fodor  found  from  the 
study  of  a  large  number  of  observations  that  the  actual  observable 
changes  were  insignificant. 

With  the  various  influences  at  work  causing  movement  of  the  soil- 
air  in  all  directions,  it  is  plain  that  the  soil,  especially  if  highly 
permeable,  is  endowed  with  a  sort  of  respiratory  function  which  keeps 
it  more  or  less  well  ventilated. 

Formerly,  it  was  V)elieved  by  Pettenkofer  and  others  of  the  "  Munich 
School  "  that  the  amount  of  carbon  dioxide  in  soil-air  might  serve  as 
an  index  of  the  amount  of  impurity  and  of  the  rate  at  which  the  latter 
is  decomposing,  and  that  comparison  of  the  amounts  obtainable  from 
different  soils  wouki  serve  to  indicate  their  relative  cleanliness.  But 
such  is  not  th(!  case  witli  soils  cfjually  ])ermeal)le,  owing  to  the  influence 
exerted  on  soil  ventilation  by  so  many  varying  and  couHicting  causes. 


286  THE  SOIL. 

Indeed,  it  has  been  proved  by  Fodor  that  a  permeable  soil  extensively 
contaminated  by  organic  filth  may  yield  less  of  this  index  of  impurity 
than  one  far  cleaner,  but  less  susceptible  to  ventilating  influences. 

Soil-water. 

The  moisture  contained  in  the  soil  may  be  designated  in  three  dif- 
ferent ways,  according  to  its  position  and  the  forces  by  Avhich  it  is 
held  in  place ;  namely,  hygroscopic,  capillary,  and  gravitation. 

Hygroscopic  water  is  that  which  adheres  to  the  surfaces  of  the  soil 
particles  in  the  presence  of  air.  A  certain  amount  of  moisture  is  con- 
densed upon  the  surface  of  most  solid  substances  exposed  to  ordinary 
dampness,  and  it  adheres  with  great  tenacity.  The  amount  of  water 
so  obtained  differs,  other  conditions  being  the  same,  according  to  the 
nature  of  the  soil,  some  soil  constituents  surpassing  others  in  their 
power  to  attract  it.  Thus,  soils  rich  in  organic  matter  (humus)  have  a 
greater  degree  of  hygroscopicity  than  others  in  which  this  constituent 
is  present  to  a  lesser  extent.  In  some  soils,  the  amount  of  hygroscopic 
water  is  very  marked  by  reason  of  the  large  amount  of  organic  matter, 
and  because  also  of  the  lai-ge  surface  area  presented  by  the  soil  particles. 
Some  idea  of  the  tenacity  with  which  this  moisture  is  retained  may  be 
derived  from  the  fact  that  air-dried  soils  which  appear  to  be  quite 
dry — the  dust  of  country  roads,  for  instance — may  yield  as  much  as  a 
tenth  of  their  weight  of  water  on  complete  drying  by  ordinary  labora- 
tory methods.  Both  the  moisture  absorbed  from  the  air  and  the  water 
held  on  the  soil  grains  by  surface  attraction  after  a  condition  of 
decided  wetness  has  been  changed  by  the  draining  away  of  the  rest, 
may  be  termed  hygroscopic. 

The  capillary  moisture  is  that  which  is  held  within  those  spaces 
which  have  been  spoken  of  as  capillary  in  their  nature.  Under 
ordinary  conditions,  these  are  intermingled  with  spaces  which  may  not 
be  so  designated  and  which  contain  air,  and  so  the  capillary  moisture 
does  not  ordinarily  equal  the  pore-volume.  The  water  in  the  capillary 
spaces  may  be  that  which  is  retained  after  thorough  wetting  from  above, 
or  it  may  have  crept  upAvard  or  laterally  from  points  completely  satu- 
rated. Capillary  movement  occurs  in  all  directions,  but  it  is  most 
marked  from  below  upward  to  points  where  water  is  being  withdrawn 
by  evaporation  or  by  the  demands  of  growing  vegetation. 

The  height  to  which  water  may  rise  by  virtue  of  this  force  depends 
upon  the  diameter  of  the  spaces;  the  smaller  the  diameter,  the  greater 
the  rise.  Jurin's  law  of  capillary  movement  is,  that  the  height  of 
ascent  of  one  and  the  same  liquid  in  a  capillary  tube  is  inversely  as 
the  diameter  of  the  tube.  Thus,  water  will  ascend  ten  times  as  high 
in  a  tube  having;  a  diameter  of  0.1  mm.  as  it  will  in  another  with  a 
diameter  of  1.0  mm.  It  follows,  therefore,  that  capillary  movement 
is  most  marked  in  soils  of  fine  texture. 

■■  Capillary  movement  is  influenced  materially  also  by  temperature 
and  by  the  nature  of  substances  held  in  solution.     It  diminishes  as  the 


SOIL- WATER.  287 

temperature  rises,  and  increases  as  the  temperature  falls,  so  that  cooling 
a  soil  uniformly  will  cause  increased  capillary  movement,  and  heating 
it  will  cause  a  fall.  But  with  uneven  temperatures,  the  motion  will  l)e 
different  according  as  the  temperatures  vary.  Thus,  if  the  lower  part 
of  a  column  of  soil  be  cooled,  the  surface  tension  of  its  contained 
water  will  be  increased  at  that  point,  and  water  will  be  attracted  from 
the  parts  above,  gravity  assisting ;  whereas,  if  it  be  heated,  its  con- 
tained water  will  be  attracted  upward. 

In  saturated  soils,  motion  of  the  water  in  any  direction  is  influenced 
very  greatly  by  temperature,  because  of  the  effect  of  heat  in  changing 
the  viscosity  of  water.  The  higher  the  temperature,  the  greater  the 
diminution  in  viscosity  and  the  freer  the  movement. 

The  influence  of  dissolved  substances  depends  upon  their  nature, 
some  favoring,  and  others  retarding,  movement.  The  rate  is  increased 
by  the  presence  of  nitrates,  and  is  diminished  by  common  salt  and 
sulphate  of  calcium  ;  but  the  favoring  influence  of  the  presence  of 
nitrates  is  couuteracted  most  markedly  by  organic  substances  produced 
in  the  decomposition  of  matters  of  vegetable  origin,  for  a  minute  trace 
of  these  completely  neutralizes  the  effect  of  such  amounts  of  the 
former  as  are  commonly  present  in  cultivated  soil. 

It  is  self-evident  that  anything  tending  to  the  diminution  of 
capillarity  of  a  soil  diminishes  the  rate  of  capillary  flow.  When  the 
soil  is  worked  in  such  a  way,  therefore,  as  to  produce  an  open,  crumbly 
condition  in  place  of  one  of  compactness,  the  rate  of  capillary  move- 
ment within  it  is  diminished  very  greatly. 

We  come  now  to  the  third  division,  which  has  been  designated  as 
gravitation- water.  This  is  the  water  which  has  drained  away  through 
the  soil  by  the  force  of  gravity  and  accumulated  in  the  subsoil  over  an 
impermeable  stratum  which  has  arrested  its  farther  downward  journey. 
This  is  what  is  commonly  known  as  ground-water,  or  subsoil-water. 
Its  zone  extends  from  the  surface  of  the  impermeable  barrier  upw^ard 
to  that  point  where  the  interstices  of  the  soil  cease  to  be  completely 
filled  with  water,  but  are  filled  partly  with  air.  This  point  is  known 
as  the  ground-water  level.  The  zone  above  it,  through  which  water  is 
moved  in  the  capillary  spaces,  is  known  as  that  of  the  capillary  soil- 
water,  and  extends  as  far  as  the  water  is  moved  through  that  force. 
Above  this,  at  and  near  the  surface,  is  the  zone  of  evaporation,  from 
which  water  is  evaporated  into  the  atmosphere. 

The  impermeable  stratum  beneath  the  subsoil-water  may  be  either 
very  fine  sand,  compact  clay,  or  rock.  It  may  be  thin  or  thick,  accord- 
ing to  circumstances.  Below  it,  there  may  be  a  succession  of  alter- 
nating permeable  and  impermeable  strata,  so  that  in  driving  deep  wells 
a  variety  of  strata  are  pierced,  and  waters  of  varying  composition  may 
be  secured.  Dense  clay  is  practically  impermeable  to  water,  but  at 
the  same  time  it  can  communicate  its  moisture  to  surfaces  with  which 
it  comes  in  immediate  contact,  a  fact  which  renders  necessary  the  in- 
ter])osition  of  damp-proof  material  in  the  foundations  of  houses  built 
upon  it. 


288  THE  SOIL. 

Rocks  vary  greatly  in  impermeability ;  the  densest  of  them  contain 
very  small  amounts  of  moisture  in  their  pores,  while  others  are  so 
porous  that  they  may  contain  as  much  as  a  third  of  their  volume  of 
water.  Again,  most  rock  deposits  are  more  or  less  fissured  and 
seamed,  and  thus  permit  to  a  greater  or  less  degree  the  passage  of 
Avater  at  these  points. 

The  water-bearing  stratum  is  usually  gravel  or  sand,  but  may 
be  porous  or  fissured  rock.  Its  depth  is  exceedingly  variable, 
depending  upon  local  geological  conditions,  and  at  two  points  not 
Avidely  separated,  it  may  be  respectively  slight  and  considerable. 

The  ground-water  is  in  constant  motion  both  laterally  and  vertically. 
Its  lateral  movement,  whatever  its  rate,  depends  upon  the  configuration 
of  the  impermeable  layer  below,  and  not  upon  that  of  the  surface  of 
the  land.  Generally  speaking,  the  direction  of  the  movement  is  toward 
the  nearest  large  body  of  water,  be  this  the  sea,  a  lake,  or  a  river ; 
but  it  is  not  often  possible  to  determine,  except  in  a  general  way,  from 
surface  observations,  whether  at  any  given  point  the  flow  is  in  one 
direction  or  another.  This  is  especially  true  when  the  water-bearing 
stratum  is  thin  and  underlaid  by  an  impermeable  stratum  of  very  irreg- 
ular conformation. 

The  rate  of  movement  is  also  exceedingly  variable ;  it  may  be  fast, 
or  slow,  or  hardly  perceptible.  In  Munich,  for  instance,  according 
to  Pettenkofer,  it  amounts  to  about  fifteen  feet  daily,  while  at 
Berlin,  it  is  only  very  slight,  and  at  times  is  wanting.  It  is 
influenced  by  the  configuration  of  the  subsurface,  by  the  perme- 
ability of  the  subsoil,  by  the  amount  of  the  accession  of  moisture 
from  rainfall  and  melting  snow,  by  the  obstacles  interposed  by  the 
roots  of  trees  and  other  plants,  by  others  at  its  outfall,  and  by  the 
withdrawal  of  moisture  by  the  needs  of  vegetation  and  of  communities 
of  men. 

The  rise  and  fall  of  the  ground-water — that  is,  its  vertical  move- 
ment— depend  chiefly  upon  the  amount  of  rainfall  ;  and,  on  the  other 
hand,  upon  the  rate  of  withdrawal  by  evaporation,  vegetation,  and 
water  supply  of  communities,  and  upon  the  freedom  of,  or  obstacles  to, 
the  outflow. 

The  effect  of  rainfall  is  generally  not  immediately  perceptible,  for 
so  much  time  intervenes  between  heavy  falls  and  penetration  that  a 
falling  of  the  ground-water  level  may  continue  to  be  observed  for  a 
long  time  after  a  period  of  great  wetness  ;  but  when  the  level  rises,  it 
is  a  proof  that  additions  have  been  received  from  above,  though  per- 
haps the  accession  has  travelled  through  a  long  distance  in  the  soil. 
When  the  level  falls,  it  is  a  sign  that  the  upper  strata  have  become  dry 
through  evaporation,  and  that  capillary  attraction  has  carried  moisture 
upA^^ard  to  replace  the  loss. 

The  rise  and  fall  of  the  ground-Avater  level  may  be  determined  by 
measuring  from  day  to  day  the  distance  between  the  surface  of  the  soil 
and  the  height  of  the  water  in  a  number  of  wells  in  a  given  locality. 
This  may  readily  be  done  by  means  of  a  tape-measure  or  chain  to  which 


SOIL- WATER.  289 

is  attached  a  rod  bearing  a  number  of  shallow  metallic  cups  which  are 
lowered  into  the  water.  The  distance  between  the  point  on  the  chain 
at  the  mouth  of  the  well  and  the  uppermost  cup  in  which  water  is 
found  indicates  the  position  of  the  water-level  with  respect  to  the 
surface. 

By  removing  obstacles  to  the  outfall  of  the  underground  river  as  it 
sometimes  is  called,  and  by  creating  new  outfalls  by  ditching  more  or 
less  deeply,  according  to  individual  conditions,  by  sinking  drainage 
wells,  or  by  laying  drain  tile  beneath  the  surface  at  such  depths  as  may 
appear  to  be  advisable,  the  level  of  the  ground-water  may  be  con- 
siderably lowered,  and  the  soil  thereby  rendered  correspondingly  drier, 
and  also,  by  reason  of  the  influence  of  water  on  soil  temperature, 
warmer. 

Sources  of  Soil-water. — The  principal  source  of  soil-water,  it  is 
hardly  necessary  to  say,  is  the  rainfall,  but  by  no  means  all  of  the 
Avater  precipitated  from  the  atmosphere  during  a  storm  penetrates  to 
the  subsoil.  Light  rains  may  be  wholly  lost  by  evaporation,  and 
heavier  ones,  especially  daring  active  vegetation,  may  penetrate  but 
very  slightly  beneath  the  surface.  In  early  spring  and  in  au- 
tumn, the  amount  which  percolates  downward  is  naturally  much 
larger  in  proportion.  A  by  no  means  insignificant  amount  of  moist- 
ure is  that  derived  by  absorption  and  condensation  from  a  moist  atmos- 
phere. In  periods  of  drought,  this  power  of  dry  soil  to  absorb  water 
from  humid  air  is  of  the  greatest  value  to  vegetation.  The  amount 
absorbed  differs  according  to  the  nature  and  hygroscopicity  of  the 
soil  elements.  Thus,  a  soil  rich  in  humus  will  attract  more  water 
than  another  composed  wholly  of  sand.  Condensation  of  water 
occurs  when  the  surface  is  cold  and  in  contact  with  moist  air.  This 
condensation  may  occur  from  above  or  from  the  rising  moist  soil  air 
just  below. 

A  third  source  of  moisture,  of  no  great  importance,  is  the  breaking 
up  of  organic  matter  into  its  constituent  elements,  in  which  process 
the  hydrogen  is  in  great  part  ultimately  released  in  combination  with 
oxygen  as  water.  Another  and  exceedingly  important  source  of  soil 
moisture,  important  not  because  of  the  amount,  but  because  of  the 
quality  of  the  water,  and  because  of  its  possible  effect  on  the  supply  of 
drinking-water  and  on  public  health,  is  the  waste  waters  incident  to 
human  life,  which  in  so  great  a  proportion  of  communities  are  dis- 
charged directly  into  the  soil,  where,  being  out  of  sight,  they  are  equally 
out  of  mind. 

Loss  of  Soil  Moisture  by  Evaporation. — The  amount  of  water 
wJjich  a  soil  loses  by  evaporation  is  influenced  by  a  number  of  factors, 
which  include  the  water  content  of  the  soil,  the  height  of  the  permeable 
layer,  the  composition  and  structure  of  the  soil,  and  the  character  of 
its  surface,  and,  ))articu]ai'ly,  whether  it  is  covered.  In  other  words, 
the  rapidity  of  the  process  is  ])r()p()rtional  to  the  combined  area  of  sur- 
faces exposed,  and  to  the  facility  for  replacing  the  loss  by  withdrawalfi 
from  below. 

19 


290  THE  SOIL. 

Influence  of  Vegetation  on  Soil  Moisture. — The  amount  of  water 
in  soils  is  iniiueuced  greatly  by  growing  vegetation,  which  requires  a 
vast  supply  for  the  proper  maintenance  of  its  functions.  It  withdraws 
it  by  absorption  by  the  roots,  which  extend  downward  to  surprising 
depths,  the  roots  of  wheat,  for  instance,  attaining  sometimes  a  length 
of  eight  feet  and  more.  From  the  roots,  the  water  passes  into  the  cir- 
culation of  the  plant,  assists  in  the  various  physiological  processes,  and 
then,  for  the  most  part,  is  given  otf  from  the  leaves  into  the  atmos- 
phere. It  has  been  calculated  by  Pettenkofer  that  an  oak  evaporates 
more  than  eight  times  the  rainfall,  and  that  the  Eucalyptus  globulus  is 
even  more  active.  The  difference  between  the  rainfall's  contribution 
and  the  amount  exhaled  represents  the  amount  M^hieh  has  been  with- 
dra'svn  by  the  roots  from  the  capillary  spaces  and  from  the  water-table 
itself.  As  the  water  in  the  capillaries  is  relinquished  by  them,  more 
comes  up  from  below  to  take  its  place.  Thus  it  is  that  a  plant  or  tree 
acts  during  the  growing  season  as  a  constantly  working  suction  appara- 
tus tending  to  dry  the  ground,  and  so  may  be  explained,  in  part  at 
least,  the  condition  of  wetness  that  is  acquired  by  some  lands  after 
removal  of  trees. 

All  growing  crops  withdraw  enormous  amounts  of  water,  and  after 
the  growth  becomes  well  advanced,  it  is  the  capillary  water  upon  which 
dependence  is  placed,  for  the  rainfall  penetrates  but  a  short  distance 
into  cultivated  laud,  and  most  of  it  is  lost  by  evaporation.  Were  it 
not  for  the  capillary  water  supply,  no  crops  could  be  raised,  except 
under  most  extraordinary  conditions  of  weather  and  by  artificial  irri- 
gation, since  but  a  short  period  of  drought  would  suffice  to  produce 
wilting.  According  to  Stockbridge,^  "The  quantity  of  water  thus 
required  and  evaporated  by  different  agricultural  plants  during  the 
period  of  growth  has  been  found  to  be  as  follows  : 

1  acre  of  wheat  exhales 409,832  pounds  of  water. 


clover  exhales 1,096,234 

sunflowers  exhales 12,585,994 

cabbage  exhales 5,049,194 

grape-vines  exhales 730,733 

hops  exhales 4,445,021 


But  the  influence  of  vegetation  on  the  water  content  of  the  soil  is 
not  limited  simply  to  its  withdrawal  and  evaporation  into  the  atmos- 
phere, for  it  acts  in  the  other  direction  to  impede  surface  flow  and  sub- 
surface drainage.  This  is  seen  more  particularly  in  the  case  of  trees 
and  forests.  The  forest  cover  keeps  the  soil  granular  and  promotes 
downward  percolation  ;  the  tree  roots,  penetrating  in  all  directions, 
present  an  effective  obstacle  to  rapid  lateral  movement  through  the  soil. 
Removal  of  forests  and  clearing  away  the  surface  of  the  forest  litter 
promote  sudden  and  destructive  freshets  in  the  springtime  and  drought 
when,  later  in  the  year,  the  water  is  needed.  The  ill  effects  of  deforest- 
ation are  noticed  particularly  in  parts  of  Maine  and  in  the  Adiron- 
dacks,  where  streams  that  formerly  ran  full  the  year  round  are  raging 
1  Eocks  and  Soils,  New  York.  1888. 


SOIL- WATER.  291 

torrents  when  the  winter's  snows  are  melting  and  but  insignificant 
brooks  or  wholly  dry  during  the  summer  months.  It  has  been  stated 
by  Major  Raymond,  of  the  U.  S.  Engineers,  that,  in  forest  areas,  four- 
fifths  of  the  rainfall  are  saved,  while  in  cleared  land  the  same  amount 
is  lost  by  evaporation  and  surface  flow. 

Other  Effects  of  Vegetation  Upon  the  Soil. — In  addition  to  its 
influence  on  the  movement  of  soil-water  and  on  its  amount,  vegeta- 
tion is  an  important  factor  in  the  determination  of  soil  temperature 
and  of  the  amount  of  mineral  matter  available  for  succeeding  growths. 
The  deeply  penetrating  roots  bring  to  the  tissues  of  the  growing  plants 
a  large  amount  of  mineral  matters  from  the  subsoil.  On  the  death 
and  decay  of  the  plant,  these  matters  are  returned  to  the  soil  at  its 
surface,  where  they  are  available  for  reabsorption  as  plant  food. 

The  effect  of  vegetation  on  soil  temperature  is  of  much  importance 
in  both  hot  and  cold  climates.  A  barren  soil  or  one  from  which  veg- 
etation has  been  stripped  absorbs  the  heat  rays  of  the  sun  more  rap- 
idly and  becomes  much  hotter  than  one  which  is  protected  by  growth 
of  any  kind.  The  air  above  the  soil  becomes  hotter,  too,  because  of 
greater  heat  radiation,  and  the  difference  in  the  surface  temperature  of 
bare  ground  and  that  covered  by  grass  or  other  vegetation  is  further 
increased  by  the  cooling  effect  of  evaporation  of  moisture  from  the 
leaves.  Herbage  acts  as  a  protection  against  excessive  heating  in  hot 
climates,  and  as  a  blanket  to  prevent  loss  of  heat  in  cold  ones.  In 
summer,  the  areas  covered  by  vegetation  are  cooler  than  those  which 
are  unprotected  against  the  direct  rays  of  the  sun,  and  in  winter,  they 
are  warmer  because  of  the  obstacle  to  heat  loss. 

Trees  obstruct  the  sun's  rays  and  impede  wind  currents,  and  thus 
the  soil  is  cooler  and  at  the  same  time  suffers  less  loss  of  moisture  by 
evaporation.  The  obstruction  of  the  wind  currents  deprives  the  soil 
air  of  one  of  the  influences  having  to  do  with  its  movement,  and  thus 
interferes  with  soil  respiration.  The  obstacle  opposed  by  trees  to  the 
motion  of  air  is  so  great  that,  in  the  interior  of  a  piece  of  woods,  the 
air  may  be  quite  calm  while  a  gale  is  blowing  outside.  In  winter,  the 
obstruction  of  the  sun's  rays  aids  in  the  conservation  of  the  soil  heat 
by  preventing  the  accumulated  snow  from  melting,  and  thus  keeps  the 
surface  protected  by  a  blanket. 

In  cold  climates  the  influence  of  trees  may  be  at  the  same  time  per- 
nicious and  beneficial ;  that  is  to  say,  pernicious,  in  that  the  ground  is 
colder  and  moister  than  it  would  be  had  the  sun's  rays  free  access, 
and  beneficial,  in  that  the  trees  afford  protection  against  wind.  The 
judicious  removal  of  trees  will  often  render  a  climate  more  equable. 
In  hot  climates,  as  in  cold,  trees  should  be  removed  only  in  case  of 
necessity  and  after  due  consideration  of  the  probable  results.  The 
hottest  spots  in  hot  countries  are  those  deprived  of  the  beneficial  influ- 
ences of  vegetation. 

It  may  not  be  out  of  place  here  to  mention  the  supposed  agency  of 
woodland  in  protecting  communities  from  "  malarial  exhalations  "  from 
swamp  localities.     That  the  interposition  of  a  belt  of  trees  has  been 


292  THE  SOIL. 

followed  in  a  number  of  instances  by  decided  improvement  in  public 
health  so  far  as  malaria  is  concerned,  cannot  well  be  denied  ;  but  the 
improvement  is  not  owing  to  the  fancied  property  of  leaves  to  con- 
dense upon  their  surfaces  the  malarial  poison,  but  to  the  fact  that  the 
Avinged  bearers  of  this  poison,  blown  along  by  the  wind,  are  filtered 
out  of  the  air  by  the  leaves,  or  themselves  seek  the  protection  thus 
afforded  against  farther  involuntary  movements,  and  attach  themselves 
to  the  leeward  side  of  leaves  and  trunks. 

Pollution  of  the  Soil. 

The  soil  receives  polluting  matters  of  infinite  variety  and  in  widely 
differing  amouuts,  but  their  nature  and  their  amount  are  of  less 
importance  relatively  than  their  point  of  entrance.  Some  of  these 
pollutions  are  unavoidable,  and  these,  indeed,  are  the  ones  concerning 
which  we  may  give  ourselves  the  least  concern ;  others  are  avoidable, 
though  not  always,  or  even  usually,  without  the  incurring  of  expense. 

The  unavoidable  pollutions  include  the  urine  and  droppings  of 
animals,  the  carcasses  of  such  as  have  died  and  have  escaped  the 
notice  of  other  animals  that  act  as  scavengers,  and  vegetable  luatters 
of  every  conceivable  kind  in  various  stages  of  decay.  Excepting 
under  very  unusual  conditions,  such,  for  instance,  as  may  exist  in 
time  of  war  or  flood  or  epidemics,  when  large  numbers  of  horses,  cattle, 
and  other  animals  are  killed  or  die,  these,  lying  at  or  near  the  surface, 
are  of  comparative  unimportance,  since,  exposed  to  natural  processes  of 
purification,  they  are  resolved  into  simple  innocuous  substances,  which 
are  absorbed  by  })lant  life  or  washed  downward  into  the  soil. 

The  avoidable  pollutions  are  mainly  those  which  man  deposits 
ibeneath  the  surface,  and  these  are  first,  and  of  minor  importance,  the 
l)odies  of  the  dead,  and  second,  of  vast  importance,  the  excreta  and 
other  organic  filth  that  constitute  sewage.  The  temporary  storage  of 
filth  in  water-tight  receptacles  built  under  ground  can,  of  course,  do 
no  harm  to  the  surrounding  soil,  but  it  is  not  into  such  that  man  usu- 
ally chooses  to  deposit  his  waste.  Water-tight  cesspools  gradually 
become  filled  and  then  require  to  be  emptied,  while  those  with  pervious 
bottoms  permit  the  escape  of  the  contents  downward,  require  no 
thought  or  care,  and  are,  therefore,  a  source  of  contentment  and  of 
saving  of  expenditure.  The  filth  thus  introduced  is,  however,  below 
the  zone  of  bacterial  activity  of  the  beneficent  kind,  and  becomes  stored 
up  in  the  subsoil  or  is  washed  away  gradually  by  the  ground-water, 
which  thereby  is  made  unfit  for  human  consumption.  Organic  matters 
deposited  in  the  upper  strata  of  the  soil  are  resolved  into  their  con- 
stituent elements  with  greater  or  lesser  rapidity  according  to  local  con- 
ditions of  distance  from  the  surface,  temperature,  degree  of  moisture, 
and  permeability  to  air,  the  process  advancing  most  rapidly  in  a  well- 
ventilated,  moderately  dry  soil  near  the  surface,  and  most  unfavorably 
in  wet,  compact  soils,  far  from  the  surface. 

The  influence  of  the  physical  condition  of  the  soil  is  observed  fre- 


POLLUTION  OF  THE  SOIL.  293 

quently  in  the  exhumation  of  bodies  for  one  cause  or  another  after  vary- 
ing periods  of  interment.  Thus,  in  open  soils,  bodies  may  disappear 
almost  completely  in  the  course  of  a  few  years,  while  in  stiff  wet 
clays  they  may  be  found  even  after  twenty  and  more  years  to  be  putrid 
masses,  still  undergoing  a  most  gradual  process  of  disintegration. 
Indeed,  it  is  stated  that  in  excavating  an  ancient  churchyard  in  Lon- 
don, the  soil  of  which  was  a  wet  clay,  bodies  were  removed  that  showed, 
after  two  centuries  of  interment,  no  materially  different  appearance 
from  that  of  others  which  had  been  buried  not  over  a  score  of  years.. 
Recently,  Dr.  A.  Riedel '  had  an  opportunity  to  compare  the  results 
of  decomposition  proceeding  in  bodies  buried  for  about  the  same  period 
in  soils  that  were  respectively  loose,  well-drained,  and  well-ventilated,, 
and  compact,  wet,  and  impermeable  to  air.  In  the  first  instance,  the 
remains  were  fairly  dry  and  quite  inoffensive  to  the  sense  of  smell ;  irt 
the  other,  they  were  a  slimy,  loathsome  mass  of  rottenness,  which  gave 
out  such  a  horrible  stench  that  the  crowd  of  idlers  that  had  gathered 
was  quickly  dissipated,  while  those  whose  duty  compelled  them  to 
remain  were  made  unpleasantly  sick,  and  could  not  rid  themselves  of 
the  smell,  which  clung  to  them  until  several  days  had  elapsed. 

In  the  decomposition  of  organic  substances  in  the  soil,  no  offensive 
emanations  are  noticed,  if  a  substantial  layer  of  earth  is  interposed 
between  them  and  the  atmosphere.  Just  as  it  has  power  to  retain 
water  in  its  interstices  and  on  the  surface  of  its  constituent  particles,, 
so  has  the  soil  the  faculty  of  absorbing  gases  and  vapors,  a  property 
which  cannot  have  escaped  the  notice  of  any  person  acquainted  with, 
the  common  earth-closet.  The  soil  acts  in  this  respect  like  charcoal, 
and  can  take  up  not  only  odors,  but  also  coloring  matters  and  other 
substances. 

Perhaps  the  most  striking  illustration  of  the  affinity  of  soil  for 
odors  is  the  fact  that  illuminating  gas  from  leaking  street  mains  has 
in  its  journey  through  the  soil  been  known  to  be  divested  of  its  odor- 
ous constituents  to  such  an  extent  that,  being  drawn  into  houses  with 
the  soil-air,  its  presence  escaped  observation  until  the  production  of 
poisonous  effects  drew  attention  to  the  existence  of  an  unusual  condi- 
tion of  the  air. 

A  like  retaining  action  is  manifested  in  a  less  marked  degree 
toward  substances  in  solution,^  which  are  held  back  by  surface  attrac- 
tion, a  fact  which  has  been  noted  repeatedly  by  hygienists  and  agri- 
cultural chemists.  This  is  more  noticeable  in  soils  of  fine  grain,  since 
such  present  a  far  greater  area  of  grain  surface.  Hoffmann^  filled  two 
cylinders  of  equal  size  with  sand  of  different  degrees  of  fineness,  but 
with  the  same  total  pore-volume,  and  to  each  was  added  from  above 
an  equal  volume  of  solution  of  common  salt,  and  then  daily,  for  ten 
days,  an  equal  volume  of  distilled  water.     The  drainage  of  each  day 

_'  .Miii)c)i(.-nLT  iiicdiciiii.slic  Wficlien.sclirirt,  .June  6,  1899. 
''■  See  paffe  295  fVn-  an  nniisually  strikinj^  example. 

'  fj'eber  flaw  Eindrinf^^en  von  Veriinreinigungen  in  Bcxlen  nnd  Grundvvasser.  Archiv 
fiir  Hygiene,  II.,  jj.  M.",. 


294  THE  SOIL. 

was  tested  as  to  its  content  of  salt,  and  it  was  found  that,  whereas 
that  from  the  coarser  sand  yielded  salt  on  the  second  day  and  gave  the 
highest  results  on  the  third,  from  which  time  the  yield  progressively 
dwindled,  that  from  the  finer  showed  no  trace  until  the  sixth  day,  and 
its  maximum  on  the  seventh.  Repetition  of  the  experiment  in  the 
same  way  in  all  particulars  yielded  identical  results.  Thus  it  is  shown 
that  pollution  travels  more  quickly  in  coarse  soils  than  in  fine. 

In  the  decomposition  of  proteid  substances  in  the  soil,  basic  sub- 
stances are  believed  by  some  to  be  formed,  which  may  be  taken  into 
the  system,  and  so  affect  the  resistance  of  the  body  to  disease  as  to 
favor  infection.     This,  however,  is  purely  hypothetical. 

As  has  been  remarked,  the  presence  of  bacteria  is  essential  for  the 
resolution  of  organic  matters  in  the  soil.  This  has  been  illustrated  in 
a  striking  manner  by  Duclaux,^  who  treated  sterile  soil  with  sterile 
organic  matters,  such  as  milk,  sugar,  and  starch  paste,  and  then  planted 
therein  peas  and  beans.  Although  the  resulting  plants  were  well  cared 
for,  they  did  not  thrive,  but  remained  as  thin  and  weak  as  though 
growing  in  distilled  water.  The  organic  matters  in  the  soil  were 
of  no  value  in  their  growth,  for  they  could  not  be  absorbed  as  such, 
but  only  after  decomposition.  The  addition  of  a  little  unsterilized 
earth  sufficed,  however,  to  start  the  required  process,  and  then  the 
growth  improved  at  once. 

Bacteria  of  the  Soil. 

The  bacteria  of  the  soil  are  found  almost  wholly  in  the  superficial 
layers,  and  below  a  depth  of  twelve  feet  their  number  is  relatively  few. 
As  they  need  organic  matter  for  their  growth  and  multiplication,  it 
may  be  inferred  that  the  greater  the  amount  present,  the  greater  will  be 
their  number.  Thus,  they  are  far  more  numerous  in  rich  garden  soil 
than  in  ordinary  sand  and  clays. 

The  conditions  most  favorable  to  their  development  are,  in  addition 
to  the  presence  of  the  organic  pabulum,  moisture  and  certain  limits  of 
temperature.  Dryness  and  extremes  of  heat  and  cold  are  all  unfavor- 
able ;  saturation  with  water  may  or  may  not  be,  according  to  the  vari- 
ety, for  there  are  some  that  in  a  Avet  rich  soil  can  go  on  decomposing 
organic  matters. 

In  ordinarily  rich  soil,  the  number  of  bacteria  ranges  from  hundred 
thousands  to  millions  per  cubic  centimeter  in  the  surface  layers,  below 
which  they  diminish  in  number  very  rapidly,  until,  at  ten  to  twelve 
feet  below  the  surface,  the  soil  is  practically  sterile,  except  for  those 
that  have  been  washed  down  or  carried  by  burrowing  animals,  or,  as 
above  stated,  deposited  by  man  in  organic  filth. 

The  soil  bacteria  are  mainly  of  the  beneficent  varieties,  the  sap- 
rophytes which  perform  only  useful  offices,  including  the  numerous 
varieties  of  the  nitrifying  organisms.  While  different  species  of  path- 
ogenic bacteria  have  been  found  in  the  soil,  and  although  certain  of 

1  Comptes  rend  us,  C. 


BACTERIA    OF  THE  SOIL.  295 

them,  the  bacilli  of  tetanus  and  of  malignant  oedema,  are  very  gener- 
ally present,  this  class  of  organisms  finds,  as  a  rule,  the  conditions 
present  in  the  soil  unfavorable  to  development. 

In  the  first  place,  the  temperature  is  too  low,  excepting  in  the  very 
uppermost  layers  in  warm  weather ;  and,  furthermore,  the  pathogenic 
kinds  cannot  thrive  in  the  presence  of  the  enormously  numerous  sap- 
rophytes, which,  in  some  manner  not  as  yet  satisfactorily  explained, 
bring  about  their  destruction.  This  action  has  been  demonstrated 
repeatedly  by  Koch  and  others,  who  showed  that  anthrax  bacilli  and 
other  pathogenic  varieties  can  grow  in  sterilized,  but  not  in  unsteril- 
ized,  soil. 

Klein^  insists  that  pathogenic  organisms  in  buried  bodies  cannot 
maintain  vitality  in  the  presence  of  B.  cadaveris  sporogenes,  which  is 
always  present  in  decomposing  bodies,  and  that,  in  most  cases,  a  month 
is  sufficient  time  to  insure  destruction.  He  buried  guinea-pigs  con- 
taining various  kinds  of  micro-organisms  within  the  abdominal  cavity, 
and  at  diflPereut  times  exhumed  them  and  made  search  for  living  speci- 
mens. He  found  that  B.  prodigiosus  lived  4  weeks,  but  not  6  ;  Staph- 
ylococcus aureus,  about  the  same;  Sp.  cholerce,  19,  but  not  28  days; 
B.  typhosus  and  B.  diphtherke,  not  longer  than  2  weeks  ;  B.  pjestis,  1 7, 
but  not  21  days,  and  B.  tuberculosis,  not  7  weeks. 

It  is  believed  that,  in  the  deeper  layers,  away  from  the  saprophytes, 
the  spores  of  pathogenic  species  may  find  a  lodgement  favorable  to 
storage,  but  not  to  development,  and  that  there  they  may  remain  with 
dormant  vitality. 

Many  examinations  of  graveyard  soils  and  of  bits  of  coffins  have 
been  made  by  Dr.  E.  H.  Wilson,  of  Brooklyn,  to  determine,  if  possible, 
the  presence  of  pathogenic  bacteria  as  well  as  the  number  of  bacteria 
as  compared  with  those  in  other  kinds  of  soils.  He  found  no  more 
bacteria  than  in  others,  and  no  pathogenic  kinds  whatever. 

There  is  one  kind  of  soil  that  has  been  found  again  and  again  to 
have  a  destructive  action  on  pathogenic  bacteria,  and  that  is  peat, 
which  kills  them  very  quickly,  probably  through  the  contained  organic 
acids. 

The  soil  acts  as  a  very  good  filter,  and  holds  back  most  of  the 
organisms,  but  by  the  aid  of  flowing  ground-water  or  water  entering 
from  above,  they  may  be  carried  through  considerable  distances.  Thus, 
Drs.  Abba,  Orlandi,  and  Rondelli,-  experimenting  on  the  filtration 
capacity  of  the  soil  about  the  filter  galleries  of  the  Turin  water  supply, 
found  that  cultures  of  Micrococcus  prodigiosus,  poured  with  large  vol- 
umes of  liquid  into  the  ground  at  various  points,  made  their  appearance 
200  meters  away  in  42  hours,  and  12  and  27.5  meters  away  in  7  hours. 
In  these  experiments  the  property  of  the  soil  for  holding  back  sub- 
stances in  solution  was  manifested  in  a  remarkable  degree,  methyl-eosiu 
and  uranin,  substances  which  impart  intense  red  and  green  coloration 
to  water,  and  which  were  added  with  the  cultures,  not  appearing  until 

'  Twenty-C'iKlitli  Annual  Report  of  the  Local  Government  Board,  Supplement. 
*  Zeitsclirift  fiir  Hygiene  unci  Infeetionskrankheiten,  XXL,  p.  66. 


296  THE  SOIL. 

long  after  the  organisms  had  passed  through.  In  the  instance  in  which 
they  appeared  in  42  hours,  the  coloring  agents  could  not  be  detected 
until  after  75  hours  had  elapsed. 

The  relation  of  the  soil  to  the  various  pathogenic  bacteria  will  be 
discussed  farther  under  separate  headings. 

Soil  and  Disease. 

The  influence  of  the  soil  on  health  and  disease  is  admitted  very 
generally,  but  is  little  understood.  We  know  that  certain  soil  condi- 
tions favor  the  occurrence  of  certain  diseases,  but  why  this  is  so  remains 
a  problem  for  future  research  to  solve. 

Our  notions  concerning  the  causal  relation  of  the  soil  are  probably 
greatly  in  error  with  respect  to  certain  diseases,  being  doubtless  exag- 
gerated as  regards  some,  and  equally  undeveloped  with  others.  Com- 
position, permeability,  temperature,  moisture,  evaporation,  soil-air,  and 
fluctuations  of  the  level  of  the  subsoil-water,  all  are  supposed  to  bear 
important  relations  to  many  of  the  diseases  of  mankind  and  of  animal 
life  in  general. 

Such  evidence  as  bears  on  the  relation  of  the  soil  to  diseases  is  given 
in  general  terms  below. 

Soil  Dampness  and  Disease  in  General. — It  has  long  been  univer- 
sally noticed  that  dampness  in  and  near  the  surface  of  the  soil  injuri- 
ously affects  the  health  of  those  dwelling  nearby.  It  causes  coldness 
of  the  soil  and  dampness  of  the  atmosphere  immediately  above,  and 
appears  to  conduce  more  particularly  to  rheumatism,  neuralgias,  and 
diseases  of  the  respiratory  tract.  It  has  been  noticed  by  many  who 
have  investigated  the  subject,  that  the  general  health  of  those  dwelling^ 
over  damp  soils  is  much  inferior  to  that  of  those  more  favorably  cir- 
cumstanced in  that  regard,  and  instances  of  improvement  on  removal 
from  damp  to  dry  localities  are  too  commonly  known  to  need  illus- 
tration. 

It  is  generally  agreed  that  a  soil  in  which  the  ground-water  level  is 
high,  five  to  ten  feet,  for  instance,  from  the  surface,  is  not  favorable  to^ 
health ;  and  that  a  deep  level,  fifteen  feet  and  more,  is  unobjectionable 
on  the  score  of  dampness.  This  being  admitted,  it  might  reasonably 
be  inferred  that  artificial  lowerins^  of  the  ground-water  will  be  fol- 
lowed  by  increase  in  salubrity,  and,  as  a  matter  of  fiict,  that  is  j)recisely 
what  does  occur.  But  it  should  be  stated,  in  order  to  be  historically- 
accurate  and  in  all  fairness,  that  while  increased  healthfulness  is  a  con- 
sequence, as  a  rule  it  is  not  the  object  sought,  for,  as  a  general  thing, 
soil  drainage,  especially  on  a  large  scale,  has  been  carried  out  to  meet 
the  demands  of  successful  agriculture  rather  than  in  consequence  of 
solicitude  for  public  health. 

The  methods  employed  may  be  stated  generally  as  increasing  the 
outlet  and  removing  obstructions  to  the  outfall.  Ditching  and  the 
construction  of  underground  channel  ways  by  means  of  drain  tile 
or   rubble   and  fieldstones   are  the  most   common   methods   of  drain- 


SOIL  AND  DISEASE.  297 

ing.  Sometimes,  drainage  wells  are  driven  at  intervals  down  through 
the  impermeable  stratum  into  an  open  subsoil,  into  which  they  then 
drain. 

The  difficulties  in  the  way  of  draining  extensive  areas  of  unhealthy 
and  agriculturally  unproductive  land  lie  chiefly  in  the  lack  of  indi- 
vidual cooperation.  Such  undertakings  must  necessarily  be  carried 
on  in  a  systematic  manner,  and  ought  always  to  be  under  the  direction 
of  some  central  authority — municipal,  state,  or  national. 

By  means  of  under-drainage,  thousands  and  thousands  of  acres  in 
various  parts  of  this  country,  notably  in  Illinois  and  Indiana,  and 
vast  areas  of  land  in  England  and  on  the  continent,  have  been  con- 
verted from  unhealthy,  malarious,  and  more  or  less  unproductive  tracts, 
into  healthy  and  richly  productive  country ;  but  the  scheme  is  not 
always  successful  in  i^lieving  a  locality  of  disease,  especially  of  malaria, 
as  has  been  proved  in  parts  of  Italy,  Australia,  and  elsewhere. 

Soil  and  Pulmonary  Tuberculosis. — There  is  an  undoubted  con- 
nection betweer;  this  disease  and  soil  dampness,  which  is  most  manifest, 
when  one  investigates  the  prevalence  of  the  disease  over  the  same  soil 
before  and  after  soil  drainage,  by  which  it  will  always  be  found  to  be 
diminished.     Why  this  is  so  we  can  only  conjecture. 

We  know  that  dampness  is  one  of  a  possibly  considerable  number 
of  factors  in  producing  predisposition  to  the  disease.  We  know  that, 
other  conditions  being  the  same,  the  disease  is  far  more  common  on  low 
damp  soils  than  on  elevated  dry  ones.  We  know  also  that  the  disease 
is  comparatively  rare  in  some  parts  of  the  earth  where  the  soil  is 
exceptionally  dry. 

The  distribution  of  the  disease  and  its  relation  to  soil  dampness  were 
first  brought  to  public  notice  by  Dr.  Henry  I.  Bowditch,^  of  Boston,, 
at  the  annual  meeting  of  the  Massachusetts  Medical  Society,  in  1862, 
who  submitted  two  propositions,  the  results  of  most  extensive  investi- 
gation, which  were,  in  substance,  that  dampness  of  the  soil,  whether 
inherent  or  acquired  by  reason  of  proximity  of  bodies  of  water,  is  an 
exciting  cause  of  consumption,  which  disease  can  be  checked  in  its 
course  or  even  prevented  by  proper  attention  to  soil  conditions. 
Shortly  afterward,  similar  conclusions  were  promulgated  in  England 
by  Dr.  Buchanan,  who  had  been  making  observations  along  the  same 
line,  not  knowing  that  Dr.  Bowditch  was  similarly  engaged.  These 
propositions  were  accepted  by  the  profession,  and  have  been  maintained 
ever  since. 

Typhoid  Fever. — It  is  believed  quite  generally  that  this  disease  is 
coniu'cted  in  some  way  with  soil  conditions  as  well  as  with  drinking-, 
water.  Indeed,  there  are  some  authorities  who  regard  the  soil  as  of 
infinitely  gn^ater  importance  in  the  causation  of  epidemics  of  this 
disease  and  of  cholera  than  drinking-water,  which  to  their  minds  has 
absolutely  no  influence  one  way  or  another.  The  Pettenkofer  theory 
of  the  cause  of  thcs(!  outl)reaks  attributes  it  to  the  soil,  from  which  the 

'  'y(,])(><j:r,\])\\\(-A\  Disli'ihiition  uikI  Local  Oi'igin  of  Consiiiii|ilion  in  M<is.sacliusetts. 
Tninsiictions,  ]WI. 


298  THE  SOIL. 

exciting  cause  is  distributed  by  the  ground  air,  which,   as   has  been 
stated,  is  in  constant  movement. 

According  to  the  distinguished  originator  of  the  soil  theory,  the  un- 
known poison  is  introduced  into  the  soil,  where,  under  proper  condi- 
tions of  organic  filth,  and  other  influences,  a  species  of  fermentation 
occurs,  the  end  product  of  which  is  the  exciting  cause,  which  is  then 
capable  of  inducmg  the  disease  in  those  by  Avhom  it  is  inhaled.  All 
important  in  this  process  is  the  vertical  movement  of  the  ground-water, 
and  it  is  certainly  true  that  over  a  long  period  of  years  of  observation 
at  Munich,  there  w^as  a  most  remarkable  coincidence  between  epidemics 
of  typhoid  fever  and  fluctuations  in  the  ground-water  level. 

The  condition  most  favorable  to  high  morbidity  was  demonstrated 
to  be  a  rapid  fall  after  an  unusually  high  level.  The  highest  death- 
rates  during  the  time  covered  occurred  during  the  years  of  lowest  level, 
and  the  lowest  rates  in  the  years  of  the  highest  level.  A  similar 
coincidence  has  been  noticed  elsewhere,  but  by  no  means  in  all  or  even 
a  majority  of  the  localities  where  investigations  have  been  made. 

The  theory  had,  for  a  time,  many  adherents,  and  the  controversy 
between  the  soil-theorists  and  the  "water-fanatics,"  as  Pettenkofer 
called  them,  was  carried  on  at  times  with  exceeding  bitterness.  But 
within  the  past  decade,  the  Avater  theory  has  been  so  thoroughly  proved 
as  the  chief,  if  not  the  sole  cause  of  extensive  outbreaks,  that  interest 
in  the  theory  has  fallen  off,  and  its  supporters  are  now  few  in  number. 
Pettenkofer  ^  himself,  however,  was  to  the  end  as  uncompromising  as  in 
the  beginning,  and  found  no  difficulty  in  applying  it  to  the  great  epi- 
demic of  cholera  in  Hamburg,  in  1892. 

The  contention  that  the  extraordinary  endemicity  that  prevailed  so 
long  at  Munich  was  due  to  the  filthiness  of  the  subsoil,  which  was 
honeycombed  with  cesspools,  cannot  lightly  be  brushed  aside,  for  it  is 
a  fact  that,  with  discontinuance  of  these  abominations,  and  with  a 
system  of  improved  sewerage,  the  typhoid  fever  rate  fell  from  its  posi-- 
tion  as  a  leader  down  among  the  lowest  known.  Nor  was  this  fall  due, 
as  has  been  claimed,  to  change  in  the  water  supply,  for  the  great  epi- 
demics had  ceased,  and  the  fall  had  long  continued,  before  the  water 
supply  was  changed. 

Experiment  has  shown  that  the  typhoid  organism  may  retain  its 
vitality  in  the  soil  for  considerable  periods  under  favoring  conditions 
of  w^armth  and  moisture.  Robertson  ^  removed  sods  from  several 
places  in  a  field,  and  wet  the  exposed  soil  with  diluted  typhoid  cultures, 
one  at  the  surface,  one  at  a  depth  of  nine  inches,  and  a  third  at  eighteen 
inches.  After  130  days,  the  bacilli  on  the  surface  had  multiplied,  and 
where  they  had  been  placed  eighteen  inches  below,  they  could  also  be 
found  in  the  surface  layer.  Later  on,  in  the  winter,  no  results  could 
be  obtained ;  but  in  the  spring,  he  moistened  the  patches  with  sterile 
bouillon  in  very  dilute  condition,  and  afterward  succeeded  in  obtain- 
ing growths. 

^  Miinchener  medicinische  Wochensclirift,  May  2,  1899. 
*  British  Medical  Journal,  Jan.  8,  1898. 


SOIL  AND  DISEASE.  299 

This  positive  result  accords  with  the  views  of  Germano/  who  found 
that  typhoid  bacilli  will  live  for  months  when  incompletely  dry  ;  but 
according  to  Fliigge,  they  do  not  survive  complete  drying  longer  than 
fifteen  days.  In  air-dried  condition  they  appear  to  have  unimpaired 
vitality  for  some  days,  according  to  Brownlee,^  who  dried  and  sterilized 
ordinary  soil  and  then  infected  it  with  a  broth  culture  of  typhoid  and 
kept  it  at  98°  F.  for  a  day.  It  was  then  left  exposed  to  the  air  for  a 
week,  during  which  time  it  became  sufficiently  dry  to  be  easily  scat- 
tered by  the  breath.  Cultures  from  this  gave  positive  results.  But 
it  should  be  remembered  that  air-dried  soil  contains  considerable 
hygroscopic  water ;  consequently  his  bacilli  were  doubtless  fairly 
well  supplied  with  the  necessary  moisture.  Of  more  importance,  ap- 
parently, than  the  question  of  moisture — for  all  soils  possess  some — is 
the  nature  of  the  contained  organic  matter.  Dr.  Sidney  Martin^  has 
shown  that  unpolluted  (virgin)  soils  are  inimical  to  the  typhoid  bacillus, 
regardless  of  the  amount  of  their  contained  organic  matter  of  vegetable 
origin,  while  specimens  containing  polluting  material  of  animal  origin 
favor  its  existence.  Such,  after  sterilization,  were  planted  successfully, 
and  it  was  learned  that,  in  the  presence  of  moisture,  differences  in  tem- 
perature had  but  little  influence.  Thus,  the  organism  thrived  about 
equally  well  when  specimens  were  kept  at  98°  F.,  at  ordinary  room 
temperature,  and  as  low  as  37°  F.  By  no  means  the  least  interesting 
observation  made  was  with  regard  to  the  duration  of  viability  of  the 
bacillus.  In  one  of  the  sterilized  polluted  soils,  the  organism  was  still 
active  at  the  expiration  of  456  days  ;  and  even  then,  after  thorough 
drying  and  pulverization,  active  growth  could  be  obtained.  In  com- 
pany with  various  species  of  bacteria,  among  which  the  predominant 
kinds  were  members  of  the  B.  coli  group,  it  was  recovered  after  50 
days'  exposure  to  temperatures  ranging  between  37°  and  61°  F. 

Later  experiments,*  in  which  the  typhoid  organism  was  planted  with 
different  soil  bacteria,  proved  that  various  species  from  a  particular  soil 
had  the  power  of  completely  exterminating  it  within  a  short  time,  while 
others  had  no  influence  whatever.  Therefore,  it  would  appear,  whether 
or  not  the  typhoid  organism  can  exist  in  a  given  soil,  will  depend  upon 
the  kinds  of  soil  bacteria  present,  as  well  as  upon  special  conditions  of 
temperature  and  dampness.  Dr.  Martin  found  the  period  of  vitality 
in  unsterilized  soils  to  be  about  1 2  days,  but  in  no  case  did  the  organism 
appear  to  multiply.  An  experiment  conducted  by  Levy  and  Kayser  ^ 
to  determine  the  duration  of  infectivity  of  this  organism  yielded  most 
interesting  results.  The  feces  of  a  typhoid  patient  were  discharged 
into  a  cemented  vault,  remained  therein  5  months,  and  were  then  spread 
on  a  clay  soil,  from  which,  after  15  days  of  winter  weather,  the  specific 
organism  was   isolated.      They  came  to  the  natural    conclusion  that 

'ZeitKchrift  fiir  Ilv^'iene  und  Infectionskrankheiten,  XXIV.,  p.  403. 

WnhVic  Health,  ,/anuiiry,  1899,  p.  272. 

'Report  of  Local  Government  Jioard,  1898,  London,  1899. 

♦Ibidem,  1900,  London,  190L 

^Centralblatt  fiir  liakteriologie,  etc.,  March  20,  190.3,  Abth.  I.,  XXXIIL,  p.  489. 


300  THE  SOIL. 

typhoid  stools  ought  always  to  be  disinfected  before  being  discharged 
into  a  privy  vault. 

The  eifect  of  temperature  changes  due  to  the  presence  of  animal  ex- 
creta mixed  with  the  soil  is  shown  by  Gaertner^  to  be  considerable. 
He  introduced  cultures  of  various  organisms  in  wire  baskets  into  the 
interior  of  compost  heaps  of  various  composition,  which  became  heated 
to  diiferent  extents,  and  observed  that  the  bacilli  of  typhoid  and 
cholera  were  the  least  resistant  of  all.  With  rapid  and  marked  heat- 
ing, their  life  was  short ;  but  it  appears  probable  that  in  the  absence 
of  heat,  even  with  the  given  surroundings,  they  may  live  through 
the  winter.  Under  the  ordinary  heating  that  occurred  in  the  compost, 
these  two  organisms  were  destroyed  in  a  week,  while  the  bacillus  of 
tuberculosis  remained  virulent  a  number  of  months. 

But  aside  from  what  we  glean  from  scientific  research  with  the  spe- 
cific organisms,  we  know  from  experience  that  there  are  many  places 
with  polluted  soils  where  typhoid  fever  was  unknown  until  the  impor- 
tation of  a  single  case  from  without,  and  that,  afterward,  sporadic  cases, 
for  which  no  convincing  explanation  is  afforded,  have  occurred  at 
varying  intervals.  And  in  country  districts,  whose  inhabitants  are- 
not  given  to  travelling  much  beyond  the  confines  of  their  farms,  it  is 
noticed  frequently  that  single  cases  occur  in  the  same  household  at 
intervals  of  a  year  or  longer. 

In  such  cases,  it  seems  hardly  reasonable  to  say  that  the  original 
case  has  left  nothing  as  the  exciting  cause  for  later  attacks,  and  that 
fresh  introductions  of  the  specific  organism  must  have  occurred  from 
some  unknown  source,  for  it  is  not  unlikely  that  the  variety  of  condi- 
tions that  affect  the  viability  of  the  organism  may,  in  some  cases,  act 
to  keep  it  alive,  and,  on  occasions,  stimulate  it  into  a  condition  of  aug- 
mented activity. 

Cholera. — Concerning  the  relation  of  this  disease  to  the  soil,  there 
is  but  little  to  be  said.  Prior  to  the  discovery  of  the  specific  organism, 
the  soil  theory  of  the  origin  of  epidemic  outbreaks  had  considerable 
vogue ;  but  now  it  is  known  that,  even  in  times  of  greatest  prevalence 
of  the  disease,  the  organism  has  never  been  found  under  natural  con- 
ditions in  the  soil.  It  can  be  kept  alive  under  certain  favorable  con- 
ditions of  moisture  and  heat  for  var}dng  periods ;  but  under  natural 
conditions  it  is  one  of  the  least  resistant  bacteria  and  quickly  dies.  We 
have  no  evidence  whatever  that  cholera  is  a  soil  disease. 

Bubonic  Plague. — This  has  been  regarded  as  a  soil  disease ;  and  it 
has  been  believed,  from  the  fact  that  rats  have  been  conspicuous  as  vic- 
tims of  it  in  the  early  stages  of  its  devastating  outbreaks,  that  these- 
animals  have  acquired  the  infection  in  the  soil,  and  have  brought  it 
to  the  surface,  and  thus  acted  as  its  carriers.  But  rats  are  notorious  as 
frequenters  of  places  where  filth  of  all  kinds  accumulates,  and  it  is 
not  strange  that  where  they  and  filth  abound,  they  become  diseased,  if 
the  infective  agent  is  present. 

The  tremendous  epidemics  that  have  raged  within  the  past  few  years. 
'  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXVIII.,  p.  1. 


SOIL  AND  DISEASE.  301 

presented  unusual  opportunities  for  extensive  study^  which  thus  far  has 
afforded  no  evidence  whatever  that  the  disease  is  soil-borne.  Some 
who  have  studied  the  disease  in  India  believe  that  soil  conditions  are 
responsible  for  the  localizing  tendency  that  is  frequently  observed,  and 
that  infection  occurs  through  skin  abrasions,  which,  in  great  numbers 
of  the  population,  exist  in  chronic  form,  on  account  of  the  prevalent 
custom  of  wearing  toe-rings  and  going  barefoot.  Others  deny  ths-i: 
infection  occurs  in  this  manner,  and  assert,  moreover,  that  the  plague 
bacillus  cannot  long  survive  in  the  soil.  Yokote,^  for  instance,  buried 
mice  dead  of  plague,  and  determined  by  successive  removals  and  ex- 
amination that  the  organisms  survived  not  longer  than  1  month.  The 
soil  in  immediate  contact  did  not  become  specifically  infected. 

Diphtheria. — Although  there  is  no  proof  that  the  bacillus  of  diph- 
theria is  found  even  as  an  occasional  lodger  in  the  soil,  there  is  a  gen- 
eral agreement  that  a  close  connection  exists  between  soil  dampness  and 
the  prevalence  of  this  disease.  It  is  true  that  experiment  has  demon- 
strated the  viability  of  the  organism  in  moist  soils  for  limited  periods, 
but  it  has  never  been  found  in  soils  other  than  those  in  which  it  was 
deposited  intentionally.  The  common  belief  is  that  a  moist  soil  is  an 
invariable  concomitant  of  unusual  prevalence,  and  that  in  times  of 
comparative  freedom  from  the  disease,  the  soil  is  dry  and  the  level  of 
the  ground- water  low,  "As  long  as  the  soil  is  well  washed  by  the 
winter's  high  tide  and  afterwards  dried  and  aerated  during  the  summer's 
low  tide,  all  goes  well :  but  so  soon  as  these  salutary  movements  are 
arrested  or  their  order  disturbed,  diphtheria  prevails,  reaching  its 
acme  of  prevalence  when  stagnation  at  a  relatively  high  level  is  most 
oomplete,"  ^ 

According  to  Dr,  S.  M.  Copeman,^  there  appears  to  be  no  direct 
relation  between  epidemics  and  rise  or  fall  of  the  ground-water,  "  pro- 
vided that  the  structure  and  atmosphere  of  the  houses  are  not  affected. 
Many  districts,  w^hich,  usually  dry,  are  liable  to  occasional  floods,  are 
remarkably  free  from  the  disease,  so  that  it  appears  that  a  persistent 
impregnation  of  the  soil  with  moisture  is  of  more  importance  than 
fluctuations  in  the  height  of  the  ground-water,  particularly  if  these 
have  any  considerable  range." 

Op])osed  to  the  views  above  expressed  are  the  conclusions  based  on 
a  most  careful  and  extensive  investigation  by  Dr,  Arthur  JN'ewsholme,* 
of  epidemics  of  diphtheria  in  all  civilized  countries  and  their  incident 
conditions  of  rainfall  and  soil  moisture.  Dr.  Newsholme's  eminence 
as  a  skilful  interpreter  of  the  value  of  statistics,  and  the  fact  that  no 
such  exhaustive  inquiry  into  this  question  has  ever  before  been  made, 
entitle  his  conclusions  to  more  than  ordinary  weight.  Admitting  that 
personal  infection  is  the  chief  means  by  which  diphtheria  is  spread  from 
town  to  town,  and  from  country  to  country,  he  summarizes  his  obser- 

'  Centralblatt  fiir  IJiikteriologie,  Abth.  L,  XXTII.,  p.  1030. 

^  Notter  iind  Firtli,  Ti'eiitise  on  Hygiene,  1896,  p.  4()3. 

'^  Stevenson  and  Mui-jjliy,  Treatise  on  Hygiene,  18V)2,  Vol.  I.,  p.  338. 

■*  The  (Jrigin  and  Spread  of  Pandemic  Diphtheria,  London,  1898. 


302  THE  SOIL. 

vatioDs  on  the  relation  between  rainfall  and  ground-water  and  the  origin 
of  epidemic  diphtheria  as  follows  : 

"  1.  An  epidemic  of  diphtheria  never  originates,  in  the  towns  and 
conntries  in  which  I  have  been  able  to  collect  facts,  when  there  has 
been  a  series  of  years  in  which  each  j^ear's  rainfall  is  above  the  average 
amount. 

"  2.  An  epidemic  of  diphtheria  never  originates  or  continues  in  a 
wet  year  {i.  e.,  a  year  in  w^hich  the  total  annual  rainfall  is  materially 
above  the  average  amount),  unless  this  wet  year  follows  on  two  or 
more  dry  years  immediately  preceding  it. 

"  3.  The  epidemics  of  diphtheria,  for  which  accurate  data  are  avail- 
able, have  all  originated  in  dry  years  (/.  e.,  years  in  which  the  total 
annual  rainfall  is  materially  below  the  average  amount). 

"  4.  The  greatest  and  most  extensive  epidemics  of  diphtheria  have 
occurred  when  there  have  been  four  or  five  consecutive  dry  years,  the 
epidemic  sometimes  starting  near  the  beginning  of  this  series,  at  other 
times  not  until  near  its  end. 

"  5.  Dry  years  imply  low  ground-water,  and  we  find,  therefore,  in 
the  years  of  epidemic  diphtheria  that  the  ground- water  is  exceptionally 
low.  The  exact  variations  in  the  ground-water  which  most  favor  epi- 
demic diphtheria  cannot,  with  the  data  to  hand,  as  yet  be  stated  ;  but 
it  is  probable  that  when  this  is  cleared  up  it  will  become  clear  why  in 
exceptional  years  which  have  a  deficient  rainfall  epidemic  diphtheria  is 
either  absent  or  but  slight." 

It  has  often  been  pointed  out  that  local  soil  conditions  causing 
dampness  of  habitations  even  in  dry  years,  such  dampness,  for  instance, 
as  obtains  in  houses  built  over  wet  impervious  clays,  conduce  to  out- 
breaks of  diphtheria  in  the  dwellers  therein  ;  but,  as  is  well  known,  such 
dampness  acts  as  a  very  important  depressant  of  the  vital  forces,  and 
prepares  the  mucous  membranes  of  the  respiratory  tract  for  the  favor- 
able reception  of  specific  organisms  of  various  kinds. 

Malaria. — It  has  ever  been  held  that  the  most  intimate  relation 
exists  between  the  soil  and  malaria,  especially  prominent  in  districts 
abounding  in  marsh  lands.  It  has  been  noticed  repeatedly  that  in 
malarioiTS  countries  the  upturning  and  excavation  of  wet  or  damp  soil 
are  commonly  folloAved  Ijy  the  occurrence  of  the  disease  among  the 
laborers  so  engaged ;  that  infection  is  more  common  among  those  who 
go  about  at  night,  and  especially  among  those  who  sleep  out-of-doors ; 
and  that  the  draining  of  marsh  lands  is  often  followed  by  the  disap- 
pearance of  the  disease.  All  of  these  facts  are  compatible  with  the 
theory  of  transmission  by  mosquitoes,  and  it  is  now  accepted  generally 
that  malaria  is  connected  with  soil  conditions  only  in  so  far  as  the 
latter  permit  the  breeding  of  the  specific  mosquitoes.  (See  Chapter 
XII.) 

Yellow  Fever. — There  is  no  evidence  of  connection  between  the 
soil  and  outbreaks  of  yellow  fever,  although  for  many  years  such  a 
relation  w^as  assumed  to  exist.  The  work  of  American  investigators 
has  proved  this  disease,  also,  to  be  mosquito-borne. 


SOIL  AND  DISEASE.  303 

Tetanus  and  Malignant  (Edema. — It  is  well  known  that  the 
organisms  of  these  two  diseases  are  found  very  commonly  in  most 
garden  soils,  in  road  dust,  and  in  soil  in  general  which  has  been  en- 
riched by  the  addition  of  decomposing  organic  matter.  But  in  spite 
of  the  fact  that  opportunity  for  infection  through  abrasions,  cuts,  and 
wounds  of  the  hands,  feet,  and  other  parts  is  a  matter  of  daily  occur- 
rence with  a  large  proportion  of  the  people,  these  diseases  are  compara- 
tively uncommon.  They  are  noticed  most  commonly  in  cases  of  severe 
injuries,  such  as  compound  fractures,  and  in  shattering  wounds  due  to 
explosives.  According  to  some  authorities  inoculation  of  spores  alone 
is  without  effect. 

An  unusual  number  of  cases  of  tetanus  is  noticed  in  various  locali- 
ties in  this  country  after  every  annual  celebration  of  Independence 
Day,  due  chiefly  to  wounds  caused  by  cannon-crackers  and  blank  car- 
tridges fired  in  toy  pistols.  In  1903,  for  example,  there  were  in  the 
country  at  large,  according  to  statistics  compiled  by  the  Journal  of  the 
American  Medical  Association,  no  fewer  than  415  cases  of  tetanus 
from  these  injuries.  In  1904  the  number  reported  fell  to  105.  Ex- 
amination of  cannon-crackers  by  Dr.  Harold  Walker  and  of  blank 
cartridges  by  Dr.  H.  G,  Wells  for  tetanus  organisms  have  yielded 
negative  results,  and  it  is  probable  that  infection  is  due  to  organisms 
already  on  the  hand  of  the  celebrant  when  the  accident  occurs. 

Anthrax. — The  bacillus  of  anthrax  has  been  found  in  the  soil  of 
pastures  in  which  infected  animals  have  been  confined,  and  it  was  thought 
at  one  time  that,  following  the  burying  of  animals  dead  with  the  disease, 
the  soil  could  be  infected  thoroughly  through  spore  formation,  the  spores 
being  brought  to  the  surface  by  earthw'Orms,  there  to  be  the  cause  of 
fresh  infections.  Now,  however,  this  view  is  regarded  as  untenable, 
since  the  spores  are  not  formed  within  the  putrefying  carcass,  and 
the  bacillus  itself  is  soon  destroyed  in  the  process  of  decomposition 
of  the  tissues.  Thus  when  a  body  is  buried,  the  organisms  are 
soon  rendered  incapable  of  reproduction  or  of  continuing  their  own 
existence. 

The  theory  that  the  spores  are  brought  to  the  surface  by  burrowing 
earthworms,  was  demolished  by  Koch,^  whose  conclusions  were  based 
upon  direct  experiment,  and  was  abandoned  by  Pasteur  himself,  who 
first  suggested  it  because  of  finding  spores  in  the  superficial  layer  of  soil 
at  a  spot  where,  two  years  previously,  a  cow,  dead  of  the  disease,  had 
been  buried  at  a  depth  of  over  two  meters,  a  depth  not  ordinarily 
reached  by  earthworms  in  their  burrowing. 

Therefore,  it  seems  most  likely  that  fresh  outbreaks  among  cattle 
grazing  on  fields  where  others  have  died  and  have  been  buried  are  due 
not  to  the  buried  organisms,  but  to  those  which  in  one  way  or  an- 
other, from  the  blood  or  dejecta  of  former  cases,  have  been  deposited 
on  the  surface.  We  have  no  evidence  whatever  that  man  is  even 
occasionally  infected  directly  with  the  disease  from  the  soil. 

1  Medical  NewH,  .June  1,  1901,  p.  854. 

*  Mittheilungen  aus  dem  kaiBerlichen  Gesundheitsamte,  1881. 


304  THE  SOIL. 

Uncinariasis. — The  disease  which  stands  forth  pre-eminently  as  a 
true  soil-disease,  concerning  whose  etiology  there  is  no  dispute,  is  un- 
cinariasis or  hook-worm  disease,  known  also  as  ankylostomiasis,  miners' 
anaemia,  brickmakers'  disease,  Egyptian  chlorosis,  and  St.  Gothard 
tunnel  disease.  It  was  first  brought  to  public  notice  in  1879  by  Per- 
roncito,  who  investigated  the  epidemic  which  occurred  among  the  work- 
men engaged  in  driving  the  St.  Gothard  tunnel,  and  discovered  the 
<^ause  of  the  profound  anaemia  to  be  the  parasite  Ankylostomum  duode- 
nale,  which  is  a  worm  about  half  an  inch  in  length,  which  attaches 
itself,  sometimes  in  enormous  numbers,  to  the  villi  of  the  upper  portion 
of  the  small  intestine,  through  which  a  constant  drain  is  made  on  the 
blood.  Not  until  recent  years,  however,  has  the  disease  attracted  the 
attention  that  its  importance  deserves,  although  it  has  long  been  known 
to  be  very  prevalent  in  Brazil,  Egypt,  India,  and  various  parts  of 
Europe,  and  especially  in  mining  districts  and  brickfields,  whence  the 
names  "miners'  aneemia"  and  "brickmakers'  disease."  In  1900,  Dr. 
Bailey  K.  Ashford  ^  made  known  its  presence  in  the  West  Indies  and 
brought  it  to  notice  as  the  cause  of  the  tropical  antemia,  which,  in 
Porto  Rico,  causes  great  misery  and  an  enormous  death-rate ;  and  in 
1902,  Dr.  Charles  AVardell  Stiles^  announced  that,  in  some  parts  of 
the  South,  it  is  the  most  common  disease  of  man,  and  that  it  is  more 
prevalent  on  the  farms  and  plantations  of  the  sand  district  than  in  the 
mining  districts.  Stiles  discovered  that,  in  this  country,  it  is  due  to 
a  species  of  ankylostomum,  not  before  described  and  not  found  in  the 
Old  World,  which  differs  in  some  important  respects  from  Ankylosto- 
mum duodenale  ( Unciaaria  duodenalis),  but  produces  the  same  effects. 
This  parasite  he  named  Uncinaria  Americana.  Shortly  after  this 
announcement  by  Stiles,  Harris  *  reported  that  a  study  of  malaria  in 
Southern  Georgia  and  Florida,  in  a  region  where  profound  anosmia  is 
most  common,  proved  that,  instead  of  malaria,  he  had  to  deal  with 
uncinariasis,  the  sufferers  showing  generally  no  malaria  parasites,  but 
being  almost  invariably  infested  with  hook-worms.  In  1903,  Ashford 
and  King  *  declared  uncinariasis  to  be  the  great  scourge  of  fully  90  per 
cent,  of  the  agricultural  laboring  classes  (about  600,000  persons)  of 
Porto  Rico.  As  an  indication  of  its  prevalence  in  the  South,  the  ex- 
perience of  Dr.  L.  M.  Warfield  ^  is  of  great  interest.  He  examined 
60  boys,  inmates  of  an  orphanage  near  Savannah,  and  found  that  no 
fewer  than  48  were  infested.  Dr.  Claude  A.  Smith,®  speaking  of 
its  prevalence  in  the  South,  says  :  "  It  seems  as  though  the  entire 
country  was  literally  saturated  with  it.  It  is  found  on  the  highlands 
as  well  as  on  the  lowlands,  and  on  the  mountains  as  well  as  on  the 
seaboard." 


^  New  York  Medical  Journal,  April  14,  1900. 

=*  Public  Health  Reports,  October  24,  1902. 

'  American  Medicine,  November  15, 1902. 

*  Ibidem,  September  5,  1903. 

^  Ibidem,  January  9,  1904. 

'  Journal  of  the  American  Medical  Association,  August  27,  1904. 


SOIL  AND  DISEASE.  305 

Within  recent  years  the  disease  has  been  found  to  exist  in  many 
parts  of  Europe  (England,  Belgium,  Hungary,  Germany),  where  its 
presence  never  before  was  suspected,  but  the  victims  have  been  chiefly 
miners,  and  the  disease  has  been  regarded  as  peculiar  to  coal-mining 
and  other  underground  occupations.  The  fact  that  this  is  no  more  the 
case  in  Europe  than  in  this  country  is  shown  by  the  observations  of 
the  Drs.  Iberer,^  who  examined  large  numbers  of  peasant  lads,  who 
never  had  worked  in  the  mines,  but  who,  nevertheless,  yielded  in  many 
instances  large  numbers  of  the  parasites,  which  fact  leads  to  the  con- 
clusion that  the  disease  is  endemic  on  the  farms.  Many  of  these 
young  men  after  an  absence  of  3  years,  during  which  time  they  were 
doing  military  service,  were  found  to  be  still  infested ;  but  they  had, 
nevertheless,  suffered  in  no  way  in  consequence.  Of  the  miners  ex- 
amined, no  less  than  94  per  cent,  yielded  the  parasites,  and  yet  no 
more  than  one-fourth  were  even  temporarily  incapacitated. 

So  long  ago  as  1895  the  disease  was  declared  by  ThornhilP  to  be 
far  more  serious  in  India,  Assam,  and  Ceylon  than  cholera,  on  account 
of  the  vast  number  of  people  affected  and  the  aggregate  direct  and  in- 
direct mortality.  He  called  attention  to  the  fact  that,  instead  of  uncin- 
ariasis, ansemia,  debility,  dropsy,  malarial  cachexia,  and  diarrhoea  were 
given  as  diagnoses.  This  is  of  especial  interest  when  we  read  that,  in 
the  district  studied  by  him,  Harris  has  shown  that  most  cases  of  malaria 
prove  to  be  uncinariasis.  The  disease  is  essentially  one  of  the  poor, 
and  its  spread  is  due  to  the  habit  of  discharging  feces  upon  the  surface 
of  the  ground.  The  eggs  of  the  parasite  are  produced  in  great  numbers 
and  escape  with  the  feces.  Deposited  on  moist  soil,  they  hatch  in 
about  24  hours,  and  the  embryos,  after  twice  shedding  their  skin,  are 
ready  in  from  4  to  5  weeks  to  infest  man.  Baker  ^  accounts  for  the 
prevalence  of  the  disease  by  the  habits  of  the  people  where  it  is  most 
common.  They  live  without  regard  to  ordinary  sanitation ;  they  are 
dirty  in  their  habits  ;  they  discharge  their  feces  wherever  they  happen 
to  be ;  they  eat  with  dirty  hands,  and  often  eat  the  dirt  itself.  Ash- 
ford  and  King  say  that,  in  the  parts  of  Porto  Rico  where  the  disease 
prevails,  there  are  practically  no  privy  vaults,  and  a  bit  of  soil  as  large 
as  a  pea  may  contain  as  many  as  50  larvse. 

While  it  is  generally  accepted  that  the  chief  portal  of  infection  is 
the  mouth,  to  which  the  parasites  are  conveyed  on  food  contaminated 
by  dirty  fingers  or  by  dirty  dishes,  or  on  unwashed  vegetables  or  fruits 
likely  to  be  spattered  with  mud,  or  perhaps  in  muddy  water,  there 
appears  to  be  ground  for  the  belief  that  a  large  proportion  of  cases  are 
due  to  infection  of  the  skin.  The  first  to  assert  that  the  parasites  can 
reach  the  intestine  through  the  skin  was  Looss,*  who  rubbed  the  larvae 

'  Munchener  medicinische  Wochenschrift,  1903,  No.  22,  p.  992. 
■■^  Indian  Mer]ical  fJazette,  September,  1895,  p.  339. 
»  Jiritisli  Medifal  Jonrnal,  March  28,  1903. 

^  Central blatt   fur   Jiakteriologie,  etc.,   1   Abt.  XXIX.,  p.  733;   XXXIIL,  Orig,, 
p.  330. 


306  THE  SOIL, 

into  the  backs  of  puppies  and  later  found  that  the  animals  contained 
the  parasites  within  their  intestines. 

Boycott  and  Haldane  ^  believ^e  that  infection  can  occur  through  the 
skin,  and  Smith  ^  appears  to  have  proved  it.  He  bound  some  earth 
containing  4-day-old  larvas  to  a  man's  wrist  and  allowed  it  to  remain 
in  contact  for  1  hour.  Almost  at  once  the  spot  began  to  itch  and 
tingle.  The  stools,  which  were  examined  at  the  time  Mith  negative 
results,  were  examined  twice  each  Aveek  thereafter  and  continued  to  be 
normal  until  the  middle  of  the  seventh  week,  when  eggs  began  to 
appear.  In  a  prior  communication  ^  he  asserted  that  ground-itch  is  the 
most  common  disease  in  the  South,  due  to  the  habit  of  going  barefoot ; 
and  Warfield*  states  that  of  the  48  boys  in  Avhom  he  found  the  para- 
site, 45  gave  a  history  of  ground- itch.  AYarfield  suggests,  however, 
that  the  way  in  which  the  patients  with  ground-itch  become  infected 
internally  is  very  simple :  that  they  scratch  their  feet  and  break  the 
vesicles  and  thus  get  the  embryos  on  their  fingers,  by  which  they  are 
conveyed  to  the  mouth.  But,  however  it  happens,  the  infecting 
material  comes  from  the  soil.  Nicholson  and  Rankin,^  also,  are  of  the 
opinion  that  ground-itch  is  the  most  imjiortant  factor  in  the  transmis- 
sion of  uncinariasis.  They  have  noted  that  where  there  is  no  ground- 
itch  there  is  little  or  no  uncinariasis,  and  that  where  one  is  common^ 
the  other  is  also.  Nearly  every  one  of  a  large  number  of  cases  studied 
by  them  gave  a  history  of  ground-itch. 

The  principal  measure  of  prophylaxis  is,  naturally,  the  discontinu- 
ance of  the  practice  of  polluting  the  surface  of  the  ground ;  but  it  is 
dijfficult  in  all  countries  to  persuade  those  who  have  never  been  accus- 
tomed thereto  to  use  latrines  of  any  kind.  In  a  privy-vault,  the 
embryos,  which  cannot  live  without  air,  will  speedily  die.  They  are 
destroyed  also  by  freezing  and  by  complete  drying,  but  soil  which  is 
apparently  dry  often  contains  considerable  moisture.  Other  preventive 
measures,  which  are  so  obvious  as  hardly  to  need  mention,  include  the 
wearing  of  shoes,  the  observance  of  personal  cleanliness,  especially  of 
the  hands,  and  discouragement  of  the  habit  of  dirt-eating. 

Goitre. — The  various  theories  connecting  individual  constituents  of 
the  soil  with  goitre  have  now  been  well-nigh  universally  abandoned,, 
since  no  one  of  them  has  been  found  to  hold  good  in  diiferent  localities 
having  the  same  general  soil  characteristics.  Thus,  the  magnesian 
limestone  theory,  which  in  some  quarters  is  still  in  favor,  can  hardly 
stand  in  the  face  of  the  fact  that,  in  some  vast  tracts  of  such  formation, 
as  in  parts  of  New  Zealand,  for  instance,  the  disease  is  practically 
unknown.  Similarly,  the  metallic  sulphides  escape  conviction,  for  in 
districts  where  they  abound  extensively,  the  disease  may  be  absent,  and 
in  others  w'here  they  are  unknown  it  may  prevail. 

^  Journal  of  Tropical  Hygiene,  January  1,  1903. 

^  Journal  of  the  American  Medical  Association,  August  27,  1904. 

=*  Ibidem,  September  19,  1903. 

*  Loc.  cit. 

»  Medical  News,  November  19,  1904. 


EXAMINATION  OF  SOILS.  307 

Epidemic  Diarrhoea. — The  great  prevalence  of  cliarrhoeal  diseases, 
especially  among  very  young  children,  during  the  hotter  months  of  the 
year,  has  long  engaged  the  attention  of  sanitarians  as  a  tremendous 
factor  in  the  always  high  death-rate  of  the  first  age  periods ;  but  be- 
yond the  observance  of  a  few  coincidences,  no  connection  has  been 
proved  to  exist  between  it  and  the  soil. 

In  the  investigation  of  milk  supplies  in  single  cases  and  in  groups 
of  cases  in  single  households  and  in  institutions,  various  very  virulent 
organisms,  including  B.  enteritidis  8porogenes,  have  been  found,  and 
it  is  not  unlikely  that  the  infective  agent,  whatever  its  origin,  owes 
much  of  its  dissemination  to  being  blown  about  in  the  dust  of  the  air. 
Observations  made  by  Drs.  Hope,  Newsholme,  and  others  indicate  that 
in  rainy  summers,  when  the  dust  is  kept  down,  the  incidence  of  diar- 
rhoea falls  notably,  and  in  unusually  dry  summers  it  shows  a  corre- 
sponding rise. 

Examination  of  Soils. 

The  complete  examination  of  a  soil  includes  chemical,  physical,  and 
bacteriological  determinations,  but  inasmuch  as  the  chemical  analysis, 
beyond  the  estimation  of  water  and  organic  matter,  is  of  no  especial 
interest  to  the  sanitarian,  though  of  great  importance  to  the  agricul- 
tural chemist,  we  shall,  with  the  exceptions  noted,  confine  ourselves  to 
the  processes  involved  in  the  physical  and  bacteriological  tests. 

In  taking  samples,  a  place  should  be  selected  which  fairly  represents 
the  locality,  and  under  some  circumstances  a  number  of  specimens 
should  be  obtained.  These  may  or  may  not  be  mixed  and  treated 
as  one.  About  two  pounds  of  the  soil  may  be  broken  up  by  being^ 
passed  through  a  coarse  sieve,  then  spread  out  and  left  for  one  or 
several  days  exposed  to  the  air,  and  to  that  extent  dried.  To  deter- 
mine the  relative  proportion  of  the  grains  of  different  sizes,  a  weighed 
amount  of  the  sample  is  now  passed  through  a  series  of  sieves  of  vary- 
ing coarseness,  made  of  metal  or  porcelain  with  circular  open  spaces, 
which  in  each  sieve  are  of  uniform  diameter.  Those  used  by  the 
German  scientists  have  openings  respectively  ^,  1,  2,  4,  and  7  mm.  in 
diameter,  by  means  of  which  a  specimen  is  separated  into  grains  of  less 
than  ^,  from  |-  to  1,  from  1  to  2,  from  2  to  4,  from  4  to  7,  and  over  7 
mm.  in  diameter.  Other  sized  openings  may  be  used,  but  these  fulfil 
all  requirements.  The  S})ecimen  is  passed  first  through  the  coarsest  of 
the  set,  and  then,  in  order,  down  to  the  finest.  If  the  particles  adhere 
firmly,  the  separation  is  done  best  with  the  assistance  of  water ;  and 
should  it  be  necessary,  a  pestle  covered  at  the  working  end  with  rub- 
ber may  also  be  employed.  The  separate  parts  are  then  dried  and 
weighed,  and  their  respective  amounts  expressed  in  percentages  of  the 
whoki. 

The  finest  particles,  that  is,  those  of  less  than  ^  mm.,  may  be  separated 
still  further  by  the  process  of  washing  in  an  elutriating  apparatus,  of 
which  there  are  several  kinds,  none  of  which,  however,  gives  results 
that  are  more   than  approximately  accurate,    since  so   many  different 


308 


THE  SOIL. 


forces  and  conditions  come  into  play  to  influence  the  process.  With 
some,  the  separation  is  effected  by  causing  the  particles  to  settle  down- 
ward through  a  volume  of  water,  the  heaviest  ones  reaching  (theoret- 
ically, but  not  wholly  in  practice)  the  bottom  first,  and  the  lightest 
settling  out  last  or  remaining  a  long  time  in  suspension. 

An  apparatus  of  this  sort  is  shown  in  Fig.  18,  which  requires  no 
explanation.  Another,  known  as  Knop's  silt  cylinder,  is  shown  in 
Fig.  19.  This  is  a  cylinder  carrying  lateral  tubes  fitted  with  stopcocks, 
situated  at  equal  distances  (10  cm.)  apart.  The  sample  is  placed  in 
the  cylinder,  which  is  then  filled  with  water  and  well  shaken.  After  a 
given  time  the  upper  stopcock  is  opened  and  the  water  above  it  is  drawn 
off.     Then  after  the  lapse  of  another  interval,  the  second  is  opened, 


Fig.  18. 


Fig.  19. 


20 
30 
40 


==^ 


t^ 


JJ 


Apparatus  for  separation  of  fine  particles  of  soil. 


Knop's  silt  cylinder. 


and  next,  in  the  same  way,  the  third.  The  process  is  repeated  until 
the  wash  water  comes  away  clear,  then  the  lowest  tube  is  opened,  and 
the  rest  of  the  water  above  the  remaining  material  drawn  off.  The 
different  portions  may  then  be  collected,  dried,  and  weighed,  and  their 
relative  proportions  expressed  as  before  in  percentages.  Or  the  residue 
may  be  dried  and  weighed  and  the  remainder  estimated  by  difference. 

By  another  method,  the  washing  is  carried  out  by  means  of  an  up- 
w^ard  flow  of  water  in  a  conical  vessel,  at  the  bottom  of  which  the 
sample  is  placed.  The  water,  delivered  through  a  tube  reaching  to 
near  the  bottom  of  the  vessel,  carries  the  lighter  finer  particles  upward 
and  out  through  the  exit  tube  near  the  top.  Such  an  apparatus,  known 
as  Schultz's,  is  shown  in  Fig.  20. 

Pore-volume. — The  pore-volume  is  determined  very  simply  by 
adding  to  a  volume  of  water  in  a  graduated  cylinder  a  known  volume 


EXAMINATION  OF  SOILS. 


309 


Fig.  20. 


Schultz's  elutriating  apparatus. 


of  soil  in  the  dry  state,  and  noting   the  height  to  which   the   water 

rises.     If,  for    instance,  to  a   liter  jar  containing    water  up    to    the 

500  cc.  mark,  we  add  500  cc.  of  dried  soil 

in  as  nearly  as  possible  its  natural  state  of 

compactness,  and  observe  that  the  level  of 

the  water  is  in  consequence   raise,d   to    the 

850  cc.   mark,  it  follows  that  the  increase, 

350  cc,  represents  the  actual   bulk  of  the 

soil  grains,  and  that  the  difference  between 

this  and  the  volume  occupied  originally  by 

the  sample  (500  cc),  that  is  to  say,  150  cc, 

represents   the   amount   of  interstitial    space 

filled  with  air.     Then,  since  500  cc  of  soil 

contains    150    cc.    of   air    space,   it    follows 

that  the   pore- volume   of   the    sample    is    x 

in  the  equation  500  :  150  :  :  100  :  a?,  or  30 

per  cent. 

In  order  to  approximate  more  closely  the 
natural  condition  of  compactness,  the  sample 
may  be  taken  from  the  soil  by  means  of  a 
metallic  cylinder  with  a  cutting  edge.  It 
is  then  dried  in  order  to  expel  the  contained 
water,  which  otherwise  would  constitute  a 
source  of  error,  and  is  then  added  to  the  water  in  the  liter  jar  as  before. 

Permeability  to  Air. — Permeability  to  air  may  be  determined  by 
forcing  measured  volumes  of  air  under  constant  pressure  through  a 
cylinder  closely  packed  with  the  sample,  and  noting  the  amount  which 
is  delivered  during  any  given  unit  of  time.  In  making  comparison 
tests  between  different  soils,  the  same  conditions  must  be  observed  in 
every  case ;  that  is  to  say,  the  length  of  the  column  of  soil  in  the  cyl- 
inder, the  pressure  employed,  and  the  unit  of  time.  A  still  farther 
condition  which  should  be  observed,  but  which  is  commonly  disre- 
garded, is  the  temperature  of  the  air,  for,  as  is  the  case  with  liquids, 
the  viscosity  of  gases  varies  with  changes  in  temperature,  though  not 
in  the  same  direction.  The  viscosity  of  liquids  is  increased  with  dimin- 
ished temperature,  whereas  in  the  case  of  gases  the  reverse  is  true. 
Disregard  of  this  fact  leads  to  important  degrees  of  error. 

The  apparatus  for  this  determination,  shown  in  Fig.  21,  comprises 
a-  gas-holder  (A),  a  gas-meter  (B),  and  a  cylinder  (C)  provided  with  a 
manometer  (D).  For  the  purpose  of  keeping  the  soil  in  position, 
tightly  fitting  perforated  disks  {E  and  F)  of  metallic  gauze  are  intro- 
duced into  the  cylinder  at  both  ends  of  the  column  of  soil. 

In  the  preparation  of  the  cylinder,  the  disk  F  is  first  introduced,  and 
then  the  soil  is  added  a  little  at  a  time,  and  made  as  compact  as  pos- 
sible by  striking  the  lower  end  of  the  cylinder  downward  with  reason- 
able force  against  the  table.  When  the  desired  length  of  column  has 
been  reached,  the  disk  E  is  intn)duced,  between  which  and  the  inlet 
end  ((t)  an  air  space  of  sufficient  size  is  left  to  insure  uniform  pressure 


310 


THE  SOIL. 


agaiust  the  entire  surface  of  the  disk.  The  inlet  end  is  closed  by 
means  of  a  tightly  fitting  rubber  stopper  having  two  perforations,  one 
of  which  carries  the  inlet  tube  from  the  gas-meter,  and  the  other  the 
manometer  indicating  the  pressure  employed. 

The  pressure  is  obtained  by  means  of  a  column  of  water  communi- 
cating with  the  chamber  of  the  gas-holder,  which  is  connected  by  a 
rubber  tube  with  the  inlet  of  the  meter ;  and  it  is  regulated  by  a  screw 


Fig.  21. 


Apparatus  for  determination  of  permeability  of  soil  to  air. 


pinchcock  on  the  outlet  tube  of  the  latter.  The  force  is  applied,  the 
reading  of  the  meter  is  noted,  and  at  the  expiration  of  the  unit  of  time, 
one,  five,  or  whatever  number  of  minutes  it  may  be,  the  reading  of  the 
meter  is  taken  again. 

Permeability  to  Water. — The  permeability  of  a  soil  to  water  is 
expressed  in  terms  indicating  the  amount  of  water  which  Avill  pass 
fi-om  above  downward  through  a  column  of  saturated  soil  during  any 


EXAMINATION  OF  SOILS. 


311 


given  unit  of  time  under  a  given  pressure.  The  apparatus  for  this 
determination,  shown  in  Fig.  22,  consists  of  a  metallic  cylinder  (^A) 
with  a  perforated  or  gauze  bottom  on  which  the  sample  of  soil  is  packed 
closely,  and  another  cylinder  (B),  likewise  of  metal,  provided  with  a 
number  of  outlet  tubes  (c),  at  regular  intervals,  preferably  of  5  or 
10  cm.  The  lower  end  of  B  fits  tightly  into  the  upper  end  of  A,  and 
the  joint  is  made  impervious  to  water  by  means  of  adhesive  plaster, 
sealing-wax,  or  other  suitable  material.  The  soil  within  the  lower 
cylinder  is  kept  in  place,  and  its  surface  kept  intact,  by  means  of  a 

Fig.  22. 


Apparatus  for  determination  of  permeability  of  soil  to  water. 

superimposed  disk  of  gauze  or  coarse  cloth.  The  outlet  tubes,  provided 
with  cocks,  serve  to  maintain  a  constant  level,  and,  therefore,  a  constant 
pressure  of  water  as  desired.  Water  is  admitted  in  a  constant  stream 
to  the  cylinder  through  its  upper  end,  by  means  of  a  rubber  tube  con- 
nected with  a  water  faucet.  If  it  be  desired  to  employ  the  highest 
pressure  obtainable  with  the  apparatus,  all  the  corks  of  the  outlet  tubes, 
except  the  upper  one,  are  kept  in  place.  In  this  case,  the  pressure 
would  })e  expressed  by  the  distance  between  the  top  of  the  soil  under 
investigation   and  the   u])perniost  outlet,  through  wlii<'li   tlie   excess  of 


312  THE  SOIL. 

water  from  the  faucet  is  allowed  to  escape,  by  way  of  a  rubber  tube 
leading  to  a  sink.  Similarly,  any  other  height  and  pressure  may  be 
employed  by  removing  the  cork  of  the  corresponding  outlet,  which 
thus  becomes  the  effluent.  Whatever  the  height  maintained,  it  is 
necessary  to  keep  the  delivery  end  of  the  inlet  tube  below  the  surface 
of  the  water 

The  process  is  as  follows  :  Having  chosen  the  pressure  and  adjusted 
the  waste  tube  to  the  proper  outlet,  the  water  is  allowed  to  run  in  and 
force  its  way  down  through  the  soil  until  the  latter  becomes  saturated. 
In  order  to  insure  complete  saturation,  it  is  best,  however,  to  immerse 
the  soil  cylinder,  in  order  that  all  the  air  may  thereby  be  displaced 
upward.  When  this  has  been  accomplished  and  water  begins  to  run 
or  drip  through  the  gauze  bottom,  the  time  is  noted,  and  the  discharged 
water  is  received  in  a  suitable  graduate.  At  the  expiration  of  the  unit 
of  time,  the  latter  is  removed  and  its  contents  measured.  The  experi- 
ment may  be  repeated  as  often  as  may  seem  advisable,  and  the  effects 
of  varying  pressures  may  also  be  determined. 

Water  Capacity. — The  power  to  hold  water  is  determined  by 
means  of  a  metallic  cylinder  of  known  capacity  with  a  gauze  bottom. 
This  is  weighed,  then  filled  with  the  dried  sample,  and  again  weighed. 
The  soil  next  is  saturated  completely  by  immersion  of  the  cylinder 
in  water,  and  then  it  is  allowed  to  drain  as  long  as  water  continues  to 
escape.  When  the  water  ceases  to  drain  away,  the  cylinder  is  wiped 
dry  outside,  and  the  weight  of  the  whole  is  taken  again.  The  increase 
in  weight  is  the  amount  of  water  retained,  and  it  may  be  stated  in 
percentage  of  the  pore-volume,  which  should  have  been  determined 
previously. 

Capillarity. — The  height  to  which  water  will  rise  in  a  column  of 
soil  by  capillary  attraction  is  determined  by  packing  the  sample  tightly 
into  a  graduated  glass  tube,  the  lower  open  end  of  which  is  covered 
with  coarse  linen  tied  securely  on,  so  as  not  to  slip.  The  tube  is  sup- 
ported with  its  cloth-covered  end  resting  in  a  shallow  dish  filled  with 
water,  which  is  kept  at  constant  level.  The  height  to  which  the  water 
rises  through  the  column  of  soil  is  noted  from  time  to  time,  until  ascent 
ceases.  The  change  in  the  color  of  the  soil,  due  to  wetting,  indicates 
the  progress  of  the  action. 

Moisture. — The  amount  of  moisture  in  a  soil  is  determined  most 
accurately  by  taking  a  sample  in  its  natural  condition,  by  means  of  a 
brass  cylinder  with  a  cutting  edge,  weighing  a  portion  of  it,  and  then 
drying  it  in  an  air  bath  at  105°  C.  until  it  ceases  to  lose  weight. 
The  diiference  between  the  original  and  final  weighings  represents  the 
amount  of  water  in  the  given  weight  of  soil.  If  it  is  desired  to  know 
the  amount  of  water  which  the  same  soil  will  absorb  from  a  saturated 
atmosphere,  the  thoroughly  dry  sample  may  next  be  placed  with  a  dish 
of  water  under  a  bell-glass.  The  confined  air  will  become  saturated 
with  aqueous  vapor  in  a  short  time,  and  this  will  be  absorbed  by  the 
soil  up  to  the  limit  of  its  capacity,  which  is  shown  when  its  weight  no 
longer  continues  to  increase. 


EXAMINATION  OF  SOILS.  313 

The  hygroscopic  moisture  of  a  soil  may  be  determined  roughly  by 
air-drying  a  sample  and  then  taking  a  known  weight  of  it  and  heating 
it  in  an  air-bath  at  105°  C. ;  or  by  exposing  it  to  a  dry  atmosphere  in 
a  bell-glass  containing  an  open  dish  of  concentrated  sulphuric  acid, 
until  it  ceases  to  lose  weight. 

Organic  and  Volatile  Matters. — Since  it  is  impossible  to  deter- 
mine by  ordinary  processes  the  exact  amount  of  organic  matter  present 
in  any  soil,  it  is  necessary  to  designate  the  diminution  in  weight  which 
occurs  on  subjecting  a  sample  to  such  a  heat  as  will  burn  off  the 
organic  matter,  and  which  represents  other  losses  than  the  latter,  as 
"  loss  on  ignition  "  or  "  organic  and  other  volatile  matter."  For  this 
determination,  the  soil  which  was  used  for  the  estimation  of  moisture, 
or  another  sample,  thoroughly  dried,  may  be  placed  in  a  platinum  dish 
and  heated  over  a  Bunsen  flame  at  no  higher  temperature  than  is  suffi- 
cient to  keep  the  dish  at  a  dull-red  heat.  When  all  the  organic  matter 
has  been  destroyed,  the  residue  is  allowed  to  cool,  and  is  then  moistened 
with  a  little  saturated  solution  of  carbonate  of  ammonium,  in  order  to 
restore  the  carbon  dioxide  that  belongs  to  the  inorganic  constituents,  then 
dried  and  gently  ignited  to  expel  the  excess  of  ammonia,  and  finally 
weighed.  The  loss  represents  organic  matter,  ammonium  salts,  nitrates, 
water  of  crystallization,  etc. 

Determination  of  COj  in  Soil  Air. — The  analysis  of  soil  air  is 
conducted  upon  the  same  principles  as  that  of  ordinary  air,  but  the 
method  employed  is  necessarily  different  so  far  as  the  obtaining  and 
handling  of  the  sample  are  concerned.  The  reagents  are  the  same  as 
required  in  the  analysis  of  atmospheric  air ;  the  apparatus,  however,  is 
quite  different.  It  consists  of  a  number  of  sections  of  water-pipe 
with  screw  joints,  one  having  a  pointed  foot,  above  which  are  a  number 
of  perforations  within  a  limited  area ;  an  absorption  tube,  in  which  the 
barium  hydrate  solution  is  held  and  through  which  the  air  is  drawn, 
and  an  aspirator.     (See  Fig.  23.) 

The  section  with  the  pointed  end  is  driven  into  the  soil,  and  the  pipe  is 
lengthened  by  the  addition  of  the  other  sections,  so  that  any  desired  depth 
may  be  reached,  and  thus  the  air  of  any  stratum  may  be  withdrawn.  The 
upper  extremity  is  connected  by  a  rubber  tube  with  the  inlet  tube  of 
the  absorption  apparatus,  which  latter  may  be  a  plain  glass  tube  about 
an  inch  in  diameter  with  a  bend  of  about  130  degrees  near  one  end. 
Better,  however,  is  the  apparatus  shown  in  the  illustration.  Here  the 
short  leg  of  the  bent  tube  is  a  large  bulb,  and  the  long  leg  is  a  series 
of  small  bulbs,  the  communications  between  which  are  of  small  diame- 
ter. In  either  case  the  inlet  tube  passes  through  a  tightly  fitting^ 
rubber  stopper  and  extends  to  a  point  just  beyond  the  bend.  The 
other  end  of  this  apparatus  is  connected  by  means  of  a  rubber  tube  with 
the  inlet  of  the  aspirator.  Any  form  of  aspirator  may  be  used,  but 
preferably  one  of  a  capacity  of  about  twenty  liters.  A  measured 
amount  of  the  dilute  solution  of  l)arium  hydrate,  sufficient  to  occupy 
the  greater  part  of  the  long  leg,  is  introduced  into  the  absorption  appa- 
ratus, and  the  connections  throughout  are  tested  to  prove  the  absence 


314 


THE  SOIL. 


of  leaks.  When  the  outlet  cock  of  the  aspirator  is  opened,  the  escape 
of  the  contained  water  creates  a  partial  vacuum,  which  is  relieved  by 
function  of  air  from  the  soil  and  through  the  whole  apparatus.  As  the 
mv  emerges  from  the  inlet  tube  of  the  absorption  apparatus,  it  passes 
upward  in  the  form  of  bubbles  through  the  reagent,  to  which  it  gives 
up  its  content  of  COg.  The  reason  for  preferring  the  bulbed  tube  is 
that  each  bubble  of  air  in  its  passage  from  one  bulb  to  the  next  above 
is  necessarily  brought  into  more  intimate  and  prolonged  contact  with 
the  reagent  than  is  the  case  when  the  plain  bent  tube  is  employed,  for 


Fig.  23. 


Apparatus  for  determination  of  COj  in  soil  air. 


here  the  air  bubbles  pass  quickly  along  the  upper  inner  surface  of  the 
tube,  and  are  not  so  exposed  to  the  reagent  as  to  lose  all  the  contained 
CO,.  For  this  reason,  it  is  necessary  to  draw  the  air  through  a  second, 
and,  perhaps,  a  series  of  such  tubes,  but  one  bulbed  tube  as  pictured 
above  is  sufficient. 

The  water  from  the  aspirator  is  measured  carefully,  and  its  amount 
indicates  the  volume  of  air  that  has  been  sucked  up  out  of  the  soil  to 
take  its  place.  When  the  desired  amount  has  been  acted  upon,  the 
stopcock  of  the  aspirator  is  closed,  and  the  reagent  in  the  absorption 


BACTERIOLOGICAL  EXAMINATION  OF  SOIL.  315 

tube  is  transferred  quickly  to  a  glass-stoppered  bottle  of  suital>le  size. 
From  this  point,  the  determination  is  the  same  as  described  in  the  chapter 
on  Air. 

Bacteriological  Examination  of  Soil. 

The  bacteriological  examination  of  the  soil  requires  necessarily  an 
intimate  acquaintance  with  bacteriological  technique,  a  subject  beyond 
the  scope  of  this  work.  It  may  be  stated  briefly  that  many  of  the 
organisms  that  inhabit  the  soil  may  be  isolated  by  adding  small  por- 
tions of  the  sifted  sample  to  liquefied  gelatin  and  then  plating,  or  by 
sprinkling  over  the  surface  of  a  nutrient  medium,  or  by  shaking  with 
distilled  water  and  transferring  thence  to  the  proper  media. 

The  many  anaerobic  forms  require,  of  course,  the  special  treatment 
of  their  class,  and  some  of  them  may  be  grown  on  ordinary  culture 
media  ;  but  many  of  the  saprophytes,  notably  the  nitrifying  organisms, 
cannot  be  isolated  by  the  ordinary  methods.  For  the  details  involved 
in  the  separation  and  identification  of  the  numerous  varieties  of  soil 
organisms,  the  reader  is  referred  to  the  standard  works  on  bacteriology. 


CHAPTEK    IV. 

WATER. 

Absolutely  pure  water,  that  is,  the  substance  composed  wholly  of 
hydrogen  and  oxygen,  and  represented  by  the  symbol  H^O,  is  never 
found  in  nature,  and  is  never  seen,  except  in  small  amounts  as  a  labora- 
tory curiosity.  In  the  broad  sense,  however,  the  word  pwre  as  applied 
to  water  conveys  the  idea  of  freedom  from  harmful  ingredients  and  of 
wholesomeness  and  suitability  for  drinking  and  for  the  preparation  of 
food.  In  nature,  all  water  contains  more  or  less  of  gaseous  and  solid 
substances  in  solution  and  suspension,  and  so  long  as  these  are  not 
present  in  such  amounts  as  to  aifect  the  quality  injuriously,  and  so  long 
as  they  are  not  intrinsically  dangerous  to  health,  the  adjective  is  com- 
monly held  to  be  appropriate.  But  in  the  sense  that  purity  involves 
the  limitation  of  the  amount  of  contained  substances  of  a  harmless 
nature,  it  becomes  a  difficult  question  where  to  draw  the  line  where 
water  ceases  to  be  pure,  and  what  term  to  apply  as  an  antonym.  In 
the  sense  that  it  involves  complete  absence  of  matters  intrinsically 
dangerous,  the  line  can  be  sharply  drawn,  and  water  which  fails  to 
satisfy  the  requirements  of  the  term  may  be  designated  indiiferently  as 
impure,  polluted,  or  contaminated. 

In  the  classic  reports  of  the  State  Board  of  Health  of  Massachusetts 
on  public  water  supplies,  waters  are  classed  as  "  normal  "  or  "  polluted  '* 
according  as  they  are  or  are  not  free  from  direct  or  indirect  pollution 
by  the  waste  products  of  human  life  and  industry.  Under  this  classi- 
fication it  follows,  naturally,  that  normal  waters  must  vary  very  widely 
in  appearance,  composition,  and  general  character,  and  that  a  normal 
water  is  not  necessarily  suitable  for  drinking,  although  incapable  of 
causing  specific  disease.  The  nature  and  amount  of  the  dissolved 
matters  cannot  but  have  considerable  influence  in  modifying  the  prop- 
erties and  effects  of  a  water. 

Waters  may  be  classified  according  to  source  as  follows  : 

1.  Rain  and  snow. 

2.  Surface-water  (rivers,  ponds,  basins,  etc.). 

3.  Ground-water  (also  known  as  subsoil -water). 

4.  Artesian  or  deep  well-water. 

RAIN. 

Rain  is  the  original  source  of  all  natural  waters  of  whatever  class. 
It  results  from  condensation  of  the  aqueous  vapor  of  the  atmosphere, 
and  in  its  descent  to  the  earth  it  takes  up  gaseous  and  suspended  mat- 
ters from  the  atmosphere,  which  to  that  extent  becomes  thereby  puri- 

316 


S  UBFA  CE-  WA  TEBS.  317 

fied.  In  the  open  country,  after  the  air  has  been  washed  for  a  while, 
the  collected  rain  is  very  clean,  and  is,  in  fact,  the  purest  form  of  nat- 
ural water.  If  its  fall  is  accompanied  by  wind  from  dusty  localities, 
it  cannot  be  obtained  in  so  clean  a  condition  within  so  short  a  time,  on 
account  of  the  greater  amount  of  suspended  matters  to  be  washed  down. 
Near  the  sea,  it  contains  more  or  less  salt ;  and  in  cities  and  large  towns, 
it  may  have  a  slightly  acid  reaction. 

In  its  passage  downward  through  the  atmosphere,  rain  absorbs  con- 
siderable air,  or,  more  properly,  constituents  of  air ;  that  is,  oxygen,  nitro- 
gen, carbon  dioxide,  and  ammonia  compounds.  Since  each  gas  has  its 
own  coefficient  of  solubility  in  water,  and  as  air  is  a  mixture  and  not 
a  chemical  union  of  gases,  it  follows  that  water  will  absorb  the  con- 
stituents of  air  separately  and  according  to  their  respective  solubilities. 
So  it  happens  that  the  absorbed  air  has  a  very  different  composition 
from  that  of  atmospheric  air,  being  much  richer  in  oxygen  and  poorer 
in  nitrogen,  its  oxygen  content  being  35  instead  of  21  per  cent.  On 
reaching  the  earth,  some  of  the  rain  is  evaporated,  some  sinks  into 
the  soil,  and  some  runs  over  the  surface  to  streams  or  other  bodies 
of  water.  The  amount  that  sinks  into  the  soil  depends  upon  the 
permeability  of  the  latter  to  water.  Thus,  a  sandy  or  gravelly  soil  will 
take  up  more  of  the  rainfall  than  a  close-grained  clay.  The  amount 
which  is  returned  to  the  atmosphere  by  evaporation  is  surprisingly 
large.  It  has  been  reckoned  by  Dalton  that  in  the  whole  of  England 
and  Wales,  about  50  per  cent,  of  the  total  annual  rainfall  is  lost  by 
evaporation.  In  the  watershed  of  the  Rhine,  the  loss  is  reckoned  at 
50  per  cent.  -,  in  that  of  the  Rhone,  at  42 ;  of  the  Seine,  at  67,  and 
of  the  Garonne,  at  35. 

SURFACE-WATERS. 

Surface-waters  are  collections  of  water  running  along  or  stored  upon 
the  earth's  surface  in  contact  with  the  atmosphere.  Under  this  head 
are  included  rivers  and  smaller  streams,  ponds,  lakes,  and  impounding 
basins.  They  vary  according  to  the  different  characters  of  the  areas 
which  they  have  drained  or  traversed,  or  in  which  they  are  stored. 
Thus,  a  water  that  has  flowed  over  a  rocky  soil  is  more  likely  to  be 
free  from  organic  impurity  than  one  that  has  flowed  over  loamy  soil  or 
has  stood  irt  swamps  ;  and  one  that  has  flowed  through  sandstone  bot- 
toms is  more  likely  to  contain  mineral  impurities  than  one  that  has 
flowed  over  the  virgin  soil  of  a  forest. 

Surface-water  means  something  more  than  the  rain  of  the  district 
plus  the  impurities  of  whatever  character,  organic  and  mineral,  which 
it  has  collected.  Rivers  and  lakes,  for  example,  are  made  up  of  rain 
that  has  run  over  the  surface  of  the  ground,  dissolving  in  its  course 
small  amounts  of  easily  soluble  matters,  and  of  water  that  has  come  up 
from  the  soil  below  through  springs,  or  that  has  tri(;kled  in  from  the 
upper  layers  of  the  soil  ;  and  tliese  latter  contribute  matters  which  may 
be  of  very  widely  different  character  from  those  obtainable  along  the 


318  WATER. 

surface,  according  to  the  geological  character  of  the  soil  strata  that  have 
been  acted  upon. 

A  river  may  take  its  origin  in  a  spring,  and  consist  for  some  time  of 
ground-water  alone,  but  usually  it  is  not  long  before  it  receives  acces- 
sions of  surface-water  and  soon  acquires  the  characteristics  of  the  latter. 
Again,  some  lakes  and  ponds  are  fed  almost  wholly  by  springs  at  their 
bottoms  and  sides ;  but  even  so,  their  waters  soon  change  in  character 
and  acquire  the  various  forms  of  aquatic  life. 

Surface-waters  may  contain  much  or  little  or  no  organic  matter, 
according  to  circumstances.  They  may  be  colored  or  colorless ;  they 
may  be  rich  or  poor  in  mineral  substances.  Those  w^hich  come  largely 
from  the  ground  will  naturally  possess  largely  the  characteristics  of 
ground-water,  and  those  free  from  accessions  from  this  source  will 
approximate  more  nearly  the  character  of  rain.  The  quality  of  surface- 
waters  is  influenced  by  the  seasons,  by  drought  and  rainfall,  by  vege- 
tation, by  rate  of  movement,  and  by  other  conditions. 


GROUND-WATERS. 

Ground-water  is  that  which  penetrates  the  soil,  sinks  to  various 
depths,  according  to  the  nature  of  the  soil,  and  accumulates  on  some 
more  or  less  impervious  stratum.  It  is  not  exposed  to  light  and  the 
atmosphere,  like  surface-water.  It  varies  widely  in  character  accord- 
ing to  the  nature  of  the  soil  over  which  it  has  once  flowed  and  through 
which  it  has  percolated.  It  enters  with  more  or  less  air  and  CO^  in 
solution,  and  comes  in  contact  with  the  soil  air  in  the  interstices^ 
which  is  much  richer  than  atmospheric  air  in  this  gas.  With  the 
assistance  of  the  CO^  which  it  has  brought,  and  that  which  it  farther 
acquires  in  the  interstices,  it  dissolves  various  mineral  constituents  of 
the  soil.  That  -which  penetrates  very  deeply  has  its  solvent  power 
increased  by  increased  temperature  and  pressure.  As  it  enters  the 
soil,  it  brings  with  it  whatever  organic  matters  it  may  have  dissolved 
out  of  the  surface  layers,  and  in  its  descent  it  may  lose  them  entirely 
through  the  action  of  the  saprophytic  bacteria  of  the  soil,  or  it  may 
acquire  still  more  if  the  soil  be  polluted  and  so  permeable  as  to  permit 
rapid  passage  downward.  It  passes  slowly  or  rapidly  through  the 
interstices  until  it  reaches  an  impermeable  stratum,  over  which  it 
accumulates,  filling  the  interstices  completely.  The  soil  at  this  point 
is  said  to  be  saturated,  and  the  upper  limit  of  saturation  is  known  as 
the  ground-water  level,  or  water  table.  Between  this  and  the  surface, 
the  water  is  in  contact  with  the  air  of  the  interstices,  and  is  known  as 
capillary  moisture.  The  water  table  is  by  no  means  necessarily  hori- 
zontal, but  follows  in  a  general  way  the  contour  of  the  surface  of  the 
soil,  and  often  it  is  much  more  irregular,  and,  by  reason  of  local  geo- 
logical conditions,  even  quite  diiferent  from  what  the  surface  formation 
would  indicate.  Thus,  at  one  point  in  a  level  stretch  of  country,  the 
table  may  be  quite  near  the  surface,  and  at  another,  a  short  distance 


GROUND- WATER. 


31^ 


away,  it  may  be  situated  much  more  deeply,  owing  to  abrupt  changes 
of  leve]  of  the  impermeable  stratum. 

Irregularity  of  the  surface  of  the  water  table  is  due  largely  also  to 
the  rainfall,  which,  coming  at  frequent  intervals,  falls  upon  surfaces  of 
differing  permeability,  so  that  while  one  part  is  still  draining  its  water 
downward,  another  has  completed  the  process  and  is  ready  for  more. 
When  drought  occurs,  however,  the  level  becomes  more  and  more  uni- 
form until  it  may  become  quite  horizontal.  With  return  of  rainfall, 
the  level  rises,  and  irregularity  of  the  surface  of  the  water  table  is 
again  produced.  The  level  at  any  point  is  influenced  also  by  the 
amount  of  water  withdrawn  from  the  soil  by  the  demands  made  upoa 
wells.  When  the  amount  of  percolation  is  exceeded  by  the  amount  of 
withdrawal,  the  level  falls  ;  when  the  conditions  are  reversed,  the  level 
rises. 

The  water  table  in  its  irregular  course  touches  the  surface  of  the 
ground  here  and  there,  and  gives  rise  to  springs  which  may  flow  the 

Fig.  24. 


Outcropping  of  water  table. 

year  round  regardless  of  drought,  or  may  dry  up  completely  with  fall 
of  the  level.  Similarly,  all  permanent  ponds  are  outcroppings  of  the 
water  table,  and  the  beds  of  rivers  as  well,  but  the  level  of  the  table 
in  the  near  vicinity  is  almost  invariably  higher  than  the  surface  of 
these  bodies.  Sometimes,  however,  the  water  level  is  so  near  the  sur- 
face that,  without  emerging  in  the  form  of  springs,  it  extends  in  a  broad 
sheet  just  at  or  below  it  and  causes  marshy  conditions.  In  Fig.  24 
the  manner  in  which  the  water  table  crops  out  in  springs  and  feeds 
lakes  and  other  bodies  of  water  is  shown. 

By  some,  the  water  table  is  spoken  of  as  an  underground  river,  a 
term  which  is  very  misleading,  in  that  it  suggests  a  body  of  water 
rather  than  a  condition  of  saturation  of  the  soil.  There  are,  to  be  sure, 
in  some  localities,  especially  in  limestone  districts,  bodies  of  water  flow- 
ing between  impermeable  strata,  and  instances  are  known  of  disap- 
pearance of  streams  into  fissures  of  rocks  and  emergence  at  a  distance 
elsewhere,  but  these  streams  are  not  a  part  of  the  water  table  as  gen- 
erally understood  and  may  not  properly  be  classed  as  ground-water. 

In  most  cases,  and  except  where  the  water  lies  in  deep  depressions 


320  WATEE. 

or  pockets  with  no  side  outlets,  the  ground-water  is  in  constant  lateral 
motion  in  the  direction  of  the  outfall,  and  this  is  commonly  the  nearest 
large  body  of  water,  either  a  lake,  or  a  river,  or  the  sea.  In  its  onward 
course  over  an  irregular  impervious  stratum,  the  movement  is  at  times 
inclined  upward  and  at  times  downward,  but  ever  in  the  same  general 
direction  laterally. 

The  rate  of  movement  is  determined  by  a  number  of  influences, 
among  which  the  most  effective  are  the  degree  of  permeability,  the 
inclination,  and  the  barometric  pressure.  The  degree  of  permeability, 
dependent  upon  the  coarseness  of  the  soil  particles,  is  of  very  great 
importance,  the  more  rapid  flow  occurring  through  the  soils  of  coarser 
texture.  The  inclination,  or,  in  other  words,  the  influence  of  contour 
in  promoting  or  preventing  the  assistance  of  gravity,  has  a  very 
decided  effect. 

The  barometric  pressure  affects  the  rate  of  movement  through  its. 
effects  on  the  air  in  the  interstices  above  the  water  level.  While  this 
air  is  itself  in  constant  movement,  it  cannot  move  quickly  because  of 
the  great  amount  of  friction  created.  Lessened  pressure  above  the 
ground  causes  the  soil  air  to  expand,  and  as  this  occurs,  the  tendency 
is  along  the  lines  of  least  resistance,  namely,  upward  and,  under  cer- 
tain conditions,  laterally,  so  that  the  water  in  the  interstices  is  assisted 
in  its  flow.  But  the  influence  of  diminished  barometric  pressure  is 
felt  almost  at  once  at  the  outfalls,  because  of  lessened  back  pressure  on 
the  water.  This  influence  may  be  measured  by  noting  the  fluctuations 
in  the  water  levels  in  wells  which  rise  as  the  barometer  falls,  and  fall 
as  it  rises.  Thus,  resistance  is  removed  at  the  outfall,  and  coinci- 
dently  the  water  is  being  pushed  along  by  the  expansive  force  of  the 
air  in  the  interstices.  With  increased  barometric  pressure,  these  condi- 
tions are  reversed  and  the  flow  becomes  less  rapid. 

The  rate  of  movement  being  so  dependent  upon  local  conditions,  it 
follows  that  it  varies  widely  in  different  soils.  In  some  places  it  is  so  slow 
as  to  be  almost  unmeasurable  ;  in  others  it  is  extremely  rapid  ;  and  even 
within  a  restricted  area,  it  may  be  exceedingly  variable  at  different 
points.  At  Budapest,  for  example,  Fodor  ^  determined  the  rate  of 
movement  at  five  different  points  to  be  95,  125,  199,  209,  and  210 
feet  daily.  The  average  of  these  figures,  167.6,  represents  unusually 
rapid  flow.  At  Munich,  the  daily  rate  of  flow  toward  the  Isar  has  been 
calculated  by  Pettenkofer  as  a  trifle  more  than  15  feet. 

Physical  and  Chemical  Characteristics  of  Water. 

At  the  standard  barometric  pressure,  760  mm.  or  29.922  inches, 
water  boils  at  100°  C.  or  212°  F.  With  lower  pressures,  it  boils  at 
correspondingly  lower  temperatures  ;  on  very  high  land,  for  example, 
it  boils  at  such  low  temperatures  that  meat  and  vegetables  cannot  be 
thoroughly  cooked  in  it.  Evaporation  occurs  at  all  temperatures, 
even  below  the  freezing-point. 

1  Boden  und  Wasser.     Brunswick,  1882. 


PHYSICAL  AND  CHEMICAL  CHARACTERISTICS  OF  WATER.  321 

Water  has  its  maximum  density  at  4°  C,  above  and  below  which 
point  it  expands.  At  0°  C.  it  freezes,  and  in  doing  so,  it  expands  to 
the  extent  of  about  9  per  cent,  of  its  volume,  and  thus  acquires  a 
specific  gravity  less  than  that  of  unfrozen  water,  in  which,  therefore,  it 
floats.  As  the  surface  freezes,  it  gives  out  heat  to  the  layer  immedi- 
ately beneath  and  thereby  causes  a  retardation  of  the  process.  As  this 
layer  becomes  cooled,  the  ice  formation  continues,  and  thus  the  growth 
in  thickness  of  the  ice  cover  proceeds  downward.  Its  specific  heat  is 
high,  and  is  taken  as  the  standard  of  comparison.  As  a  conductor  of 
heat  it  stands  very  low. 

Water  is  the  most  universal  solvent  known,  there  being  but  few  sub- 
stances which  are  not  acted  upon  by  it  to  some  extent.  It  takes  up 
all  known  gases,  and  its  solvent  power  for  them  is  greater  according  as 
the  temperature  is  depressed  and  the  pressure  increased.  In  the  case 
of  substances  other  than  gases,  with  few  exceptions  its  solvent  power 
is  increased  with  increased  temperature. 

Appearance. — Pure  water  is  clear,  and,  in  proportion  as  it  contains 
dissolved  air  and  carbon  dioxide,  is  bright  and  sparkling.  Brilliancy 
of  appearance  is,  however,  by  no  means  conclusive  evidence  of  purity, 
some  extensively  contaminated  waters  showing  remarkable  brightness. 
Turbidity  of  water  is  due  to  organic  and  mineral  matters  in  suspen- 
sion ;  the  organic  matters  may  be  ordinary  dead  vegetable  and  animal 
substances  or  microscopic  living  plants  and  animals. 

Some  public  supplies  derived  from  rivers  are  distinctly  muddy  in 
appearance.  The  slight  degrees  of  turbidity  designated  as  milkiness  and 
ojxdescence  are  due  commonly  to  very  minute  clay  particles,  which  may 
remain  in  suspension  for  a  long  time,  even  when  the  vessel  con- 
taining the  water  is  allowed  to  stand  undisturbed.  Sewage  matters 
also  may  give  these  same  appearances.  Turbidity  due  to  clay  may  be 
removed  readily  by  the  addition  of  various  substances,  as  lime,  alum, 
and  sulphuric  acid,  which  cause  the  particles  to  agglutinate  and  settle 
out.  Water  which  is  apparently  clear  when  viewed  in  an  ordinary 
glass  vessel  may  be  seen  to  have  decided  turbidity  when  viewed  through 
a  depth  of  a  foot  or  two  against  a  pure  white  surface. 

Some  ground-waters  which  are  quite  clear  when  drawn  may  acquire 
a  turbid  appearance  on  standing,  due  to  the  presence  of  compounds  of 
iron  which  undergo  changes  in  composition  and  become  precipitated. 
In  such  cases,  the  turbidity  is  accompanied  by  the  development  of 
color,  which,  however,  disappears  on  the  completion  of  the  process  of 
oxidation  of  the  .iron  compounds  and  their  separation  by  sedimentation. 

Color. — Water  may  have  color  or  not,  according  to  circumstances. 
Surface-waters  may  derive  it  from  contact  with  grasses,  leaves,  woody 
matters  iii  general,  and  peat,  the  degree  of  color  being  dependent  upon 
the  length  of  time  of  contact  and  upon  the  character  of  the  substances. 
Different  kinds  of  leaves,  for  example,  impart  different  shades  and 
kinds  of  color,  but  not  always  to  the  extent  that  their  ajipearance 
would  indicate.  The  dark-colored  dried  leaves  of  the  oak,  for  instance, 
might  be  expected  t<j  yield  a  mucli  darker  infusion  than  the  much 
21 


322  WATER. 

lighter  colored  leaves  of  the  maple,  but  such  is  not  the  case,  as  may 
be  proved  readily  by  experiment ;  and  those  of  the  butternut  give  a 
color  that  is  surprisingly  light  in  comparison.  Long  contact  with 
swamp  vegetation  causes  a  deep  reddish-brown  color,  which  is  often 
very  stable  on  long  keeping.  jN^ot  all  surface-waters,  however,  are 
exposed  to  color-imparting  substances,  and  waters  of  this  class  may  be 
free  from  color. 

Ground-waters  of  good  quality  are  ordinarily  colorless  or  appear  to 
have,  when  viewed  through  considerable  depths  against  a  white  surface, 
a  faint  bluish  or  greenish-blue  tinge.  Sometimes  they  contain  iron  and 
organic  matter  in  combination,  and  have  in  consequence  a  brownish  tint, 
which,  by  reason  of  very  slow  oxidation,  may  persist  for  a  long  time. 
Color  derived  otherwise  than  from  contact  with  vegetable  matter  is 
accompanied  usually  by  more  or  less  turbidity.  Absence  of  color  is 
not  a  sign  of  purity,  for  polluted  waters  may  be  quite  free  from  it ; 
nor  is  its  presence  an  indication  of  unfitness  for  domestic  use. 

Reaction. — The  dissolved  carbon  dioxide  in  water  tends  to  give  it  a 
slightly  acid  reaction,  but  most  potable  waters  are  very  faintly  alkaline 
to  delicate  indicators,  owing  to  minute  amounts  of  alkaline  carbonates. 
Rain-waters,  especially  in  the  vicinity  of  cities  and  large  towns,  are 
generally  slightly  acid  on  account  of  impurities  of  the  atmosphere, 
arising  from  combustion.  Peaty  waters  also  are  slightly  acid  on 
account  of  organic  acids  produced  by  the  action  of  the  peculiar  bacteria 
existing  in  peat.  River-waters  in  mining  districts  often  contain  con- 
siderable amounts  of  free  mineral  acids. 

Odor. — Pure  water  has  no  odor,  but  good  surface-waters  containing 
coloring  matters  have  more  or  less  odor,  which  is  especially  marked  on 
heating.  It  is  generally  suggestive  of  vegetable  matter,  and  may  be 
characterized  variously  as  grassy,  peaty,  etc.,  according  to  the  impres- 
sion produced.  Such  odors  may  persist  even  on  long  boiling,  while 
those  due  to  dissolved  gases  will  disappear  quickly  on  heating.  Many 
otherwise  good  surface-waters  are  particularly  prone  to  the  develop- 
ment of  disagreeable  odors  attributable  to  minute  living  organisms. 

The  subject  has  been  studied  very  extensively  by  Mr.  Gary  N. 
Calkins,^  who  states  that  odors  in  drinking-waters  "may  be  produced 
by  the  putrefactive  decomposition  of  the  body  plasm  through  the  agency 
of  bacteria,  and  by  the  excretion  of  certain  products  of  growth,  or  by 
the  liberation  of  products  by  the  physical  disintegration  of  the  body 
or  breaking  down  of  the  enclosing  cell  walls.  These  three  causes  give 
rises  to  three  classes  of  odors,  as  follows  :  (1)  odors,  of  chemical  or 
putrefactive  decomposition,  (2)  odors  of  growth,  and  (3)  odors  of 
physical  disintegration." 

The  group  of  plants  popularly  known  as  "  blue-green  algse " 
{Schizophyceoi)  is  a  very  common  cause  of  the  well-known  "  pig-pen  " 
and  "  grassy  "  odors  so  frequently  observed  in  shallow,  stagnant,  and 
relatively  warm  waters.  Certain  of  the  Diatomacece  frequently  cause 
serious  trouble  by  imparting  aromatic  (geranium)  and  fishy  odors 
^  Report  of  the  State  Board  of  Health  of  Massachusetts  for  1892,  p.  355. 


PHYSICAL  AND  CHEMICAL   CHARACTERISTICS  OF  WATER.  323 

and  disagreeable  taste.  Of  these,  the  most  prominent  is  Asierionella 
foniiosa,  foaud  very  commonly  in  large  ponds  and  reservoirs  of  surface- 
water,  and  growing  with  especial  luxuriance  in  open  reservoirs  of  ground- 
water. According  to  Whipple  and  Jackson,^  3000  asterionella  per  cc. 
of  water  may,  under  favorable  conditions,  impart  an  odor  easily  recog- 
nized by  the  consumer.  Several  species  of  Uroglena,  commonly,  but 
according  to  G.  T.  Moore,^  perhaps  incorrectly,  classed  with  the  Infu- 
soria, cause  much  trouble  by  the  liberation,  during  disintegration,  of  oil 
globules  which  impart  fishy,  oily  odors  and  tastes.  These  oil  globules 
are  yielded  by  many  other  varieties  of  water  organisms. 

While  sewage  matters  impart  mouldy  or  musty  odors  to  water,  it 
should  not  be  inferred  that  these  odors  are  of  themselves  indicative  of 
sewage  pollution,  for  good  surface-waters  sometimes  acquire  them  on 
standing. 

Sometimes  it  will  be  noticed  that  water  on  long  boiling  not  only  con- 
tinues to  evolve  a  vegetable  odor,  but  gives  it  oif  in  greater  intensity. 
This  is  true  j^articularly  of  waters  rich  in  algse.  If  they  are  first  filt- 
ered, the  odor  will  not  be  given  off  on  boiling.  But  other  waters  may 
continue  to  evolve  odors  even  after  filtration.  Peaty  waters,  for  in- 
stance, often  persist  in  yielding  odor  on  long  boiling,  and  this  is  not 
affected  in  any  way  by  filtration.  Waters  containing  products  of  physi- 
cal disintegration  and  various  other  substances  also  are  not  influenced 
by  filtration. 

Odors  which  disappear  on  boiling  may  develop  again  after  a  time  if 
their  cause  is  not  removed ;  if,  however,  the  matters  from  which  they 
are  derived  are  no  longer  present,  the  odor  will  not  return.  Some 
most  troublesome  odors  are  known  to  be  the  results  of  decay.  The 
public  supply  of  Boston  was,  in  1878,  seriously  affected  in  this  way, 
and  gave  off  an  odor  which  was  likened  to  that  of  cucumbers.  This 
was  investigated  by  Professor  Ira  Remsen,  who  found  the  cause  to  be 
decomposition  of  a  fresh-water  sponge. 

Water  sometimes  contains  sulphuretted  hydrogen  from  reduction  of 
sulphates  by  bacterial  action,  and  sometimes  mixtures  of  products  of 
organic  decomposition  which  suggest  that  gas.  Very  marked  and 
most  offensive  odors  are  due  often  to  the  presence  of  dead  animals,  such 
as  toads  and  mice  in  wells,  and,  when  they  arise,  the  remedy  is  ob- 
vious. Some  wells  become  stagnant  at  the  bottom,  and  if  organic 
matter  is  present,  it  may  cause  foul  odor,  suggestive  of  dead  animals, 
by  putrefaction  in  the  absence  of  a  sufficient  supply  of  dissolved 
oxygen.  Stagnation  may  be  prevented  by  connecting  the  pump  nearer 
the  bottom,  or  by  filling  up  the  unnecessary  space  with  clean  gravel 
and  sand. 

Odors  in  water  are  not  necessarily  indicative  of  danger  to  health, 
but  distinctly  unpleasant  ones  are  quite  sufficient  as  a  disqualification, 
on  account  of  the  repugnance  which  their  use  for  drinking  and  other 
domestic  purposes  would  cause.     On  the  other  hand,  as  in  the  case  of 

^  .Journal  of  the  New  England  Water- Works  Association,  September,  1899. 
'  American  Journal  of  Phai-macy,  .January,  1900. 


524  WATER. 

'Color,  absence  is  not  indicative  of  purity,  for  dangerous  waters  may  be 
inodorous. 

Taste. — Pure  water  has  no  distinct  taste,  and,  whatever  the  impres- 
sion made,  it  is  due  to  dissolved  gases.  That  this  is  so,  is  most 
evident  when  one  compares  the  taste  of  a  well-aerated  water,  before 
and  after  heating  to  the  boiling-point  with  subsequent  cooling.  Saline 
constituents  impart  no  distinct  taste  unless  they  are  present  in  quite 
large  amounts,  as  in  waters  of  a  high  degree  of  permanent  hardness. 
The  only  substance  which  imparts  taste  when  it  is  present  in  very 
small  quantities  is  iron.  Dissolved  organic  matters  cause  no  taste,  un- 
less present  in  considerable  amount  and,  as  a  rule,  accompanied  by  odor. 

Water  containing  very  little  coloring  matter  is  often  said  to  taste 
distinctly,  but  it  should  be  remarked  that  the  senses  of  taste  and  smell 
are  often  influenced  unconsciously  by  the  sense  of  sight,  and  colored 
water  supposed  to  have  both  odor  and  taste  may,  if  drunk  in  the  dark, 
give  no  impression  of  either. 

Badly  tasting  water,  whether  dangerous  or  not,  is  objectionable  on 
the  same  grounds  as  mentioned  under  odor.  Not  only  is  absence  of 
bad  taste  no  evidence  of  purity,  but  it  is  well  known  that  waters  con- 
taining the  products  of  oxidation  of  sewage  are  often  remarkable  for 
unusual  palatability. 

Substances  Found  Normally  in  Water. 

These  include  : 

1.  Gases  in  solution. 

2.  Organic  matters  in  solution  and  in  suspension. 

3.  Mineral  matters  in  solution  and  in  suspension. 

1.  Gases. — First  in  importance  is  air.  Strictly  speaking,  water  con- 
tains no  air  as  such,  but  only  the  constituents  of  air,  for  the  oxygen 
and  nitrogen,  dissolved  by  water,  are  not  present  in  the  same  propor- 
tion in  which  they  exist  in  the  atmosphere.  In  salt  water,  the  varia- 
tions in  their  proportions  are  less  wide.  We  shall,  however,  consider 
the  two  gases  as  air.  The  dissolved  oxygen  is  the  important  element. 
One  hundred  volumes  of  water  at  15°  C.  will  dissolve  nearly  3  vol- 
umes of  oxygen  (2.99),  and  at  20°,  2.80  volumes,  and  it  is  not  alto- 
gether removed  by  boiling. 

The  amount  of  oxygen  in  solution  is  fairly  constant  in  waters  of 
uniform  composition  freely  exposed  to  the  atmosphere,  but  when  they 
receive  additions  of  sewage  and  other  oxidizable  matters  they  begin  to 
lose  it.  River-waters  may  thus  show  notable  differences  in  the  amount 
of  dissolved  oxygen  present  in  samples  taken  above,  within,  and  below 
towns  situated  on  their  banks.  The  Thames  and  the  Seine,  for  in- 
stance, show  this  in  a  remarkable  degree.  The  progressive  dmiinution 
is  due  to  the  constant  access  of  organic  matter,  which  undergoes  oxida- 
tion at  the  expense  of  the  dissolved  oxygen.  When  a  river-water  is 
deprived  of  its  dissolved  oxygen  in  this  manner,  or  by  reason  of 
chemical  changes   due  to  the  inflow  of  sewage  from  manufacturing 


SUBSTANCES  FOUND  NORMALLY  IN  WATER.  325 

establishments,  containing  compounds — ferrous,  for  instance — having  a 
strong  affinity  for  oxygen,  fish  life  cannot  be  supported.  Absence  of 
fish  in  polluted  streams  is  due  much  more  to  diminution  of  dissolved 
oxygen  than  to  the  poisonous  effects  of  organic  sewage. 

Aeration  of  water  is  influenced  very  largely  by  the  dust  which  falls 
into  it,  for  each  particle  carries  with  it  more  or  less  adherent  air,  a.-> 
may  readily  be  seen  when  one  drops  small  particles  into  water  and 
observes  their  descent.  Aeration  of  water  proceeds  to  great  depths, 
as  is  shown  by  chemical  analysis  of  samples  of  water  obtained  by  deep 
sounding,  and  also  by  the  fact  that  great  numbers  of  organisms 
which  require  oxygen  for  their  respiration  are  found  far  beneath  the 
surface ;  but  water  at  40  and  50  feet  below  the  surface  may  contain  nO' 
oxygen.  Water  from  deep  wells  is  very  commonly  free  from  dissolved 
oxygen,  because  of  abstraction  by  compounds  of  iron  or  manganese,, 
organic  matters,  and  other  substances. 

The  presence  of  considerable  dissolved  oxygen  in  water  leads  tO' 
beneficial  changes  in  the  organic  matter  present.  Diminished  oxygen 
permits  the  development  of  low  forms  of  vegetable  life,  which  fre- 
quently give  rise  to  unpleasant  tastes  and  odors.  Their  growth  is 
inhibited  by  a  large  degree  of  aeration,  and  their  disagreeable  effects, 
are  thereby  prevented. 

Carbon  Dioxide. — The  carbon  dioxide  contained  in  water  is  derived 
largely  from  the  atmosphere,  and  in  great  part  from  the  soil,  where  it 
is  present  in  abundance.  Its  amount  in  any  water  depends  upon  a 
number  of  circumstances  :  upon  the  amount  carried  in  by  rain  and 
dust,  the  character  of  the  soil,  and  the  extent  of  oxidation  of  organic 
matter  occurring  in  the  interstices.  It  is  greatest  in  amount  at  great 
depths,  and  it  may  constitute  almost  the  entire  content  of  dissolved 
gases.  It  has  been  calculated  that  the  ocean  contains  about  ten  times 
as  much  as  the  entire  atmosphere. 

2.  Organic  Matter. — The  organic  matters  in  water  are  of  both  ani- 
mal and  vegetable  origin,  and  consist  of  organisms,  products  of  organic 
life,  and  results  of  disintegration  and  decomposition.  The  animal 
matters  include  dead  and  living  organisms  and  dissolved  and  sus- 
pended products  of  animal  life  and  decay,  such  as  albuminous  sub- 
stances, urea,  and  tissues.  In  the  tropics  and  subtropics,  ova  and 
young  of  various  parasites  are  common.  Ordinarily  our  interest  in 
organic  matter  from  animal  sources  is  confined  to  the  products  of 
human  life  as  represented  by  sewage,  which  may  contain  the  exciting 
causes  of  specific  diseases  (see  Bacteria  in  Water,  page  332).  Vege- 
table organic  matter  exists  as  living  and  dead  organisms  and  tissues  in 
suspension,  soluble  and  suspended  substances  given  off  during  life,  and 
soluble  matters  extracted  by  the  water  after  death. 

The  vegetable  organisms  are  represented  by  very  numerous  species 
f)f  microscopic  ))]ants,  which  act  l)eneficial]y  by  absorbing  the  products 
of  organic  decomposition  for  their  growth,  l)ut  whi(;h  may,  on  the  other 
hand,  under  favorable  conditions,  become  the  source  of  much  trouble 
by  over-abundant  growth,  disintegration,  and  decay.     They  may  pro])- 


326  WATER 

erly  be  regarded  as  normal  constituents  of  surface-waters,  for  they  are 
always  present  in  such,  and,  moreover,  they  develop  quickly  in  stored 
ground- water  exposed  to  light  and  air.  When  they  die,  most  species 
appear  to  decay  rather  slowly,  and  the  products  of  their  decomposition 
are  absorbed  by  new  growths ;  but  when  present  in  great  abundance, 
the  progress  of  decay  may  exceed  that  of  growth,  and  then  their 
products  may  accumulate  and  cause  foulness. 

There  is  one  form  of  microscopic  organisms,  belonging  to  the  class 
of  fungi,  which  merits  special  mention  :  Crenothrix  Kuhnkma.  This 
is  a  filamentous  plant  with  cells  no  larger  than  the  ordinary  bacteria. 
It  grows  chiefly  in  ground-waters  which  contain  organic  matter  and 
iron,  the  latter  of  which  ingredients  it  fixes  in  the  form  of  ferric  oxide 
in  the  gelatinous  sheath  of  its  filaments,  which  thereby  become  yellow, 
yellow  brown,  or  brown  in  color.  It  causes  great  annoyance  by  the 
rapidity  with  which  it  grows  in  water-pipes,  the  lumen  of  which  is  not 
infrequently  completely  occluded.  This  may  occur  more  readily  where 
the  surface  presents  roughness  and  imperfections,  to  which  the  growths 
may  attach  themselves.  When  the  filaments  are  broken  oif  and  become 
disseminated  through  the  water,  the  latter  is  rendered  unfit  for  laundry 
use  on  account  of  the  iron-rust.  Sometimes,  it  gives  rise  to  disagree- 
able odors  and  an  inky  taste.  It  may  be  very  troublesome  within  the 
tubes  of  driven  wells,  or  in  the  reservoirs,  as  well  as  in  the  distributing 
pipes.  Sometimes,  it  may  be  seen  in  large  aggregated  masses  floating 
about  on  the  surface  of  stored  water.  By  its  extensive  growth  in 
pipes,  it  may  seriously  affect  a  whole  public  supply. 

The  presence  of  living  forms,  either  vegetable  or  animal,  indicates 
that  the  water  contains  at  least  whatever  food  materials  are  necessary 
for  their  existence,  but  not  necessarily  that  these  are  in  excess.  Algse, 
for  instance,  require  mineralized  nitrogenous  matter  (nitrates),  and 
other  substances ;  fungi  suggest  the  presence  of  carbohydrates,  pro- 
teids,  and  mineral  substances  common  to  domestic  sewage ;  infusoria 
suggest  organic  decomposition.  Dissolved  vegetable  matters  ordinarily 
amount  to  but  little  in  weight.  Even  in  some  very  brown  waters, 
whose  appearance  ^vould  suggest  large  amounts,  they  may  be  present  to 
the  extent  of  not  more  than  1  or  2  parts  in  100,000. 

The  organic  matters,  both  animal  and  vegetable,  which  are  of  inter- 
est to  the  sanitarian,  consist  chiefly  of  carbon,  hydrogen,  oxygen,  and 
nitrogen,  with,  in  many  cases,  small  amounts  of  phosphorus  and  sul- 
phur. In  the  process  of  decomposition,  which  owes  its  inception, 
progress,  and  completion  to  bacterial  activity,  the  carbon  is  combined 
with  oxygen  to  form  carbon  dioxide,  and  the  hydrogen  unites  in  part 
with  nitrogen  to  form  ammonia,  the  presence  of  which  in  water  in- 
dicates that  the  process  of  decomposition  is  under  way.  In  its  turn,  as 
will  be  shown  later,  the  ammonia  is  converted  eventually  to  nitric  acid, 
which  unites  with  bases  to  form  nitrates. 

Ammonia. — From  the  standpoint  of  sanitary  significance,  ammonia 
in  water  is  of  prime  importance.  Only  under  very  unusual  conditions 
does  it  exist  in  the  form  of  hydrate,  but  usually  as  chloride  or  car- 


SUBSTANCES  FOUND  NORMALLY  IN  WATER.  327 

bonate.  We  speak  of  it  commonly  as  free  ammonia,  for,  on  boiling  the 
water,  these  salts  are  decomposed  and  the  ammonia  is  expelled  in  the 
steam.  Among  the  direct  sources  of  ammonia  in  water  is  rain,  which 
brings  it  down  out  of  the  atmosphere  in  varying  amounts  according  to 
location.  Rain  always  contains  it,  but  more  is  present  in  that  of 
thickly  populated  districts  than  in  the  open  country.  In  one  instance, 
reported  by  Drown,^  it  was  found  to  the  large  extent  of  0.0564  in 
100,000.  Its  presence,  however,  in  surface-  and  ground- waters  is 
due  for  the  most  part  to  decomposition  of  nitrogenous  organic  matter. 
It  is  not  abundant  in  ordinary  unpolluted  waters,  but  is  present  often 
to  a  very  considerable  extent  in  that  of  deep  driven  wells.  Here  its 
origin  is  not  always  clear ;  in  some  cases  it  is  supj^osed  to  be  referable 
to  coal  deposits,  in  others  to  reduction  of  accumulated  nitrates. 

Under  ordinary  conditions  in  surface-waters,  ammonia,  after  conver- 
sion to  nitrates,  is  absorbed  very  quickly  })y  growing  vegetation,  and 
the  more  active  the  conversion  and  the  growth,  the  greater  the  appro- 
priation. For  this  reason,  water  from  the  same  source  will  often  show 
less  on  analysis  in  summer  than  in  winter.  But  activity  of  vegetation 
is  not  responsible  alone  for  this  difference  in  amount,  for  in  the  case  of 
large  bodies  of  water,  as  lakes  and  ponds,  the  rate  of  movement  of  the 
water  has  great  influence.  During  the  warmer  months,  when  the 
upper  layers  are  warmer  and  consequently  lighter  than  the  lower,  the 
latter  become  necessarily  stagnant  and  stratified.  The  ammonia  which 
accumulates  in  these  lower  strata  does  not,  therefore,  come  to  the  sur- 
face until  cold  weather  approaches.  Then  the  upper  layers  become 
more  dense  and  tend  toward  the  bottom,  causing  a  displacement  of  the 
Jower  layers  toward  the  surface  and  general  uniform  mixing  of  the 
entire  volume  of  water.  Another  element  in  the  stirring  up  of  the 
water  of  ponds  and  lakes  is  the  action  of  wind,  which,  however, 
does  not  extend  beyond  twenty  feet.  Still  another  influence  to  be  con- 
sidered is  that  of  springs  at  the  bottom  and  sides,  which  tend  to  keep 
the  water  in  motion.  In  the  case  of  flowing  rivers,  the  water  is  of 
comparatively  uniform  composition  at  all  depths. 

Ammonia  is  very  characteristic  of  sewage  pollution,  the  oxidation  of 
which  yields  it  in  abundance  under  conditions  which  do  not  permit  it 
to  be  rapidly  oxidized  to  nitric  acid. 

Ammonia  as  it  occurs  in  drinking-water  is  of  itself  incapable  of 
producing  harmful  effects.  Its  amount,  however,  is  of  greater  or  lesser 
significance  according  to  circumstances  :  that  from  clean  and  properly 
stored  rain-water  is  of  far  less  significance  than  that  from  other  waters. 
In  the  one,  it  may  be  considerable  in  amount  and  mean  but  little ;  in 
others,  it  is  usually  evidence  of  decomposition  of  organic  matter.  Its 
amount  in  good  water  is  not  large,  and  on  account  of  oxidation  and 
absorption  by  vegetable  growth  it  does  not  accumulate.  And  even  in 
sewage-polluted    waters,   when    vegetation     is    active,    oxidation    and 

'  Massachusetts  State  P>o;u-(l  of  Health:  Report  oa  Water  Supply  and  Sewerage. 
Boston,  LS'.ii).      I 'ml  1,  p.  502. 


328  WATEB. 

absorption  may  so  diminish  its  amount  that,  taken  alone,  it  might 
lead  to  false  conclusions  as  to  the  character  of  the  water. 

Albuminoid  Ammonia. — The  so-called  albuminoid  ammonia  is  am- 
monia which  is  produced  in  the  process  of  analysis  of  water  by  the 
action  of  alkaline  permanganate  of  potassium  on  nitrogenous  organic 
matter  hitherto  undecomposed.  The  result  of  the  action  is  a  splitting 
up  of  the  organic  matter  and  the  conversion  of  the  nitrogen  to  ammonia, 
which,  as  is  the  case  with  "  free  "  ammonia,  passes  out  of  the  water  in 
the  steam.  This  matter  may  be  of  either  animal  or  vegetable  origin, 
and  its  character  is  of  far  greater  importance  than  the  amount  of  the 
yield.  Thus,  a  water  grossly  polluted  by  sewage  may  yield  less  than 
another  quite  free  from  such  contamination,  but  rich  in  dissolved 
vegetable  matter  of  no  great  sanitary  importance. 

Animal  organic  matter  is  decomposed  much  more  rapidly  than  veg- 
etable matter,  some  kinds  of  which  are  remarkably  permanent,  such, 
for  mstance,  as  the  substances  which  impart  the  brown  color  to  the 
waters  of  swamps.  Animal  matter  is  richer  in  nitrogen  than  vege- 
table matter,  and  consequently  a  stated  amount  of  albuminoid  ammonia 
represents  decomposition  of  a  larger  amount  of  the  latter  than  of 
the  former.  In  other  words,  a  small  amount  of  animal  matter  will 
yield  as  much  albuminoid  ammonia  as  a  large  amount  of  vegetable 
matter. 

Inasmuch  as  animal  matters  are  of  far  greater  significance  than  vege- 
table matters,  it  must  be  clear  that  the  amount  of  albuminoid  ammonia 
is  of  less  importance  than  its  origin.  And  since,  in  the  analysis  of 
water,  the  ammonias  themselves  give  no  indication  of  their  origin,  their 
siffuificauce  can  be  measured  onlv  M'ith  the  aid  of  estimations  of  other 
substances  ;  and  often,  also,  a  knowledge  of  the  source  of  the  water  and 
its  surroundings  will  be  required. 

Nitrites  and  Nitrates. — The  ammonia  formed  in  the  first  stage  of 
decomposition  and  that  washed  out  of  the  air  by  rain  are  oxidized 
eventually  to  nitrates  under  the  influence  of  the  so-called  nitrifying  bac- 
teria, and  this  stage  marks  the  completion  of  the  process.  The  nitric 
acid  formed,  coming  in  contact  with  earthy  and  alkaline  carbonates, 
attacks  them  and  unites  with  the  bases  to  form  nitrates  and,  in  so  doing, 
liberates  carbon  dioxide.  The  nitrifying  process  occurs  not  alone  in  the 
body  of  the  water  itself,  but  to  a  much  greater  extent  in  the  interstices 
of  the  soil,  so  that  a  water  rich  in  all  manner  of  organic  substances 
undergoes,  under  favorable  conditions,  this  purifying  process  in  the 
fullest  degree  when  it  enters  the  soil  at  the  surface  and  percolates  slowly 
downward.  Before  the  stage  of  complete  nitrification  is  reached,  there 
is  an  intermediate  stage,  that  of  nitrous  acid  and  nitrites,  but  it  is 
probable  that  the  time  during  which  a  given  amount  of  nitrogen  on  its 
way  to  mineralization  remains  in  the  nitrous  form  is  extremely  short ; 
in  fact,  the  step  from  ammonia  to  nitric  acid  is  practically  instantaneous. 
Nitrates  are  seldom  absent  in  either  surface-  or  ground-waters,  and  may 
be  present,  especially  in  the  latter,  in  quite  large  amount  (as  much  as  6 
or  7  or  more  parts  in  100,000) ;  while,  on  the  other  hand,  nitrites  are 


SUBSTANCES  FOUND  NORMALLY  IN   WATER.  329 

not  ordinarily  present  in  unpolluted  waters,  and  as  little  as  yttoTT  P^^^ 
in  100,000  of  any  water  is  looked  upon  as  ''high." 

It  is  a  fact  that  nitrates  are  reduced  very  readily  to  nitrites,  and 
farther  back  to  ammonia,  and  even  to  nitrogen  gas  itself,  l)y  a  variety 
of  organisms  which  act  in  the  absence  of  oxygen.  These  are  known 
as  the  denitrifying  bacteria,  and  while  these  species  are  doubtless 
very  numerous,  only  a  limited  number  have  been  isolated  and  identified. 
Their  action  is  inhibited  by  oxygen,  as  has  been  proved  by  Stutzer  and 
Maul,^  who  found  that  the  process  of  denitrification  ceases  in  cultures 
through  which  a  stream  of  oxygen  is  passed.  This  was  confirmed  by 
Weissenberg,  who  observed,  further,  that  when  the  bacteria  were  culti- 
vated in  small  volumes  of  nitrate  bouillon  in  flasks  of  such  shape  that 
the  surface  of  the  liquid  was  very  great  in  comparison  to  its  depth, 
and  exposed  to  the  air,  they  did  not  act. 

These  bacteria  are  common  in  sewage  in  which  the  conditions  for 
their  growth  apd  activity — absence  of  dissolved  oxygen,  for  instance — 
are  present.  Grimbert^  has  shown  that  B.  typhosus  and  B.  coll  com- 
munis reduce  nitrates  and  amido  principles  in  culture  media.  The 
production  of  gas  appears  to  be  a  result  of  the  secondary  reaction 
on  the  amido  compounds  by  the  nitrous  acid  formed  through  bacterial 
action. 

Small  amounts  of  nitrites  in  water  may  be  derived  from  the  air  by 
absorption  or  by  the  cleansing  action  of  rain,  and  may  be  due  to  con- 
tact of  metallic  surfaces,  brickwork,  and  new  masonry  with  the  nitrates 
in  solution  ;  but  they  are  almost  never  present  in  what  are  called  large 
amounts  (one  part  in  a  hundred  million)  except  as  an  indication  of 
sewage  pollution. 

The  disproportion  between  the  amounts  of  nitrites  and  nitrates  in 
water  may  also,  perhaps,  be  explained  as  follows  :  The  nitrates  are  the 
final  stage  of  complete  oxidation ;  they  do  not  go  on  to  a  higher  form^ 
but,  being  permanent  in  character,  accumulate  in  the  water,  unless  with- 
drawn by  vegetable  life  or  reduced.  The  nitrites  cannot  accumulate 
as  such,  but  are  converted  to  the  higher  form.  Thus,  the  lower  form 
is  constantly  passing  into  the  higher,  and  is  stored  as  such. 

Nitrates  vary  considerably  in  amount,  owing  to  various  causes. 
They  are  almost  always  present  in  both  surface-  and  ground-waters,, 
unless  there  is  some  process  at  work  causing  a  reduction  to  nitrites. 
In  unpolluted  surface-waters  they  are  usually  low  in  amount,  but 
such  waters  generally  contain  more  nitrogen  in  this  form  than  as 
ammonia.  They  do  not  accumulate  greatly  in  such  waters  during  the 
warmer  months,  for  they  are  absorbed  largely  by  growing  vegetation. 
Hence  they  are  more  abundant  in  winter.  In  the  warmer  months  they 
may  be  absorbed  almost  wholly  by  growing  algse. 

Ground-waters  contain  little  or  much,  according  to  circumstances  ; 
in  virgin  and  thinly  settled  districts  the  amount  is  small ;  in  others,  it 
is  usually  fairly  high.     In  the  former,  it  is  mainly  from  the  ammonia 

1  Centralblatt  fiir  Kaktei-iologie,  Abth.  TI.,  Bd.  2,  1896,  p.  473. 
*  AnnaleH  de  I'Institut  PaHteur,  Jan.,  1899. 


330  WATER. 

of  the  rain  and  that  formed  in  the  decay  of  the  organic  matters  nat- 
urally in  the  soil ;  in  the  latter,  it  is  due  largely  and  mainly  to  the 
ammonia  of  domestic  sewage. 

Ground-waters  rich  in  nitrates,  when  exposed  to  light  and  air, 
generally  become  more  or  less  rich  in  vegetable  growth,  and  poorer  in 
nitrates. 

Like  ammonia,  nitrates  in  water  are  not  of  themselves  in  any  way 
harmful  in  the  amounts  found.  They  simply  represent  what  was  once 
organic  nitrogen,  but  now  completely  mineralized.  Nor  is  their  pres- 
ence any  indication  of  the  nature  of  the  original  organic  matter,  whether 
animal  or  vegetable,  and  this  can  be  inferred  only  when  other  constit- 
uents are  considered.  When  present  in  considerable  or  very  high 
amounts,  they  indicate  a  corresponding  degree  of  jxist  pollution,  per- 
haps nearby  existing  pollution,  and  the  possibility  of  future  danger 
from  its  recurrence.  Therefore,  high  nitrates  should  sometimes  be 
looked  upon  with  suspicion. 

And,  furthermore,  it  should  be  borne  in  mind  that  the  evidence  of 
extensive  mineralization  does  not  preclude  the  existence  of  present 
processes  and  the  presence  of  active  pathogenic  micro-organisms,  for 
organic  matter  may  be  oxidized  rapidly  in  the  presence  of  living  patho- 
genic germs.  Sometunes,  very  large  amounts  of  nitrates  are  found  in 
the  waters  of  very  deep  wells,  so  large  that  they  cannot  be  explained 
by  the  supposition  of  oxidized  sewage.  In  these  cases  the  cause  is 
surmised  to  be  fossil  remains  or  natural  nitrate  deposits. 

The  presence  of  nitrites  in  water  is  of  far  greater  importance  than 
that  of  nitrates.  It  means  that  fermentative  changes  are  in  progress, 
and  that  oxidation  is  not  being  completed.  When  this  condition 
obtains,  nitrites  may  be  very  persistent.  Sometimes,  they  mean  a 
reduction  of  the  nitrates,  which  takes  place  mainly  under  the  iufliT^nce 
of  denitrifying  organisms,  quite  likely  to  be  present  in  large  numbers 
in  decomposing  organic  matter.  Sometimes,  neither  nitrates  nor 
nitrites  are  present  in  sewage-polluted  water ;  in  such  cases,  either 
they  have  not  been  formed  or  they  have  been  completely  reduced. 

When  nitrites  are  present  at  the  expense  of  the  nitrates  by  the  action 
of  metallic  surfaces,  lead  and  iron,  for  example,  the  metals  themselves 
are  present  in  at  least  detectable  traces. 

3.  Mineral  Matters. — Chlorine  as  common  salt  is  a  normal  constit- 
uent of  all  waters.  Rain-water  takes  it  up  from  the  air  in  small  traces, 
particularly  near  the  sea  coast.  In  the  specimen  of  rain  referred  to  on 
page  327  as  rich  in  ammonia,  the  chlorine  content  was  0.13  per  100,000, 
which  is  much  in  excess  of  that  found  in  many  inland  waters.  The 
amount  of  chlorine  normally  present  in  the  water  of  a  district  depends 
on  location  and  other  conditions.  It  is  influenced  very  greatly  by 
proximity  to  the  sea,  the  air  above  which  contains  necessarily  more 
than  that  at  a  distance  inland.  It  varies  in  amount  in  the  same  water 
with  diiferences  in  the  amount  of  rainfall  and  evaporation,  and  in  the 
direction  of  the  wind. 

Chlorine  increases  dh-ectly  with  the  population,  and  its  amount  is 


SUBSTANCES  FOUND  NORMALLY  ZA    WATER.  331 

influenced  very  greatly  by  a  proper  system  of  sewerage  which  carries 
the  sewage  matter,  rich  in  common  salt,  beyond  the  limits  of  the  drain- 
age area.  When  its  amount  rises  above  the  normal  of  a  locality,  it  is 
indicative  of  sewage,  though  not  necessarily  of  recent  pollution.  As 
we  have  seen,  the  organic  matters  become  mineralized,  and  no  longer 
■exist  in  their  original  form ;  but  no  such  change  occurs  in  the  chlorides, 
which  remain  fixed  and  unchanged,  and  they  may  be  the  only  evidence 
remaining.  Thus  a  water  polluted  by  sewage  may  have  its  organic 
nitrogen  converted  to  nitrates,  and  these  in  turn  may  be  absorbed  by 
vegetable  growth ;  it  may  be  clear,  colorless,  odorless,  and  palatable, 
free  from  pathogenic  bacteria,  and  in  every  way  suitable  for  drinking, 
but,  nevertheless,  the  chlorine  remains  as  a  witness  that  pollution  has 
occurred  in  the  past. 

According  to  Professor  Drown,  in  a  general  way  4  families,  or  20 
persons,  per  square  mile  will  add  on  an  average  0.01  part  of  chlorine 
per  100,000  to  the  water  of  a  district  in  seasons  of  average  flow,  and 
more  in  time  of  drought. 

Other  Mineral  Matters. — The  total  amount  of  dissolved  mineral  mat- 
ter in  any  drinking-water  depends  upon  the  character  of  the  soil  with 
which  the  water  has  been  in  contact,  upon  the  length  of  time  of  expos- 
ure, and  upon  the  amount  of  carbon  dioxide  held  in  solution.  Not  even 
the  hardest  and  most  insoluble  rocks  wholly  escape  the  solvent  power 
of  water  :  no  mineral  is  absolutely  insoluble.  Silicate  of  aluminum, 
which  is  least  acted  upon,  is  soluble  to  the  extent  of  about  1  part  in 
200,000.  Silicious  rocks  in  general  are  attacked  only  very  slightly, 
while  limestones  are  dissolved  with  comparative  ease,  and  yield  con- 
siderable calcium  and  magnesium  carbonates,  especially  if  the  water  is 
rich  m  free  carbon  dioxide.     Gypsum  also  is  acted  upon  very  freely. 

Some  waters  contain  very  large  amounts  of  mineral  matter,  derived 
from  deeply  situated  natural  deposits.  The  Carlsbad  springs,  for  ex- 
ample, are  said  to  bring  annually  to  the  surface  enormous  amounts  of 
sodium  chloride  and  calcium  carbonate,  besides  2,500  kilos  of  calcium 
fluoride,  600,000  of  sodium  carbonate,  and  11,000,000  of  sodium 
sulphate. 

Besides  the  ordinary  salts  of  the  alkalies  and  alkaline  earths,  most 
natural  waters  contain  at  least  very  minute  amounts  of  iron.  Appre- 
ciable amounts  of  iron  make  water  unsuitable  for  general  domestic  and 
technic  purposes.  It  causes  staining  of  clothes  if  used  in  the  laundry, 
and  headache,  dyspepsia,  and  constipation  if  used  habitually  for  drink- 
ing. It  cannot  be  used  for  dyeing,  and  as  little  as  1  part  in  1,000,000 
makes  it  unsuitable  for  use  in  bleacheries.  A  quarter  of  a  grain  per 
gallon  is  sufficient  to  impart  a  distinct  chalybeate  taste. 

The  permissible  total  amount  of  dissolved  mineral  constituents 
cannot  be  stated,  l)ut  50  parts  in  100,000  are  generally  held  to  be 
excessive. 

Hardness. — Hardness  is  the  capacity  a  water  has  for  decomposing 
soap.  It  depends  on  the  amount  of  salts  of  Mg  and  Ca  in  solution, 
and  hence  upon  the  cliaracter  of  the  soil  with  which  the  water  has  been 


332  WATER. 

in  contact.  Water  from  rocks  which  yield  lime  and  magnesia  will 
probably  be  hard,  while  that  from  those  composed  of  alnmina,  silica,, 
etc.,  will  probably  be  soft.  Some  sandstones  will  yield  soft  and  others 
hard  water,  according  to  the  nature  of  the  cement  which  binds  the 
grains  together.  The  elements  causing  hardness,  particularly  the  cal- 
cium salts,  have  the  property  of  making  new  combinations  w^th  the 
fatty  acids  of  the  soap,  and  preventing  the  formation  of  a  lather  until 
they  have  been  satisfied  :  1  grain  of  chalk,  for  instance,  will  use  up  8 
of  ordinary  soap  before  any  effect  can  be  produced ;  hence  enormous 
waste  of  soap  occurs  from  the  use  of  hard  water. 

Hardness  is  divided  into  "  temporary "  and  "  permanent."  The 
former  is  due  to  salts  which  are  removable  by  boiling ;  the  latter,  to 
those  which  are  not  thereby  affected. 

Water  containing  considerable  free  CO^  can  take  up  and  hold  con- 
siderable carbonate  of  lime  by  means  of  this  gas.  Some  claim  that  the 
carbonate  is  changed  to  bicarbonate,  but  this  compound  has  never  been 
isolated.  If  the  gas  be  expelled  by  heating,  the  solvent  power  no- 
longer  remains,  and  the  amount  so  held  is  precipitated,  and  then  can 
exert  no  more  influence  ui  causing  hardness.  The  chloride  and  sul- 
phate of  calcium  are  not  affected  by  boiling.  Magnesium  carbonate  is 
precipitated,  but  redissolves  on  cooling. 

The  difference  between  the  original  hardness  and  the  hardness 
remaining  after  boiling  is  the  "  temporary "  hardness.  Permanent 
hardness  is,  then,  due  to  those  salts  not  affected  by  boiling,  that  is, 
to  calcium  sulphate  and  chloride,  and  magnesium  salts ;  and  if  above 
5  parts  in  100,000,  is  commonly  regarded  as  excessive  and  injuri- 
ous. Calciiun  sulphate  is  not  alone  objectionable  in  drinking-water, 
but  also  in  water  used  in  boilers,  since  it  is  less  soluble  in  hot 
than  in  cold  water,  and  thus  forms  a  "  scale."  Scale  is  of  two  kinds  : 
that  due  to  the  temporary  hardness,  easily  removed ;  and  that  from 
CaSO^  which  is  hard,  very  adherent,  and  removed  with  difficulty. 
The  latter  is  deposited  the  more  freely,  the  higher  the  temperature  of 
the  water. 

Boiler  scale  sometimes  is  due  also  to  other  causes.  For  instance, 
A.  Reichard  '  has  reported  a  case  wdiere  serious  difficulty  was  caused  by 
the  formation  of  a  scale  of  silica  and  lime  from  a  water  which  contained 
only  2.30  parts  of  lime  and  magnesia,  but  as  much  as  2.60  of  silica. 
Boiler  scale  causes  great  loss  of  fuel,  by  interfering  with  the  transmis- 
sion of  heat  to  the  water.  Hardness  is  not  only  undesirable  in  water- 
used  in  the  laundry  and  bath,  but  also  in  that  used  for  cooking  pur- 
poses, for  it  makes  certain  of  the  vegetables  hard  and  indigestible. 

Bacteria  in  Water. 

The  ordinary  water  bacteria  are  of  the  harmless  and  beneficent  kinds, 

which,  depending  upon  dead  organic  matter  for  sustenance,  bring  about 

its  conversion  into  simple  chemical  substances.     How  many  species  of 

these  saprophytic  organisms  exist  in  water  cannot  be  said,  but  about 

^  Chemiker  Zeitung,  1896,  p.  65. 


BACTERIA   IN  WATER.  333 

two  hundred  varieties  have  thus  far  been  described.  They  may  be 
present  in  small  or  in  enormously  large  numbers  without  being  neces- 
sarily of  hygienic  significance,  although  usually  their  existence  in  large 
numbers  indicates  the  presence  of  an  abundance  of  organic  matter,  and 
yet  they  may  thrive  and  multiply  enormously  in  water  containing  al- 
most no  organic  food  materials.  Indeed,  multiplication  occurs  more 
rapidly  in  pure  than  in  polluted  water,  but  diminution  in  number  is  also 
more  rapid.  In  impure  water,  they  multiply  slowly,  but  their  growth 
is  persistent,  and,  under  ordinary  natural  conditions,  sudden  marked 
diminution  in  number  does  not  occur. 

The  ordinary  water  bacteria  are  found  in  much  greater  abundance  in 
surface-waters  than  in  those  derived  from  the  soil.  Indeed,  many 
observers,  including  Koch  and  Fraenkel,  have  maintained  that  waters 
from  the  unpolluted  subsoil  are  practically  sterile.  This,  however,  has 
been  shown  by  Sedgwick  and  Prescott  ^  to  be  not  the  case.  Using  im- 
proved methods  of  investigation,  and  paying  special  attention  to  the 
nature  of  their  culture  media,  these  observers  demonstrated  conclusively 
that  wholly  unpolluted  springs,  wells,  and  tube  wells  may  yield  consid- 
erable numbers  of  bacteria  and  sometimes  a  greater  abundance  than  is 
contained  in  some  surface-waters.  In  their  paper  they  state  "  that  the 
plates  are  remarkable  not  only  for  the  slow  growth  of  the  species 
present,  but  also  for  the  absence  of  liquefying  colonies,  and,  in  many 
cases,  for  the  abundance  of  chromogenic  varieties.  These  facts  are 
especially  important  as  indicating  the  total  absence  of  contamination  by 
ordinary  surface-water,  and,  as  far  as  they  go,  they  strengthen  the  con- 
Udence  with  which  well-protected  ground-waters  may  be  regarded  as 
sources  of  public  water  supplies."  Their  conclusions  and  results  have 
been  confirmed  a  number  of  times  by  other  competent  investigators  else- 
where. Ground- waters,  when  brought  to  the  surface  and  exposed 
to  the  air,  soon  become  rich  in  the  ordinary  forms  of  bacteria,  which 
find  in  them  the  conditions  necessary  for  extraordinarily  rapid  multi- 
plication. 

Surface-waters  vary  very  much  in  their  bacterial  content  according 
as  the  conditions  present  at  any  one  time  favor  or  retard  growth  and 
accessions.  Sunshine,  influx  of  food  material  or  of  substances  inimical 
to  bacterial  life,  sedimentation,  and  growth  of  higher  organisms  act  for 
or  against  increase.  Suspended  matters  in  their  descent  carry  down 
with  them  the  bacteria  that  have  gathered  upon  them  or  have  been 
entangled  by  contact.  The  diminution  in  their  number  by  this  means 
is  more  marked  in  still  waters  than  in  rivers  with  rapid  motion.  The 
growth  of  algse  and  other  water  plants  causes  diminution  by  removal 
of  the  nutrient  materials  upon  which  the  bacteria  depend,  and  probably 
thrcnigh  some  other  influence  not  yet  discovered.  The  increase  in 
bacteria,  sometimes  noticed  during  the  colder  months,  is  explained  by 
Frankland^  by  the  fact  that  in  winter  much  water  runs  in  over  the 
surface  from  manured  fields. 

'  Report  of  the  State  Board  of  Health  of  MaHsafhuwetts  for  1894,  p  435. 
'  The  Bacterial  Purification  of  Water,  London,  1897. 


334  WATEE. 

Besides  those  forms  whose  Datural  habitat  is  water,  others  are  often 
present  whose  natural  habitat  is  the  bodies  of  man  and  animals,  and 
which,  in  water,  are,  therefore,  in  an  unnatural  medium.  These 
forms,  which  include  the  pathogenic  varieties,  probably  do  not  increase 
in  number  in  water,  whether  the  latter  be  pure  or  extensively  polluted. 
They  live  for  a  certain  time,  retaining  their  virulence  in  undiminished 
degree,  and  then  tend  to  become  modified  in  this  respect  and  rapidly  to 
disappear.  Tho  germs  of  cholera  have  been  found  in  Seine  water  in 
an  active  state  after  seven  days,  and  in  ordinary  driuking-waters  as 
long  as  twenty  days  after  addition.  The  typhoid  fever  organism  will 
live  for  longer  or  shorter  periods,  according  to  circumstances  ;  it  has  been 
found  in  very  pure  water  after  more  than  seven  weeks,  while  in  badly 
polluted  water  its  life  is  very  short.  Sunshine  and  temperature  appear 
to  have  veiy  decided  influence  upon  its  vitality.  The  influence  of  sun- 
shine is  modified  by  the  depth  of  the  water  in  which  the  organism  is 
suspended.  Buchuer  ^  has  shown  that  the  rays  of  the  sun  will  kill 
cultures  of  the  typhoid  bacillus  at  a  depth  of  about  five  feet  in  four 
and  a  half  hours,  while  at  double  that  depth  their  eifects  are  hardly 
jjerceptible.  While  it  is  true  that  this  organism  survives  longer  in. 
cold  than  in  warm  weather,  it  cannot  be  said  definitely  that  the  rea- 
son lies  in  any  inherent  greater  resistance  to  the  influence  of  cold 
than  to  that  of  heat ;  and,  indeed,  it  seems  more  probable  that  the 
explanation  is  to  be  found  in  the  fact  that  in  warm  weather  the  con- 
ditions are  more  favorable  to  the  growth  of  the  common  species  of 
Mater  bacteria  which  are  believed  to  secrete  substances  which  exert  a 
toxic  influence  on  pathogenic  varieties  and  cause  them  to  disappear. 
The  belief  that  such  toxins  are  secreted  is  strengthened  by  the  researches 
of  Frankland,^  who  shows  that  waters  which  do  not  favor  bacterial 
multiplication  are  changed  in  this  particular  on  being  boiled.  He 
found  that,  while  anthrax  spores  were  much  diminished  in  number  or 
actually  destroyed  in  a  short  time  in  unsterilized  water,  their  numbers 
were  not  reduced  and  their  virulence  remained  unimpaired  in  sterile 
water  after  upward  of  seven  months.  These  toxic  substances  are  pre- 
sumably not  secreted  by  all  forms  of  water  bacteria,  but  only  by 
certain  species  w^hich  may  or  may  not  be  present  in  any  given  water, 
and  it  is  regarded  as  most  likely  that  they  are  not  inimical  to  the  same 
extent  to  all  varieties  of  pathogenic  bacteria,  but  that  substances  harm- 
less to  one  kind  may  act  fatally  on  another.  In  general,  it  may  be 
stated  that  pathogenic  bacteria  which  form  spores  retain  their  vitality 
and  virulence  longest  in  any  kind  of  water. 

Concerning  the  significance  of  B.  coli  communis,  which  is  exceedingly 
common  in  drinking-Avater,  there  is  much  diflFerence  of  opinion. 
Kruse,^  in  1894,  asserted  that  this  organism  is  so  ubiquitous  that  it 
cannot  be  regarded  as  characteristic  of  sewage,  and  in  this  position  he 
has  received  the  support  of  a  number  of  other  investigators,  who  have 

^  Centi-alblatt  fur  Bakteriologie  und  Parasitenkunde,  XI.  p.  781 

^  Journal  of  State  Medicine,  January,  1894. 

^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten  XVII.,  p.  1. 


WATER  SUPPLIES.  335 

succeeded  in  isolating  the  organism  from  all  waters  examined,  although 
in  many  cases  it  was  necessary  to  emjjloy  large  volumes  of  the  samples. 

The  committee  of  the  Laboratory  Section  of  the  American  Public 
Health  Association,  to  which  the  question  of  the  significance  of 
jB.  coli  in  water  supplies  was  referred,  reported  ^,  in  October,  1903,  that, 
in  spite  of  the  fact  that  numerous  investigators  have  found  the  organism 
where  it  could  not  directly  be  traced  to  sewage  or  fecal  pollution,  the 
colon  test  of  water  is  a  safe  index  of  pollution  ;  that  their  number 
rather  than  their  mere  presence  should  be  used  as  a  criterion  of  recent 
sewage  pollution  ;  that  evidence  of  the  presence  of  B.  coli  in  a  majority 
of  1  cc.  samples  should  be  required  for  a  conclusion  that  a  water  is 
sewage  polluted ;  and  that  the  examination  of  large  (100-1000  cc.) 
samples  for  B.  coli  should  be  discouraged  (one  of  five  members  dis- 
senting). On  the  question  of  the  desirability  of  isolating  streptococci 
as  well  as  £.  coli,  to  confirm  suspicious  evidence  of  pollution  offered 
by  B.  coli,  there  was  no  agreement,  but  great  diversity  of  opinion. 

According  to  Clark  and  Gage,^  of  the  Lawrence  Experiment  Station, 
whose  conclusions  are  based  on  the  results  of  examination  of  some 
16,000  samples  of  water  from  all  sources  and  of  more  than  2000 
miscellaneous  samples  of  shellfish,  sea-water,  ice,  milk,  dust,  excrement, 
etc.,  the  colon  bacillus,  occurring  more  numerously  than  all  other 
bacteria  in  normal  sewage,  is  the  most  valuable  index  of  sewage. 
When  a  considerable  number  of  samples  from  the  same  source  are 
examined,  100  cc.  samples  frequently  give  more  information  as  to 
quality  than  do  single  cubic  centimeter  samples.  In  filtered  polluted 
water,  bacterial  tests  are  of  greater  value  than  chemical  analysis ;  and 
disturbing  factors  in  filtration,  shown  slightly  or  not  at  all  by  ordinary 
bacterial  counts,  are  often  shown  strongly  by  B.  coli  tests. 

WATER  SUPPLIES. 

Immediate  sources  of  water  supply  comprise  :  1.  Stored  rain.  2. 
Surface-waters,  including  rivers,  lakes,  and  gathering  basins.  3. 
Ground-waters,  including  wells,  filter  galleries,  and  springs. 

1.   STORED  RAIN. 

Where  other  water  is  not  obtainable,  and  where  the  natural  water  is 
unfit  for  drinking  or  for  washing  and  other  domestic  purposes,  stored 
rain-water  is  used.  If  this  is  collected  under  proper  precautions  to 
prevent  the  presence  of  extraneous  matters  of  undesirable  character 
from  the  receiving  area,  and  properly  stored,  it  constitutes  a  most 
wholesome  supply.  But  excepting  where  rainfall  occurs  with  regu- 
larity and  frequence,  the  uncertainty  of  sup])ly,  especially  in  periods  of 
drought,  acts  as  a  great  drawback.  An  inch  of  rainfall  is  equivalent  to 
o.Ol  U.  S.  gallons  per  square  yard,  or  27,152  gallons  per  acre,  but 

1  Public  Health  Papers  and  Reports,  XXIX,  p.  356. 
»  Ibidem,  p.  38G. 


336  WATER. 

onlv  a  small  proportion  of  this  falls  upon  surfaces  (roofs,  etc.)  from 
^vhich  it  may  be  collected. 

The  total  collecting  area  of  the  roof  of  any  building  depends  not 
upon  the  shape  and  style  of  the  roof,  but  upon  the  amount  of  ground 
occupied  by  the  building.  Thus,  a  house  40  feet  square  will  have 
practically  1,600  square  feet  of  watershed,  or,  allowing  for  the  projec- 
tion of  the  eaves,  somewliat  more,  and  this  whether  the  roof  be  flat, 
pitched,  gambrel,  mansard,  or  irregularly  disposed.  Upon  such  an 
iirea,  1  inch  of  rain  will  yield  nearly  a  thousand  (997)  gallons.  The 
mean  annual  rainfall  of  Massachusetts  is  43.17  inches,  and  on  this 
basis,  a  roof  of  this  size  would  receive  in  a  year  over  43,000  gallons, 
which  would  allow  for  all  the  needs  of  the  occupants,  for  drinking, 
cooking,  bathing,  laimdry,  and  other  purposes,  nearly  120  gallons  per 
diem.  But  under  ordinary  conditions  of  storage  in  cisterns,  a  very 
large  amount  of  loss  occurs  through  evaporation,  and  thus  the  daily 
allowance  would  fall  somewhat  below  this  figure. 

In  collecting  rain  from  roofs,  it  is  very  necessary  to  insure  cleanli- 
ness of  the  supply,  by  allowing  the  first  flow  to  run  to  waste,  thereby 
avoiding  contamination  by  dirt,  leaves,  bird-droppings,  soot,  and  other 
matters  deposited  upon  the  roof  and  collected  in  the  gutters.  A  num- 
ber of  automatic  devices  are  in  use  for  the  purpose  of  diverting  the 
first  washings  away  from  the  conductors.  After  this  has  been  done, 
they  change  position,  so  that  the  subsequent  fall  is  saved  and  stored. 

Irregularity  in  precipitation  is,  as  has  been  remarked  above,  a  serious 
drawback  to  reliance  upon  rain  as  a  sole  supply.  Partly  owing  to  a 
general  belief  that  great  battles,  in  M'hich  large  quantities  of  explo- 
sives are  used,  are  commonly  followed  by  heavy  rain,  numerous  experi- 
ments have  been  tried  toward  breaking  drought  by  discharging  power- 
ful explosives  in  the  upper  strata  of  the  atmosphere,  but  without 
success.  As  a  matter  of  fact,  the  idea  of  connection  between  battles 
and  rainfall  is  by  no  means  new,  and  has,  indeed,  come  down  from 
times  antedating  the  use  of  gunpowder  in  warfare.  Furthermore,  in- 
vestigation of  government  records  has  shown  that  the  popular  belief 
has  no  foundation  in  fact,  and  that  great  battles  have  been  as  often 
followed  by  periods  of  fair  weather  as  by  days  of  storm. 

Rain-water  requires  no  aeration,  for  in  its  descent  it  has  absorbed 
<'onsiderable  air ;  but  melted  snow  and  ice  should  be  shaken  with  air 
or  poured  rej^eatedly  from  one  vessel  to  another,  in  order  that  they  may 
lose  the  flat  taste  so  characteristic  of  unaerated  water.  Moreover,  their 
use  in  the  flat  condition  is  believed  to  conduce  to  gastric  derangement. 
Snow-water  is  usually  more  impure  than  rain,  because  the  snowflakes, 
by  reason  of  their  larger  surface,  are  more  efficient  in  removing  dust 
and  dirt  from  the  air. 

Cisterns  for  storage  of  rain  should  be  so  constructed  and  arranged 
as  to  admit  of  easy  inspection  and  cleansing.  They  should  be  kept 
covered,  so  as  to  exclude  dirt  and  dust  of  all  kinds,  insects,  mice,  and 
other  animals,  and  to  shut  off  light  as  well,  for  the  presence  of  light 
is  an  important  aid  to  the  development  of  lower  plant  forms.     The 


SUEFACE- WATERS.  337 

best  materials  for  their  constructiou  are  bricks,  stone,  cement,  and 
slate.  Cement  makes  a  good  lining  if  one  is  desired  ;  mortar,  how- 
ever, is  objectionable  on  account  of  the  solvent  power  of  water  upon 
lime,  which  will  cause  progressive  increase  in  hardness.  Cisterns 
should  be  provided  with  overflow  pipes  discharging  into  the  open  air 
rather  than  into  the  house  sewer,  and  their  exits  should  be  protected 
by  wire  netting  against  the  entrance  of  leaves  and  small  animals. 

2.  SURFACE-WATERS. 

For  public  supplies,  especially  of  large  communities,  surface-waters, 
as  rivers,  lakes,  and  collecting  basins,  are  generally  more  available  than 
ground- waters. 

Large  rivers  and  lakes  are,  unfortunately,  very  commonly  subject  to 
most  extensive  pollution  by  sewage  of  large  communities  and  manu- 
facturing establishments  along  their  borders,  and  by  the  waste  products 
discharged  into  them  from  sailing  vessels  and  steamships.  Many 
rivers  are  subject  to  progressive  increase  of  pollution  by  reason  of 
serving  as  the  most  convenient  receptacle  for  the  sewage  of  a  succession 
of  towns  and  cities  located  at  intervals  from  the  source  to  the  mouth. 
Thus,  one  town  takes  its  water  from  a  point  above  and  discharges  its 
sewage  at  another  place  below ;  a  second,  farther  down,  takes  the 
already  contaminated  water,  and  in  its  turn  discharges  its  sewage  at 
another  convenient  point,  and  so  on  for  the  rest  of  the  course.  On 
account  of  the  dangers  attending  the  use  of  such  waters,  some  process 
of  treatment  is  imperatively  demanded  to  remove  the  objectionable 
elements.  The  different  processes  available  for  this  work  are  considered 
elsewhere. 

The  public  mind  is  being  awakened  gradually  to  the  wrong  practised 
upon  one  community  by  another  by  the  discharge  of  untreated  sewage 
into  what  is  its  only  available  water  supply.  In  the  case  of  cities 
located  upon  the  shores  of  the  Great  Lakes  and  other  large  bodies  of 
fresh  water,  it  is  commonly  the  case  that  the  intake  of  the  water  sup- 
ply is  located  at  no  very  great  distance  from  the  outfall  of  the  main 
sewers.  Smaller  rivers  and  lakes  may  be  subject  to  the  same  influences, 
though  in  lesser  degree  ;  but,  in  general,  it  may  be  said  that  these  are 
controlled  more  easily,  especially  when  they  lie  wholly  within  the 
jurisdiction  of  a  single  law-making  power. 

Basins  for  the  collection  and  storage  of  rainfall  and  surface-waters 
are  constructed  by  throwing  a  dam  across  a  valley  or  other  convenient 
depression.  Experience  has  taught,  that,  even  though  involving  large 
expenditure,  it  is  best  to  strip  ofl^  the  surface  layers  in  order  to  get  rid 
of  all  organic  matter  and  vegetation,  which,  if  left  in  place,  may  prove 
fruitful  sources  of  trouble.  The  water  which  gathers  in  them  has  op- 
portunity to  rid  itself  of  much  of  its  suspended  matters  by  sedimenta- 
tion, and  is  more  often  used  without  further  treatment  than  otherwise. 

All  surface-waters  contain  more  or  less  active  vegetation,  and  on 
that  account  should  always  be  kept  exposed  to  light  and  air,  otherwise 

22 


338  WATEB. 

the  minute  plants  will  die,  and  in  their  decomposition  give  rise  tO' 
unpleasant  odor,  appearance,  and  taste.  Storage  reservoirs  should 
have  sufficient  depth  to  prevent  the  water  from  becoming  heated  to  an 
unpleasant  degree  during  the  warm  months  of  summer.  In  shallow 
reservoirs,  this  is  found  to  be  a  common  occurrence. 

All  sources  of  surface-water  for  public  supply  should  be  carefully- 
guarded  against  sewage  contamination.  It  is  often  necessary  to  secure 
protection  from  pollution  by  taking  great  tracts  of  land  and  keeping- 
them  free  from  human  habitations  and  industrial  plants. 

3.  GROUND-WATERS. 

Some  large  communities  and  many  small  ones  where  no  suitable 
bodies  of  surface-water  are  available  for  public  supplies,  and  the  major- 
ity of  thinly  settled  districts  which  do  not  admit  of  public  waterworks, 
depend  upon  the  ground-water  as  the  source  of  supply.  For  public  dis- 
tribution, the  water  thus  derived  is  stored  in  suitable  reservoirs,  which 
often  must  be  covered,  in  order  to  exclude  light.  Ground-water  is 
destitute  of  plant  life,  but  is  generally  more  or  less  rich  in  mineral 
constituents — nitrates,  and  lime  salts,  for  example — which  constitute 
appropriate  plant  food.  If  exposed  to  air  and  light,  vegetable  growth  may 
start  up  and  become  very  luxuriant,  and  give  rise  to  unpleasant  tastes  and 
repulsive  odors,  while  exclusion  of  light  and  air  prevents  the  difficulty. 

For  individual  domestic  supply,  storage  is  not  ordinarily  necessary, 
the  water  being  obtained  only  as  immediately  needed  or  pumped 
periodically  into  small  distributing  tanks. 

In  general,  unpolluted  ground-water  of  not  excessive  hardness  is 
preferable  to  surface-water,  on  account  of  the  greater  exposure  of  the 
latter  to  the  many  risks  of  pollution.  But  it  should  be  borne  in  mind 
that  all  sources  of  supply,  both  surface-  and  ground-waters,  may,  under 
one  condition  or  another,  be  subject  to  polluting  influences,  and  that  the 
conditions  prevailing  in  one  locality  are  likely  to  be  quite  different  from 
those  in  another. 

Ground-water  is  obtained  from  springs,  or  by  sinking  wells,  or  by 
constructing  filter  galleries. 

Springes  are  merely  local  outcroppings  of  the  water-table,  and  are 
very  subject  to  variations  in  the  volume  of  outflow.  In  time  of  drought, 
they  sometimes  cease  their  flow  completely,  because  of  fall  in  the  level 
of  the  ground-water ;  and  this  may  happen  even  in  the  case  of  those 
located  at  the  foot  of  high  hills  or  mountains.  The  popular  mind 
endows  springs  with  a  remarkable  and  unvarying  degree  of  purity,  but 
they  share  with  other  waters  the  likelihood  of  becoming  polluted.  The 
possibility  of  contamination  after  and  even  at  the  point  of  issuance  from 
the  ground  is  too  often  overlooked. 

Springs  are  common  to  some  localities  and  rare  in  others  of  similar 
contour,  their  presence  or  absence  being  determined  by  conditions  not 
of  the  surface,  but  of  the  geological  formations  below.  In  Figs.  25 
and  26  are  shown  in  profile  two  depressions  having  the  same  contour. 


GROUND- WATER. 


339 


but  with  very  clifFerent  arrangement  of  the  underlying  strata.  In  Fig. 
25  the  formation  favors  the  outcropping  of  springs ;  in  Fig.  26  the 
opposite  is  the  case. 


Fig.  25. 


Fig.  26. 


Wells  may  be  classed  as  dug,  driven,  and  bored.  Sometimes  they 
are  divided  also  into  deep  and  shallow  ;  but  these  terms  as  a  basis  of 
classification  are  of  doubtful  utility,  since  there  can  be  no  general  agree- 
ment as  to  the  line  of  division  between  them,  and  because  of  the 
absence  of  any  necessarily  distinctive  peculiarities  in  the  water  yielded 
by  ordinary  wells  of  different  depths.  It  is  not  uncommon  to  meet 
with  general  statements  that  the  water  of  shallow  wells  is  dangerous  to 
health,  and  should,  therefore,  be  avoided,  and  that  all  shallow  wells 
should  be  condemned  and  filled.  As  will  be  seen,  however,  shallow 
wells  are  not  necessarily  dangerous,  nor  are  deep  ones  always  safe  by 
reason  of  mere  depth. 

By  some  writers,  the  term  deep  is  applied  to  wells  which  obtain  their 
water  from  below  the  first  impervious  stratum,  through  and  beyond 
which  they  have  been  extended ;  while  the  term  shallow  is  applied  to 
those  which  draw  from  what  we  designate  as  the  ground-water ;  that  is, 
that  collected  over  the  stratum  above  mentioned,  regardless  of  the  depth 
at  which  it  lies.  With  these  meanings,  it  follows  that  a  shallow  well 
may  extend  farther  downward  than  another  classed  as  deep. 

The  ordinary  dug  well  is  a  hole  dug  in  the  soil  down  as  far  as  is 
necessary  to  reach  water,  and  lined  with  brick  or  stone,  or,  better,  with 
earthenware  tubes  of  large  diameter  made  for  the  purpose  in  short 
lengths  with  bevelled  edges  to  secure  good  joints.  All  brick  and  stone 
linings  should  be  well  bedded  in  cement,  except  near  the  bottom,  and 
should  be  faced  with  the  same  material  throughout  their  upper  part. 
The  imj)ervious  lining  is  necessary  for  the  prevention  of  the  entrance 
of  surface  washings ;  but  it  is  very  generally  the  case,  in  some  parts  of 


340  ~  WATER. 

the  country  at  least,  that  the  well  is  lined  simply  with  field-stones, 
without  cement,  not  for  the  purpose  of  insuring  freedom  from  surface 
impurities,  but  to  prevent  the  sides  from  caving  in.  With  a  proper 
lining,  no  surface-water  can  enter  until  it  has  passed  through  a  depth 
of  soil  sufficient  to  insure  proper  filtration  and  purification. 

A  dug  well  should  not  be  left  open,  but  should  be  closed  completely 
against  the  entrance  of  dirt,  leaves,  and  animals,  such  as  toads,  moles, 
mice,  and  rats.  The  cover  should  be  supported  on  a  well-set  curb,  and 
be  sufficiently  tight  to  prevent  the  return  of  water  spilled  or  allowed 
to  run  to  waste.  A  manhole  with  a  trapdoor  should  be  provided  as  a 
means  of  inspection  and  cleaning. 

For  bringing  the  water  to  the  surface,  pumps  should  be  used,  and 
not  buckets  worked  by  windlass  or  well-sweep.  In  country  districts 
it  is  a  common  practice  to  employ  buckets  made  from  kegs,  originally 
used  as  containers  for  white  lead.  It  is  hardly  necessary  to  call  atten- 
tion to  the  injury  which  may  be  caused  by  the  use  of  such  vessels. 

The  pump  may  stand  directly  in  the  well  or  away  from  it  and  con- 
nected therewith  by  means  of  a  pipe  running  laterally  and  downward. 
The  latter  is  the  better  way,  as  any  water  wasted  at  the  pump  is  pre- 
vented by  location,  if  by  nothing  else,  from  running  back  into  the 
well,  and,  moreover,  the  covering  of  the  well,  if  of  wood,  is  not  continu- 
ally subjected  to  wetting,  which  promotes  its  decay.  The  best  form  of 
pump  is  the  simple  lifting  pump,  made  of  iron  or  of  wood,  and  con- 
sisting of  an  evenly-bored  barrel,  closed  at  the  lower  part  by  a  valve 
opening  upward,  and  a  piston  containing  another.  The  upward  stroke 
of  the  piston,  by  producing  a  vacuum,  causes  the  water  to  pass  through 
the  lower  valve,  and  its  downward  stroke  forces  the  water  confined  in 
the  barrel  through  the  upper  valve,  and  then  the  succeeding  strokes  lift 
and  discharge  it  continuously.  The  old-fashioned  chain  pumps  cannot 
be  used  without  more  or  less  chance  of  exposure  to  contamination 
from  above. 

The  action  of  the  wind  is  very  commonly  employed  as  a  labor-saver 
for  pumping  water  not  only  from  the  well,  but  upward  into  reservoirs 
and  distributing  tanks.  For  this  purpose  a  variety  of  wind-mills  have 
been  put  upon  the  market. 

There  are  also  a  number  of  makes  of  hot-air  engines  that  are  very 
efficient  and  not  unduly  expensive. 

Driven  wells,  otherwise  known  as  "  Norton's  tube  wells,"  "  Ameri- 
can," and  "  Abyssinian  "  wells,  are  made  by  driving  iron  tubes  of  a 
diameter  varying  from  IJ  to  4  inches,  according  to  the  needs  of  indi- 
vidual cases,  into  the  ground  until  water  is  reached.  The  first  length 
driven  in  is  provided  with  a  pointed  perforated  foot,  through  which  the 
water  enters  the  tube.  When  this  length  is  driven  sufficiently  far,  an- 
other is  screwed  to  it  and  the  driving  is  continued,  additional  lengths 
being  screwed  on  as  necessary.  When  water  is  reached — and  this  is 
ascertained  by  means  of  a  weighted  string  let  down  inside  the  tube 
from  time  to  time — a  pump  is  applied  and  the  water  lifted.  The  first 
that  comes  contains   sand  or  fine  gravel  and  dirt,  and  as  this  is  more 


GROUND- WATER. 


341 


and  more  removed  from  below,  a  pocket   is  formed  which  constitutes 
an  underground  reservoir. 

Fio.  27. 


Perv iove-s  ' ■'  "• 


Orou  ,1  if- 


,'  'Zat/'e'T  '-'_.' 


Norton  tube  well. 


Bored  wells  differ  but  little  from  tube  wells  ;  in  fact,  they  are  prac- 
tically the  same  except  in  the  method  of  their  making.  They  are 
drilled  or  bored  through  solid  rock  and  other  strata,  and  are  lined  or 
not  with  iron  pipe,  backed  with  cement  according  to  circumstances. 
Their  cost  is  much  greater  than  that  of  the  ordinary  Abyssinian  well, 
since  the  labor  required  is  much  greater.  Sometimes  it  is  necessary, 
after  proceeding  several  hundred  feet  with  no  results,  to  resort  to 
blasting  at  the  bottom,  so  as  to  shatter  the  rock  and  form  waterways 
to  the  well. 

It  is  self-evident  that  wells  of  these  two  kinds  last  mentioned  can- 
not, under  ordinary  circumstances,  become  contaminated  with  surface 
washings.  Both  forms  are  used  very  commonly  not  only  for  individ- 
ual, but  for  public,  supplies.  In  the  latter  case,  they  are  driven  in 
groups,  or  "  gangs,"  the  size  of  which  varies  according  to  the  amount 
of  water  required.  Increase  in  demand  should  be  met  by  extension 
of  the  system  rather  than  by  over-forcing,  for  the  latter  will  cause  an 
undue  lowering  of  the  water  level  and  tend  strongly  to  bring  water 
downward  from  the  upper  strata  at  such  a  rate  as  to  preclude  the  puri- 
fication which  normally  is  brought  about  by  the  saprophytic  bacteria 
of  the  soil. 

In  the  case  of  an  ordinary  well,  the  bottom  should  be  considerably 
below  the  l(!vel  of  the  ground-water,  so  that  when  this  falls,  the  well 
will  not  run  dry,  and  also  because  the  fartiicr  the  withdrawal  by 
I)iun[)ing  carries  the  level  of  the  well  IjcIow  that  of  the  water-table,  the 


,342 


WATER. 


faster  will  be  the  flow  toward  the  well,  and  the  greater  the  supply 
immediately  available.  But  deepening  a  well  for  the  purpose  of  in- 
creasing the  supply  sometimes  has  the  very  opposite  effect,  and  may 
even  cause  it  to  run  practically  dry.  Suppose,  for  example,  the  im- 
pervious layer  is  underlaid  by  a  thick  stratum  of  coarse  gravel,  and  in 
the  process  of  deepening  the  well  this  stratum  is  entered  :  instead  of  an 
increase  in  the  supply,  it  then  may  happen  that  the  water  flowing  into 
the  well  finds  a  ready  exit  downward  by  the  force  of  gravity  into  the 
interstices  of  the  gravel,  and  the  usefulness  of  the  well  is  terminated. 
(See  Fig.  28.) 

Included  under  bored  wells  are  those  known  as  Artesian.  These 
are  bored  through  impervious  strata  until  a  stratum  is  reached  in 
which  the  water  is  under  hydrostatic  pressure  sufficiently  strong  to 
force  it  to  the  surface,  or  at  least  to  a  point  nearly  as  high,  the  rise 

Fig.  28. 


How  a  well  may  be  spoiled  by  being  deepened. 


depending  upon  the  height  reached  by  the  water-bearing  stratum  in 
higher  land  elsewhere.  In  Fig.  29  is  shown  a  formation  favorable  to 
the  obtaining  of  water  by  means  of  this  class  of  wells.  The  water  in 
the  soil  above  the  first  layer  of  clay  may  be  reached  by  sinking  wells 
of  the  ordinary  kinds.  Below  this  is  a  second  supply  confined  between 
two  impervious  strata  inclining  upward.  The  higher  this  formation 
extends  above  the  level  of  the  outlet  J.  of  a  well  sunk  into  it  at 
that  point,  the  greater  will  be  the  pressure  at  B  and  the  higher  the 
rise  of  the  water.  Thus,  if  it  extends  upward  to  C,  for  example,  the 
water  will  not  simply  fill  the  tube,  but  will  be  thrown  some  distance 
into  the  air.  In  some  cases,  although  the  head  developed  is  very  con- 
siderable, the  water  does  not  come  to  the  surface,  because  of  the  extent 
of  leakage  into  the  upper  pervious  strata  of  the  soil. 

Sometimes  the  wells  are  connected  with  true  underground  rivers, 
and  sometimes  with  apparently  inexhaustible  reservoirs  which  have 
held  the  water  in  storage  for  ages.     Sometimes  they  derive  their  water 


GROUND-WATER. 


343 


from  fissures  draining  away  the  water  of  surface  rivers  and  lakes,  as  is 
proved  by  the  occasional  occurrence  in  the  overflow  of  small  fish  with 
€yes. 

Artesian  wells  have  been  known  in  China  and  Egypt  from  very 
ancient  times,  and  centuries  ago  they  were  introduced  into  the  prov- 
ince of  Artois  (Artesium),  from  which  their  name  is  derived.  They 
are  exceedingly  numerous  in  the  western  and  southwestern  parts  of  the 
United  States,  where  they  have  produced  enormous  results  in  convert- 
ing arid,  waste  lands  into  fertile  farms.  Some  of  them  are  exceedingly 
deep,  and  pass  through  stratum  after  stratum  of  different  formations 
before  water  is  reached. 

Since  the  temperature  of  the  earth  increases  1  degree  Fahrenheit  for 
about  55  feet  of  depth,  it  follows  that  water  from  these  very  deep  wells 

Fig.  29. 


2/1  r/.  Imj. 
Geolog[ieal  formation  favorable  to  the  obtaining  of  water  by  means  of  artesian  wells. 

is  materially  warmer  than  that  from  the  upper  subsoil.  Distinctly  hot 
water  from  deep  sources  is  rarely  fit  for  ordinary  domestic  purposes, 
because  of  the  large  amount  of  mineral  matters  present  in  solution  by 
reason  of  the  greater  solvent  power  of  water  when  hot  than  when  cold. 
Thus  they  acquire  an  abundance  of  salts,  which,  taken  into  the  body^ 
influence  its  functions  and  act  as  medicines.  The  presence  of  organic 
matters  is  of  importance  on  account  of  their  reducing  power.  The 
sulphuretted  hydrogen  so  common  to  mineral  springs  is  due  to  the 
action  of  these  matters  on  sulphates. 

Irrespective  of  the  changes  wrought  by  increased  temperature, 
the  water  yielded  by  this  class  of  wells  varies  very  widely  in  charac- 
ter. It  may  bear  no  resemblance  whatever  to  the  other  waters  of 
the  same  district,  nor  is  there  any  reason  why  it  should,  for  the  con- 
ditions at  the  surface  and  at  points  hundreds  of  feet  below  are  quite 


344  WATER. 

different.  Moreover,  one  cannot  know  how  far  the  water  has  travelled 
from  where  it  originally  entered  the  soil  to  the  point  where  it  makes  its 
escape. 

Of  waters  from  four  such  wells  sunk  within  the  limits  of  the  city  of 
Boston  to  depths  of  from  870  to  2,503  feet,  two  were  extensively  im- 
pregnated with  common  salt  and  other  mineral  matter,  one  was  very 
rich  in  both  vegetable  and  mineral  substances,  and  the  fourth  was  rich 
in  both  these  and  sulphuretted  hydrogen. 

Drainage  Area  of  Wells. — As  to  the  amount  of  soil  which  is  drained 
by  a  well,  there  can  be  no  general  rule.  It  is  commonly  asserted  that 
the  amount  drained  may  be  described  as  an  inverted  cone,  having 
the  bottom  of  the  well  as  its  apex,  and  a  base  with  a  radius  equal  to 
twice  the  depth  of  the  M'ell.  But  much  depends  upon  the  nature  and 
configuration  of  the  surrounding  soil,  and  the  extent  to  which  pumping 
is  carried.  If  the  soil  be  sandy  and  open,  the  base  will  be  much  larger 
than  if  it  be  clayey  and  close.  If  extensively  pumped,  the  well  will 
drain  a  greater  area  than  if  the  demands  be  moderate ;  in  fact,  the 
amount  of  water  removed  by  pumping  has  a  greater  influence  in  deter- 
mining the  drainage  area  than  mere  depth.  But  other  things  being 
equal,  the  nature  of  the  water-bearing  stratum  determines  the  distance 
to  which  the  measurable  influence  of  pumping  is  felt. 

Pollution  of  Wells. — In  general,  it  may  be  stated  that,  as  between 
wells  of  different  depths,  the  shallower  are  more  subject  to  polkition  than 
the  deeper,  because  of  the  fact  that  the  latter  have  the  advantage  of  the 
greater  opportunity  for  perfect  filtration-  through  the  soil.  But  both 
are  subject  to  pollution  by  unoxidized  matters  which  enter  the  soil 
below  the  upper  few  feet  in  which  the  nitrifying  organisms  already 
referred  to  are  found,  as,  for  instance,  from  leaching  cesspools  and  leak- 
ing drains.  It  is  a  practice  only  too  common,  even  on  estates  of  con- 
siderable size,  where  the  excuse  of  limited  area  cannot  obtain,  to  locate 
the  well  and  the  cesspool  very  near  together.  To  avoid  the  necessity 
of  having  to  remove  the  contents  of  the  cesspool  as  occasion  demands 
Avhen  this  receptacle  is  made  water-tight,  and  to  avoid  the  expense 
attending  this  kind  of  construction,  the  bottom  is  generally  left  open, 
so  that  the  house  sewage  may  drain  away  into  the  surrounding  soil. 
Connection  between  the  cesspool  and  the  well  may  take  considerable 
time  or  may  occur  quickly,  but,  once  established,  contamination  goes 
on  uninterruptedly.  Often  it  happens  that  the  direction  of  the  flow 
of  filth  through  the  soil  is  wholly  away  from  the  well,  and  contamina- 
tion may  never  occur ;  but  this  is  a  jjoint  that  can  never  be  determined 
in  advance. 

It  is  a  common  belief  that,  if  the  well  is  located  in  higher  ground 
than  the  cesspool,  there  can  be  no  danger  of  pollution  of  its  water. 
This,  however,  is  a  most  fallacious  proposition,  for  it  is  not  so  much 
the  location  of  the  outlet  of  the  well  that  determines  the  possibility  of 
pollution,  as  the  relative  position  of  the  cesspool  and  the  point  where 
the  water  enters  the  well.  In  Fig.  30  is  illustrated  the  manner  in 
which  the  supply  yielded  to  a  pump  placed  at  a  point  considerably 


QROUND-WATER. 


345 


above  the  location  of  the  cesspool  is  polluted  directly  by  the  liquid 
filth  issuing  from  the  latter.  Again,  the  geological  formation  may  be 
such  that  a  cesspool  on  higher  ground  than  the  nearby  well  will  have  no 
influence  on  the  purity  of  the  water.  Thus,  a  ledge  of  rock  may  crop 
up  between  them,  as  shown  in  Fig.  31,  and  divert  the  flow  of  polluting 
matters  away  from  the  well. 

Fig.  30. 


How  a  well  located  on  high  ground  may  be  polluted  by  the  contents  of  a  cesspool  lower  down. 

In  locating  wells  and  cesspools,  property  owners  not  infrequently 
lose  sight  of  the  fact  that,  while  they  can  govern  the  disposition  of  the 
surface  of  their  respective  estates,  the  conditions  that  obtain  in  the  soil 
below  are  quite  beyond  their  control.  In  consequence,  they  may 
attempt  to  guard  against  pollution  of  their  own  water  supplies  by  their 
own  excretory  products,  without  regarding  the  possibility  of  contami- 
nation by  those  of  their  neighbors. 

Fig.  31. 


How  a  cesspool  located  on  high  ground  may  fail  to  pollute  a  well  lower  down. 

The  water  of  newly  dug  wells  is  often  of  such  a  character  as  to  lead 
to  the  perhaps  false  conclusion  that  it  is  probably  polluted  by  sewage. 
It  is  generally  turbid,  and  may,  on  analysis,  yield  results  which,  in 
case  the  analyst  has  not  full  information  concerning  it,  may  seem  to 
warrant  a  condemnatory  report.  It  may  yield  figures  indicating  a  high 
content  of  organic   matters,  which   may   disappear   as   the   use   of  the 


346  WATER. 

water  becomes  established.  It  may  even  show  imdeniable  evidence  of 
the  presence  of  human  wastes,  for  those  engaged  in  the  digging  and 
the  stoning  may  be  more  interested  in  the  completion  of  the  work  than 
in  the  perfect  purity  of  the  supply,  and  may  be  disinclined  to  go  up  to 
the  surface  for  the  purpose  of  relieving  the  calls  of  nature.  On  all  ac- 
counts, therefore,  it  is  better  to  await  the  results  of  a  later  examination, 
than  to  condemn  and  abandon  too  hastily  a  supply,  which,  within  a 
^iiort  time,  may  prove  to  be  of  exceptional  purity. 

Very  deep  wells  may  become  badly  polluted  by  filth  which  gains 
access  through  open  channel-ways,  as  fissures  in  rock.  A  good  ex- 
ample of  this  is  recorded  in  the  Sanitary  Inspector  for  December, 
1896  :  A  well  bored  500  feet  into  red  sandstone  drained,  through 
fissures,  all  the  shallow  wells  in  the  vicinity.  These  being  of  no  use 
as  wells,  were  then  utilized  as  cesspools,  and,  draining  again  through 
the  fissures,  caused  the  well  to  become  so  foul  that  it  had  to  be  aban- 
doned. Dr.  A.  C.  Houston  ^  shows  how  deepening  a  well  may,  in  a 
similar  manner,  cause  its  ruin.  A  Avell  of  pure  water,  114  feet  deep, 
was  deepened  by  farther  boring  to  294  feet,  when  its  yield  was  then 
found  to  be  impure.  At  a  distance  of  800  feet  was  an  old  quarry, 
into  which  drained  the  sewage  of  25  persons.  By  fissures  in  the  sand- 
stone, this  reached  the  water  stratum  tapped  by  the  extension  of  the 
well  and  thus  spoiled  the  water. 

On  account  of  the  possibility  of  contamination  of  shallow  wells  by 
the  entrance  of  surface  washings  from  above,  Koch  recommends  that 
pipes  be  placed  in  position  so  as  to  reach  the  water  stratum,  and  that 
then  the  wells  be  filled  up,  first  with  stone  and  coarse  gravel,  and 
toward  the  top,  for  at  least  six  feet,  with  fine  sand.  By  this  pro- 
cedure, the  well  is  converted  really  into  an  Abyssinian  well,  and  is 
protected  from  surface  contamination  quite  as  well  as  though  it  had 
originally  been  driven   instead  of  dug. 

Filter  Galleries. — A  filter  gallery  is  a  large  underground  tunnel 
sunk  parallel  to  a  river  or  lake  and  near  to  it ;  it  is  in  reality  nothing 
more  than  a  horizontal  well.  The  idea  which  led  to  their  construction 
was  that  in  this  way  the  river  water,  percolating  outward  from  its  bed 
through  the  soil.  Mould  be  secured  in  a  'filtered  state,  and  would  ac- 
cumulate in  the  underground  reservoirs.  Although  this  method  of 
obtaining  water  has  been  attended  by  most  excellent  results,  the  fact 
remains  that  the  water  so  collected  comes  not  from  the  river,  but  from 
the  ground  on  its  hither  side ;  that  is  to  say,  it  is  the  ground-water 
intercepted  on  its  way  to  the  river. 

The  water  of  a  river  does  not,  except  under  unusual  conditions, 
percolate  outward,  for  the  silty  matters  deposited  in  its  flow  clog  the 
interstices  in  the  soil  of  its  bed  and  banks,  and  act  as  a  valve  against 
its  egress.  The  ground-water,  flowing  to  the  river,  finds  its  way  in 
through  the  silt,  which  gives  way  inward  against  the  side  of  least 
resistance.  Thus  the  silt  yields  to  ingress,  and  is  a  bar  to  egress 
of  water. 

^  Edinborough  Medical  Journal,  Nov.,  1894. 


CLASSIFICATION  OF   WATERS.  347 

The  fact  that  the  flow  of  ground-water  is  toward  rather  than  away 
from  rivers  and  other  large  bodies  of  water  is  well  shown  by  the  fact 
that  fresh  water  is  obtainable  from  wells  sunk  in  close  proximity  to 
high-water  mark  on  the  sea-coast.  Such  may  be  not  even  slightly 
brackish,  although  sometimes  they  are  distinctly  so  by  backward  diffu- 
sion of  the  salts.  In  the  latter  case,  removal  a  short  distance  back- 
ward obviates  the  difficulty. 

That  the  water  derived  from  a  filter  gallery  is  not  due  to  percolation 
from  the  river  along  which  it  lies,  is  farther  proved  by  the  fact  of  dif- 
ference in  composition,  and  especially  in  hardness. 

Classification  of  Waters  from  the  Sanitary  Standpoint. 

From  the  standpoint  of  wholesomeness,  waters  may  be  divided  into 
two  classes :  1.  Those  free  from  sewage  contamination.  2.  Those 
polluted  by  sewage. 

Unpolluted  waters  are  not  necessarily  suitable  for  domestic  use,  pre- 
senting as  they  do,  wide  variations  in  character.  They  may  be  clear, 
colorless,  odorless,  and  palatable,  and  contain  but  little  organic  and 
mineral  matter ;  or  they  may  have  high  color,  turbidity,  disagreeable 
odor  and  taste,  and  a  high  content  of  dissolved  and  suspended  sub- 
stances. A  water  which,  by  reason  of  appearance,  odor,  and  taste,  due, 
for  instance,  to  luxuriant  growth  of  algae  or  other  forms  of  life,  is 
repugnant  to  the  senses,  should  not  be  recommended  for  use,  although 
incapable  of  producing  a  specific  disease.  Such  an  one  requires  no 
chemical  analysis  to  determine  its  fitness,  the  evidence  of  the  senses 
being  quite  sufficient. 

Unpolluted  waters  free  from  such  qualities  as  render  them  repug- 
nant to  the  senses,  and  of  low  content  of  organic  and  mineral  matters, 
are  suitable  for  general  purposes  without  regard  to  their  classification 
as  surface-  or  soil-waters.  But,  in  general,  it  is  held  commonly  that 
an  unpolluted  soft  ground- water  of  good  composition  is  preferable  to 
one  of  surface  origin. 

Polluted  waters  may  be  divided  into  two  classes,  according  as  the 
pollution  is  direct  or  indirect.  Direct  pollution  by  sewage  is,  it  is 
hardly  necessary  to  say,  of  prime  importance,  because  of  the  danger  of 
transmission  of  specific  diseases  and  of  lowering  the  physiological  re- 
sistance of  the  system.  But  even  direct  pollution  may  be  productive 
of  no  harmful  results,  provided  sufficient  time  elapses  between  the 
entrance  of  the  sewage  at  a  given  point  and  the  use  of  the  water  at  a 
distance  to  permit  of  the  disposal  of  the  noxious  elements  by  natural 
processes.  Thus,  a  volume  of  sewage  entering  the  upper  part  of  a 
large  system  of  public  supply  may  not  reach  the  distributing  pipes  for 
several  months,  during  which  time  its  dangerous  qualities  will  have 
di.sap])eared.  Notwithstanding  this  fact,  however,  direct  pollution  of 
drinking-water  should  be  prevented  by  all  means  available,  on  account 
of  possible  risk,  and  even  on  aesthetic  grounds  alone. 

Indirect  pollution  is  of  far  less  importance  than  direct.     In  indirect 


348  WATER. 

pollution  the  organic  matters  of  the  sewage,  including  bacteria,  are  filt- 
ered through  the  soil,  in  which  they  are  held  back  mechanically  and 
more  or  less  completely  oxidized  before  the  containing  water  reaches 
its  ultimate  destination.  As  to  what  may  be  called  a  safe  limit  of  dis- 
tance from  sources  of  pollution,  no  fixed  rule  can  be  given  :  each  case 
must  be  judged  according  to  its  circumstances.  The  soil  as  a  whole 
has  enormous  capacity  for  purifying  water  of  its  contained  organic 
substances  and  bacteria,  both  by  mechanical  retention  and  by  oxidation 
processes  set  in  motion  by  the  bacteria  which  inhabit  it.  But  all  soils 
have  not  this  power  in  an  equal  degree,  and  the  conditions  favorable  to 
its  exercise  are  not  always  present  to  the  same  extent.  The  soils  most 
favorable  for  perfect  filtration  and  purification  are  sandy  and  gravelly  ; 
in  these,  the  water  is  exposed  in  thin  layers  on  the  individual  grains  to 
the  air  in  the  interstices.  The  latter  should  be  neither  too  coarse  nor 
too  fine.  If  too  coarse,  the  passage  of  water  is  too  rapid  ;  if  too  fine, 
not  sufficient  air  can  be  present  at  the  same  time.  The  organisms  are 
found  only  in  the  upper  few  feet  of  soil,  and  it  is  here  also  that  the  con- 
tained air  is  richest  in  oxygen.  When  the  necessary  conditions  for 
filtration  are  present  in  a  given  soil,  the  water  which  percolates  through 
and  reaches  the  ground-water  is  quite  free  from  bacteria  of  any  kind, 
even  though  the  surface  is  contaminated  extensively.  Where  the  soil 
is  very  open  and  permeable  to  water  or  fissured,  polluting  materials 
may  pass  through  so  rapidly  that  they  undergo  but  slight  change  on  the 
way,  while  with  a  not  too  fine  soil,  through  which  water  passes  with 
slowness,  purification  by  bacterial  action  may  be  completed  within  a 
very  short  distance. 

Again,  there  may  be  greater  safety  at  a  point  quite  near  to,  but  on 
one  side  of  a  center  of  pollution,  than  at  another  at  a  considerable 
distance  away  on  the  other  side,  owing  to  the  direction  of  the  flow  of 
water.     Thus,  in  Fig.  32,  the  point  S,  located  quite  near  the  point  of 

Fio.  32. 


©  —     —  0-0 


entrance  of  the  polluting  material  P  into  the  soil,  is  far  better  situated 
in  respect  to  possible  contamination  of  water  by  P,  than  the  point  D 
on  the  other  side  but  farther  away,  since  the  movement  of  the  water  in 
the  soil  is,  as  indicated  by  the  arrows,  from  S  toward  D,  and  all 
impurities  entering  between  the  two  move  from  the  one  toward  the  other. 
Similarly,  the  point  S  may  stand  in  the  relation  of  point  D  to  some 
other  polluting  influence. 

For  the  determination  of  the  question  whether  a  given  well  is 
receiving  pollution  from  any  given  point,  recourse  is  had  to  the  diffusi- 
bility  of  coal-tar  colors,  such  as  fluorescein.  An  ounce  of  this  sub- 
stance will   impart  a   very  decided  color  to  an  enormous  volume  of 


PURIFICATION  OF   WATER.  349 

water ;  and  when  it  is  added  to  the  contents  of  a  leaching  cesspool,  it 
will  accompany  the  escaping  pollution  and  reveal  to  the  eye  the  presence 
of  the  latter  in  any  neighboring  well-water.  Pollution  may  thus  be 
traced  sometimes  through  hundreds  of  feet  of  fairly  close  soil. 

Purification  of  Water. 

Before  proceeding  to  the  consideration  of  methods  employed  to  bring 
about  purification  of  water  supplies,  a  few  words  are  necessary  on  the 
subject  of  "  self-purification  "  of  surface-waters.  A  river  shows,  for 
instance,  at  a  given  point  in  its  course  a  certain  amount  of  impurity ; 
at  another  point  farther  down,  this  is  found  to  be  considerably  lessened  ; 
and  farther  yet,  the  diminution  is  still  more  marked.  This  progressive 
lowering  is  attributed  to  the  property  the  water  possesses  of  bringing 
about  its  own  purification.  The  practical  beginning  of  this  theory  was 
the  assertion,  made,  in  1869,  by  the  British  Royal  Commission  on 
Water  Supplies,  that  sewage,  diluted  twenty  times  or  more  by  river- 
water  into  which  it  is  discharged,  will  be  completely  oxidized  before  it 
has  travelled  more  than  a  dozen  miles.  Two  years  later,  the  Rivers 
Pollution  Commission  reported  strongly  against  accepting  this  idea,  and 
concluded  that  oxidation  proceeds  with  such  extreme  slowness,  even 
when  the  polluting  matters  are  diminished  very  largely  by  pure  water, 
that  not  only  will  a  flow  of  a  dozen  miles  not  suffice,  but  that  there  is 
no  river  in  the  United  Kingdom  sufficiently  long  to  accomplish  the 
result  claimed.  It  was  then  believed  that  whatever  changes  occur  are  the 
combined  result  of  oxidation  and  subsidence.  It  is  now  recognized  that 
these  agencies,  assisted  by  more  important  ones,  namely,  dilution,  vege- 
tation, and  bacterial  action,  do  in  many  cases  produce  very  great 
changes,  while  in  others  the  results  are  only  partial  and  of  no  especial 
value.  Drs.  R.  Emmerich  and  F.  Brunner  ^  showed  that  in  spite  of  the 
large  amount  of  sewage  matters  poured  into  the  Isar  in  its  course 
through  Munich,  the  water  after  two  hours'  flow  below  the  city  was 
practically  as  pure  chemically  as  it  was  before  it  reached  it.  Jordan  ^  has 
shown  that,  after  thirty-four  miles'  flow,  the  Illinois  River  is  practically 
free  from  sewage  bacteria.  E.  Duclaux  ^  has  shown  the  same  to  be 
true  of  the  Seine,  and  other  observers  have  proved  it  of  certain  other 
rivers  in  England,  Germany,  and  elsewhere.  On  the  other  hand,  oppo- 
site results  have  been  obtained  by  other  workers  in  the  same  field. 

Oxidation  undoubtedly  plays  a  more  or  less  important  part  in  some, 
but  by  no  means  in  all,  cases.  Dr.  T.  Meymott  Tidy  proved  experi- 
mentally that  water  containing  sewage  could  lose  about  half  its 
organic  matter  in  from  six  to  nine  hours  when  made  to  run  one  mile 
in  glass  troughs  with  abundant  aeration.  Professor  William  P.  Mason,* 
on  the  other  hand,  agitated  water  in  a  bottle  fastened  to  the  connecting 
rod  of  a  horizontal  engine  with  a  ten-inch  stroke  of  75  to  the  minute, 

'  Die  cliemisclien  Verilnderiingen  des  Isarwassers,  Munich,  1878. 

^  .Joiimal  of  Kx])eriinental  Medicine,  Dec,  1900,  p.  271. 

•■'  AniiJiles  de  I'lnstilut  Pasteur,  1894. 

*  Water  Supply,  New  York,  1897,  p.  175. 


350  WA  TER. 

and  found  that  after  9,000  concussions  there  was  but  a  trifling  diminu- 
tion in  the  amount  of  organic  matter.  A  large  measure  of  purification, 
so  far  as  numbers  of  bacteria  are  concerned,  is  caused  by  agitation 
when  there  are  solid  particles  in  suspension  in  the  water.  This  has 
been  well  shown  by  Percy  Frankland/  who  observed  a  decrease  of 
96.65  per  cent,  in  the  number  of  bacteria. 

Dilution  by  access  of  rain,  melting  snow,  ground-water,  and  other 
clean  influents,  aflFects  chemical  composition  favorably,  but  assists,  for  a 
time  at  least,  increase  in  the  numbers  of  pathogenic  and  other  bacteria. 
Professor  Kebrehl's  ^  daily  bacteriological  examinations  of  river-water 
at  Prague  proved  that,  in  general,  the  number  of  bacteria  increases  with 
rising  water,  and  is  subject  to  very  wide  variations,  due  to  a  number 
of  causes,  among  which  he  mentions  changes  in  the  rate  of  flow,  with 
consequent  alteration  of  conditions  influencmg  sedimentation,  and  the 
influx  of  temporary  pollutions,  such  as  washings  from  streets  and  dung- 
heaps,  which,  under  some  circumstances,  have  greater  influence  than 
the  regular  unclean  influents. 

Sedimentation,  which  formerly  was  believed  to  play  a  very  great 
part  in  the  improvement  of  river-waters,  acts  to  only  a  slight  extent  in 
those  which,  like  the  Isar,  move  swiftly.  It  is  favored  by  slowing  of 
the  current,  especially  at  the  river  mouth  ;  and  when  it  occurs  it  has  a 
very  marked  influence  on  the  number  of  bacteria,  especially  if  the  water 
be  muddy.  This  has  been  shown  by  Bruno  Kriiger,-*  who,  by  a  series 
of  experiments,  proved  that  chemically  indifferent  substances  in  a  state 
of  minute  subdivision  exert  a  greater  influence,  the  more  slowly,  up  to  a 
certain  limit,  they  settle  ;  w^hile  other  matters,  which  act  both  mechanic- 
ally and  chemically,  such  as  Kme  and  hard  wood  ashes,  produce  still 
greater  effects.  In  still  water,  as  small  lakes  and  ponds,  sedimentation 
goes  on  unobstructed. 

Bacterial  action  as  a  purifying  agent  is  favored  by  alkalinity  and 
retarded  by  acidity.  It  may  be  important  or  not,  according  to  circum- 
stances. Destruction  of  pathogenic  species  by  the  saprophytic  class  is 
delayed  by  dilution  by  unpolluted  water,  which,  as  above  stated, 
favors  their  increase  for  a  short  time,  after  which  they  rapidly  decline 
in  number. 

Vegetation  was  not  taken  into  account  by  the  earlier  observers,  but 

has  now  been  placed  at  the  head  of  the  important  influences  in  the 

process.     Pettenkofer  *  asserted  that  the  greater  part  of  self-purification 

is  due   to  the  growth  of  algse   and  other  low  forms  of  vegetable   life, 

which  clean  the  water  of  its  impurities  in  the  same  way  that  the  higher 

forms  take  up  and  dispose  of  the  manurial  matters  of  cultivated  land. 

This   view  is   endorsed  by  T.  Bokorny,^  who  proved  that   these  plants 

^  Joviraal  of  State  Medicine,  Jamiaiy,  1894. 

^  Bacteriologische  unci  kritische  Studien  iiber  die  Verunreinigung  und  Selbstreini- 
gung  der  Fliisse.     Archiv  fiir  Hygiene,  XXX.,  p.  32. 

*  Die  physikalische  Einwirkung  von   Sinkstoffen  auf  die  im  Wasser  befindlichen 
Mikroorganisraen.     Zeitschrift  fiir  Hygiene,  VII.,  p.  86. 

*  Znr  Selbstreinigung  der  Fliisse.     Archiv  fiir  Hygiene,  XII.,  p.  269. 

^  Ueber  die  Betheiligung  chlorophyllfiihrender  Pflanzen  an  der  Selbstreinigung  der 
Fliisse.     Archiv  fiir  Hygiene,  XX.,  p.  181. 


PURIFICATION  OF   WATER.  351 

take  up  all  manner  of  organic  substances,  including  volatile  fatty  acids, 
amido  acids,  glucose,  and  urea.  He  showed  that  the  water  of  the  Isar 
contains  vast  numbers  of  alg£e,  to  whose  action  much  of  the  changes 
noted  by  Emmerich  and  Brunner  were  undoubtedly  due. 

Methods  of  Purification. — The  methods  employed  for  the  purifica- 
tion of  water  embrace  : 

1.  Chemical  treatment. 

2.  Boiling  and  distillation. 

3.  Filtration. 

1.  Chemical  treatment  is  employed  to  cause  the  formation  of  insolu- 
ble precipitates,  which  settle  out  and  entangle  suspended  matters,  in- 
cluding bacteria,  in  their  descent. 

Alum,  for  instance,  added  to  the  extent  of  a  quarter  of  a  grain 
to  a  grain  per  gallon  of  natural  water  containing  a  moderate  amount 
of  CaCOg,  is  decomposed,  and  forms  an  insoluble  gelatinous  hydrate^ 
which  combines  with  the  organic  matters  imparting  color  and  set- 
tles out  as  a  flocculent  precipitate,  which  entangles  the  suspended 
matters,  including  the  bacteria.  The  sulphuric  acid,  set  free  by  the 
decomposition  of  the  salt,  unites  with  the  lime  or  other  bases  present,^ 
and  is  thus  neutralized,  and  the  calcium  sulphate  thus  formed  carries 
down  suspended  matters  in  the  same  manner.  If  an  excess  of  alum  is 
added,  it  will  necessarily  appear  in  the  purified  water,  and  be  objection- 
able on  account  of  its  eifect  on  the  system,  and  in  the  bath  and  in 
washing. 

In  case  of  deficiency  in  CaCO^,  lime-water  sometimes  is  supplied^ 
and  identical  results  obtained.  The  addition  of  freshly  precipitated 
alumina  serves  the  purpose  equally  well,  and  avoids  the  presence  of  the 
sulphuric  acid  resulting  from  the  decomposition  of  alum. 

Alum  removes  practically  all  the  bacteria,  as  has  been  proved  by  V. 
and  A.  Babes,^  Professor  E.  Ray  Lankester,  and  others.  The  use  of 
alum  in  the  purification  of  water  is  not  of  recent  origin  :  it  was  de- 
scribed as  early  as  1830  by  Felix  d'Arcet,^  who  mentions  its  extensive 
use  in  Egypt. 

Lime-water  or  milk  of  lime,  added  to  water  containing  calcium  car- 
bonate held  in  solution  by  carbon  dioxide,  causes  precipitation  of  the 
former  by  uniting  with  the  latter.  It  thus  withdraws  the  solvent  from 
active  service,  causes  precipitation  of  that  which  was  held  in  solution, 
and,  becoming  itself  converted  to  an  insoluble  substance,  is  precipitated. 
So  a  double  precipitation  occurs.  But  water  thus  treated  is  not  neces- 
sarily limited  in  its  changes  to  a  removal  of  its  excess  of  calcium  car- 
bonate, for,  in  the  precipitation  of  this  substance,  considerable  other 
matter  may  be  carried  down  mechanically,  and  bacteria  are  lessened 
decidedly  in  number. 

Permanganate  of  potassium  is  used  more  or  less,  particularly  in  wells 
in    India  during    tli(;   prevalence  of    cholera   epidemics.     Enough    is 

'  Cy-ntiMRihitt  fiir  Ji!iktcrioloj(ie  iind  Parasitenkundc,  li)02,  XIL,  p.  45. 
'  Note  relative  a  la  clarification  de  I'eau  dn  Nil,  et  en  g(5neral  des  eaux  contenant 
(les  substances  terreuses  en  suspension.     Annales  d'llygiene  pidjlique,  IV.,  p.  375 


352  WATER. 

added  to  secure  a  slight  pink  tinge,  which  indicates  a  slight  excess. 
This  acts  as  an  oxidizing  agent  with  good  results.  For  example,  Dr. 
P.  W.  O'Gorman  ^  relates  that  during  an  outbreak  at  Midnapore,  the 
number  of  cases,  117,  was  supposed  to  have  been  kept  down  by  its 
use.  These  occurred  in  all  parts  of  the  town,  excepting  in  the  Euro- 
pean quarter  and  at  the  jail.  The  former  used  water  which  was 
filtered  or  boiled  and  filtered,  and  at  the  jail  especial  care  was  taken  of 
the  water  supply.  Forty-six  public  and  private  wells  were  disinfected 
with  the  salt,  and  the  outbreak  thereupon  ceased.  An  ounce  or  ounce 
and  a  half  or  more,  according  to  the  size  of  the  well,  was  dissolved  in 
a  bucket,  poured  into  the  well,  and  stirred  about.  If  after  half  an 
hour  the  water  showed  a  red  tinge,  it  was  considered  that  enough  had 
been  added  ;  if  not,  more  was  added  until  a  tinge  was  seen.  Accord- 
ing to  Hankin,^  enough  of  the  salt  to  insure  a  reddish  tint  lasting 
twenty-four  hours  should  be  added  ;  but  care  should  be  taken  not 
to  add  so  much  that  fish,  frogs,  and  turtles,  put  into  wells  to  keep  the 
water  clean,  are  killed  and  the  water  spoiled  by  their  putrefaction. 
Dhiugra  ^  states  that  this  method  can  be  relied  upon  only  under  cer- 
tain conditions,  and  even  then  its  action  is  not  continuous.  The  agent 
must  expend  itself  first  in  oxidizing  organic  matter  and  nitrites  before 
attacking  organisms,  which,  for  their  destruction,  require  it  in  fairly 
strons:  solution.  He  believes  the  method  to  be  fallacious  in  theorv, 
defective  m  techuic,  and  impossible  of  practical  application. 

Sodium  hypochlorite,  "  chlorinated  soda,"  and  chlorinated  lime, 
^'  chloride  of  lime,"  are  sometimes  used,  but  in  the  case  of  both  not 
Avithout  great  risk  of  imparting  disagreeable  taste.  Moritz  Traube  * 
gives  a  simple  method  of  purification  by  means  of  the  latter  agent, 
which,  added  to  the  extent  of  less  than  half  a  gram  to  a  hundred  liters, 
kills  all  bacteria  within  two  hours.  The  excess  of  the  agent  is  neu- 
tralized by  the  addition  of  somewhat  less  than  half  the  amount  of  sul- 
phite of  sodium,  which,  added  somewhat  in  excess,  does  no  harm, 
since  it  is  soon  oxidized.  The  assertion  is  made  that  water  thus  treated 
possesses  no  disagreeable  taste  and  has  its  hardness  not  appreciably 
increased. 

The  "  Woolf"  method  consists  in  adding  a  2  to  3  per  cent,  solution 
of  salt  decomposed  by  a  current  of  electricity  of  sufficient  strength. 
This  is  equivalent  to  adding  the  sodium  hypochlorite  itself,  which 
agent,  according  to  Hiinermann  and  Deiter,^  can  destroy  in  ten 
minutes  all  typhoid,  cholera,  and  coli  organisms  contained  in  a  liter  of 
water,  when  enough  is  employed  to  give  40  milligrams  of  eflFective 
chlorine.  The  sodium  compound  is  more  efficient  than  chloride  of 
lime,  for  the  whole  of  its  available  chlorine  is  almost  instantly  dif- 
fused through  the  water  and  acts  at  once.  After  purification,  the 
chlorine  is  neutralized  by  means  of  sodimn  sulphite  (140  of  sulphite  to 

^  Indian  Medical  Gazette,  July,  1896. 

2  Ibidem,  July,  1896. 

^  British  Medical  Journal,  Aug.  17,  1901. 

*  Zeitschrift  fiir  Hygiene  und  Infectionski-ankheiten,  XVI.,  p.  149. 

°  Deutsche  medicinische  Wochenschrift,  1901,  p.  391. 


PURIFICATION  OF  WATER.  353 

40  of  chlorine),  and  the  water  is  then  practically  unaltered  in  appear- 
ance, taste,  smell,  and  hardness,  but  only  when  the  amounts  of  the 
compounds  to  be  added  have  been  most  carefully  determined. 

Chlorine  as  such  is  used  also  to  some  extent ;  but,  although  eifective, 
it  is  open  to  the  objections  that  apply  to  the  use  of  the  hypochlorites, 
of  which  it  is  the  active  agent. 

Bromine  also  has  its  advocates  as  a  chemical  purifier,  both  on  a 
small  and  on  a  large  scale.  Schumburg  ^  recommends  a  process  which 
is  said  to  kill  in  five  minutes  nearly  all  of  the  ordinary  bacteria  and 
all  pathogenic  organisms  found  in  water.  He  uses  a  solution  of 
20  parts  each  of  bromine  and  potassic  bromide  in  100  of  water,  1  cc. 
of  which  suffices  to  sterilize  5  liters  of  Spree  water.  After  five  minutes' 
contact,  the  bromine  is  neutralized  with  ammonia,  and  the  result  is  a 
clear,  tasteless,  sterile  water.  Very  hard  waters  and  grossly  polluted 
river  and  marsh  waters  require  larger  amounts,  because  of  the  presence 
of  lime  salts  in  the  former  and  of  ammonia  in  the  latter,  which  com- 
bine with  the  bromine  before  it  has  opportunity  to  act  as  a  germicide. 
With  such  waters  it  is  necessary  to  add  enough  of  the  solution  to 
produce  a  yellow  tinge  which  will  persist  at  least  half  a  minute.  In 
any  case,  whatever  the  amount  of  the  bromine  solution  used,  an  equal 
volume  of  9  per  cent,  ammonia  water  should  be  added.  (In  a  later 
communication,  sodium  sulphite  is  recommended.)  This  process  is 
recommended  particularly  for  use  in  the  army,  and  in  the  tropics,  for 
ships'  supplies,  and  for  individual  use  in  times  of  epidemics.  A  kilo- 
gram of  bromine  is  said  to  suffice  to  sterilize  16,000  liters  of  ordinary 
water.  In  practice,  however,  the  process  has  not  met  with  a  large 
measure  of  success.  Schiider  ^  has  tried  the  scheme,  and  finds  it  unre- 
liable. It  was  tested  in  the  Soudan  Expedition  in  1898,  but  the 
difficulties  attending  its  use  were  enough  to  lead  to  its  abandonment. 

Treatment  with  metallic  iron  in  the  form  of  borings  and  punchings 
is  employed  in  a  number  of  places  in  Europe  with  most  successful 
results.  The  best  known  of  the  processes  in  which  this  agent  is 
employed  is  that  of  Anderson,  in  which  the  water  is  delivered  into 
long  iron  cylinders,  on  the  inner  surface  of  which  are  curved  partial 
diaphragms  which,  as  the  apparatus  slowly  revolves,  carry  upward  the 
pieces  of  iron,  which  fill  about  a  tenth  of  the  volume  of  the  cylinder, 
and  cause  them  to  shower  constantly  downward  through  the  water  in 
its  passage.  The  carbon  dioxide  in  the  water  attacks  the  iron  and 
forms  ferrous  carbonate,  which,  when  the  water  is  discharged  into  the 
open  air,  V)ecomes  oxidized  and  converted  to  ferric  hydrate.  This  floc- 
culent  matter  entangles  much  of  the  organic  matters,  including  the 
bacteria,  and  then  the  whole  is  passed  through  sand  filters,  the  effluent 
from  which  is  very  pure  and  practically  sterile.  The  process  is  unneces- 
sarily expensive,  involving  as  it  does,  in  addition  to  the  first  cost  of 
the  ])]ant,  considcii'uble  outlay  for  power  and  other  items,  while  the  same 
results  in  the  end  ]nay  be  obtained  by  the  more  simple  process  of  sand 

'  Deutsche  medicinische  Wochenschrift,  March  4,  1897. 

'  ZeitHchrift  fur  Hygiene  mi.l  liifcctionsknmkheiten,  XXXVII.  (190]),  p.  307. 
2.", 


354  WATER. 

filtration  alone.  Moreover,  it  appears  that  with  peaty  waters,  the 
organic  constituents  of  which  form  soluble  compounds  with  the  iron,  the 
results  are  unsatisfactory. 

The  use  of  ozone  has  been  recommended  as  a  very  efficient  method 
of  sterilizing  drinking-water,  and  experiments  on  a  large  scale  have 
yielded  favorable  results.  Experimenting  on  very  small  quantities 
with  a  Siemens-Halske  apparatus,  Weyl  ^  found  that  2.3  milligrams  of 
ozone  were  sufficient  to  destroy  99  per  cent,  of  the  bacteria  contained 
in  200  cc.  of  water  from  the  Tegel  Lake.  With  3  and  4  milligrams, 
he  obtained  complete  sterilization  of  0.5  liter  of  water  containing  6,000 
bacteria  to  the  cc.  For  purification  on  a  large  scale,  the  impure  water 
is  caused  to  percolate  through  a  tower  filled  with  pebbles,  through 
which  the  ozonized  air  passes  upward.  The  Siemens-Halske  apparatus 
used  wall  produce  20  grams  of  ozone  in  an  hour.  The  bacteria  are 
reduced  at  least  99  per  cent,  and  the  percentage  of  organic  matter  is 
greatly  diminished,  but  the  process  is  at  present  very  imperfect,  for 
more  than  70  per  cent,  of  the  ozone  produced  is  lost.  The  ozonized 
water,  althoagh  free  from  odor,  has  an  unpleasant  taste,  and  with  many 
persons  its  use  causes  derangement  of  the  stomach.  This  fault  neces- 
sitates further  electrolytic  treatment  with  alumiinmi  electrodes,  whereby 
aluminum  hydrate  is  formed  and  the  water  is  clarified  and  freed  from 
ozone. 

Sodium  bisulphate  has  been  recommended  by  Parkes  and  Rideal  ^  in 
the  proportion  of  15  grains  to  the  pint.  They  state  that  B.  typhosus 
is  killed  within  five  minutes,  but  recommend  a  contact  of  fifteen  min- 
utes, in  order  to  insure  sterility.  Warner^  has  found  that  this  is 
sufficient  to  cause  a  striking  reduction  in  the  number  of  added  germs^ 
but  not  complete  sterilization.  In  most  cases,  B.  typhosus  is  destroyed 
in  thirty,  and  B.  cholerce  in  ten,  minutes.  Contrary  to  the  statement 
that  the  agent  imparts  an  agreeable  acid  taste,  Warner  finds  that  to 
some  persons  the  taste  is  unpleasant,  and  to  all  would  probably  become 
irksome.  Moreover,  a  person  consuming  5  pints  of  water  in  a  day 
would  swallow  75  grains  of  the  salt,  which  would  tend  to  increase 
rather  than  to  quench  thirst. 

Chemical  purification  of  water  sometimes  occurs  without  the  inter- 
vention of  processes  especially  provided,  of  which  fact  Professor  Leff- 
mann  *  records  a  conspicuous  instance.  The  Schuylkill  River  in  the 
upper  part  of  its  course  receives  much  refuse  mine-water,  and  becomes 
impregnated  with  iron  salts  and  free  mineral  acids.  "  In  its  course  of 
about  one  hundred  miles  it  passes  over  an  extensive  limestone  district, 
and  receives  several  large  streams  highly  charged  with  calcium  car- 
bonate. The  result  is  a  neutralization  of  the  acid  and  a  precipitation 
of  the  iron  and  much  of  the  calcium.  The  river  becomes  purer,  and 
at  its  junction  with  the  Delaware  River,  at  Philadelphia,  it  contains 

^  Centrablatt  fiir  Bakteriologie,  XXVI. 

^  Transactions  of  the  Epidemiological  Society,  London,  XX.,  1900-1901. 

»  Public  Health,  July,  1901,  p.  700. 

*  Examination  of  Water  for  Sanitary  and  Technic  Purposes,  Phila.,  1895,  p.  14. 


DOMESTIC  FILTERS.  355 

neither  free  sulphuric  nor  hydrochloric  acid,  only  traces  of  iron,  and 
but  a  small  amount  of  calcium  sulphate.  In  this  manner  there  is  pro- 
duced a  soft  water,  superior  to  that  of  the  river  near  its  source,  or  to 
the  hard  waters  of  the  middle  Schuylkill  region." 

2.  Boiling  and  Distillation. — Boiling  as  a  means  of  purification  has 
been  practised  from  very  early  times,  and,  in  fact,  was  advised  by  Hip- 
pocrates (460—377  B.  c. )  for  the  avoidance  of  enlargement  of  the  spleen. 
This  process  is  quite  etticient  so  far  as  destruction  of  the  micro-organ- 
isms is  concerned,  but  it  does  not  diminish  the  amount  of  organic 
matter.  It  does,  however,  reduce  the  amount  of  dissolved  mineral 
matter,  in  that  calcium  carbonate  held  in  solution  by  carbon  dioxide 
is  precipitated,  and  calcium  sulphate,  being  less  soluble  in  hot  than  in 
cold  water,  tends  to  separate  <5ut.  Boiling  is  available  only  to  a 
limited  extent ;  that  is,  it  is  a  process  which  can  be  carried  out  in  the 
household,  but  not  on  a  large  scale  before  public  distribution  of  water. 
Boiled  water  is  not  palatable  until  aeration  has  restored  the  proper 
taste,  but  this  is  easily  accomplished  by  passing  it  from  one  vessel  to 
another,  or  by  agitation  in  contact  with  air. 

Distillation  constitutes  a  most  efficient  process  for  obtaining  pure 
water.  This  process  produces  necessarily  a  sterile  water,  which,  how- 
ever, needs  thorough  aeration.  In  the  apparatus  used  in  the  United 
States  Navy,  the  steam  goes  to  the  condensers  in  company  with  air,  so 
that  condensation  and  aeration  occur  coincidently.  While  no  bacteria 
from  the  original  water  can  pass  over  into  the  distillate,  other  volatile 
matters  can  and  do,  and  instances  are  common  to  prove  that  the  dis- 
tillate of  a  foul  harbor  water  may  produce  nausea  and  diarrhoea  in  all 
who  drink  it. 

3.  Filtration  is  a  process  of  purification  which  is  most  efficient  and 
available  for  large  water  supplies.  It  is  employed  on  an  extensive  scale 
by  numerous  large  cities  in  Europe  and  in  this  country.  Before  describ- 
ing the  process,  however,  it  is  in  order  to  consider  filtration  in  the 
household. 

DOMESTIC   FILTERS. 

The  domestic  filters  in  common  use  are,  as  a  rule,  useless  except  for 
the  removal  of  suspended  matters,  such  as  iron-rust,  dirt,  and  other 
coarse  particles,  and  worse  than  useless  in  respect  of  bacteria,  the  re- 
moval of  which  is  claimed  but  not  accomplished,  in  that  they  engender 
a  false  sense  of  safety,  while  they  favor  the  growth  and  multiplication 
of  organisms.  Most  of  them  are  small  affairs  for  attachment  to  a 
water  faucet,  filled  with  a  filtering  medium  of  coarse  sand,  animal  char- 
coal, sponge,  ground  glass,  wool,  felt,  and  other  substances  which  strain 
out  the  visible  suspended  matters  not  a  whit  better  than  the  simple 
flannel  bag  in  common  use  in  New  England  and  elsewhere  a  quarter  of 
a  century  ago.  They  permit  the  passage  of  a  good  stream,  and  this  fact 
itself  is  prf)of  of  their  inefficiency  as  bacteria  filters,  for  any  material 
suffi(;iently  coarse  to  permit  ra]»id  passage  of  water  is  not  sufficiently 
fine  to  hold  back  such  exceedingly  minute  suspended  matters  as  bacteria. 


356 


WATER. 


Fig.  33. 


Chamberland-Pasteur  filter. 


Most  of  the  materials  used  become  very  foul  in  a  short  time,  and  in 
consequence  the  water  is  richer  in  bacteria  on  issuing  than  it  was 
before  entrance.  Theoretically,  animal  charcoal, 
on  account  of  its  oxidizing  action,  should  be  an 
ideal  filtering  medium,  and  at  first  it  will  re- 
move a  large  proportion  of  the  bacteria  and  more 
or  less  of  any  coloring  matters.  But  very  shortly 
it  becomes  foul ;  the  calcium  phosphate  which 
it  contains  is  of  great  assistance  to  the  growth  of 
bacteria ;  cleaning  is  impossible,  and  the  effluent, 
if  stored,  soon  becomes  very  foul  and  unpleasant. 
The  only  domestic  filters  worthy  of  the  name 
are  those  which  remove  mechanically  all  the 
bacteria  of  the  water  and,  at  the  same  time,  add 
nothing  of  their  own  substance  to  the  water. 
Such  are  the  Chamberland-Pasteur,  the  Berke- 
feld,  and  others  based  on  the  same  principle. 
In  these,  the  filtering  medium  is  unglazed,  well- 
baked,  hollow,  porcelain  cylinders  closed  at  one 
end  like  a  test-tube,  enclosed  within  a  metallic 
or  glass  jacket,  with  sufficient  intervening  space 
for  the  water,  which  enters  directly  from  the  tap 
under  its  usual  pressure  or  "  head."  The  open  lower  end  of  the 
■cylinder  discharges  the  water,  which  passes  directly  through  the  walls 
of  the  cylinders,  or  "  bougies,"  in  the  same  way  in  which  it  would  go 
through  blotting-paper.  The  material  is  such  a  very  fine  strainer  that 
it  excludes  all  suspended  matters  whatsoever.     (See  Fig.  33.) 

The  bougies  of  the  Chamberland-Pasteur  filter  are  made  of  well- 
baked  kaolin  of  the  proper  degree  of  porosity  and  hardness ;  formerly 
those  of  the  Berkefeld  filter  were  made  of  a  soft  friable  infusorial  earth 
peculiar  to  Germany,  called  Kieselguhr,  but  as  they  were  very  brittle 
and  very  liable  to  fracture  while  being  cleaned,  they  are  now  made  of 
a  special  blend  of  clays  used  in  the  manufacture  of  the  finest  porcelain. 
Bougies  of  other  makes  are  of  porcelain  of  varying  grades. 

All  these  filtering  tubes  are.  purely  mechanical  in  their  action,  and 
remove  none  of  the  matters,  poisonous  or  otherwise,  in  solution. 
While  they  remove  and  retain  on  their  external  surface  all  the  bacteria, 
they  cannot  prevent  the  growth  of  the  organisms  from  without  inward 
through  their  walls,  and,  indeed,  this  occurs  so  quickly  that,  in  order 
to  secure  absolutely  sterile  water  continuously,  it  is  necessary  to  clean 
and  sterilize  the  bougies  daily,  and  thus  it  is  advisable  to  have  two 
sets,  one  of  which  can  be  cleaned  while  the  other  is  in  use. 

It  has  been  proved  repeatedly  that  normal  water  and  water  artifi- 
cially and  extensively  infected  will  yield  on  the  first  day  of  the  use  of  a 
clean  bougie  a  perfectly  sterile  filtrate,  and  that  on  the  second  or  third 
day  a  very  small  number  of  bacteria  will  most  likely  be  present ;  but 
these  are  invariably  ordinary  water  bacteria,  and  if  the  pathogenic 
varieties  occur  in  the  filtrate,  they  come  considerably  later.     Repeated 


FILTRATION  OF  PUBLIC  SUPPLIES.  357 

experiments  with  water  infected  with  B.  coli  eommunis,  B.  typhosus^ 
and  B.  cholene  have  failed  to  prove  the  passage  of  any  of  these  organ- 
isms, while  the  ordinary  water  bacteria  go  through  very  readily.  To 
secure  a  regular  supply  of  wholesome  if  not  completely  sterile  water, 
it  is,  therefore,  sufficient  to  clean  the  tubes  by  scrubbing  and  boiling 
or  by  baking  about  twice  a  week.  It  appears,  however,  that  the 
Chamberland-Pasteur  and  Berkefeld  bougies  are  not  equal  in  efficiency,, 
for  Horrocks  ^  has  succeeded  in  growing  B.  typhosus  through  the  walls, 
of  the  latter.  He  attributes  this  result  to  the  larger  size  of  the  lacunar 
spaces  and  to  the  consequently  diminished  immobilizing  and  devitalizing 
influences.  Since  the  shortest  time  required  for  the  bacilli  to  traverse 
the  bougie  is  four  days,  sterilization  by  means  of  boiling  water  should 
be  carried  out  every  three  days,  in  order  to  insure  complete  safety 

In  general,  the  requirements  of  a  satisfactory  domestic  filter  may  h&. 
stated  as  follows  :  It  should  yield  a  sufficient  supply  of  clear,  colorless, 
water,  free  from  taste  derived  from  the  filter  itself;  should  arrest; 
all  bacteria  and  their  spores  ;  and  should  be  simple  in  construction,  and 
offered  at  a  low  price.  Thus  far,  those  made  on  the  principle  of  the 
Chamberland-Pasteur  filter  have  met  these  requirements  best.  Their 
introduction  into  use  in  the  French  army  in  1889  was  followed  within 
two  years  by  a  reduction  of  more  than  50  per  cent,  in  the  number  of. 
cases  of  typhoid  fever  occurring  therein. 

Filtration  of  Public  Supplies. 

Filtration  on  a  large  scale  is  accomplished  by  the  aid  of  fine  sand  in 
filter  beds  of  proper  construction,  which  act  both  mechanically  and 
biologically.  The  first  beds  of  which  we  have  accurate  knowledge 
were  those  constructed  by  Simpson  in  London,  in  the  year  1829, 
which  were  intended  primarily  for  the  removal  of  dirt  and  other  sus- 
pended matters  causing  turbidity.  The  process  was  regarded  at  that 
time  as  a  purely  mechanical  one,  and  though  in  course  of  time  this 
kind  of  filtering  medium  came  into  very  extensive  use,  it  was  gen- 
erally believed  that  as  carried  on  there  was  no  marked  chemical 
change  in  the  water,  and  that  what  did  occur  was  attributable  to  oxi- 
dation of  organic  matter  by  air  in  the  interstices  of  the  sand.  This 
was,  indeed,  the  view  held  generally  up  to  the  time  when  the  extensive 
researches  begun  by  the  State  Board  of  Health  of  Massachusetts  in  the 
summer  of  1887  proved  the  great  influence  of  biological  agencies,  al- 
though it  had  been  shown  by  Meade  Bolton,  Herseus,  Plagge,  Pros- 
kauer,  and  others,  that  filtration  removed  all  but  a  trifling  percentage 
of  micro-organisms,  and  that  water  bacteria  exerted  some  influence  on 
the  amount  of  the  usual  constituents  of  water. 

Although  sand  filtration  of  public  supplies  is  of  comparatively  recent 
origin,  its  use  for  individual  house  supplies  antedates  Simpson  by  at 
lea.st  a  century  and  a  half,  for  Portius,"  writing  in  1(385,  relates  that 

'  British  Medical  .Tonmal,  June  15,  IPOl,  p.  1471. 

'^  Da  rnilitis  in  castri.s  Hanitato  tucnrla,  iuuttom  Liica  Antonio  Portio,  Vienna,  1685. 


358 


WATER. 


the  Venetians  were  accustomed  to  filter  their  drinking-water  through 
layers  of  sand  within  their  cisterns,  in  order  to  rid  it  of  disagreeable 
odor  and  taste. 

The  first  beds  constructed  by  Simpson  were  broad  basins  twelve  feet 
in  depth,  with  impervious  bottoms  and  sides,  containing  layers  of  stones, 
gravel,  and  sand,  which  occupied  half  their  depth.  Beneath  the  stones 
were  laid  ordinary  drain  pipes,  through  which  the  filtered  water  was 
discharged.  As  the  top  layers  of  sand  became  clogged,  they  were 
scraped  and  renewed.  The  beds  of  the  present  day  are  constructed  on 
very  similar  lines.  They  are  virtually  immense  tanks  of  varying  size, 
shape,  and  construction.  The  walls  are  sometimes  vertical,  but  more 
often  sloping,  sometimes  built  of  stone  or  concrete,  and  sometimes  con- 
sisting of  ordinary  embankment.  Upon  the  paved  bottom  of  a  bed  is 
laid  a  system  of  perforated  or  disjointed  drain  pipes  leading  to  a  cen- 
tral culvert  or  well,  from  which  the  filtered  product  is  drawn.  Above 
the  drains  are  successive  layers  of  coarse  gravel,  fine  gravel,  coarse 

Fig.  34. 


Partial  vertical  section  of  one  form  of  filter  bed. 


sand,  and,  at  the  top,  one  of  fine  sand  from  three  to  five  feet  in  depth. 
(See  Fig.  34.) 

The  fine  sand  is  sharp-grained  in  character,  such  as  is  obtainable 
at  the  seashore,  and  it  should  not  contain  clay  or  other  material  of 
similar  minuteness  of  particle  ;  if  present,  such  should  be  removed 
completely  by  thorough  washing.  As  to  the  size  of  the  sand  parti- 
cles, it  may  be  stated  generally  that  the  finer  the  grain,  the  better  the 
effluent ;  but,  it  should  be  added,  the  more  rapidly  it  becomes  clogged 
and  the  more  frequently  it  needs  to  be  scraped  ofP,  and  finally,  the  more 
difficult  it  is  to  wash  for  future  use.  With  the  finest  sands,  the 
bacteria  are  removed  absolutely,  but  filtration  pi'oceeds  so  slowly  that 
their  use  is  not  practicable.  The  most  efPective  size  of  grain  is  a 
matter  on  which  opinions  difPer ;  but  whatever  the  size  adopted,  it  is 
important  that  care  be  taken  to  insure  uniformity.  It  is  stated 
variously  to  be  from  a  fifth  to  one  millimeter  in  diameter,  that  is, 
the    diameter    of  a    sphere    in   volume    equal    to    that    of   the    grain 


FILTRATION   OF  PUBLIC  SUPPLIES.  359 

without  regard  to  the  shape  of  the  latter.  The  higher  figure  is  the 
one  adopted  by  the  authorities  at  Hamburg, 

Before  the  water  is  applied  to  the  bed,  it  may  be  advisable — and 
if  it  is  from  a  turbid  river,  it  will  be  necessary — to  allow  it  to  stand 
several  days  in  a  settling  basin  or  reservoir,  in  order  that  the  sus- 
pended matters  may  subside,  and  thus  the  too  rapid  clogging  of  the 
interstices  of  the  sand  with  mud  be  prevented  or  retarded.  Observ- 
ance of  this  precaution  will  result  in  lessened  necessity  of  frequent 
cleaning.  Not  only  are  the  suspended  matters  lessened  in  amount, 
but  organic  matters  in  solution  may  be  destroyed  more  or  less  com- 
pletely by  bacterial  action,  and  the  bacteria,  too,  may  be  diminished  in 
number  by  being  carried  down  with  the  settling  matters  with  which 
they  are  in  contact,  and  by  the  death  of  the  less  hardy  varieties.  In 
the  case  of  waters  from  ponds  and  lakes,  the  preliminary  sedimenta- 
tion proceeds  in  situ  and  the  settling  tank  is  not  needed. 

The  water  is  delivered  continuously  at  the  surface  of  the  bed  by 
devices  automatically  regulated,  and  percolates  downward  through 
the  various  layers  of  sand  and  gravel  to  the  outlet  pipes.  Except 
with  very  fine  sands,  the  first  water  of  the  effluent  is  not  much,  if 
any,  purer  than  the  original,  but  in  a  short  time  a  sediment  layer  is 
formed  on  the  surface  and  a  slimy  algoid  growth  occurs.  This  super- 
ficial layer  acts  both  mechanically  and  by  its  contained  bacteria  to 
cause  the  removal  and  oxidation  of  organic  matter  and  destruction 
of  bacteria.  The  resulting  effluent  is  quite  pure  and  practically  sterile. 
The  Lawrence  filter,  for  instance,  removes  more  than  97.50  per  cent, 
of  the  organisms  present  in  the  water  as  delivered,  and  the  reduction 
is  still  more  marked  at  the  house  service  pipes,  where  99.17  per  cent. 
is  recorded,  the  increase  in  purification  being  supposedly  due  to  the 
fact  that  their  necessary  food  material  has  been  removed,  and  hence 
they  cannot  long  survive.  At  Hamburg,  Altona,  Stuttgart,  London, 
and  other  places,  the  reduction  in  bacteria  is  about  the  same  as  at 
Lawrence. 

All  organic  matters  are  not  acted  upon  to  the  same  extent  during 
filtration ;  some  are  decomposed  very  rapidly  and  mineralized,  while 
others  are  attacked  so  slowly  that  complete  removal  during  the  short 
period  elapsing  between  entrance  and  exit  is  often  quite  impossible. 
This  latter  class  includes  the  brown  coloring  matters  so  commonly 
present  in  surface-waters.  These  are  very  stable  compounds  :  they 
persist  during  long  storage  and  are  nitrified  but  slowly.  In  the  proc- 
ess of  chemical  treatment  with  alum,  however,  they  are  coagulated 
and  removed  very  quickly. 

The  slime  layer,  mud  layer,  or  "  schmutzdecke,"  is  believed  by 
some  to  constitute  the  sole  actual  filtering  medium,  the  sand  beneath 
acting  only  as  a  means  of  support.  But  experiments  conducted  at 
Lawrence  and  elsewhere  sliow  that  this  is  not  true,  and  tliut  if  the 
gnsatest  care  be  exercised  not  to  disturl)  the  immediately  undei'lying 
sand,  almost  the  whole  of  the  slime  layer  may  be  stripped  off  without 
causing  any  change  in  the  bacteria  count.     The  greater  part  of  the 


360  WATER. 

work  is  done  in  the  upper  layers  of  the  bed,  and  yet  bacterial  efficiency 
is  not  necessarily  established  as  soon  as  a  coating  has  been  formed. 
A  perfectly  new  filter  does  not  show  its  best  results  until  it  has  been 
in  use  for  some  little  time,  during  which  the  sand  particles  for  a 
considerable  depth  become  coated  with  the  jelly-like  deposit. 

The  active  agents  in  bringing  about  the  death  of  the  bacteria  con- 
tained in  the  effluent  and  in  accomplishing  the  destruction  and  miner- 
alization of  the  organic  matters  are  of  the  same  class  of  nitrifying 
organisms  as  are  constantly  at  work  in  the  soil.  The  death  of  the 
bacteria  is  not  directly  due  to  the  process  of  nitrification,  for  it  has 
been  proved  that  a  xery  marked  increase  in  the  jorocess  is  not  neces- 
sarily accompanied  by  any  diminution  in  the  number  of  organisms 
which  manage  to  pass  through  to  the  drains.  It  is  possible  that  the 
supposed  relation  of  cause  and  eifect  is  merely  a  coincidence  of  con- 
ditions, that  is,  that  the  conditions  favorable  to  nitrification  are 
unfavorable  to  the  vitality  of  the  ordinary  bacteria.  It  is  also  pos- 
sible that  through  nitrification  the  latter  are  deprived  of  at  least  part 
of  the  food  materials  necessary  to  their  continued  existence  and  mul- 
tiplication. 

Nitrification  sometimes  ceases  suddenly  after  it  has  been  proceeding 
for  a  long  time  at  a  proper  rate,  and  then,  after  an  interval,  begins 
again  without  apparent  reason.  One  explanation  oifered  is  that  the 
process  begins  only  when  a  certain  amount  of  nitrogenous  matter 
has  accumulated  within  the  interstices,  that  it  then  proceeds  until  the 
store  is  consumed,  and  that  pending  a  further  accumulation  the 
process  lapses.  In  M'inter  it  does  not  begin  again  until  the  tem- 
perature of  the  effluent  reaches  at  least  39°  F.,  but  after  it  is  once 
started  it  is  unaffected  by  a  fall  to  35°.  The  most  favorable  tem- 
peratures for  the  process  are  those  of  the  hot  summer  months. 

As  to  the  rate  of  filtration,  it  is  important  that,  whatever  the  rate,  it 
shall  be  uniform  all  over  the  filter.  It  has  been  proved  by  the  Massa- 
chusetts State  Board  of  Health  that  2,000,000  gallons  per  day  can  be 
filtered  through  each  acre  of  filter  bed  with  the  removal  of  substantially 
all  the  bacteria  originally  present.  The  Imperial  Board  of  Health  of 
Germany  fixes  2,500,000  gallons  per  acre  as  the  maximum  amount  per- 
missible. Koch's  three  rules  of  filtration  are  that  the  rate  of  down- 
ward movement  should  not  exceed  100  millimeters  an  hour,  that  the 
filtrate  of  each  section  should  be  examined  daily  while  the  bed  is  at 
work,  and  that  filtered  water  containing  more  than  100  bacteria  to 
the  cc.  should  not  be  allowed  to  enter  the  pure  water  reservoir,  but 
should  be  rejected  or  refiltered.  The  bacteriological  test  is  much 
superior  to  chemical  analysis  for  watching  the  efficiency  of  a  filter, 
and  a  simple  count  is  quite  sufflcient  without  attempting  to  identify 
the  species. 

When  the  filter  begins  to  discharge  slowly  on  account  of  the  extent 
of  the  algoid  growth  at  the  surface,  it  is  not  safe  to  increase  the  press- 
ure unduly  by  flooding  the  bed  with  an  increased  depth  of  water,  for, 
as  was  shown  by  an  experience  at  Berlin,  such  a  procedure  may  force 


FILTRATION   OF  PUBLIC  SUPPLIES.  361 

the  bacteria,  which  have  accumulated  largely  in  the  meshes  of  the 
growth,  down  through  the  filter  at  such  a  rate  that  they  are  not  de- 
stroyed by  the  usual  agencies.  In  this  case  the  water  level  was  raised 
two  feet,  with  the  result  that  the  portion  of  the  city  which  was  supplied 
with  the  water  of  that  particular  bed  was  visited  by  an  epidemic  of 
typhoid  fever.  The  same  sort  of  accident  occurred  at  Altona  some 
years  ago,  when,  a  year  after  successfully  going  through  the  cholera 
epidemic  which  devastated  the  neighboring  city  of  Hamburg  so  exten- 
sively, a  defect  in  the  filter  beds  was  followed  by  an  outbreak  of 
cholera,  which  disease  had  then  died  out  in  Hamburg. 

When  the  sediment  layer  becomes  so  thick  and  dense  that  with  the 
maximum  pressure  allowable  the  required  amount  of  water  fails  to 
pass,  it  becomes  necessary  to  scrape  off  the  inch  or  so  that  has  formed, 
and  then  to  proceed  as  though  the  bed  were  new. 

It  will  require,  as  a  rule,  several  days  for  the  formation  of  a  new 
sediment  layer,  and  until  it  is  well  developed  the  effluent  should  either 
be  rejected  or  pumped  back.  The  frequency  with  which  a  bed  will 
require  to  be  scraped  depends  upon  individual  circumstances,  such  as 
the  size  of  the  grains,  the  character  of  the  water  as  applied,  the  rate  of 
movement,  the  season  of  the  year.  The  removal  of  the  top  is  not 
difficult.  It  is  quite  compact  and  distinct  from  the  sand  beneath  it, 
and  is  readily  pared  off  with  shovels  or  other  tools.  Successive  clean- 
ings may  take  place  without  replacement  of  the  sand,  until  the  depth 
of  the  filtering  material  is  reduced  to  about  15  inches,  but  not  below 
12.  The  scraped-off  sand  may  be  washed  thoroughly  in  a  machine  for 
the  purpose  until  a  sample  in  a  beaker  yields  no  turbidity  to  clean 
water,  and  it  may  then  be  stored  until  needed  for  future  application. 

Experiments  have  been  tried  repeatedly  in  Massachusetts,  Berlin, 
and  elsewhere  in  sterilizing  sand  by  boiling  it  in  water  or  otherwise 
subjecting  it  to  high  temperatures,  and  then  determining  its  efficiency. 
The  results  have  proved  invariably  that  more  bacteria  are  found  m  the 
filtrate  than  in  the  original  water,  and  this  is  explained  by  the  suppo- 
sition that  the  bacteria  that  enter  find  in  the  cooked  organic  matter  a 
food  supply  most  favorable  to  enormous  multiplication,  and  that  the 
bacteria  in  the  washed  sand  are  necessary  for  the  destruction  of  organic 
matter  and  of  some  of  the  varieties  of  water  bacteria. 

During  and  immediately  after  the  scraping  process,  the  bed  is  neces- 
sarily out  of  use,  and,  therefore,  it  is  necessary,  in  order  to  insure  con- 
tinuous filtration,  to  have  a  number  of  separate  beds,  and  to  scrape  them 
in  turn.  In  this  way,  while  one  is  out  of  use,  the  others  can  carry  on 
the  work. 

In  cold  weather,  owing  to  increased  viscosity  of  the  water,  the  rate 
of  filtration  is  less  than  in  the  warmer  months.  In  very  cold  climates, 
the  formation  of  thick  ice  makes  proper  cleansing  of  the  surface  im- 
possible ;  and  imperfect  scraping  causes  imperfect  filtration.  The  re- 
moval of  the  ice  augments  considerably  the  cost  of  maintenance,  and 
this  item  alone  is  one  of  sufficient  importance  to  warrant  the  expense 
of  covering  the  beds.     But  aside  from  cost,  the  efficiency  of  the  process 


362  WATER. 

is  so  much  greater  and  the  danger  oi"  epidemics  of  water-borne  disease 
is  so  much  diminished  that  the  plant  in  a  cold  climate  should  always  be 
covered.  With  an  uncovered  filter  subject  to  freezing  temperatures, 
imperfect  filtration  is  almost  sure  to  occur  periodically,  and  this  is  indi- 
cated by  an  increase  in  the  daily  bacteria  count.  Thus,  Wallichs  ^  has 
noted  that  after  freezing  had  occurred  in  the  filters  of  Altona  in  Feb- 
ruary, 1886,  January,  1887,  February,  1888,  and  January,  1891,  the 
number  of  germs  m  the  filtered  water  rose  considerably,  and  in  each 
instance,  in  the  following  month,  there  Avas  an  unusual  increase  in  the 
amount  of  typhoid  fever. 

Freezing  of  the  surface  causes  imperfect  filtration  by  bringing  it 
about  that  the  bed  is  overworked  in  those  places  which  are  still  pervious. 
The  application  of  water  to  the  frozen  surface  thaws  the  ice  slowly  and 
unequally,  and  where  the  filter  is  active,  it  is  doing  the  work  of  its 
frozen  neighboring  areas. 

Scraping  of  a  bed  below  the  ice  cake  is  performed  with  a  machine 
which  runs  between  the  sand  and  the  ice,  cuts  the  layer  and  receives  it 
in  a  bag  as  fast  as  it  is  removed.  It  is  dragged  from  side  to  side  with- 
out breaking  the  ice  above  it. 

Covering  a  filter  is  advantageous  in  another  direction,  for  by  the 
exclusion  of  light,  growths  of  algse  are  inhibited,  and  there  is,  there- 
fore, less  need  of  frequent  cleaning. 

On  the  other  hand,  open  filters  get  the  benefit  of  the  sterilizing  in- 
fluence of  direct  sunlight,  but  this  is  more  than  offset  by  the  promotion 
of  luxuriant  growth  of  algae  and  other  microscopic  plants  in  the  warmer 
months.  It  is  sometimes  hardly  possible  to  keep  filters  in  good  work- 
ing order  in  summer  owing  to  these  growths,  which  clog  the  interstices 
very  quickly  and  cause  diminished  efficiency  just  at  a  time  when  the 
demand  for  water  is  greatest.  The  coincidence  of  greater  demand  and 
more  frequent  cleaning  does  not  permit  of  sufficient  intervals  of  rest 
after  the  completion  of  the  scraping  process. 

In  what  is  known  as  "  intermittent  filtration,"  the  filter  bed  is  used 
for  the  reception  of  water  during  part  of  one  day,  say  sixteen  hours,  or 
even  during  several  days,  and  then  is  allowed  to  drain  off  and  rest  for 
a  while.  As  the  water  drains  away,  the  interstices  of  the  sand  become 
filled  with  air,  that  is,  the  bed  becomes  aerated,  and  thus  the  nitrify- 
ing bacteria  which  bring  about  the  destruction  of  organic  matter  and 
its  subsequent  mineralization  to  nitrates  are  assisted  to  maintain  their 
vitality.  The  intermittent  process  is  superior  to  the  continuous  in 
that  nitrification  proceeds  more  strongly,  the  organic  matter  is,  there- 
fore, more  completely  removed,  and  the  ordinary  bacteria  do  not  sur- 
vive so  long  in  aerated  sand  ;  but,  on  the  other  hand,  it  is  inferior  in 
that,  being  so  much  out  of  active  use,  the  main  plant  needs  to  be  so 
much  the  larger  for  the  accomplishment  of  a  given  amount  of  work. 
As  a  matter  of  fact,  however,  all  sand  filters  are  at  one  time  or  another 
intermittent,  since  each  time  a  bed  is  scraped  the  water  is  drained  away, 
and  the  space  formerly  occupied  by  it  is  then  filled  with  air.  Sometimes 
^  Deutsche'  medicinische  Wochenschrift,  1891,  p.  25. 


FILTRATION  OF  PUBLIC  SUPPLIES.  363 

it  is  proposed  to  put  the  water  through  a  process  of  double  filtration, 
that  is,  to  pass  the  filtrate  on  to  another  bed  for  still  further  purification. 
But  if  the  first  filtration  has  been  carried  out  properly,  the  filtrate  will 
have  been  deprived  of  all  the  materials  necessary  for  the  formation  of 
the  real  filtering  surface  on  the  second  bed.  Thus  the  passage  of  the 
water  through  a  second  filter  would  be  much  in  the  nature  of  a  mere 
form,  for  it  would  pass  practically  unchanged. 

Sand  filtration,  when  properly  managed,  has  proved  itself  so  efficient 
that  the  number  of  cities  and  towns  making  use  of  it  is  growing  almost 
daily.  Although  protection  of  a  supply  at  its  source  may  be  prefer- 
able to  pollution  followed  by  sand  filtration,  it  is  not  always  so  trust- 
worthy, since  pollution  may  creep  in  by  accident  at  any  time  in  the 
best  guarded  supplies.  The  ideal  course  is  protection  at  the  source, 
followed  by  filtration  before  distribution.  This  is  the  method  now 
adopted  by  the  authorities  of  a  number  of  cities  in  Europe. 

"Mechanical  Filtration." — In  some  places,  particularly  in  the 
United  States,  the  water  supply  is  treated  in  what  are  known  as 
mechanical  filters,  of  which  there  are  a  number  of  varieties,  all  based 
on  a  common  principle.  Such  a  machine  consists  chiefly  of  an  iron 
or  wooden  cylinder  filled  with  rather  coarse  sand  or  crushed  quartz, 
through  which  the  water  passes  by  gravity  or  is  driven  under  pressure 
at  a  much  faster  rate — from  50  to  150  times  faster  than  it  moves  in  a 
bed.  To  take  the  place  of  the  sediment  layer  which  forms  in  the  latter, 
an  artificial  film  is  produce<:l  by  the  use  of  alum  as  a  coagulant.  This 
is  formed  quickly  and  serves  the  same  purpose,  though  not  with  the 
same  thoroughness.  The  filter  is  called  mechanical  only  because  power 
and  mechanical  devices  are  employed  in  regulating  the  rate,  pressure, 
the  application  of  the  alum  solution,  and  the  raking  and  shaking  of  the 
sand  in  the  process  of  cleaning,  which  process  it  is  necessary  to  carry 
out  at  short  intervals.  Instead  of  removing  the  top  layer,  the  whole 
body  of  sand  is  thoroughly  agitated  and  washed.  Filtered  water  is 
pumped  through  from  below  for  five  or  ten  minutes,  and  the  sand  layer 
is  agitated  by  revolving  rakes  or  by  compressed  air  introduced  from 
below.  The  process  is  not  suited  to  all  water  supplies,  but  for  the 
highly  colored  and  turbid  waters  so  common  in  the  South  and  West  it 
is  particularly  well  adapted,  and  is  cheaper,  more  efficient,  and  more 
easily  managed  than  filtration  through  beds  of  sand.  With  careful  man- 
agement, upward  of  99  per  cent,  of  bacteria  are  removed. 

Destruction  of  Algse. 

For  the  destruction  of  overgrowths  of  algae,  Moore  and  Kellerman  ^ 
recommend  the  use  of  copper  sulphate  in  extreme  dilution  (about  1  part 
of  the  crystals  to  4  or  5  millions  of  water).  In  the  practical  appli- 
cation of  this  agent  to  ponds  or  reservoirs,  the  crystals  are  placed  in 
gunny  sacks,  which  are  then  drawn  through  the  water  by  means  of 
row-boats,  which  traverse  the  area  in  concentric  lines  from  25  to  40  feet 

^  U.  S.  Department  of  Agriculture,  Bureau  of  Plant  Industry,  Bulletin  04. 


364  WATER. 

apart.  The  process  has  been  tried  in  various  places  with  results 
varying  from  complete  success  to  utter  failure.  In  some  instances,  the 
destruction  of  one  species  of  algse  has  been  followed  by  overgrowths 
of  equally  objectionable  and  more  hardy  forms.  The  assertion  that 
the  copper  is  quickly  precipitated  is  disputed  by  many  who  have  given 
the  process  a  trial,  and  the  claim  that  pathogenic  bacteria  are  destroyed 
with  the  algae  appears  to  have  little,  if  anything,  to  support  it. 

Removal  of  Hardness. 

On  account  of  the  enormous  waste  of  soap  as  well  as  loss  of  time 
which  the  use  of  hard  waters  in  washing  entails,  and  of  the  injury  to 
which  boilers  and  hot-water  pipes  are  subject  from  their  action,  it  often 
becomes  necessary  to  apply  some  remedy  whereby  the  degree  of  hard- 
ness may  be  lessened.  This  may  be  accomplished  by  the  aid  of  heat 
or  by  the  addition  of  chemicals.  Boiling,  as  we  have  seen,  drives  off 
the  contained  carbon  dioxide  and  causes  precipitation  of  the  carbonates 
which  have  been  held  m  solution  by  this  agent,  but  it  has  no  effect 
on  the  salts  which  cause  the  permanent  hardness.  For  use  on  a  large 
scale  for  public  supplies,  this  means  is  hardly  applicable,  on  account 
of  the  cost  of  plant  and  of  fuel ;  but  for  domestic  purposes  the  cost 
is  comparatively  slight,  in  that  the  fuel  necessary  in  cooking  may  be 
utilized  coiucidently  for  the  purpose  of  heating  water.  For  the  chemical 
treatment  of  hard  waters,  the  first  process  devised  was  that  of  Clark, 
patented  in  1841.  This  process  is  based  upon  the  affinity  of  caustic  lime 
for  carbon  dioxide,  with  which  it  forms  the  practically  insoluble  carbonate. 

On  the  addition  of  lime  water  to  water  containing  chalk  and  mag- 
nesium carbonate  held  in  solution  by  carbon  dioxide,  the  reaction  occurs, 
and  a  double  precipitation  of  the  carbonates  present  and  of  that  formed 
is  brought  about.  The  process  is  veiy  economical  so  far  as  cost  of 
material  is  concerned,  in  that  a  few  cents'  worth  of  lime  will  remove  an 
amount  of  hardness  which  will  decompose  many  dollars'  w^orth  of  soap. 
Lime  water,  however,  does  not  affect  the  chlorides  and  sulphates,  and 
hence,  like  boiling,  reduces  only  the  temporary  hardness.  For  the 
employment  of  this  process  on  a  large  scale,  various  forms  of  apparatus 
have  been  invented,  consisting  of  chambers,  or  tanks,  in  which  the 
lime  is  mixed  with  water  and  from  which  the  mixture  passes  into  other 
large  receptacles,  wherein  it  meets  the  water  to  be  treated.  Thence, 
according  to  the  nature  of  the  apparatus,  the  water  passes  on  to  settling 
tanks  or  to  mechanical  filters,  where  separation  of  the  precipitate  is 
completed.  The  largest  plant  of  this  kind  in  the  world  is  located  at 
Southampton,  England,  where  2,000,000  gallons  of  water  are  treated 
daily  at  what  may  well  be  regarded  as  an  almost  insignificant  cost. 
The  building  in  which  it  is  installed  covers  less  than  a  seventh  of  an 
acre,  and  is  sufficiently  large  to  accommodate  additional  apparatus 
whereby  its  working  capacity  may  be  increased  by  half.  Whatever  the 
forms  of  apparatus  employed,  the  process  must  be  carefully  supervised, 
and  the  amount  of  lime  added  must  be  constantly  regulated  ;  for  if  too 


ACTION  OF   WATER   ON  LEAD  AND   OTHER  METALS.        365 

little  is  employed,  the  full  extent  of  possible  softening  is  not  reached, 
while  with  too  much,  the  water  is  made  alkaline  and  the  carbonate  of 
magnesium  is  retained. 

Caustic  soda  may  be  used  for  softening  waters  containing  carbon 
dioxide  and  the  salts  causing  permanent  hardness.  Added  in  proper 
amount  to  combiue  with  all  of  the  free  carbon  dioxide,  it  forms  car- 
bonate of  sodium,  which,  in  its  turn,  attacks  and  decomposes  the  other 
salts  and  causes  their  precipitation.  Sodium  carbonate  itself  may  be 
added  in  the  absence  of  free  carbon  dioxide  to  bring  about  the  same 
result.  In  some  processes  for  softening  water,  both  lime  and  caustic 
soda  or  sodium  carbonate  are  employed,  the  object  being  the  reduction 
of  both  temporary  and  permanent  hardness. 

Removal  of  Iron. 

Some  ground-waters  contain  iron  in  such  amounts  as  to  be  objection- 
able, both  on  account  of  its  influence  on  the  system  and  because  of  its 
production  of  stains  on  lineu  and  other  textiles  in  the  laundry.  There 
are  two  principal  methods  of  removing  it,  both  of  which  depend  upon 
the  conversion  of  the  ferrous  compounds  into  the  ferric  form,  with  con- 
sequent separation  as  a  precipitate.  These  are  filtration  and  aeration. 
Filtration  may  be  conducted  through  sand  or  coke  or  animal  charcoal, 
and  with  either  material  the  iron  in  solution  is  exposed  to  the  action  of 
air  in  the  interstices  and  becomes  oxidized  to  the  sesquioxide,  which  is 
left  on  the  filtering  material.  If  the  air  supply  is  insufficient,  and  if 
there  is  much  organic  matter  present  in  the  water,  the  sesquioxide  may 
be  reduced  to  the  ferrous  form  and  again  pass  into  solution.  When 
ground-water  containing  less  than  3  parts  of  iron  per  1,000,000  is  ex- 
posed in  large  volumes  to  air,  the  iron  will  settle  out  almost  completely 
within  a  day  or  a  day  and  a  half. 

Another  method  of  removal  by  chemical  treatment  involves  the  use 
of  ferric  chloride  and  caustic  lime  in  the  proportion  of  1  and  5  to  10 
grams  respectively  to  each  100  liters  of  water.  By  this,  the  "  Kronke  " 
method,  all  the  iron  can  be  removed,  but  it  necessitates  the  use  of  a 
mixing  tank,  constant  attention,  and  eventual  filtration  for  the 
removal  of  the  precipitated  iron. 

Action  of  Water  on  Lead  and  Other  Metals. 

Action  on  Lead. — The  question  as  to  the  best  material  for  house- 
mains  and  distributing  pipes  is  always  an  interesting  one,  and  never 
more  so  than  when  a  considerable  number  of  persons  in  a  community 
])cgin  to  show  symptoms  of  lead-poisoning,  and  evidence  is  presented 
which  incriminates  the  water  sup[)ly.  Aside  from  the  matter  of  cost, 
the  advantage  of  using  lead  pi])es  lies  in  the  comparative  ease  with 
which  lead  is  worked,  since  it  may  be  bent  to  any  necessary  extent, 
and  thus  may  l)e  fitted  to  all  manner  of  irregularities  of  construction 
without  the  need  of  th(!  frequent  cutting,  thread-making,  and  coupling, 
wiiich  the  use  of  inflexible  material  involv^es. 


366  WATER. 

All  ordinary  waters  have  a  greater  or  lesser  tendency  to  attack  lead, 
according  to  the  nature  and  amount  of  the  substances  held  in  solution. 
The  commonly  accepted  statement,  that  pure  soft  water  is  prone  to  at- 
tack lead,  and  that  hard  waters  tend  to  protect  it  by  forming  incrusta- 
tions over  the  exposed  surface,  is  true  only  in  part,  for  some  very  pure 
soft  waters  exert  only  very  slight  action,  while  some  very  hard  ones  act 
with  unusual  intensity. 

Waters  containing  very  small  amounts  of  organic  and  mineral 
matters  act  or  not,  according  as  they  contain  much  or  little  dissolved 
oxygen  or  carbon  dioxide,  or  both. 

A  chemically  pure  water  would  probably  exert  no  action  whatever 
on  chemically  pure  lead,  but  commonly  neither  the  one  substance  nor 
the  other  is  seen  in  such  a  state  of  purity.  Ordinary  distilled  water, 
however,  which  is  a  nearer  approach  to  absolute  purity  than  any  other 
natural  water  can  be,  will,  under  certain  conditions,  act  very  corrosively, 
the  conditions  being  the  presence  of  the  above-mentioned  gases.  It  is 
held  generally  that  either  oxygen  or  carbon  dioxide  alone  in  water  has 
but  little  influence,  but  that  the  two  together  act  with  varying  inten- 
sity up  to  a  certain  point,  directly  proportionate  to  the  amount  of  car- 
bon dioxide.  This  belief,  based  on  experimental  observations  of 
Miiller,^  was  strengthened  by  Drs.  Antony  and  Benelli,"  who  found 
that  the  highest  results  in  lead  corrosion  were  obtained  by  the  use  of 
aerated  water  charged  with  carbon  dioxide.  Investigating  the  plumbo- 
solveut  property  of  a  particidar  water,  A  Liebrich  ^  came  to  the  same 
conclusion  :  that  the  simultaneous  presence  of  air  and  carbon  dioxide 
favors  action,  while  either  alone  has  no  power.  Recently,  however,  a 
very  extensive  inquiry  into  the  subject  of  metallic  contamination  of 
water  supplies  has  been  conducted  by  ]\Ir.  H.  AV.  Clark,*  chemist  of 
the  State  Board  of  Health  of  Massachusetts,  whose  results  indicate  that 
oxygen  is  the  more  actively  corrosive,  and  that  either  gas  can  act  alone. 
He  employed  distilled  water,  freed  in  the  first  place  as  completely  as 
possible  from  these  and  all  other  gases,  and  then  impregnated  with 
known  amounts  of  either  or  both.  Clean  bright  lead  pipe  in  equal 
amounts  was  placed  in  half-gallon  bottles  filled  with  water  containing 
the  gases  in  the  proportions  stated  below,  then  sealed  and  set  aside  at  a 
temperature  of  68°  F.  for  one  week,  at  the  end  of  which  time  the 
amount  of  lead  taken  up  was  determined.  The  results  are  shown  in 
the  following  table  : 


No. 

Gases  present. 

Amount  of  lead  taken  up 
(parts  per  100,000). 

1 

2,4100 

2 
3 
4 

Carbon  dioxide  4  parts  per  100,000 

Carbon  dioxide  20  parts  per  100,000 

Oxygen  ^q  of  saturation,  CO2  4  parts  per  100,000  .    ■ 

0.4993 
0.8935 
0.0861 

^  Journal  fiir  praktische  Chemie,  Series  2,  36,  p.  317. 
^  Gazetta  chiraica  italiana,  Jan.  21,  1896,  p.  275. 
^  Zeitschrift  fiir  angewandte  Chemie,  1898,  p.  703. 
*  Annual  Report  for  1898,  p.  541. 


ACTION  OF   WATER   ON  LEAD  AND   OTHER  METALS.        367 

A  specimen  of  lead  in  a  bottle  containing  water  from  which  the 
oxygen  had  been  boiled  out  as  completely  as  possible,  and  the  carbon 
dioxide  removed  by  barium  hydrate,  was  kept  at  82°  F.  for  a  week  un- 
changed. At  the  end  of  the  second  week,  slight  action  was  discernible 
in  spots  on  the  surface,  and  analysis  showed  0.0774  part  per  100,000 
of  water.  A  specimen  of  ordinary  distilled  water  in  a  bottle  with  a 
small  air  space  in  the  upper  part  attacked  a  similar  piece  of  lead  pipe 
to  such  an  extent  that  it  yielded  10.58  parts  per  100,000.  In  this  case, 
the  temperature  at  which  the  water  was  kept  was  81°  F. 

Inasmuch  as  all  drinking-water  contains  more  or  less  air  in  solution, 
oxygen  is  always  present  in  some  amount,  and  since,  furthermore,  car- 
bon dioxide  is  also  generally  present,  it  follows  that,  unless  substances 
with  a  decidedly  deterrent  influence  are  present,  more  or  less  corrosion 
is  to  be  expected.  Numerous  instances  of  chronic  lead-poisoning 
due  to  water  rich  in  carbon  dioxide  are  on  record.  At  Sommerfeld,^ 
for  instance,  where,  in  1888,  numerous  cases  occurred,  it  was  found 
that  the  very  pure  water,  rich  in  this  gas,  dissolved  lead  to  the  extent 
of  about  6  milligrams  per  liter.  At  Lowell,  Massachusetts,  numerous 
cases  were  observed  during  the  years  1898  and  1899,  and  it  was  dis- 
covered that  one  source  of  supply  was  rich  in  dissolved  oxygen,  and 
that  the  other,  which  caused  by  far  the  greater  number  of  cases,  was 
rich  in  carbon  dioxide. 

Professor  A.  W.  Hoffmann  believes  that  a  moderate  amount  of  car- 
bon dioxide  lessens  corrosion  by  forming  a  protective  coating  of  car- 
bonate, but  that  an  excess  of  the  gas  dissolves  it  as  bicarbonate.  The 
gas  is  said  also  to  have  no  action  on  lead  coated  with  suboxide. 

Water  containing  free  acid  of  any  kind  attacks  lead.  Sulphuric 
acid,  which  is  supposed  erroneously  to  form  an  absolutely  insoluble 
compound,  the  sulphate  of  lead,  is  particularly  active.  In  the  ordinary 
chemical  sense,  sulphate  of  lead  is  insoluble  in  water ;  but  in  the  hy- 
gienic sense,  it  is  sufficiently  soluble  to  be  capable  of  producing  serious 
symptoms.  This  acid  is  not  an  uncommon  constituent  of  water  in 
minute  amounts,  especially  in  the  vicinity  of  cities  and  large  towns, 
where  it  exists  in  the  atmosphere  as  an  impurity  due  to  the  combustion 
of  coal.  The  peat  acids  also  have  considerable  action  on  lead,  but 
they  are  not  always  present  in  waters  from  peaty  deposits.  Some  very 
brown  waters  appear  to  exert  but  slight  action,  while  others  are 
intensely  corrosive.  The  peat  acids  are  due  supposedly  to  the  growth 
of  certain  micro-organisms  found  in  peaty  soils,  for  a  neutral  sterilized 
decoction  of  peat  to  which  a  small  amount  of  fresh  peat  is  added  will 
in  a  short  time  develop  an  acid  reaction  and  ability  to  dissolve  lead. 
Liebrich  ^  reports  a  peaty  water  poor  in  carbon  dioxide  and  carbonates 
which  took  up  300  parts  of  lead  per  100,000  over  night,  and  more 
when  calcium  carbonate  was  added. 

The  ammonium  compounds  and  the  nitrates  have  been  supposed 
commonly  to  have  a  marked  corrosive  action  on  lead.     That  this  sup- 


'  Deutscyie  Vierteljahrsschrift  fiir  ciffentliche  OeHundheitspflege,  Suppl. 
^  Zeitschrift  fur  augewandte  CJiemie,  1898,  p.  703, 


XXIV. 


368  WATER. 

position  is  correct,  has  been  proved  amply  by  Mr.  Clark's  researches ; 
but  intense  action  is  manifested  only  when  the  water  containing  them  is 
exposed  to  air. 

The  constituents  of  water  which  tend  to  bring  about  corrosion  of 
lead  are,  then,  carbon  dioxide,  oxygen,  ammonia,  nitrates,  and  free 
acids.  The  substances  which,  on  the  other  hand,  exert  a  protective 
action  include  chlorides,  carbonates,  and  silicates,  and,  probably,  sul- 
phates. According  to  Crookes,  Odling,  and  Tidy,  0.5  grain  of  silica  to 
the  imperial  gallon  is  sufficient  to  afford  complete  protection  in  all  but 
exceptional  cases,  even  when  free  acids  are  present ;  but  certain  waters 
containing;  considerable  amounts  of  silica  are  known  to  be  corrosive 
to  a  decided  extent.  The  protection  due  to  silica  may  be  obtained  by 
allowing  the  water  to  flow  through  broken  flint,  flint  and  chalk,  or 
limestone,  but  such  treatment  sometimes  has  the  undesirable  efi*ect  of 
increasing  corrosive  power. 

Sodium  and  calcium  carbonates  are  very  efficient.  The  bicarbonate 
of  sodium  is  generally  present  in  those  very  soft  waters  which  have 
the  slightest  action  ;  calcium  carbonate  is  efficient  whether  or  not  car- 
bon dioxide  is  present  in  the  water  at  the  same  time.  Four  grains  per 
gallon  are  generally  considered  to  be  quite  sufficient  to  afford  protection 
under  most  circumstances.  As  an  illustration  of  the  influence  of  this 
agent,  may  be  cited  the  fact  that  the  very  pure  water  with  which  Glas- 
gow is  supplied  has,  before  its  entrance  to  the  aqueduct,  a  marked 
plumbo-solvent  property,  but  loses  it  entirely  in  its  passage  to  the  city, 
owing  to  contact  with  this  substance.  In  1887,  the  water  of  Dessau 
was  treated  successfully  with  calcium  carbonate.  Sodium  carbonate  is 
■even  more  efficient  than  the  calcium  salt,  but  is  not  always  equal  to  the 
bicarbonate.  At  Emden,  in  1897,  treatment  with  the  latter  was  suc- 
cessful after  the  carbonate  had  failed. 

Inasmuch  as  the  influences  for  and  against  corrosion  are  numerous 
and  conflicting,  the  surest  method  of  determining  whether  a  given 
water  will  attack  lead  is  to  ascertain  the  truth  by  actual  experiment. 

Regardless  of  the  character  of  a  ^vater  itself,  it  may  be  said  that  its 
action  is  greater  if  the  lead  is  in  contact  with  other  metals,  so  that  a 
galvanic  couple  is  formed.  Such  may  occur,  for  instance,  when  a  tin- 
lined  lead  pipe  is  bent  so  that  the  lining  is  fractured.  Then  the  two 
metals  being  in  contact  with  each  other  in  a  more  or  less  saline  liquid, 
the  lead,  being  the  more  easily  oxidized,  is  dissolved.  Again,  the  tin 
lining  may  develoj)  weak  spots  which  may  become  corroded,  and  as 
soon  as  the  lead  casing  is  reached,  galvanic  action  becomes  established. 
Lead  pipe  containing  a  small  percentage  of  tin  will  yield  more  lead  to 
water  than  will  ordinary  lead  pipe,  especially  if  free  carbon  dioxide  is 
present. 

A  new  lead  surface  will  yield  more  than  an  old  one,  as  is  shown  by 
Professor  Mason,  who  found  that  the  same  water,  stored  for  three  and 
a  half  months  in  contact  Avith  new  and  old  lead,  yielded  58.10  and  3.65 
parts  per  1,000,000,  respectively. 


ACTION  OF   WATER   ON  LEAD  AND   OTHER  METALS.        369 

Hot  water  is  more  corrosive  tlian  cold ;  and  in  the  case  of  either,  the 
solvent  power  is  increased  by  pressure. 

The  result  of  the  continuous  ingestion  of  minute  amounts  of  lead 
may  be  nil  or  the  production  of  more  or  less  marked  manifestations 
of  chronic  lead-poisoning.  From  the  fact  that  lead-pipe  is  in  very 
general  use  for  house-mains  and  distributing  pipes,  and  that  chronic 
lead-poisoning  is,  comparatively  speaking,  a  not  very  common  trouble, 
it  seems  reasonable  to  conclude  that  with  the  great  majority  of  persons 
the  metal  is  eliminated  with  sufficient  rapidity  to  prevent  accumulation 
and  cumulative  action.  In  Massachusetts,  notwithstanding  the  enor- 
mous use  of  lead  for  service-pipes,  in  but  few  communities  has  there 
been  any  considerable  amount  of  lead-poisoning  reported,  and  in  all  of 
these  the  water-supply  conies  from  driven  wells. 

Occasionally,  fatal  lead-poisoning  is  caused.  In  one  such  case, 
re]5orted  by  V.  Schneider,^  the  water  was  very  soft  (hardness  1.40)  and 
contained  0.95  milligram  of  lead  per  liter.  After  three  months'  use 
of  the  water,  a  girl  of  seventeen  died  with  all  the  characteristic  symp- 
toms of  lead-poisoning.  Aiialysis  of  the  organs  yielded  lead  to  the 
extent  of  7.5  milligrams  from  the  oesophagus,  stomach,  and  duodenum, 
and  24.7  milligrams  from  the  kidneys,  liver,  and  spleen. 

Action  on  Iron. — Corrosion  of  iron  is  favored  by  the  presence  of 
nitrates,  nitrites,  ammonium  compounds,  mineral  and  organic  acids, 
chloride  of  magnesium,  oxygeu,  and  carbon  dioxide.  The  latter  is 
especially  active,  as  has  been  shown  by  Professor  Leffmann  aud  by  R. 
Petit.  The  latter,^  investigating  the  cause  of  the  destructive  action  of 
water  rich  in  this  gas  and  poor  in  lime,  placed  a  certain  amount  of  iron 
filings  in  each  of  three  vessels,  one  of  which  contained  ordinary  water, 
the  second  contained  water  through  which  a  stream  of  carbon  dioxide 
was  conducted  for  several  minutes,  aud  the  third  was  filled  with  water 
to  which  sufficient  caustic  lime  had  been  added  to  bind  the  dissolved 
carbou  dioxide  and  to  give  an  alkaline  reaction  to  phenolphthalein.  After 
a  time,  the  iron  in  each  specimen  was  determined,  with  the  following 
results,  which  prove  the  great  influence  of  the  gas  : 

1.  3.15  milligrams  per  liter. 

2.  200.60  miligrams  per  liter. 

3.  Only  traces. 

Both  cast-iron  and  wrought-iron  pipes  may  be  acted  upon  rapidly 
unless  their  inner  surfaces  are  covered  by  some  protective  coating,  such 
as  asphaltum,  aud  even  then  at  the  joints  where  the  protecting  surface 
is  not  continuous  or  becomes  detached.  Some  surface-waters  form  a 
protective  layer  of  vegetable  matter  on  the  surface  of  the  pipe,  and  this 
is  far  more  efficient  than  artificial  applications,  and  possesses  the  addi- 
tional merit  of  im])arting  no  unpleasant  taste. 

Action  on  Zinc. — On  account  of  the  action  of  water  on  plain  iron 
])ipc.-,  ])ipc.s  of  gnlvanizcd  iron,  that  is,  iron  coated  within  and  without 
with  metallic  zinc,  have  been   recommended.     This  lining,  however,  is 

'  (JesHndheits-Tngenieiir,  Mardi  31,  1S97. 
^  Comptes  rendtis,  1890,  p.  1278. 

24 


370  WATER. 

corroded  very  easily,  especially  if  the  water  contains  oxygen,  carbon 
dioxide,  ammonia,  or  nitrates,  and  the  water  is  made  milky  by  the 
oxide  and  carbonate  in  suspension. 

Whether  or  not  the  zinc  compounds  occurring  in  water  can  be  pro- 
ductive of  harm,  is  a  point  on  which  authorities  differ.  But  at  least  it 
must  be  admitted  that  they  may  cause  chronic  and  obstinate  constipa- 
tion, even  M'hen  present  only  in  small  amounts,  and  that  zinc  is  not  a 
cumulative  poison.  Dr.  John  C.  Thresh  ^  mentions  a  case  of  obstinate 
constipation  in  a  child,  due  to  the  use  of  drinking-water  which  passed 
through  a  half  mile  of  galvanized  pipe.  Kelief  followed  discontinu- 
ance of  the  supply. 

Gimlette  ^  has  reported  an  extensive  outbreak  of  poisoning  attributed 
to  water  stored  in  galvanized  iron  tanks.  Of  56  consumers,  43  were 
attacked  with  gastro-intestinal  troubles,  the  symptoms  presented  being 
colic,  diarrhoea  with  consequent  anaemia  and  emaciation,  and  a  spurious 
kind  of  dysentery.  Analysis  of  the  water  revealed  large  amounts  of 
zinc. 

Analysis  of  water  drawn  from  galvanized  pipes  often  has  revealed 
very  large  amounts  of  zinc.  Messrs.  J.  A.  and  E.  W.  Voelcker* 
record  an  interesting  case  in  which  the  hot-water  pipes  of  a  house 
supplied  by  water  piped  a  half  mile  through  galvanized  iron,  were 
blocked  completely  by  a  deposit  of  zinc.  The  water  was  very  pure 
and  soft,  and  contained  but  6  grains  of  total  solids  per  gallon.  The 
deposit  contained  64.32  per  cent,  of  basic  carbonate  and  21.96  per 
cent,  of  oxide  of  zinc. 

Zinc  is  sometimes  a  normal  constituent  of  water.  Myelins  *  found 
about  0.5  grain  per  gallon  in  the  water  supply  of  Tuteudorf,  and 
Carl  T.  Morner^  has  reported  the  presence  of  0.015  part  of  zinc  car- 
bonate per  1,000,000  in  the  water  of  a  well  near  Upsala.  This  well^ 
which  was  about  fifteen  feet  deep,  had  been  in  use  for  more  than  a  year. 
The  water  was  submitted  for  analysis  solely  on  account  of  its  peculiar 
taste,  and  beyond  the  fact  that  it  yielded  zinc,  the  source  of  which 
could  not  be  determined,  the  results  of  the  analysis  were  very  favor- 
able. No  unpleasant  effects  had  been  noted  among  those  who  used 
the  water.  Two  springs  in  Missouri,  according  to  Hillebrand,®  yield 
much  larger  amounts.  In  both,  the  zinc  exists  in  the  form  of  sul- 
phate. The  yield  amounts  to  120.5  and  132.4  parts  per  1,00,000^ 
respectively. 

Action  on  Tin. — It  is  supposed  commonly  that  tin  is  unaffected 
by  w^ater,  but  such  is  far  from  being  the  case.  Tin  is  attacked  by 
water  to  a  considerable  extent,  although  not  so  readily  as  the  other 
metals  mentioned  ;  but  the  compounds  formed  are,  so  far  as  we  know, 
incapable  of  causing  the  slightest  injury  to  the  system,  and  this  metal 

^  Water  and  Water  Supplies,  London,  1896. 
^  British  Medical  Journal,  Sept.  7,  1901. 

*  The  Analyst,  July,  1896. 

*  Ibidem,  IV.,  p.  51. 

^  Ujasala  Liikareforenings  Forhandlingar,  1898,  Vol.  III. 
^  United  States  Geological  Survey,  Bulletin  No.  13. 


WATER  AND  DISEASE.  371 

is  recommended  highly  as  a  lining  for  iron  pipes.      Its  cost  alone  pre- 
vents it  from  supplanting  lead  for  house-mains  and  distributing  pipes. 

Water  and  Disease. 

The  use  of  impure  water  for  drinking  and  other  domestic  purposes 
may  be  a  direct  cause  of  disease,  and  such  water  is  supposed  also  to 
act  upon  the  system  in  such  a  way  as  to  lower  the  resistance  of  the 
body  to  the  action  of  infectious  matters ;  but  it  should  be  borne  in 
mind  that  the  nature  of  the  polluting  material  is  of  far  greater  impor- 
tance than  its  mere  amount.  To  maintain  that  water  containing  any- 
considerable  amount  of  organic  matter,  regardless  of  its  character  and 
source,  will  tend  inevitably  to  produce  a  general  impairment  of  health, 
is  as  great  an  error  as  to  underrate  the  danger  possible  to  arise  from  a 
small  amount  of  specific  contamination.  It  is  quite  as  improbable,  for 
instance,  that  the  amount  of  dissolved  vegetable  matter  necessary  tO' 
yield  albuminoid  ammonia  in  what  may  be  designated  "  considerable  "' 
amount  can  do  any  great  injury,  even  when  constantly  ingested,  as  that 
an  infusion  of  tea,  which,  by  the  same  process  of  analysis,  would  yield 
results  which  would  be  startling  in  comparison,  could  of  itself  conduce 
to  the  development  of  an  infectious  disease. 

Alarmists  may  reject  as  unsuitable  for  household  purposes  a  water 
containing  an  amount  of  vegetable  matter  sufficient  to  give  a  yellow- 
brown  color,  and  accept  as  sufficiently  pure  another  containing  less 
organic  matter  and  less  mineral  matter,  but  with  it  the  micro-organisms 
of  infectious  disease.  They  go  to  the  extreme  of  saying  that  organic 
matter  in  solution  must  "lower  the  tone,"  and  should,  therefore,  be 
avoided,  and  if  asked  why  this  is  so,  fall  back  on  "  general  principles  " 
and  "common  sense,"  upon  wdiich  so  much  illogical,  unexplainable 
theory  is  based.  As  a  matter  of  fact,  we  know  that  water  which  is  in 
a  sense  impure,  but  not  specifically  polluted,  may  be  used  year  in  and 
year  out  without  injury.  We  know,  farther,  that  water  containing 
much  less  organic  matter,  but  infected  with  bacteria  of  certain  kinds,  is 
likely  to  cause  disease  in  at  least  a  proportion  of  those  who  use  it  once, 
occasionally,  or  habitually.  We  know  also  that  a  water  once  specific- 
ally polluted  may,  under  similar  conditions,  be  polluted  again,  and  in 
the  interval  may  be  of  good  quality. 

We  know  that  water  containing  large  amounts  of  dissolved  vege- 
table matter  in  process  of  decomposition '  or  of  a  definitely  poisonous 
character  may  produce  disturbances  of  a  very  serious  nature ;  that  an 
abundance  of  minute  water  plants,  as  alg^e,  and  animal  organisms,  as 
infusoria,  may  produce  ill  effects ;  that  decomposing  animal  matters 
sometimes  yield  toxic  substances  of  great  potency,  and  that  excessive 
mineral  matter  in  suspension  or  solution  is  not  without  its  deleterious 
effV'cts. 

Thcrd'orc,  it  may  be  laid  (htwn  as  a  general  rule,  regardless  of  the 
fact  that  all  impurities  do  not  necessarily  breed  disease  or  undermine 
the   health,  that  all    water  containing   or  likely  to   contain   domestic 


372  WATER. 

sewage,  abundant  growths  of  minute  vegetable  and  animal  organisms, 
decomposing  matter  of  animal  origin,  dissolved  vegetable  matter  of  an 
inherently  toxic  nature  or  undergoing  decomposition,  or  excessive 
amounts  of  mineral  matter,  should  not  be  accepted  as  fit  for  human 
consumption.  Especially  should  we  bear  in  mind  that  polluted  water 
which  is  quite  free  from  disease  organisms  and  toxic  matters  to-day 
may  contain  them  in  abundance  to-morrow. 

Disorders  Connected  with  Mineral  Matter. — It  is  noticed  very 
commonly  that  when  one  changes  suddenly  from  the  use  of  a  soft 
water  to  another  that  is  quite  hard,  there  follows  a  temporary  disturb- 
ance of  the  functions  of  the  digestive  apparatus.  The  most  marked 
effect  is  usually  constipation  with  occasional  diarrhoea.  Loss  of  appe- 
tite and  slight  nausea  are  not  uncommoru  The  effects  are  due  to  the 
influence  of  the  salts  causing  permanent  hardness.  Change  from  hard 
to  soft  water  is  quite  as  likely  to  cause  unacccustomed  looseness  of  the 
bowels  from  the  withdrawal  of  this  influence  on  the  intestinal  secre- 
tions. Just  how  much  of  any  one  of  these  salts  may  be  said  to  be  dis- 
tinctly injurious  to  health  is  a  matter  of  doubt,  but  commonly  from  10 
to  15  parts  in  100,000  of  water  are  regarded  as  undesirable.  It  has 
been  asserted  that  the  use  of  hard  water  is  one  of  the  chief  causes  of 
stone  in  the  bladder,  but  such  a  connection  is  extremely  improbable. 
How  the  use  of  carbonate  and  sulphate  of  calcium  can  bring  about  a 
deposit  of  uric  acid,  or  of  oxalate  of  calcium,  or  of  phosphates  in  the 
bladder,  can  hardly  be  explained.  The  fact  also  that  stone  is  very 
common  in  some  districts  where  water  is  soft,  and  rare  in  some  others 
where  it  is  hard,  suggests  that  the  cause  is  to  be  looked  for  rather  in 
the  individual  himself — his  food,  his  metabolism,  his  habits  of  life, 
and,  perhaps,  hereditary  predisposition. 

Suspended  mineral  matter,  as  clay  and  marl,  will  often  cause  diar- 
rhoea in  persons  not  habituated  to  its  ingestion,  and  not  infrequently  in 
those  who  are. 

The  disease  most  commonly  connected  with  mineral  matters  in  water 
is  goitre.  That  this  disease  may  be  produced  by  drinking-water,  can 
hardly  be  doubted,  for  it  is  a  Avell-known  fact  that  in  Switzerland  and 
France,  for  instance,  there  are  wells  which  yield  waters  which  are  used 
successfully  for  the  intentional  production  of  the  disease,  with  the  view 
to  escape  compulsory  military  service.  The  enlargement  is  not  neces- 
sarily a  permanent  disfigurement ;  disuse  of  the  water  may  be  followed 
by  disappearance  of  the  swelling,  but  oftentimes  the  disease  thus  inten- 
tionally acquired  persists. 

The  exciting  cause  has  been  attributed  to  the  presence  or  absence  of 
certain  mineral  substances,  but  the  wide  variety  of  the  supposed  agents 
is,  of  itself,  strong  evidence  of  the  poor  foundation  upon  which  the 
mineral  matter  theory  rests.  It  is  noticed,  for  instance,  that  in  some 
districts  where  the  disease  is  especially  prevalent,  the  soil  is  largely 
magnesian  limestone,  and  that,  as  might  be  supposed,  the  ground-water 
is  rich  in  lime  and  magnesium  salts.  Therefore,  it  is  reasoned,  mag- 
nesian limestone  must  be  the  cause ;  but  there  are  many  such  districts 


WATER  AND  DISEASE.  373 

where  goitre  is  unknown.  More  than  that,  the  disease  is  endemic  in 
some  quarters  where  the  water  is  soft  and  almost  free  from  lime  and 
magnesium  salts.  Again,  it  has  been  attributed  to  the  presence  of  cer- 
tain salts  of  iron,  but  this  theory  also  cannot  bear  the  test,  for  these 
may  be  present  where  no  goitre  is  seen,  and  may  be  absent  where  the 
disease  prevails.  Absence  of  iodine  is  another  explanation  based  on 
nothing  worthy  of  credence. 

The  most  probable  cause  is  now  believed  by  some  to  be  an  organism 
which  flourishes  in  the  water.  The  first  to  promulgate  this  theory 
were  Italian  observers,  who,  in  1890,  reported  facts  of  interest  bearing 
on  the  question,  since  which  time,  other  observers,  particularly  in  India, 
have  contributed  farther  evidence  of  its  probable  truth. 

The  most  striking  facts  have  been  presented  by  Surgeon-Lieutenant 
E.  E.  Walters,^  whose  observations  were  pursued  in  a  district  in  India 
2,000  feet  above  sea-level,  with  extremely  porous  soil  and  a  water  sup- 
ply containing  but  slight  amounts  of  organic  and  mineral  matter,  and 
but  minute  traces  of  iron.  The  inhabitants,  who  live  under  the  same 
climatic  conditions,  but  with  different  occupations,  may  be  divided 
into  two  classes  :  the  native  Bhutias  and  the  Sepoy  troops  from  the 
northwest  provinces.  The  former  are  carriers  and  coolies ;  they  are 
omnivorous,  but,  by  reason  of  poverty,  mostly  vegetarians.  Their 
chief  diseases  are  goitre,  syphilis,  and  malaria.  The  temporary  inhab- 
itants, the  Sepoys,  are  all  vegetarians,  and  are  a  healthy  lot,  practically 
free  from  syphilis,  and  living  under  excellent  hygienic  conditions.  They 
had  been  in  the  district  twenty  months.  Examination  of  169  Bhutias 
showed  that  more  than  75  per  cent,  had  goitre ;  nearly  70  per  cent,  of 
those  over  twelve  years  of  age  were  afflicted.  Of  380  Sepoys  examined, 
54  per  cent,  had  goitre.  The  Bhutias  say  that  their  goitres  increase 
during  the  rainy  season,  and  this  is  borne  out  by  the  out-patient  register 
and  regimental  admission  book  for  1895.  All  the  British  officers,  too, 
had  suffered  from  enlarged  thyroids  durmg  the  preceding  rainy  season. 
Their  drinking-water  Avas  passed  through  a  Pasteur  filter ;  all  other 
water  used  was  taken  as  tea  or  soda.  Taking  up  the  several  conditions 
which  have  been  alleged  as  the  cause  of  the  process,  he  shows  them 
to  be  not  at  fault  in  this  particular  district.  Iron  was  present  in  the 
water  in  only  minute  quantities,  and  the  highest  degree  of  permanent 
hardness  was  but  3.5.  As  to  lime  as  a  cause,  it  appears  that  many  of 
the  Bhutias  without  goitres  are  great  eaters  of  lime,  while  of  the  Sepoys, 
who  never  touch  it,  more  than  50  per  cent,  developed  goitres  within 
twenty  months  after  arrival.  The  theory  that  the  disease  is  due  to 
carrying  heavy  loads  up  and  down  hills,  might  satisfy  in  the  case  of 
the  Bhutias,  but  not  in  that  of  the  Sepoys,  who,  though  not  carriers, 
yet  have  gcntre.  Farther,  as  to  age,  it  appears  that  55  per  cent,  of 
the  children  under  twelve  had  no  goitres  after  living  there  all  their 
lives,  or  about  the  same  percentage  as  developed  them  among  the  Sepoys 
after  a  visit  of  only  twenty  mr)nths.  He  believes  the  disease  to  be  due 
to  an  organism  of  the  amccba  type,  with  a  selective  power  against  the 
'  British  Medical  .Journal,  September  11,  1897. 


374-  WATER. 

thyroid  or  its  secretion.  For  a  time  the  system  opposes  it,  and  some- 
times successfully ;  but  when  the  cause  overpowers  the  phagocytic 
resources  of  the  system,  the  thyroid  enlarges  in  the  effort  to  combat 
the  poison.  Under  thyroid  feeding  (two  5-grain  tabloids  daily)  the 
records  show  a  weekly  diminution  of  a  quarter  to  half  an  inch  in  the 
circumference  of  the  Sepoys'  necks,  but  when  the  treatment  ceases, 
the  gland  again  increases  in  size.  That  is  to  say,  additional  resisting 
power  is  conferred  by  thyroid  tabloids,  which  keep  the  poison  in  check 
and  allow  the  gland  to  recover  its  normal  size ;  but  on  withdrawing 
the  accessory  agent,  there  is  diminished  resistance  and  then  again  an 
increase  in  size. 

Disorders  Connected  with  Organic  Pollution. — Ordinary  vege- 
table matter  in  suspension  and  abundant  growths  of  algse  and  other 
water  plants  sometimes  cause  diarrhoeal  troubles,  but  they  do  not  cause 
specific  disease.  Peaty  matters  in  solution  have  now  and  then  appeared 
to  be  connected  with  intestinal  derangement,  but  we  have  no  absolute 
knowledge  that  they  actually  have  been  or  can  be  a  cause  of  such 
trouble. 

We  know  three  epidemic  diseases  which  we  may  say  with  certainty 
can  be  carried  by  water.  These  are  :  cholera,  typhoid  fever,  and 
dysentery,  but  it  is  said  commonly  that  water  is  a  great  factor  in  the 
spread  of  diphtheria,  yellow  fever,  and  malaria.  In  the  case  of  diph- 
theria, the  weight  of  evidence  is  certainly  against  its  being  a  water-borne 
disease.  There  is  some  evidence  of  its  spread  through  the  use  of  a, 
common  water  supply,  but  in  these  cases  there  is  usually  a  common 
drinking  vessel,  and  probably  a  preexisting  case  of  the  disease  among 
the  drinkers.  The  diphtheria  organism  cannot  long  survive  in  water 
which  is  not  very  extensively  polluted. 

As  to  yellow  fever,  there  is  no  evidence  whatever  of  value,  but  in 
the  older  literature  of  hygiene  many  outbreaks  attributed  to  polluted 
water  are  recorded.  In  the  light  of  our  present  knowledge,  these 
instances  have,  naturally,  no  standing,  but  in  justice  to  those  who 
recorded  them  it  must  be  said  that,  before  the  discovery  that  the  disease 
was  mosquito-borne,  the  evidence  presented  seemed  to  be  uncontro- 
vertible. For  example,  outbreaks  occurring  at  sea  aboard  ships  that 
recently  had  been  in  infected  ports,  where  the  water-casks  had  been 
refilled,  could  not  be  attributed  to  telluric  influences,  and  the  replenished 
water-supply  offered  the  only  explanation. 

As  with  yellow  fever,  so  with  malaria,  abundant  evidence  of  con- 
nection with  water  as  a  cause  has  been  recorded,  although  the  fact  has 
long  been  known  that  water  from  malarial  districts  may  be  used  by 
communities  at  a  distance  without  harm,  as  is  the  case  with  the  city  of 
Rome. 

One  of  the  best  cases  which  have  been  accepted  as  proof  of  trans- 
mission by  water  is  that  reported  by  Laveran,  who  failed,  however,  to 
furnish  certain  facts  which  our  present  knowledge  would  require.  A 
detachment  of  soldiers  drank  at  a  certain  well,  and  then  enjoyed  a 
hearty  meal ;  another  detachment  ate  first,  and  later  drank  from  the 
same  well.     Of  the  former,  all  became  sick  with  malaria  ;  of  the  latter, 


WATER  AND  DISEASE.  375 

not  one  was  affected.  The  difference  in  the  results  was  thought  to  be 
due  to  the  fact  that  those  who  escaped  took  no  water  until  the  gastric 
juice  was  secreted  in  the  process  of  digestion.  Quite  a  number  of 
cases  are  recorded  in  which  men  on  shipboard  have  used  the  water  of 
certain  casks  which  others  had  declined,  the  former  becoming  sick  with 
malaria,  and  the  latter  escaping. 

There  is  evidence  that  certain  animal  diseases  may  be  spread  by 
water  containing  the  specific  organism.  Hog  cholera  and  anthrax 
have  certainly  been  spread  by  water  into  which  the  bodies  of  those  that 
had  died  of  these  diseases  had  been  thrown,  and  glanders  may  be 
.spread  from  horse  to  horse  by  the  use  of  a  common  drinking  trough. 

The  diseases  of  greatest  interest  in  connection  with  drinking-water 
are  two  which  we  know  can  be  spread  by  infected  water — cholera 
and  typhoid  fever.  The  first-mentioned  happens,  with  us,  to  be  one  of 
minor  interest,  inasmuch  as  it  is  a  most  uncommon  visitor ;  the  other, 
however,  is  always  with  us,  and  we  have,  therefore,  constant  oppor- 
tunity for  observation  of  the  influence  of  polluted  water  in  its  causa- 
tion. 

The  strongest  proof  of  the  value  and  efficiency  of  the  purification  of 
water  by  filtration  through  sand  is  the  drop  which  occurs  in  the  mor- 
tality from  typhoid  fever  Ayhen  a  community  abandons  the  use  of  un- 
treated polluted  water,  and  adopts  this  method  of  improving  the  quality 
without  <?hanging;  the  source  of  supply.  The  city  of  Lawrence,  Mass- 
achusetts, for  example,  prior  to  and  including  part  of  the  year  1893, 
used  the  unfiltered  water  of  the  Merrimac  River,  into  which  is  poured 
the  sewage  of  a  succession  of  large  cities  and  towns  having  an  aggre- 
gate population  of  several  hundred  thousands.  In  the  year  mentioned, 
the  process  of  filtration  was  adopted,  and  good  results  were  almost 
immediately  evident.  Following  are  the  death-rates  from  typhoid  fever 
per  10,000  of  population  for  the  four  years  immediately  preceding  and 
for  the  same  period  following  the  change  : 


Preceding  change. 

Year  of  change. 

Following  change. 

1889  .    .    .12.7 

1890  .    .    .  13.4 

1891  .  .  .  n.9 

1892  .    .    .  10.5 

1893  ...  8.0 

1894  ...  4.7 

1895  ...  3.1 

1896  ...  1.9 

1897  ...  1.6 

It  is  but  fair  to  add  that  about  half  the  deaths  from  the  disease  in 
1894  and  1895  were  of  persons  who  persisted  in  drinking  unfiltered 
water  directly  from  the  canals. 

The  city  of  Hamburg  adopted  filtration  in  May,  1893,  after  a  most 
devastating  epidemic  of  cholera  in  the  preceding  year.  Typhoid  fever 
had  always  claimed  a  very  large  number  of  victims  annually,  and  dur- 
ing the  four  years  1 890-1 89.''>,  the  death-rate  from  the  disease  was  2.6 
per  10,000;  but  in  the  ne.xt  two  (1894-1895),  it  fell  to  0.75. 

Comparison  of  typlioid  death-rates  of  cities  using  polluted  waters 


376  WATEB. 

with  those  of  others  using  pure  or  purified  waters  is  most  convincing 
both  of  the  efficiency  of  filtration  and  of  the  disastrous  results  of  neg- 
lecting to  protect  the  public  from  the  dangers  of  impure  supplies.  The 
cities  of  Chicago  and  Berlin  may  well  be  selected  for  comparison, 
having  approximately  the  same  number  of  inhabitants.  Chicago  takes 
its  water  from  Lake  Michigan,  into  which  vast  volumes  of  sewage  are 
poured  at  various  points,  and  uses  it  without  purification.  Berlin  is 
supplied  by  two  lakes,  Tegel  and  Miiggel,  which  are  protected  so  far  as 
possible  from  pollution,  but,  nevertheless,  every  gallon  used  is  filtered. 
During  the  years  1890—1894,  the  death-rates  from  this  one  disease 
averaged  84  per  100,000  at  Chicago,  and  but  8,  or  less  than  one-tenth 
as  high,  at  Berlin.  Between  1889  and  1893,  Chicago  suffered  unusu- 
ally from  typhoid,  and  in  1891  the  typhoid  mortality  reached  159.7 
per  100,000.  At  this  time,  the  intake  was  situated  but  a  few  hundred 
feet  from  the  shore,  and,  in  consequence  of  the  ravages  of  the  disease, 
a  tunnel  was  built,  extending  the  intake  four  miles  into  the  lake.  The 
result  of  this  extension  was  an  immediate  marked  fall  in  the  number 
of  cases,  but  nothing  comparable  to  what  might  reasonably  be  expected 
had  the  water  been  subjected  to  filtration. 

The  experience  of  Philadelphia  within  recent  years  furnishes  a  most 
instructive  example  of  the  danger  of  using  polluted  water.  During 
the  first  six  months  of  the  year  1899,  in  a  population  of  over  a  million, 
7038  cases  of  typhoid  fever,  with  800  deaths,  were  recorded.  During 
the  first  five  weeks  of  1902,  510  cases  occurred,  with  49  deaths. 
Between  January  1  and  April  11,  1904,  in  a  population  of  about 
1,300,000,  there  occurred  nearly  2500  cases;  and  of  these,  no  fewer 
than  389  were  reported  in  a  single  week,  this  number  being  the  largest 
ever  reported  in  any  week  in  the  history  of  the  city.  In  that  part  of 
the  city  to  which  the  new  supply  of  filtered  water  was  furnished,  there 
was  an  almost  immediate  fall  in  the  typhoid  rate,  the  immediate  neigh- 
borhood not  so  supplied  continuing  to  maintain  a  much  higher  rate. 

Typhoid  Infection  of  Water  Supplies. — Typhoid  infection  of  a 
water  supply  may  be  direct  or  indirect.  Direct  infection  occurs  through 
the  entrance  of  ordinary  sewage  containing  the  essential  organism,  or 
of  faeces  or  urine  discharged  along  the  banks  of  a  river  or  lake,  for 
example,  by  persons  suffering  with  or  convalescent  from  the  disease. 
Indirect  infection  occurs  from  discharges  deposited  in  or  upon  the  soil, 
and  thence  washed  by  rain  into  bodies  of  water  or  downward  into  wells. 
Ordinary  sewage  pollution  is  not  sufficient  to  bring  about  an  outbreak 
of  the  disease,  nor  will  specific  pollution  necessarily  always  be  followed 
by  the  occurrence  of  cases.  The  specific  organism  has  only  a  limited 
tenure  of  life,  and,  in  the  absence  of  conditions  favorable  to  its  exist- 
ence, it  may  perish  before  it  reaches  the  consumer.  Moreover,  the 
number  present  may  be  very  small  and  the  effects  produced  so  slight 
as  to  occasion  little  notice.  It  is  to  be  borne  in  mind  that  not  every 
mouthful  of  a  polluted  supply  contains  the  organism,  and  that  not 
every  person  to  whose  system  it  gains  access  must  necessarily  come 
down  with  the  disease. 


WATER  AND  DISEASE.  377 

Until  quite  recently,  it  has  been  supposed  that  the  infecting  organ- 
isms had  their  origin  only  in  the  faeces  of  preexisting  cases ;  but  it  is 
now  known  that  this  is  far  from  being  the  case,  and  that  they  exist  in 
the  faecal  discharges  during  only  the  early  stages  of  the  disease,  or  up 
to  the  twentieth  day  or,  perhaps,  even  somewhat  later,  Petruschky ' 
has  shown  that  the  urine  may  contain  millions  of  living  bacilli  in  each 
cubic  centimeter,  and  that  they  may  be  found  for  many  weeks,  and  even 
after  convalescence  is  well  established.  They  may  appear  as  early  as 
the  fifteenth  day,  when,  perhaps,  they  are  no  longer  demonstrable  in  the 
faeces.  Dr.  Mark  W.  Richardson  ^  found  them  in  very  large  numbers 
and  in  practically  pure  culture  in  the  urine  of  nine  out  of  thirty-eight 
patients.  They  appeared  late  in  the  course  of  the  disease,  and  continued 
to  be  eliminated  in  several  of  the  cases  after  discharge  from  the  hos- 
pital. These  observations  of  Petruschky  and  Richardson  have  been 
confirmed  by  other  bacteriologists.  It  appears,  then,  that  an  apparently 
well  person  is  capable  of  infecting  a  water  supply  to  a  greater  extent 
and  with  less  optical  evidence,  or  none  at  all,  by  a  discharge  of  urine 
into  a  water  course  than  an  evidently  sick  one  by  a  deposit  of  his  faeces 
into  it  or  upon  its  banks. 

Whatever  the  mode  of  infection  of  a  public  water  supply,  the  results^ 
if  any,  are  seen  in  an  increase  in  the  number  of  cases  ordinarily  occur- 
ring in  the  community  supplied,  and,  except  in  those  instances  where 
the  disease  is  spread  by  infected  shellfish  or  other  foods,  any  considerable 
augmentation  of  cases  points  unmistakably  to  the  consumption  of  pol- 
luted water,  even  though  the  system  of  filtration  is  followed.  In  the 
latter  instance,  investigation  almost  certainly  will  show  some  defect  in 
the  filters,  or  that  their  capacity  has  been  overtaxed.  Even  after  sub- 
sidence of  the  outbreak,  the  disease  may  continue  to  be  more  prevalent 
than  usual  for  some  little  time,  especially  in  the  absence  of  a  proper 
system  of  sewerage. 

Influence  of  Introduction  of  Public  Water  Supplies  on  Typhoid 
Rates. — Contrary  to  what  might  be  expected,  the  highest  death-rates 
from  typhoid  fever  in  thickly  settled  countries  are,  generally  speaking, 
not  in  the  crowded  cities,  but  in  the  towns  which  have  no  public  water 
supplies.  In  Massachusetts,  for  example,  the  5  towns  highest  in  this 
respect  had,  during  the  eighteen  years  prior  to  1890,  an  average  typhoid 
death-rate  of  12.82  per  10,000  of  population,  while  the  average  of  the 
five  highest  rates  for  cities  with  public  supplies  was  but  7.65,  and  of 
all  the  cities  of  the  Commonwealth  only  4.62.  In  the  town  with  the 
highest  mortality,  Ware,  the  average  for  fifteen  years  prior  to  1866 
was  16.5  in  10,000;  in  that  year  a  public  supply  was  introduced, 
and  at  the  expiration  of  four  years  the  mortality  had  diminished  60 
per  cent. 

In  1870,  only  20  cities  and  towns  in  Massachusetts  had  modern 
public  supplies;  at  the  end  of  1806,  all  of  the  32  cities  and  127  of 
the  322  towns,  comprising  89.8  per  cent,  of  the  entire  population,  were 

'  Ccntralhliitt  fiir  ]',:ikU-r\(,]<,^\ii  iind  Piiriisitenkiinde,  1898,  XXIIT.,  No.  14. 
'■^  .Journal  of  Kxpcriinental  Medicine,  May,  1898. 


378 


WATER. 


thus  prov^ided,  and  but  3  towns  with  populations  exceeding  3500  had 
none;  at  the  end  of  1904,  but  8  per  cent,  of  the  entire  population  of 
2.805,000  were  without  public  supplies,  and  this  was  made  up  very 
largely  of  the  very  small  towns  with  scattered  inhabitants,  where  the 
introduction  of  public  works  would  be  beyond  the  financial  possibilities. 
As  a  result  of  this  very  general  introduction  of  a  common  supply  in 
place  of  that  derived  from  individual  wells,  largely  of  the  open  variety 
and  situated  in  close  proximity  to  sources  of  pollution,  a  decided 
decline  in  typhoid  fever  has  been  noticed.  This  result  is  by  no  means 
peculiar  to  Massachusetts,  but  is  found  to  be  the  consequence  wherever 
the  selection  of  the  source  is  made  with  judicious  care  and  measures 
are  taken  to  protect  it  from  avoidable  pollution.  It  is  not  to  be  sup- 
posed, however,  that  the  mere  introduction  of  a  common  supply 
without  the  observance  of  this  necessary  precaution  will  best  serve 
the  interests  of  the  public  health.  In  the  following  table,  compiled  by 
Mr.  Hiram  F,  Mills, ^  is  shown  the  change  in  the  typhoid  death-rates 
per  10,000  in  each  of  the  cities  of  Massachusetts  which  introduced 
water  within  the  vears  1869  to  1877  : 


Cities. 


Holyoke     .  . 

L.ivvrence   .  . 

Lowell    .    .  . 

Fall  River  . 

Springfield  . 

Taunton      .  . 
!N()rtl)ampton 

Lynn  .    .    .  . 
Kew  Bedford 

Kewton  .    .  . 

Maiden  .    .  . 

Fitcliburg  .  . 

^Vobnrn .    .  . 
Somerville 

Chelfsea  .    .  . 

Waltham    .  . 


Yearly   number 
of  deaths  from 
tvplioid  fever 
per  10,000, 1859 
to  1868. 


10, 


Date  of  intro- 
duction of 
water  supply. 


1873 

1875 
1872 
1874 
1875 
1876 
1871 
1871 
1869 
1876 
1870 
1872 
1873 
1867 
1867 
1873 


Yearly  number 

of  deaths  from 

tvphoid  fever 

per  10,000,  1878 

to  1889. 


8.93 
8.33 
7.63 
6.32 
5.29 
5.02 
4.04 
3.87 
3.80 
3.65 
3.54 
3.16 
2.95 
2.95 
2.89 
2.42 


Deaths  in 
second  period 
per  hundred 

of  those  in 
first. 


133 
100 
124 
81 
55 
82 
37 
43 
49 
56 
44 
30 
36 
69 
48 
30 


It  will  be  noticed  that  of  these  sixteen  cities  there  were  three  which 
showed  no  improvement,  and  two  of  these  were  worse  off  than  before. 
The  reason  for  this  is  clear.  All  three  are  manufacturing  cities, 
situated  on  rivers  polluted  by  sewage.  At  Holyoke,  while  the  public 
supply  is  but  slightly  liable  to  contamination,  the  operatives  in  the  fac- 
tories used  water  from  two  other  sources,  subject  to  gross  pollution  ; 
namely,  from  the  canals,  the  entrance  of  one  of  which  is  situated  close 
to  the  outlet  of  one  of  the  main  sewers  of  the  city,  and  from  wells 
indirectly  supplied  by  the  canals.  Comparison  of  the  death-rates  from 
typhoid  fever  among  those  of  different  occupations,  brought  out  the 
fact  that  the  opei^atives   in  the  mills  which   used  canal  water   suffered 


'■  22d  Annual  Report  of  the  State  Board  of  Health  of  Massachusetts,  1890,  p,  534. 


WATER  AND  DISEASE.  379 

from  the  disease  three  times  as  much  pro  rata  as  all  other  persons. 
Lowell  and  Lawrence,  at  the  time  mentioned,  were  using  the  polluted 
water  of  the  Merrimac  River.  Lowell  took  its  supply  fourteen  miles 
below  the  point  of  entrance  of  the  sewage  of  Nashua,  N.  H.,  and  con- 
sumed it  without  treatment.  Lawrence  drew  upon  the  same  supply, 
after  its  enrichment  by  the  sewage  of  Lowell,  at  a  point  but  nine  miles 
below  the  outfall  of  the  latter' s  sewage.  In  1891,  Lowell  suffered 
unusually  from  typhoid  fever  by  reason  of  the  additional  contamina- 
tion by  fgeces  of  typhoid  patients  discharged  into  Stony  Brook,  a  small 
tributary  of  the  Merrimac,  only  three  miles  above  the  intake  of  the 
water- works. 

The  conditions  of  all  three  places  have  since  been  changed.  At 
Holyoke,  warnings  were  posted  for  the  benefit  of  the  operatives ; 
Lowell  abandoned  the  river  in  favor  of  ground-water  in  1893,  and  in 
the  same  year  Lawrence  instituted  filtration.  In  all  of  the  three  cities 
the  expected  happened  ;  namely,  a  marked  diminution  in  the  death-rate. 

Examination  of  the  above  table  reveals  the  fact  that  in  the  majority 
of  the  sixteen  cities  the  reduction  in  the  typhoid  death-rate  was  most 
pronounced.  In  some  of  them,  the  diminution  has  proceeded  to  a 
much  greater  extent  than  is  shown  here.  In  1896,  three  cities  with  an 
aggregate  population  of  70,000  showed  less  than  1  death  per  10,000 
from  this  disease,  and  in  one  of  them,  Woburn,  there  was  none  at  all. 

Examples  of  Typhoid  Fever  Epidemics  and  of  Limited  Out- 
Ijreaks  Traced  to  Infected  Water. — For  the  purpose  of  illustrating 
to  what  an  extent  specifically  polluted  water  can,  under  favorable  con- 
ditions, bring  about  a  sudden  outbreak  or  explosion,  the  following 
cases  have  been  selected  from  the  many  which  are  to  be  found  in  the 
literature  of  hygiene. 

Epidemic  at  Lausen,  Switzerland. — This  best  known  and  most  often 
quoted  of  epidemics  of  typhoid  fever  was  practically  the  first  one  of 
any  considerable  extent  to  be  traced  undisputably  to  the  use  of  spe- 
cifically polluted  water,  although  many  outbreaks,  large  and  small, 
had  been  ascribed  to  the  use  of  water  "  containing  considerable  organic 
matter,"  and  only  supposedly  infected. 

Up  to  1872,  this  village  of  780  inhabitants  had  not  been  visited  by 
typhoid  fever,  even  in  sporadic  cases,  for  sixty  years.  On  August  7th, 
with  no  previous  warning,  ten  persons  were  seized,  and  during  the 
next  ten  days  nearly  sixty  more.  The  number  of  cases  increased 
from  day  to  day  until  130  persons,  or  one-sixth  of  the  entire  popula- 
tion, had  been  seized.  So  large  a  percentage  of  involvement  pointed 
to  some  common  cause,  and  the  immunity  enjoyed  by  the  inmates 
of  a  group  of  houses  not  connected  with  the  public  water  supply 
directed  attention  to  the  latter,  which  was  derived  from  a  spring  at 
the  foot  of  a  ridge  al)out  300  feet  high,  between  the  village  and  the 
Fiihrler  valley.  In  this  valley,  at  a  point  between  one  and  two  miles 
distant  from  Lausen,  was  an  isolated  farm  where  dwelt  a  man  who, 
on  June  10th,  shortly  after  his  return  from  a  visit,  was  taken  sick 


380  WATER. 

with  typhoid  fever.  Before  the  end  of  July,  three  cases  more  devel- 
oped in  the  same  house.  The  discharges  of  all  four  were  thrown 
into  a  brook  in  which  the  family  washing  was  done,  and  which  served 
to  irrigate  the  meadows  below.  Whenever  it  was  dammed  up  for 
this  purpose,  the  volume  of  the  water  supply  beyond  the  ridge  was 
noticeably  increased.  Between  July  loth  and  the  end  of  the  month, 
the  meadows  had  been  submerged  by  this  process,  and  in  three  weeks 
from  the  beginning  of  the  operation,  the  explosion  occurred  in 
Lausen. 

The  sequence  of  events  was,  then,  the  appearance  of  the  initial  case 
on  June  10th,  and  of  three  more  in  the  same  house  before  the  end  of 
July,  the  daily  pollution  of  the  water  of  the  brook,  the  damming  of 
the  brook  in  the  middle  of  July,  and  the  appearance  of  the  first  cases 
in  Lausen  on  August  7th.  Everything  pointed  to  direct  connection 
between  the  impounded  water  and  the  spring  a  mile  or  more  distant 
on  the  other  side  of  the  ridge,  and  its  existence  was  established  by 
dumping  about  a  ton  of  salt  into  the  brook  and  noting  its  speedy 
appearance  in  the  Lausen  spring.  As  a  very  large  amount  of  flour, 
deposited  at  the  same  place,  gave  no  evidence  of  its  appearance,  even 
in  traces,  it  was  proved  that  the  Avater  passed  through  a  coarse  filter- 
ing medium  rather  than  through  an  open  underground  passage. 

The  Plymouth,  Pa.,  Epidemic. — The  town  of  Plymouth,  Pennsylvania, 
had,  at  the  time  of  the  epidemic  in  1885,  a  population  of  about  8,000 
people.  The  general  water  supply  was  derived  from  a  mountain 
brook,  which  was  dammed  at  intervals  so  as  to  form  a  series  of  im- 
pounding reservoirs,  but  a  large  part  of  the  population  was  supplied 
bv  individual  wells.  A  citizen  who  spent  the  Christmas  holidays  at 
Philadelphia  returned  in  January  to  his  home,  ill  with  typhoid  fever, 
and  had  a  very  protracted  sickness.  During  the  entire  period,  his 
excreta,  which  were  in  no  way  disinfected,  were  thrown  upon  the  snow 
and  ice  on  a  slope  not  forty  feet  away  from  the  brook,  at  a  point  mid- 
way between  two  of  the  dams.  At  this  time  the  brook  was  frozen 
over,  and  it  remained  so  until  the  approach  of  spring.  During  the  last 
third  of  the  month  of  March,  there  was  a  sudden  period  of  warmth, 
and  the  snow  and  ice  began  to  melt.  Shortly  afterward,  the  warm 
spring  rains  began,  and  the  ice  and  snow  and  frozen  excreta  upon  the 
slope  were  melted,  and  the  entire  accumulation  was  washed  into  the 
brook,  and  thence  into  the  water  mains.  Within  three  weeks  there- 
after, cases  of  typhoid  fever  by  the  score  made  their  appearance 
throughout  the  town.  On  some  days,  more  than  a  hundred  new 
cases  were  reported,  and  on  one,  the  number  reached  nearly  two 
hundred.  The  total  number  of  seizures  has  variously  been  stated, 
the  lowest  estimate  being  1,000  and  the  highest  1,500.  The  number 
of  deaths  was  not  less  than  114,  and  has  been  placed  as  high  as  150. 

It  was  discovered  that  the  epidemic  was  limited  practically  to  those 
whose  houses  were  supplied  by  the  town  mains,  and  to  those  who, 
while  supplied  at  home  by  wells,  drank  of  the  public  supply  while 
absent  from  home  during  working  hours.     This  distribution  Avas  par- 


WATER  AND  DISEASE.  381 

ticularly  emphasized  in  one  street,  where  the  houses  on  one  side  all 
had  one  or  more  cases,  while  those  on  the  other  had  none  at  all. 
The  former  were  supplied  by  the  town  mains,  and  the  latter  depended 
upon  wells. 

Outbreak  at  Uvernet. — A  somewhat  similar  outbreak,  on  a  much 
smaller  scale,  is  reported  by  Dr.  Dupard '  as  occurring  at  a  small  vil- 
lage in  the  Alps,  the  details  of  which  are  as  follows  :  In  October,  1898, 
a  detachment  of  157  infantry  soldiers  were  quartered  in  four  houses  in 
the  village,  each  house  sheltering  approximately  a  fourth  of  the  men. 
In  one,  where  37  were  quartered,  there  appeared  within  a  few  weeks  22 
cases  of  typhoid  fever,  6  of  which  terminated  fatally.  At  the  time  of 
seizure,  there  were  no  other  cases  in  the  village,  nor  did  any  appear  in 
any  other  house  than  this  one.  Investigation  revealed  the  fact  that,  a 
few  days  before  the  arrival  of  the  troops,  a  child  of  ten  years  had  been 
taken  ill  with  the  disease  in  another  house  situated  on  higher  ground, 
about  400  feet  away  from  the  house  in  question.  Where  the  child  lay 
ill,  there  was  no  privy,  and  his  excreta  were  thrown  upon  the  ground 
in  a  neighboring  field.  His  soiled  clothes  were  washed  in  the  spring 
nearby.  At  the  time  of  the  soldiers'  arrival,  a  number  of  heavy  rains 
occurred,  by  which  the  surface  impurities  of  the  soil  in  the  neighbor- 
hood of  the  house  where  the  child  lived  would,  by  reason  of  the  incli- 
nation of  the  ground,  be  washed  toward  the  house  occupied  by  the 
soldiers.  This  was  supplied  by  water  from  a  small  stream  through 
a  rude  main  constructed  of  worm-eaten  hollow  loffs  laid  in  a  shallow 
depression  in  the  surface  of  the  soil.  There  could  be  no  question  of 
the  probability  of  contamination  of  this  supply  by  the  fsecal  discharges 
thrown  upon  the  ground  in  the  vicinity,  and  in  the  absence  of  any  other 
cases  and  with  the  high  percentage  of  seizures  in  the  one  house,  no 
other  explanation  appears  to  be  possible. 

Epidemic  at  Ashland,  Wisconsin,  in  1893-94. — This  outbreak  is  one 
of  peculiar  interest,  in  that,  in  addition  to  serving  as  an  excellent  illus- 
tration of  the  danger  of  using  the  same  body  of  water  as  a  place  for 
the  disposal  of  scAvage  and  as  a  source  of  drinking-water,  it  was  made 
the  basis  of  an  action  at  law,  which  established  the  liability  of  water 
companies  and  municipalities  in  case  of  sickness  and  death  caused  by 
the  distribution  and  use  of  infected  water. 

The  city's  supply  is  derived  from  an  arm  of  Lake  Superior,  Che- 
quamegon  Bay,  upon  which  the  city  is  situated.  This  bay,  which  is 
about  twelve  miles  long,  and  of  an  average  width  of  five,  varies  from 
eight  to  thirty-six  feet  in  depth.  North  of  the  city,  and  extending 
outward  in  a  northwestwardly  direction,  is  a  breakwater  constructed 
for  the  protection  of  the  harbor  against  northerly  gales ;  and  between  it 
and  the  city  the  mouth  of  tlie  water  intake  is  located  about  a  mile 
fn^m  the  shore.  (See  Fig.  35.)  Tlie  sewage  of  the  city  is  discharged 
further  to  the  west  and  south.  Tl>e  currents  in  the  bay  follow  the 
course  indicated  by  the  arrows  in  the  figure,  and  carry  the  sewage 
toward  the  breakwater  mikI   over  tlic  mouth  of  the  intake.     This  con- 

'  Lyon  i.H'.liciil,  J;in.  1,  ]  809,  p.  5. 


382 


WATER. 


dition  of  affairs  was  brought  to  the  attention  of  the  company  by  the 
health  boards  of  the  city  and  state  repeatedly,  but  without  results. 
That  the  water  was  polluted,  was  evident  on  mere  ocular  inspection,  for 
it  was  often  cloudy  or  markedly  turbulent.  During  the  winter  of 
1893—94,  typhoid  fever  made  its  appearance  in  the  city,  and  from  the 
initial  cases  a  disastrous  epidemic  developed,  which  led  to  the  establish- 
ment of  a  model  filtering-plant. 

The  action  at  law  referred  to  above,  was  brought  by  the  widow  of 
one  of  the  victims.  In  evidence,  it  was  shown  that  he  lived  continu- 
ously in  Ashland,  and  drank  no  water  other  than  that  supphed  by  the 

Fig.  35. 


Conditions  obtaining  at  Ashland,  Wis.,  prior  to  the  epidemic  of  1893-94. 


water  company ;  that  previous  to  his  seizure  the  disease  had  prevailed 
in  the  city,  and  that  the  discharges  from  the  antecedent  cases  had 
passed  into  the  waters  of  the  bay  by  way  of  the  city  sewers.  The 
court  found  for  the  plaintiff  in  the  sum  of  $5,000. 

Epidemic  at  Luneburg  in  1895. — The  ancient  town  of  Liineburg,  with 
a  population  of  22,000,  has  a  system  of  sewers  which  empty  at  two 
points  into  the  small  River  Ilmenau.  The  public  water  supply  is  in 
the  hands  of  a  number  of  se^Darate  corporations,  which  had  their  origin 
in  mediaeval  guilds ;  and  as  the  two  jDrincipal  ones  supply  the  same 
parts  of  the  town,  it  happens  that  their  mains  run  through  the  same 
streets,  and  that  not  alone  adjoining  houses,  but  even  different  stories 


WATER  AND  DISEASE.  383 

of  the  same  building  are  supplied  by  either  one  according  to  circum- 
stances. The  Raths  Company  furnishes  a  ground-water  which  is  per- 
fectly good,  except  for  its  rather  high  content  of  iron,  which  sometimes 
has  caused  more  or  less  trouble.  The  other  large  corporation,  known 
as  the  Abts  Company,  obtains  its  water  from  the  Ilmenau,  usually  at  a 
point  above  the  town  ;  but  between  July  1 5th  and  20th,  it  drew  it  from 
a  place  in  the  middle  of  the  town,  opposite  the  pumping-station,  where 
the  water  was  extremely  impure.  Previous  to  these  dates,  typhoid 
fever,  which  was  always  present  in  some  amount  in  the  town,  had 
begun  to  appear  to  an  unusual  extent ;  and  in  the  first  half  of  August, 
there  was  a  sudden  and  remarkable  increase  in  the  number  of  cases. 
On  the  termination  of  the  outbreak,  205  cases  had  been  reported,  169, 
or  82.44  per  cent.,  of  which  were  among  families  supplied  with  the 
water  of  the  river. 

It  was  proved  that,  for  a  period  of  some  days,  which  included  the 
dates  above  mentioned,  the  diarrhoeic  discharges  of  a  young  girl,  sick 
with  typhoid  fever,  were  thrown,  without  being  disinfected,  into  the 
river  at  a  point  about  300  feet  above  the  intake  and  on  the  same  side. 
In  addition  to  this  one  source  of  the  causative  agent  which  produced 
such  a  sudden  rise  in  the  curve,  it  was  known  that  the  river  had  been  pol- 
luted by  the  discharges  of' another  patient  in  May,  and  that  the  epidemic 
had  its  real  beginning  in  June.  It  is  conceivable  that  in  a  town  where 
the  house  supplies  are  so  complicated  that  different  stories  have  differ- 
ent kinds  of  water,  a  fair  percentage  of  the  victims  of  an  epidemic  may 
acquire  the  disease  through  neighborhood  visiting,  though  their  own 
domestic  supply  is  of  the  proper  quality.  In  this  whole  outbreak,  only 
17.56  per  cent,  of  the  cases  were  among  people  whose  premises  were 
supplied  by  the  other  companies. 

Epidemic  at  Zehdenick  in  1897. — This  was  a  local  outbreak  traced 
to  the  contamination  of  a  well  by  the  discharges  of  a  child  sick  with 
typhoid  fever.  The  water  was  used  by  the  inmates  of  the  houses  in 
the  immediate  vicinity,  and  the  disease  was  limited  to  them  alone. 
Of  303  persons  making  up  the  29  households  of  the  neighborhood,  94, 
or  nearly  a  third,  were  seized  within  a  short  period,  while  not  another 
case  was  knowui  in  the  town.  The  inmates  of  nine  houses  within  the 
infected  area,  who  obtained  their  water  from  another  source,  were  un- 
touched. 

Limited  Outbreak  Among  Soldiers. — An  infantry  regiment,  returning 
from  the  autumn  manoeuvres,  passed  through  a  small  village  -svhere 
typhoid  fever  existed,  and  halted  for  water.  Two  days  afterward,  3 
men  were  seized  with  great  suddenness,  and  within  two  weeks,  36  men 
were  down  with  the  disease.  They  had  been  exposed  to  no  other 
source  of  infection,  and  other  troops  who  passed  through  the  same  vil- 
lage without  stopping  for  water  were  unaffected.  Knowing  the  day 
when  the  infection  occurred,  and  since  in  every  case  the  onset  was 
marked  by  very  acute  symptoms,  Dr.  Emil  Jauchen  ^  was  able  to 
determine  the  exact  p(!riod  of  incubation  :  3  were  seized  on  the  second 
'  Wiener  klinische  Wochenschi'ift,  July  7,  1898. 


384  WA  TEE. 

day,  7  on  the  third,  6  on  the  fourth,  4  on  the  fifth,  4  on  the  sixth, 
5  on  the  seventh,  and  7  between  the  ninth  and  the  fourteenth.  The 
short  periods  are  explainable  by  the  fact  that  the  men  were  in  a 
state  of  exhaustion  at  the  time  of  drinking,  and  all  took  copious 
draughts. 

Epidemic  at  Butler,  Pa.,  in  1903. — Butler,  Pennsylvania,  is  a  thriving 
city  of  about  16,000  inhabitants,  supplied  with  water  from  three  sources, 
two  of  which  are  situated  at  diiferent  points  on  Connoquenessing  Creek, 
and  the  third  is  an  impounding  reservoir  on  Thorn  Run,  which  is 
the  chief  tributary  of  the  creek.  On  August  28,  1903,  the  dam  at 
Boydstowu,  some  seven  or  eight  miles  above  Butler,  was  carried  away, 
and  the  main  source  of  supply  being  thus  lost,  the  water  company  was 
obliged  to  use  water  from  the  Thorn  Run  reservoir  and  to  pump  directly 
from  the  creek  at  the  pumping-station.  Before  distribution,  the  water 
was  treated  in  a  rapid  mechanical  filter,  from  which  it  was  sent  to  the 
city  reservoir.  On  October  21,  the  filter  plant  was  shut  down  for 
repairs,  and  during  the  next  ten  days  the  city  was  supplied  with  un- 
filtered  water,  taken  directly  from  the  creek  at  the  pumping-station. 
On  November  2,  an  epidemic  of  typhoid  fever  began,  and  so  rapidly 
did  it  spread  that,  by  December  17,  no  less  than  8  per  cent,  of  the  popu- 
lation (1270  cases)  had  been  attacked,  and  56  persons  had  died.  That 
the  epidemic  was  due  to  the  water-supply  was  emphasized  by  the  fact 
that  a  portion  of  the  city,  known  as  Springdale,  with  a  population  of 
about  2500,  not  provided  with  city  water,  but  supplied  by  deep  wells, 
was  almost  wholly  exempt,  there  being  but  2  cases  within  the  district. 
The  source  of  the  infection  was  not  far  to  seek.  Throughout  the  sum- 
mer and  autumn,  fairly  numerous  cases  of  typhoid  fever  had  occurred 
at  various  points  on  the  watershed,  and  there  was  ample  opportunity 
for  the  dejecta  to  be  carried  into  the  numerous  small  tributaries  and 
thence  into  the  creek.  In  one  house,  for  example,  provided  with  a 
privy  overhanging  a  small  stream  which  empties  into  the  creek  within 
a  short  distance  from  the  pumping-station,  there  occurred,  subsequent 
to  October  1,  no  fewer  than  5  cases  of  the  disease.  In  another  house 
near  Thorn  Run  dam  there  was  a  case  about  the  middle  of  August,  and 
this  was  followed  by  3  others. 

Epidemic  at  Ithaca,  N.  Y.,  in  1903. — At  the  time  of  this  outbreak,  Ithaca, 
Kew  York,  the  seat  of  Cornell  University,  was  a  city  of  about  13,000 
people,  with  an  additional  student  population  of  nearly  3000.  Its 
location  and  surroundings  are,  in  general,  unusually  favorable  to  health  ; 
in  1900,  the  death-rate  from  all  causes  was  but  16.3  per  thousand.  The 
public  water-supply  was  furnished  by  three  creeks,  which  flow  into 
Lake  Cayuga,  but  many  of  the  population  depended  upon  private  wells, 
of  which  there  are  about  1500  within  the  corporate  limits.  The  water 
company  which  supplied  the  city  proper  derived  its  water  from  Six-mile 
Creek  and  Buttermilk  Creek ;  the  University  was  supplied  by  Fall 
Creek,  under  its  own  management.  The  watersheds  of  these  three 
creeks  are  not  large  and  they  are  more  or  less  thickly  populated. 
Abundant  opportunities  exist  for  direct  infection  of  all  three  creeks, 


WATER  AND  DISEASE.  385 

privies  and  outhouses  being  situated  in  many  instances  Avithin  a  few  feet 
of  the  banks.  On  Six-mile  Creek  alone,  according  to  Dr.  George 
A.  Soper,  the  probable  sources  of  infection  at  the  time  of  the  epidemic 
numbered  a  hundred  or  more.  The  conditions  existing  within  the 
watershed  of  Buttermilk  Creek  are  said  to  have  been  equally  bad, 
while  those  along  Fall  Creek  were  even  worse,  although,  as  will  be 
seen,  this  source  of  supply  appears  not  to  have  been  specifically  pol- 
luted. In  addition  to  the  usual  sources  of  contamination  of  the  water 
of  Six-mile  Creek,  there  were  employed  during  November  and  part  of 
December,  1902,  about  60  laborers  in  the  construction  of  a  dam,  but 
careful  inquiry  failed  to  show  the  existence  of  any  sickness  among  them 
during  the  period  of  their  employment. 

The  public  supply  had  long  been  viewed  with  suspicion,  and  many 
of  the  population  who  used  it  were  accustomed  to  boil  the  water  before 
drinking  it.  Diarrhoeal  disturbances  and  a  mild  form  of  typhoid  fever, 
known  as  "  Ithaca  fever,"  had  for  many  years  been  very  common. 
During  January  and  February,  1902,  it  is  said  that  there  were  nearly 
100  cases  of  typhoid  fever  in  the  city.  During  the  spring  of  that 
year,  repeated  bacteriological  and  chemical  analyses  of  the  water  of 
Six-mile  Creek,  taken  from  the  service  pipes,  yielded  results  w^hich 
indicated  dangerous  pollution,  and  the  people  were  w^arned  through 
the  newspapers  against  its  use  without  previous  boiling.  On  January 
1,  1903,  several  cases  of  undoubted  typhoid  fever  were  reported,  and 
thereafter  the  number  reported  daily  increased  to  such  an  extent  that, 
on  February  2,  there  were  no  fewer  than  237  cases  under  treatment. 
By  the  middle  of  March  nearly  800  cases  had  been  reported,  but  the 
actual  number  of  persons  affected  was  undoubtedly  much  larger.  It 
is  asserted  that  more  than  1000  cases  existed  at  that  time,  and  that 
during  the  first  six  months  of  the  year  there  were  more  than  1300. 

Investigation  showed  that  those  infected  were  users  of  the  water 
supplied  by  the  water  company,  and  that  practically  no  cases  occurred 
among  those  who  drank  well-water  from  Fall  Creek.  Although  the 
University  was  supplied  by  the  latter,  a  large  proportion  of  the  student 
body  lived  in  boarding-houses  supplied  by  the  company,  and  among 
these  the  epidemic  found  many  victims.  Accounts  as  to  the  number 
of  students  seized  are  very  variable,  for  a  large  proportion  left  town 
during  the  height  of  the  outbreak  and  were  sick  elsewhere ;  but  they 
agree  that  several  hundred  were  seized  and  more  than  40  died. 
According  to  Coville^,  about  200  students  had  typical  typhoid  after 
leaving  town. 

Although  it  was  evident  that  the  cause  of  the  disease  was  the  water 
of  Six-mile  Creek  and  perhaps  that  of  Buttermilk  Creek,  it  w^as  im- 
possible to  trace  the  original  infection  ;  but  the  head-waters  of  the 
former  drain  a  district  within  which  considerable  typhoid  fever  had 
been  known  to  exist  within  previous  years,  and,  as  has  been  stated, 
there   was  abundant   opportunity   for   any  infective   material  to   have 

*  American  Medicine,  January  19,  1904. 
25 


386  WATER. 

reached  the  water  directly.  Furthermore,  the  rate  of  flow  is  so  great 
and  the  total  volume  of  water  so  small  that  infective  matter  discharged 
into  the  head-waters  could  have  reached  the  pumping-station' within 
four  hours  ;  and,  there  being  no  storage,  it  could  have  been  delivered 
in  a  fresh  condition  to  the  consumers. 

Asiatic  Cholera. — This  disease,  which  is  endemic  in  India,  whence 
it  makes  periodical  excursions  to  other  parts  of  the  world,  sometimes 
most  widespread  and  with  the  most  disastrous  results,  is,  perhaps, 
more  exclusively  than  typhoid  fever,  a  water-borne  disease.  Since 
the  discovery  by  Koch  of  the  exciting  cause,  and  the  detection  of 
the  same  in  drinking-water  during  epidemics  of  the  disease,  the 
older  theories  of  its  method  of  spread  have  been  abandoned  save 
by  the  few  remaining  adherents  of  the  "localist"  theory,  M'hom 
not  even  the  facts  revealed  during  and  after  the  great  epidemic  of 
1892  can  move  from  their  dogged  attachment  to  the  creed  of  their 
revered  teacher. 

During  the  course  of  the  widespread  devastating  epidemic  of  1892, 
which  in  its  journey  from  the  valley  of  the  Ganges  through  Persia 
claimed  20,000  victims  in  Teheran  alone,  and  in  its  course  through 
Russia  destroyed  215,157  more,  and  which  extended  through  Ger- 
many, Austria,  France,  Belgium,  Holland,  and  even  to  the  harbors  of 
the  Western  Hemisphere,  no  moi'e  instructive  example  of  the  connection 
between  the  disease  and  polluted  water  and  of  the  immunity  conferred 
by  the  use  of  a  pure  supply  could  have  been  yielded  or  desired  than 
the  experience  of  Hamburg,  Altona,  and  Wandsbeck.  These  cities  ad- 
join one  another  so  closely  that  there  is  no  visible  line  of  demarkation, 
and  in  a  geographical  sense  they  may  be  regarded  as  one  place.  In 
one  important  respect,  however,  the  three  places  diifer  very  materially  ; 
namely,  their  public  water  supplies.  Wandsbeck  was  supplied  with 
filtered  water  from  a  lake  but  little  subject  to  pollution ;  Altona  drew 
upon  the  Elbe  at  a  point  below  the  entrance  of  the  sewage  of  Hamburg, 
but  filtered  the  water  through  sand ;  Hamburg  used  unfiltered  water 
from  the  Elbe  above  the  city.  During  the  summer  of  1892,  or  between 
August  17th  and  October  23d,  Hamburg,  with  a  population  of 
640,000,  had  nearly  17,000  cases  of  cholera,  of  which  slightly  more 
than  half  terminated  fatally  ;  Altona,  with  a  population  about  a  quarter 
as  large,  had  but  500  cases,  or  only  one-thirty-fourth  as  many  (400  of 
these  are  supposed  to  have  come  from  Hamburg),  and  Wandsbeck  had 
practically  none.  Very  noticeable  was  the  fact  that  where  Hamburg 
and  Altona  come  together,  the  Hamburg  side  was  plentifully  sprinkled 
with  cases,  while  the  other  was  comparatively  free  (see  Fig.  36),  and 
this  was  still  more  particularly  remarked  along  a  certain  street  that  for 
a  distance  formed  the  boundary  line,  in  which  the  houses  on  the  Ham- 
burg side  had  plenty  of  cases  and  those  opposite  had  none.  Almost  as 
though  intended  for  the  purpose  of  marking  yet  more  sharply  the  dis- 
tribution of  the  two  kinds  of  water,  it  happened  that  a  group  of  tene- 
ment houses  on  the  Hamburg  side  of  the  boundary  was  supplied  with 
water  from  the  Altona  mains,  and  in  these  houses,  densely  peopled  by 


WATER  AND  DISEASE. 


387 


the  laboring  class,  not  a   single   case   occurred,  while  in   neighboring 
houses  the  disease  was  raging. 

Thus  we  have  a  most  eloquent  instance  of  the  value  of  sand  filtra- 
tion, and  of  the  danger  of  using  polluted  supplies.  Hamburg's  un- 
filtered  water  came  from  above  the  city,  while  Altona  had  to  depend 
upon  water  which,  before  being  filtered,  had  received  the  entire  sewage 
of  more  than  three-quarters  of  a  million  people.  The  initial  specitiq 
pollution  of  the  river- water  was  traced  back  to  Russian  emigrants, 
herded  in  barracks  on  one  of  the  wharves  pending  their  embarkation 
for  the  United  States.  At  the  time  of  the  outbreak,  there  were,  on  an 
average,  about  a  thousand  of  these  people  on  hand  all  the  time.  Many 
of  them  came  from  districts  in  Russia  which  had  been  and  were  then 
suffering  severely  from  cholera,  and  all  were  well  supplied  with  dirty 
clothing  and  blankets,  some  of  which  they  washed  while  they  were 
being  detained.     It  is  believed  that  among  the  thousands  that  had 


Fig.  36. 


Portion  of  the  boundary  line  between  Hamburg  and  Altona.    The  dots  indicate  cases  of  cholera. 

arrived,  there  must  have  been  some  mild  cases  of  the  disease,  or  at 
least  some  convalescents  with  cholera  germs  still  in  their  evacuations 
two  or  three  weeks  after  recovery.  All  of  the  sewage  matters  of  every 
description  from  these  people  were  discharged  directly  into  the  river  at 
the  wharf. 

With  the  exception  of  a  few  straggling  cases,  there  was  no  cholera  in 
either  of  the  two  cities  from  October  23d  to  December  6th,  when  a 
small  outbreak  occurred  in  Hamburg.  This  reached  its  culminating 
point,  5  cases  in  one  day,  on  the  26th,  and  then  the  disease  began  to 
reappear  in  Altona,  but  under  very  different  conditions  from  those 
which  characterized  the  epidemic  in  August.  Of  the  500  cases  which 
then  occurred,  about  400  were  connected  in  one  way  or  another  with 
Hamburg,  but  in  the  later  rmtbrcak,  most  of  the  patients  were  of  the 
well-to-do  class  of  workmen  whose  occupation  did  not  call  them  to 
Hamburg — women,  young  children,  inmates   of   hospitals,  and   others 


388  WATER. 

having  no  reason  to  go  there.  Consultation  of  the  records  of  bac- 
teriological examination  of  the  Altona  filtered  water  sho^yed  an  increase 
in  the  first  week  of  December,  and  again  in  the  last  days  of  that 
month,  and  at  intervals  in  January,  which  indicated  that  some  disturb- 
ance must  have  occurred  in  the  working  of  the  filters.  Investigation 
showed  where  the  fault  lav,  and  also  its  nature  :  the  surface  of  the  sand 
had  been  frozen  imder  the  mud  layer,  and  had  thawed  over  only  a  part 
of  its  area,  so  that  the  whole  work  of  the  filter  was  thrown  upon  a 
part.  The  imperfect  w^orking  in  early  December  was  not  follow^ed  by 
cholera,  for  at  that  time  the  river  was  practically  free  from  the  germs. 
Then  came  the  few  new  cases  in  Hamburg,  27  in  number,  and  rein- 
fection of  the  Elbe,  followed  by  faulty  working  of  the  Altona  filters, 
and  consequent  distribution  of  a  small  amount  of  infective  material 
through  the  water  mains.  The  organisms  were  found  in  the  water  just 
below  the  mouth  of  the  main  sewer  of  Hamburg,  and  also  in  one  of 
the  settling  basins  of  the  filter  plant,  where  the  water  stood  prior  to 
delivery  to  the  beds. 

The  Propagation  of  Cholera  in  India. — As  has  been  stated,  the  home 
of  cholera  is  India,  and  so  long  as  the  natives  are  faithful  to  their 
religion  and  to  the  observance  of  old-estal)lished  customs,  just  so  long 
will  that  country  supply  the  rest  of  the  world  with  occasional  infection. 
Considering  the  extreme  conservatism  of  all  classes  of  East  Indians  and 
the  national  reverence  of  the  Hindoos  for  holy  places,  it  may  be  safe 
to  predict  that  before  any  marked  change  for  the  better  is  accomplished, 
the  rest  of  the  civilized  world  will  have  advanced  so  far  in  sanitary 
affairs  that  cholera  will  be  feared  no  more  than  varicella.  As  illustrative 
of  what  sanitary  reform  in  India  would  have  to  encounter,  the  follow- 
ing extracts  from  the  report  of  Dr.  Simmons,  quoted  by  Professor 
]\Iason,  will  be  found  of  interest.  It  may  be  stated  by  way  of  ex- 
planation that  Orissa,  below  mentioned,  is  a  province  covering  more 
than  24,000  square  miles,  every  part  of  which  is  holy  ground.  Every 
town  contains  consecrated  land  and  is  filled  wdth  temples,  and  every 
little  hamlet  has  its  shrine. 

"  The  drinking-water  supply  is  derived  from  W'clls,  so-called  '  tanks  ' 
or  artificial  ponds,  and  the  water-courses  of  the  country.  The  wells 
generally  resemble  those  in  other  parts  of  Asia.  The  tanks  are  exca- 
vations made  for  the  purpose  of  collecting  the  surface-water  during  the 
rainy  season  and  storing  it  up  for  the  dry.  Necessarily  they  are  mere 
stagnant  pools.  The  water  is  used  not  only  to  quench  thirst,  but  is 
said  to  be  drunk  as  a  sacred  duty.  At  the  same  time,  the  reservoir 
serves  as  a  large  washing-tub  for  clothes,  no  matter  how  dirty  or  in 
what  soiled  condition,  and  for  personal  bathing.  Many  of  the  water- 
courses are  sacred ;  notably  the  Ganges,  a  river  1,600  miles  long,  in 
whose  waters  it  is  the  religious  duty  for  millions,  not  only  of  those  living 
near  its  banks,  but  of  j)ilgriuis,  to  bathe  and  to  cast  their  dead. 

"  The  Hindoo  cannot  be  made  to  use  a  latrine.  In  the  cities  he  digs 
a  hole  in  his  habitation ;  in  the  country  he  seeks  the  fields,  the  hill- 
sides, the  banks  of  streams  and  rivers,  when  obliged  to  obey  the  calls 


WATER  AND   DISEASE.  389 

of  nature.  Hence  It  is  tliat  the  vicinity  of  towns  and  the  banks  of 
the  tanks  and  water-courses  are  reeking  with  filth  of  the  worst  de- 
scription, which  is  of  necessity  washed  into  the  public  \vater  supply 
with  every  rainfall.  Add  to  this  the  misery  of  pilgrims,  their  poverty 
and  disease,  and  their  terrible  crowding  into  the  numerous  towns 
which  contain  some  temple  or  shrine,  the  object  of  their  devotion, 
and  we  can  see  how  India  has  become  and  remains  the  hot-bed  of  the 
cholera   epidemic. 

"  In  the  United  States  official  report,  the  horrors  incident  upon  the 
pilgrimages  are  detailed  with  appalling  minuteness.  W.  W.  Hunter, 
in  his  Orissa,  states  that  24  high  festivals  take  place  annually  at  Jug- 
gernaut. At  one  of  them,  about  Easter,  40,000  persons  indulge  in 
hemp  and  hasheesh  to  a  shocking  degree.  For  weeks  before  the  car 
festival  in  June  and  July,  pilgrims  come  trooping  in  by  thousands 
every  day.  They  are  fed  by  the  temple  cooks  to  the  number  of 
90,000.  Over  100,000  men  and  Avomen,  many  of  them  unaccustomed 
to  work  or  exposure,  tug  and  strain  at  the  car  until  they  drop  ex- 
hausted and  block  the  road  with  their  bodies.  During  every  month, 
of  the  year  a  stream  of  devotees  flows  along  the  great  Orissa  road  from 
Calcutta,  and  every  village  for  three  hundred  miles  has  its  pilgrim 
encampments. 

"  The  people  travel  in  small  bands,  which  at  the  time  of  the  great 
feasts  actually  touch  each  other.  Five-sixths  of  the  whole  are  females,, 
and  95  per  cent,  travel  on  foot,  many  of  them  marching  hundreds  and 
even  thousands  of  miles,  a  contingent  having  been  drummed  up  from 
every  town  or  village  in  India  by  one  or  other  of  the  three  thousand 
emissaries  of  the  temple,  who  scour  the  country  in  all  directions  in 
search  of  dupes.  When  those  pilgrims  who  have  not  died  on  the  road 
arrive  at  their  journey's  end,  emaciated,  with  feet  bound  up  in  rags  and 
plastered  with  mud  and  dirt,  they  rush  into  the  sacred  tanks  or  the  sea, 
and  emerge  to  dress  in  clean  garments.  Disease  and  death  make  havoc 
with  them  during  their  stay ;  corpses  are  buried  in  holes  scooped  in  the 
sand,  and  the  hillocks  are  covered  with  bones  and  skulls  washed  from 
their  shallow  graves  by  the  tropical  rains. 

"  The  temple  kitchen  has  the  monopoly  of  cooking  for  the  multitude, 
and  provides  food  which,  if  fresh,  is  not  unwholesome.  Unhappily,  it 
is  presented  before  Juggernaut,  so  becoming  too  sacred  for  the  minutest 
portion  to  be  thrown  away.  Under  the  influence  of  the  heat  it  soon 
undergoes  putrefactive  fermentation,  and  in  forty-eight  hours  much  of 
it  is  a  loathsome  mass  unfit  for  human  food.  Yet  it  forms  the  chief 
sustenance  of  the  pilgrims,  and  is  the  sole  nourishment  of  thousands 
of  l)eggars.  Some  one  eats  it  to  the  very  last  grain.  Injurious  to  the 
njbiist,  it  is  deadly  to  the  weak  and  wayworn,  at  least  half  of  whom 
reach  the  place  suffering  under  some  form  of  bowel  complaint.  Badly 
as  they  are  fed,  the  poor  wi'ctclies  arc,  worse  lodged. 

"  Thf)se  who  liave  the  teiii[)oi'ai'y  shelter  of  fotu'  walls  are  housed  in 
hovels  built  ii|)on  mud  })latfornis  ?iboiit  four  feet  high,  in  the  center  of 
each  of  wliir-h  is  the  hole  which  receives  the  ordure  of  the  liousehold, 


390  WATER. 

and  around  which  the  inmates  eat  and  sleep.  The  platforms  are  covered 
with  small  cells  without  any  windows  or  other  apertures  for  ventilation, 
and  in  these  caves  the  pilgrims  are  packed,  in  a  country  where,  during 
seven  months  out  of  twelve,  the  thermometer  marks  from  85°  to 
100°  F.  Hunter  says  that  the  scenes  of  agony  and  suffocation  enacted 
in  these  hideous  dens  baffle  description.  In  some  of  the  best  of  them, 
thirteen  feet  long  by  ten  feet  broad  and  six  and  one-half  high,  as  many 
as  eighty  persons  pass  the  night.  It  is  not,  then,  surprising  to  learn 
that  the  stench  is  overpowering  and  the  heat  like  that  of  an  oven.  Of 
300,000  who  visit  Juggernaut  in  one  season,  90,000  are  often  packed 
together  for  a  week  in  5,000  of  these  lodgings.  In  certain  seasons, 
however,  the  devotees  can  and  do  sleep  in  the  open  air,  camping  out 
in  regiments  and  battalions,  covered  only  by  the  same  meagre  cotton 
garments  that  clothe  them  by  day. 

"  The  heavy  dews  are  unhealthy  enough  ;  but  the  great  festival  falls 
at  the  beginning  of  the  rains,  Avhen  the  water  tumbles  in  solid  sheets. 
Theii  lanes  and  alleys  are  converted  into  torrents  or  stinking  canals, 
and  the  pilgrims  are  driven  into  the  vile  tenements.  Cholera  invariably 
breaks  out.  Living  and  dead  are  huddled  together.  In  the  numerous 
so-called  corpse-fields  around  the  town  as  many  as  forty  or  fifty  bodies 
are  seen  at  a  time,  and  vultures  sit  and  dogs  lounge  lazily  about  gorged 
with  human  flesh.  In  fact,  there  is  no  end  to  the  recurrence  of  inci- 
dents of  misery  and  humiliation,  the  horrors  of  Avhich,  says  the  Bishop 
of  Calcutta,  are  unutterable,  but  which  are  eclipsed  by  those  of  the 
Teturn  journey.  Plundered  by  priests,  fleeced  by  landlords,  the  sur- 
viving victims  reel  homeward,  staggering  under  their  burdens  of  putrid 
food  wrapped  up  in  dirty  clothes,  or  packed  in  heavy  baskets  or  earth- 
enware jars.  Every  stream  is  flooded,  and  the  travellers  have  often  to 
sit  for  days  in  the  rain  on  the  bank  of  a  river  before  a  boat  will  venture 
to  cross. 

"At  all  these  points  the  corpses  lie  thickly  strewn  around  (an  Eng- 
lish traveller  counted  forty  close  to  one  ferry),  which  accounts  for  the 
prevalence  of  cholera  on  the  banks  of  brooks,  streams,  and  rivers. 
Some  poor  creatures  drop  and  die  by  the  way  ;  others  crowd  into  the 
villages  and  halting-places  on  the  road,  where  those  who  gain  admit- 
tance cram  the  lodging-places  to  over-flowing,  and  thousands  pass  the 
night  in  the  streets,  and  find  no  cover  from  the  drenching  storms. 
Groups  are  huddled  under  the  trees  ;  long  lines  are  stretched  among 
the  carts  and  bullocks  on  the  roadside,  their  hair  saturated  with  the 
mud  on  which  they  lie ;  hundreds  sit  on  the  wet  grass,  not  daring  to 
lie  down,  and  rocking  themselves  to  a  monotonous  chant  through  the 
long  hours  of  the  dreary  night. 

"  It  is  impossible  to  compute  the  slaughter  of  this  one  pilgrimage. 
Bishop  Wilson  estimates  it  at  not  less  than  50,000.  And  this  descrip- 
tion might  be  used  for  all  the  great  Indian  pilgrimages,  of  which  there 
are  probably  a  dozen  annually,  to  say  nothing  of  the  hundreds  of 
smaller  shrines  scattered  through  the  peninsula,  ^ch  of  which  at- 
tracts  its  minor  hordes   of  credulous  votaries.     So  that   cholera   has 


PARASITES  AND  DRINKING-WATER.  391 

abundant  opportunities  for  spreading  over  the  whole  of  Hindostan 
every  year  by  many  huge  armies  of  filthy  pilgrims  ;  and  the  country 
itself  well  deserves  the  reputation  it  universally  possesses  of  being  the 
birthplace  and  settled  home  of  the  malady." 

Parasites  and  Drinking-water. 

There  is  abundant  evidence  of  the  agency  of  drinking-water  in  the 
spread  of  certain  of  the  animal  parasites,  but  with  respect  to  certain 
others  the  danger  is  much  over-rated  (tape-worms),  or,  indeed,  imag- 
inary (trichinae). 

Eound  worms,  Ascaris  lumbricoides,  undoubtedly  are  spread  in  part 
by  water.  The  female  deposits  enormous  numbers  of  eggs  in  the  small 
intestine,  and  these  are  expelled  in  the  fseces.  Whether  the  freshly 
discharged  eggs  are  capable  of  reproducing  the  worm,  is  a  matter  of 
doubt;  but  it  seems  probable  that  the  intervention  of  another  host  is 
necessary.  Wherever  this  parasite  is  known  to  prevail  extensively,  the 
people  use  polluted  water  for  drinking. 

Pin  worms,  or  seat  worms,  Oxyuris  vermicularis,  are  spread  probably 
by  water.  They  locate  in  the  caecum  and  upper  colon,  where  the  female 
deposits  eggs  in  large  numbers,  which,  reaching  a  water-supply  after 
being  discharged  through  the  bowel,  may  be  taken  into  the  stomach, 
where  the  envelope  of  the  embryo  is  disintegrated  by  the  gastric  juice. 
The  larvse  develop  in  the  small  intestine  and  come  to  maturity  in  about 
four  weeks. 

Guinea  worms,  Dracunculus  medinensis,  are  said  to  invade  the  body 
through  the  skin  during  bathing  or  through  the  stomach  in  drinking- 
water  ;  the  evidence  of  the  latter  method  is  definite.  In  the  stomach, 
the  embryos  are  developed  rapidly,  and  soon  the  impregnated  female 
proceeds  from  the  alimentary  canal  to  the  subcutaneous  tissues  in  various 
parts  of  the  body,  where  she  finally  breaks  through  the  skin  and  escapes. 
The  living  embryos  which  are  then  liberated,  finding  their  way  into 
fresh  water,  enter  the  bodies  of  the  common  fresh-water  flea,  Cyclops 
quadricornis,  which  acts  as  the  intermediate  host  and  conveys  the 
organism  to  the  human  stomach.  In  a  case  reported  by  Dr.  John 
Patterson,^  the  patient  had  an  abscess  on  the  upper  part  of  the  left  tibia, 
from  which,  when  it  was  excised,  a  portion  (4  inches)  of  a  worm  was 
removed.  Later,  he  had  an  abscess  and  sinus  of  the  left  calf,  followed 
by  a  swelling  back  of  the  inner  malleolus,  and  in  this  a  portion  of  a 
Avorm,  25  inches  in  length  and  devoid  of  a  head,  was  found.  Dr. 
Edward  Francis  ^  had  under  observation  for  six  weeks  at  the  U.  S. 
Immigrant  Hospital  (N.  Y.),  a  native  of  the  Gold  Coast,  who  arrived 
in  June,  1901,  with  a  history  of  having  been  troubled  with  these  para- 
sites during  the  preceding  three  months.  During  his  stay  at  the  hos- 
pital five  worms  appeared  :  one  on  the  front  of  the  right  ankle,  one  on 
the  dorsum  of  the  right  foot,  one  on  the  front  of  the  left  ankle,  one 

^  Medical  Kccorfl,  October  7,  1899. 

^  American  Medicine,  October  2G,  1901. 


392  WATER. 

below  the  left  external  malleolus,  and  one  on  the  dorsum  of  the  left 
foot,  near  the  toes.  One  worm  presented  26  inches  in  one  piece;  the 
others  measured  10  to  IS  inches,  but  were  removed  in  pieces. 

Whip  worms,  Trichocephalus  dispar,  which  are  said  to  be  extremely 
common  in  Paris  and  some  other  places  outside  the  tropics,  are  spread 
wholly  by  water,  without  which  the  emb,ryo  cannot  develop  within  the 
egg.  Taken  into  the  stomach,  the  envelope  is  dissolved  and  the  liber- 
ated larva  attaches  itself  to  the  wall  of  the  intestine,  where  it  proceeds 
very  slowly  to  develop.  It  does  not  reach  full  maturity  until  about  a 
year  has  elapsed, 

Filaria  sanguinis  hominis,  the  parasite  which  produces  chyluria,  hsema- 
tochyluria,  and  elephantiasis,  is  believed  to  tind  its  way  into  the  system 
through  water  contaminated  by  mosquitoes  which  have  sucked  the  blood 
of  persons  suffering  from  the  parasite.  The  adult  female  produces  an 
enormous  number  of  minute  embryos,  which  pass  into  the  blood ;  and 
when  these  are  taken  into  the  stomach  of  the  moscpiito,  they  wander 
to  other  parts  of  the  insect,  where  they  become  farther  developed,  and 
later  may  be  transferred  to  water,  through  which  they  are  believed  to 
pass  into  the  human  stomach,  where  the  cycle  is  completed.  This  para- 
site is  not  confined  wholly  to  the  trctpics,  and  occasionally  is  seen  in  our 
Southern  States.      (See  Chapter  XII.) 

Bilharzia  hsematobia,  the  cause  of  a  peculiar  hsematuria  common  in 
parts  of  Africa,  is  believed  by  many  to  be  transmitted  by  drinking- 
water  contaminated  by  the  urine  of  persons  suffering  with  the  diseage. 
The  embryos  probably  enter  the  system  of  some  other  organisms,  which 
play  the  part  of  intermediate  hosts  and  advance  their  development  one 
stage. 

Ankylostommn  duodenale  (Uncinaria  duodenalis),  the  cause  of  the 
anaemia  formerly  supposed  to  be  peculiar  to  miners  and  others  engaged 
in  underground  operations,  was  until  recently  believed  to  be  disseminated 
chiefly  by  polluted  water ;  but,  as  has  been  said  in  the  consideration 
of  the  relation  of  soil  to  disease,  this  idea  is  no  longer  tenable,  the 
chief,  if  not  the  only,  source  of  infection  being  soil  polluted  by  the 
intestinal  discharges  of  those  already  infected  with  the  parasite. 

Strongyloides  intestinalis,  the  parasite  of  an  endemic  diarrhoea  of 
Cochin  China,  first  described  by  French  investigators  who  discovered 
its  rhabditiform  embryos  in  the  stools  of  soldiers  returning  from  China 
in  1876,  was  found  by  Perroncito  to  occur  in  association  with  Anlcylos- 
tomum  duodenale  in  the  discharges  of  laborers  afflicted  with  "  St.  Gothard 
tunnel  ansemia",  has  been  reported  in  various  countries  of  Europe,  in 
Egypt,  Brazil,  the  Indies,  and  Philippine  Islands,  and  within  recent 
years  in  various  parts  of  the  United  States.  According  to  Dr.  M.  L. 
Price  \  the  occurrence  of  eggs  in  the  stools  is  very  rarely  observed, 
unless  there  coexists  an  uncinarial  infection,  and  the  parasite  is 
probably  introduced  by  way  of  the  mouth  as  the  filariform  embryo, 
though  infection  of  animals  has  been  produced  by  means  of  the  eggs. 
He  believes  that  the  vehicle  by  which  the  parasite  gains  access  to  the 
^  Journal  of  the  American  Medical  Association,  September  12  and  19,  1903. 


JOE.  393 

system  is  frequently  the  drinking  water,  but  that  fresh  vegeta]:)les  from 
land  manured  with  human  excreta  play  a  part.  It  is  the  belief  of 
Stiles  that  the  geographical  distribution  of  the  parasite  in  this  country 
will  be  found  to  correspond  to  that  of  uncinaria. 

ICE. 

It  is  a  common  idea  that  ice  is  necessarily  pure,  because,  in  freezing, 
"water  purifies  itself."  Ice  may,  however,  be  quite  as  impure  as  the 
original  water  or  very  pure,  according  to  circumstances.  The  first  for- 
mation is  quite  likely  to  contain  impurities,  such  as  the  dust  and  other 
matters  floating  on  the  surface.  Under  ordinary  conditions,  the  un- 
purities  will  be  limited  to  this  layer,  for,  in  the  growth  of  the  ice  from 
above  downward,  all  but  traces  of  dissolved  substances  and  practically 
all  of  the  suspended  matters  are  excluded. 

Ice  may  become  impure  in  several  ways.  If  snow  falls  upon  it  and 
becomes  wet  either  by  rain  or  by  water  from  below,  and  then  freezes 
and  becomes  part  of  the  ice,  it  will  contain  all  the  impurities  which  have 
been  washed  out  of  the  air.  If,  while  the  ice  is  thin,  holes  are  cut  so 
as  to  permit  flooding  from  below,  it  will  contain  all  the  impurities  of 
the  water.  Cut  from  shallow  ponds,  it  will  be  pure  or  impure  accord- 
ing to  the  quality  of  the  water  and  the  depth  to  which  it  freezes.  Water 
from  such  ponds,  if  polluted  by  surface  washings  or  sewage  matters,  is 
likely  to  yield  ice  which,  when  melted,  will  give  off  offensive  odors. 

It  is  a  common  belief  that  bacteria  are  killed  in  ice,  but  many 
varieties  will  retain  their  vitality  in  it  for  a  very  long  time.  As  early 
as  1871,  Burdon  Sanderson  showed  that  even  the  purest  ice  is  likely 
to  contain  them  in  some  degree.  Chantemesse  and  Widal  proved  in 
1882,  Prudden  in  1887,  and  Riche,  Frankel,  and  others  at  different 
times,  that  pathogenic  bacteria  may  maintain  their  vitality  to  a  sur- 
prising degree  in  ice,  and  that  the  bacillus  of  typhoid  fever  is  particu- 
larly resistant.  Prudden  ^  showed  that  ice,  made  from  water  which 
contained  them  to  an  innumerable  extent,  yielded  at  the  expiration  of 
103  days  no  less  than  7,348  per  cc. 

Bacteria  are  resistant  not  only  to  the  ordinary  low  temperature  of 
ice,  for  Pictet  and  others  have  proved  that  even  the  extraordinary  cold 
of  liquefied  air,  — 315°  F.,  is  not  sufficient  to  destroy  them.  On  the 
other  hand,  Sedgwick  and  Winslow,^  W.  H.  Park,^  and  H.  W.  Hill,^ 
who  have  made  independent  investigations  of  the  possible  danger  of 
ice  as  a  cause  of  outbreaks  of  typhoid  fever,  agree  that  it  is  but 
slight.  Sedgwick  and  Winslow  found  that  the  bacilli  perish  rapidly  ; 
50  per  cent,  at  the  end  of  the  first  week,  90  per  cent,  in  two  weeks, 
and  practically  all  (2  or  3  in  1000  remained)  after  twelve  weeks.  It 
is  pointed  out  by  the  several  observers  named  that  the  majority  of 
bacteria  in  water  are  eliminated  in  the  process  of  freezing ;  that  the 
majority  of  those  included  die  within  a  few  weeks  ;  that  the  bacteria 

'  Medical  Recf)i-(1,  March  26,  1887. 

'^  Ahstract  in  Keviic  Scicnlifi(|ue,  Ajiril  28,  1000. 

"  .Journal  of  tlic  IJoston  Society  oF  Medical  Sciences,  IV.,  j).  213. 

*  Boston  Medical  and  Siir/^ical  .Journal,  November  21,  1901. 


394  WATER. 

in  ice  are  commonly  harmless  in  character ;  and  that  cities  which  use 
ice  from  polluted  streams  (e.  g.,  New  York,  Lowell,  Lawrence)  suffer 
apparently  none  at  all  therefrom.  The  State  Board  of  Health  of 
Massachusetts  says  (Annual  Eeport  for  1900),  concerning  the  bacterial 
content    of   the    domestic    supply,  "  In   not   one   instance   of  the  still 

freezing  of  ordinarily  polluted  water have  we  been  able  to  find  B.  coli 

in  the  ice  formed." 

Recent  experience  at  Ogdensburg,  K.  Y.,  seems  to  indicate  that  ice 
taken  from  a  polluted  river  having  a  fairly  rapid  flow  may,  however,  be 
a  source  of  danger.  In  October,  1902,  after  almost  total  freedom  from 
typhoid  fever  for  nearly  two  years,  an  outbreak  occurred  among  the 
inmates  of  the  St.  Lawrence  State  Hospital,  the  water-supply  of  which 
was  beyond  reproach.  The  attack  was  purely  local,  other  users  of  the 
water  not  being  affected.  The  possibility  of  infection  from  other 
sources  having  been  eliminated,  attention  was  directed  to  the  ice,  and 
it  appeared  that,  about  six  days  before  the  development  of  the  first 
cases,  a  new  sup])ly  taken  from  the  St.  Lawrence  River  and  stored 
for  more  than  seven  months  had  been  brought  into  use.  Sjjecimens  of 
the  ice  yield  a  black  sediment,  which,  on  examination  by  Hutchings 
and  Wheeler,^  was  found  to  contain  bacilli,  cultures  of  which  responded 
to  the  tests  for  B.  typhosus,  including  clumping  when  treated  with 
serum  from  a  typhoid  patients 

Artificial  ice  is  frozen  in  blocks  of  the  size  and  shape  of  the  tanks 
in  which  the  water  is  held.  As  the  entire  mass  of  water  in  each  tank 
is  frozen,  it  naturally  must  contain  in  its  inner  portion,  which  is  the 
last  to  freeze,  all  of  the  matters  originally  contained.  Unless  the  water 
used  is  pure  and  colorless,  the  ice  will  not  be  of  good  quality,  and,  par- 
ticularly in  the  center,  will  not  be  of  good  appearance.  When  colored  or 
impure  water  is  used,  it  is  a  common  practice  to  remove  the  impurities 
and  coloring  matters  by  tapping  the  center  before  the  freezing  process 
is  completed,  and  drawing  off  the  liquid  in  which  they  have  become 
concentrated.  On  account  of  the  possible  retention  of  part  or  all  of 
the  contained  impurities  and  bacteria  of  the  water  from  which  it  is 
made,  artificial  ice  should  be  manufactured  only  from  distilled  water 
or  from  natural  water  of  the  highest  degree  of  purity. 

CHEMICAL  EXAMINATION  OF  WATER. 

Collection  of  Samples. — In  taking  samples  of  water  for  chemical 
analysis,  great  care  is  necessary  in  order  to  secure  specimens  which 
shall  be  fairly  representative  of  the  supply  under  investigation.  They 
should  be  taken  only  in  clean  glass  bottles  or  demijohns  of  from  half 
a  gallon  to  a  gallon  capacity,  and  never  in  stone  jugs,  tin  cans,  or 
wooden  kegs.  The  best  form  of  bottle  has  a  glass  stopper,  but  a 
perfectly  clean  cork  is  unobjectionable.  In  spite  of  directions  most 
carefully  given,  one  often  sees  specimens  sent  in  stone  jugs  stopped 
with  wooden  plugs  wrapped  with  old  cotton  rags  or  pieces  of  news- 
*  American  Journal  of  the  Medical  Sciences,  October,  1903,  p.  680. 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.   395 

paper  to  secure  a  tighter  fit,  and  sometimes  smeared  with  shoemakers' 
wax,  pitch,  or  even  tallow.  Analysis  of  such  specimens  is  likely  to 
give  results  of  no  value  whatever,  for  it  should  be  remembered  that  we 
are  dealing  with  exceedingly  small  amounts  of  ammonia  and  other 
products,  and  that  anything  short  of  absolute  cleanliness  of  receptacles 
introduces  error. 

The  bottle,  supposedly  clean  at  the  start,  should  be  rinsed  thoroughly 
with  the  water  to  be  sampled,  then  filled  to  the  neck,  and  securely 
stoppered.  If  the  sample  comes  from  a  pump,  the  barrel  of  the  latter 
should  be  emptied  completely  of  the  water  which  has  been  standing  in 
it  for  any  length  of  time  ;  if  from  a  pipe,  the  water  should  be  allowed 
to  run  to  waste,  until  the  whole  of  the  original  contents  has  escaped ; 
if  from  a  pond  or  other  body  of  water,  the  bottle  should  be  plunged 
sufficiently  far  beneath  the  surface  to  avoid  the  entrance  of  floating 
matters,  and  at  a  sufficient  distance  from  the  banks  to  avoid  matters 
that  hug  the  shore. 

After  the  sample  is  secured,  as  little  time  as  possible  should  elapse 
before  beginning  the  analysis,  because  of  the  rapidity  with  which 
changes  occur  in  the  organic  matters,  ammonia,  nitrites,  and  nitrates. 


Determination  of  Free  Ammonia  and  Albuminoid  Ammonia. 

Solutions  Required:  1.  Standaed  Solution  of  Ammonium 
Chloeide. — Dissolve  3.138  grams  of  pure  dry  ammonium  chloride 
in  1  liter  of  distilled  water  free  from  ammonia.  One  cc.  of  this  solu- 
tion represents  1  mgr.  of  ammonia. 

2.  Standard  Dilute  Solution  of  Ammonium  Chloride. — 
Dilute  10  cc.  of  the  strong  solution  up  to  1  liter  with  water  free  from 
ammonia.     One  cc.  of  this  solution  represents  0.01  mgr.  of  ammonia. 

3.  Solution  of  Sodium  Carbonate. — Dissolve  200  grams  of  pure 
sodium  carbonate  in  1  liter  of  water  free  from  ammonia. 

4.  Alkaline  Potassium  Permanganate. — Dissolve  8  grams  of 
potassium  permanganate  and  200  grams  of  caustic  potash  in  2  liters 
of  distilled  water,  and  boil  down  to  1  liter,  to  get  rid  of  any  free  am- 
monia present.  Fifty  cc.  of  this  solution  are  required  for  each  anal- 
ysis. The  author  finds  it  convenient  to  omit  the  boiling-down  proc- 
ess when  the  solution  is  prepared,  and  to  take  100  cc.  and  boil  down  to 
50  at  the  time  of  analysis.  This  insures  freedom  from  ammonia  when 
used,  and  avoids  the  bumping  which  is  so  likely  to  occur  when  the  cold 
solution  is  added  during  the  process  of  distillation. 

5.  Nessler's  Reagent. — Dissolve  35  grams  of  potassium  iodide  in 
150  cc.  of  distilled  water.  Dissolve  about  16  grams  of  corrosive  sub- 
limate in  300  cc.  of  distilled  water.  Add  the  latter  to  the  former, 
both  solutions  being  cold.  Then  add  200  grams  of  caustic  soda,  dis- 
solved in  0.5  liter  of  distilled  water,  and  mix  thoroughly.  Next  add, 
with  constant  stirring,  a  saturated  solution  of  con-osive  sublimate  until 
the   precipitate  which  forms  is  permanent ;  then  dilute  the  whole  to  1 


396 


WATER. 


liter.  Let  stand  until  clear,  when  the  supernatant  liquid  should  have 
a  pale-straw  color. 

6.  Ammonia-feee  Watee. — This  may  be  obtained  by  distilling 
water  made  slightly  acid  with  sulphuric  acid.  The  first  25-50  cc.  of 
distillate  should  be  rejected,  and  the  next  50  cc.  should  be  tested  with 
Nessler's  reagent.  If  no  color  appears,  the  distillate  is  ammonia-free, 
and  the  operation  may  then  be  continued  until  the  contents  of  the  re- 
tort are  reduced  to  very  small  volume.  If  the  test  shows  traces  of 
ammonia,  successive  portions  should  be  tested  until  a  negative  result 
is  secured.  It  is  well  to  prepare  a  goodly  supply,  and  to  keep  it  on 
hand  in  glass-stoppered  bottles. 

Apparatus  Required. — Distilling  Apparatus. — Some  analysts  pre- 
fer glass  retorts  ;  others,  distilling  flasks  with  side  tubes.  Whichever 
is  used,  the  connection  with  the  Liebig  condenser  should  be  tight. 
The  author  prefers  a  distilling  flask,  with  a  side  tube  of  such  a  size 
that  it  enters  the  condenser  tube  easily,  but  without  making  a  loose 
joint.  A  bit  of  clean  rubber  tubing  on  the  side  tube  may  serve  to 
make  the  joint  more  perfect  at  the  point  of  entrance.     The  mouth 

Fig.  37. 


Distilling  apparatus  used  in  determining  the  ammonias  in  water. 

of  the  flask  should  be  closed  with  a  rubber  stopper  with  a  single  per- 
foration, carrying  a  funnel  tube  which  reaches  to  the  bottom  of  the 
flask. 

The  flask  or  retort  may  be  heated  either  by  a  rose  burner  or  by  the 
free  flame  of  a  Bunsen  lamp.  In  laboratories  where  water  analysis 
is  conducted  on  a  large  scale,  it  is  found  convenient  to  have  the  dis- 
tilling flasks,  arranged  in  the  form  of  batteries,  connected  with  block 
tin  condensing  tubes  which  j)ass  through  a  common  cooling-tank  fed 
by  a  single  tap. 

In  Fig.  37  is  shown  the  form  of  apparatus  which  the  author  finds 
convenient  for  ordinary  work. 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.  397 

Nesslerizing  Tubes. — For  making  the  determination  of  ammonia  by 
the  colorimetric  method,  tubes  of  colorless  glass,  about  12|  x  |  inches, 
with  a  mark  at  the  50  cc.  point,  are  required. 

Determination. — The  flask  and  condenser  are  rinsed  with  ammo- 
nia-free water,  0.5  liter  of  the  water  and  5  cc.  of  sodium  carbonate 
solution  are  introduced  into  the  flask,  and  heat  is  applied.  The  dis- 
tillate is  collected  either  in  the  Nessler  tubes  or  in  50  cc.  flasks,  from 
which  it  is  transferred  to  the  tubes  ;  and  when  three  portions  of  50 
cc.  each  have  been  collected,  all  of  the  free  ammonia  in  the  sample 
will  have  passed  over. 

On  beginning  the  distillation,  100  cc.  of  the  unconcentrated  alka- 
line permanganate  solution  are  heated  in  a  small  flask  and  boiled 
down  to  50  CO.,  and  on  the  completion  of  the  distillation  for  free 
ammonia,  the  hot  reagent  is  added  through  the  tunnel  tube,  and 
boiling  is  continued.  If  the  reagent  has  been  concentrated  in  ad- 
vance, 50  cc.  are  added.  The  nitrogenous  organic  matter  is  now 
attacked  by  the  permanganate  solution  and  more  ammonia  is  evolved. 
While  this  in  no  way  differs  from  the  free  ammonia,  it  is  given  the 
distinguishing  name  "albuminoid  ammonia,"  to  indicate  its  origin. 
The  process  is  now  continued  as  long  as  ammonia  passes  over,  but 
usually  no  reaction  is  observed  after  four  portions  of  50  cc.  have 
been  collected.  In  the  laboratory  of  the  State  Board  of  Health  of 
Massachusetts,  it  is  the  custom  to  fill  five  tubes,  and  then  to  cease 
distilling.  To  each  of  the  tubes  containing  the  ammonias,  2  cc. 
of  Nessler's  reagent  are  added.  In  the  presence  of  ammonia,  a  yel- 
lowish-brown color  is  produced,  the  depth  of  which  depends  upon  the 
amount  of  ammonia  present.  Some  exceptionally  rich  waters  yield 
such  an  amount  of  ammonia  that  a  precipitate  is  formed  on  addi- 
tion of  the  reagent.  Then  it  is  necessary  to  repeat  the  process,  and 
to  take  an  aliquot  part  of  the  distillate  and  dilute  it  with  anmionia- 
free  water  to  50  cc.  before  nesslerizing.  Should  a  precipitate  again 
occur,  a  smaller  part  should  be  taken,  and  so  on  until  the  proper 
reaction  is  obtained.  The  amount  in  the  whole  distillate  may  then  be 
determined  mathematically.  Having  nesslerized  the  several  tubes, 
the  next  step  is  to  determine  the  amounts  present  by  comparison  of 
colors  with  a  scale  made  as  follows  :  Into  a  series  of  tubes,  held  in 
a  rack,  different  amounts  of  the  weaker  solution  of  ammonium  chlo- 
ride are  introduced,  then  ammonia-free  water  is  added  to  each  up  to 
the  50  cc.  mark,  each  tube  inverted  to  insure  thorough  mixing,  and, 
finally,  2  cc.  of  Nessler's  reagent  added  to  each.  A  convenient  scale 
is  secured  by  using  0.25,  0.50,  0.75,  1.00,  1.50,  2.00,  2.50,  3.00, 
3.50,  4.00,  and  5.00  cc,  representing  0.0025,  0.0050,  0.0075,  0.010, 
0.015,  0.020,  0.025,  0.030,  0.035,  0.040,  and  0.050  mgr.  of  ammo- 
nia. The  first  of  these  will  have  a  very  faint  yellowish-brown  tint, 
and  the  last  a  very  decided  reddish-brown  color,  while  the  intervening 
tubes  show  a  progressive  dee]>ening.  With  these  tubes,  the  distillates 
are  com])ared,  and  the  matching  of  colors  gives  the  desired  results. 
If  a  given  tube  falls  between  any  two  of  the  scale,  a  new  comparison 


398  WATER. 

tube  may  be  prepared ;  but  the  practised  eye  can  determine  very  accu- 
rately without  this  extra  aid.  Having  read  the  color  of  each  tube, 
the  amounts  of  those  representing  the  free  ammonia  are  added  together, 
and  the  total  multiplied  by  2,  to  get  the  amount  per  liter  of  water ; 
the  same  process  is  carried  out  for  the  determination  of  the  albu- 
minoid ammonia.  The  results  represent  parts  per  million,  since  1 
liter  equals  1,000,000  milligrams. 

Example. — The  three  free-ammonia  tubes  show  0.023,  0.006, 
0.000:  total  0.029  mgr. ;  multiplied  by  2  =  0.058  per  liter.  By 
moving  the  decimal  point  one  place  to  the  left,  we  have  0.0058  part 
per  100,000,  in  which  terms  the  results  ordinarily  are  expressed. 

Precautions. — Since  the  depth  of  color  caused  by  Nessler's  reagent 
is  affected  more  or  less  by  temperature,  and  since  in  all  processes  of 
comparison  the  conditions  must  be  the  same  so  far  as  is  possible,  the 
reagent  should  not  be  added  until  the  distillates  and  the  contents  of 
the  comparison  tubes  have  the  same  temperature.  Equality  in  this 
respect  is  secured  without  any  manipulation  or  trouble  by  leaving  the 
tubes  over  night,  so  that  all  will  acquire  the  temperature  of  the  room. 
It  is  hardly  necessary  to  point  out  that  the  air  of  the  room  in  which 
the  distillation  is  conducted  should  be  quite  free  from  laboratory 
fumes,  such  as  ammonia  and  sulphiu^etted  hydrogen,  which,  being 
absorbed  by  the  distillate,  would,  in  the  one  case,  give  erroneous 
results,  and,  in  the  other,  react  upon  the  mercury  salt  in  the  Nessler's 
reagent. 

The  heat  applied  to  the  distilling  flask  should  be  so  regulated  that 
the  time  required  for  each  portion  of  50  cc.  will  be  about  fifteen 
minutes,  since  with  more  rapid  distillation  there  is  likely  to  be  some 
loss  of  ammonia  by  imperfect  condensation. 

The  reading  of  the  tubes  should  not  be  undertaken  until  at  least 
five  minutes  have  elapsed  after  the  addition  of  the  reagent.  The 
extreme  depth  of  color  obtainable  is  reached  somewhat  within  that 
time. 

The  practice  of  some  analysts  of  distilling  the  free  ammonia  out  in 
one  lot  of  150  or  200  cc,  collecting  the  albuminoid  ammonia  in 
another  single  portion  of  200  or  250  cc,  nesslerizing  a  portion  of  each, 
and  calculating  the  total  amount  of  each  by  multiplication  by  the 
proper  factor,  gives  correct  results  ;  but  it  has  been  shown  that  by  pro- 
ceeding in  this  way,  one  may  lose  useful  information  obtainable  from  a 
knowledge  of  the  rate  at  which  the  ammonia  is  evolved,  since  organic 
matter,  well  advanced  in  decomposition,  yields  it  more  copiously  in  the 
first  distillate,  whereas  fresh  material  yields  it  more  slowly  and  uni- 
formly. 

Some  analysts  make  duplicate  distillations  of  one  water  at  the  same 
time,  determining  the  free  ammonia  in  one  specimen,  and,  by  add- 
ing the  permanganate  at  the  start  in  the  other,  determining  the 
total  free  and  albuminoid  ammonia  together.  By  subtracting  the 
lesser  from  the  greater,  the  amount  of  albuminoid  ammonia  is 
obtained. 


DETERMINATION   OF  FREE  AND  ALBUMINOID  AMMONIA.    399 


Permanent  Ammonia  Standards. — In  order  to  avoid  the  necessity 
of  preparing  standards  ea(;li  time  they  are  required,  for  those  made  as 
above  soon  undergo  change,  Mr.  D.  D.  Jackson  ^  has  proposed  making 
a  permanent  set  with  potassium  platinic  chloride  and  cobaltous  chloride, 
with  which,  with  a  little  practice,  the  Nessler  solution  may  be  prepared 
to  fit  exactly.  Since  his  method  of  preparing  the  latter  diifers  mate- 
rially from  that  above  described,  it  is  reproduced  here :  "Dissolve  61.75 
grams  of  potassium  iodide  in  250  cc.  of  redistilled  water,  and  add  a 
cold  solution  of  mercuric  chloride  which  has  been  saturated  by  boiling 
with  excess  of  the  salt.  Pour  in  the  mercury  solution  cautiously,  and 
add  an  amount  just  sufficient  to  make  the  color  a  permanent  bright 
red.  With  a  little  practice,  the  exact  depth  of  color  can  be  easily 
duplicated.  It  will  take  a  little  over  400  cc.  of  the  mercuric  chloride 
solution  to  reach  this  end  point.  Dissolve  the  red  precipitate  by  add- 
ing exactly  0.75  gram  of  powdered  potassium  iodide.  Then  add  150 
grams  of  potassium  hydrate  dissolved  in  250  cc.  of  water.  Make  up 
to  1  liter.  Mix  thoroughly  and  allow  the  precipitate  formed  to  settle. 
It  is  best  to  make  up  a  large  amount  of  Nessler  solution,  and  if  by  its 
use  the  ammonia  standards  do  not  fit  the  artificial  ones  prepared  from 
the  platinum  and  cobalt  solutions,  a  little  more  mercuric  chloride  to 
increase  sensitiveness,  or  potassium  iodide  to  decrease  it,  will  bring  the 
Nessler  solution  to  the  point  where,  if  just  2  cc.  are  used,  the  regular 
ammonia  standards  will  exactly  fit  the  artificial  ones.  .  .  .  Of 
course,  each  new  lot  of  Nessler  solution  should  be  compared,  to 
see  that  it  has  the  proper  degree  of  sensitiveness  to  fit  the 
standards." 

To  prepare  the  permanent  standards,  two  separate  solutions,  one  of 
potassium  platinic  chloride  and  one  of  cobaltous  chloride,  are  necessary. 
The  first  is  made  by  dissolving  2  grams  of  the  salt  in  a  small  amount 
of  water,  adding  100  cc.  of  strong  hydrochloric  acid,  and  diluting  to  1 
liter.  The  second,  by  dissolving  12  grams  of  the  salt  in  water, 
adding  100  cc.  of  strong  hydrochloric  acid,  and  diluting  to  1 
liter. 

"  Varying  amounts  of  these  two  solutions  are  required,  because  the 
color  of  the  Nessler  standards  becomes  more  and,  more  reddish  as  the 
amount  of  ammonia  increases.  The  standards  are  made  up  in  50  cc. 
Nessler  tubes  1.7  cm.  {W")  in  diameter  and  21  cm.  (8J")  from  the 
bottom  to  the  50  cc.  mark."  Sixteen  standards  are  prepared  with  dis- 
tilled water  up  to  the  50  cc.  mark,  as  follows : 

Pt.  solution.        Co.  solution. 


1.0 

+ 

0.0 

1.8 

+ 

0.0 

3.2 

+ 

0.0 

4.5 

+ 

0.1 

5.9 

+ 

0.2 

7.7 

+ 

OJi 

9.4 

+ 

0.9 

10.4 

+ 

\.?> 

mmonia. 

Pt.  solution 

Co. 

solution. 

Ammonia 

mgr. 

cc. 

cc. 

mgr. 

0.000 

12.7 

+ 

2.2 

=r 

0.020 

0.001 

15.0 

+ 

3.3 

= 

0.025 

0.003 

17.3 

+ 

4.5 

^= 

0.030 

0.005 

19.0 

+ 

5.7 

= 

0.035 

0.007 

19.7 

+ 

7.1 



0.040 

0.010 

19.9 

+ 

8.7 

■= 

0.045 

0.013 

20.0 

+ 

10.4 

= 

0.050 

0.015 

20.0 

+ 

15.0 

= 

0.060 

Teclinology  Quarterly,  XIII.,  No.  4,  December,  1900. 


400  WATER. 

While  these  agree  perfectly  with  the  regular  Nessler  ammonia  stand- 
ards on  lengthwise  examination,  they  do  not  at  all  agree  on  side  view, 
the  artificial  standards  appearing  decidedly  pink,  instead  of  brownish 
3"e]low. 

Determination  of  Other  Nitrogen  Compounds. — Preliminary 
Treatment. — Should  the  specimen  of  water  have  an  appreciable  color, 
due  to  dissolved  vegetable  matters,  it  is  necessary,  before  attempting 
the  determination  of  the  above-mentioned  substances  or  of  the  chlorides, 
to  decolorize  a  sufficient  volume  by  means  of  milk  of  alumina.  This 
is  prepared  by  mixing  gradually  very  dilute  solutions  of  sodium  hydrate 
or  ammonia  and  alum  or  aluminum  sulphate ;  the  resulting  precipitate 
is  allowed  to  settle,  and  is  then  washed  several  times  by  decantation. 
The  water  used  in  washing  should  be  free  from  chlorides,  nitrates,  and 
nitrites.  If  strong  solutions  are  used,  the  gelatinous  precipitate  soon 
undergoes  change  both  in  appearance  and  character.  It  becomes  chalky 
and  loses  its  property  of  removing  color.  In  order  to  remove  all 
coloring  matter,  0.5  liter  of  the  water  may  be  shaken  in  a  flask  with  a 
few  cc.  of  the  thick  "  milk,"  and  then  filtered  through  paper.  By  this 
means,  the  most  highly  colored  swamp  waters  are  made  colorless  in  a 
very  few  minutes. 

Determination  of  Nitrogen  as  Nitrites. — Solutions  Required. — 1. 
SuLPHANiLiC"  Acid  Solutiox  (paramidobonzene-sulphonic  acid). — Dis- 
solve 0.50  gram  in  150  cc.  of  acetic  acid  (sp.  gr,  1.040). 

2.  Naphthylamine  Solution  (a-amidonaphthalene). — Dissolve 
€.10  gram,  in  20  cc.  of  boiling  water,  filter,  and  add  180  cc.  of  acetic 
acid  (sp.  gr.  1.040). 

3.  Standaed  Sodium  jSTitrite  Solution. — Dissolve  0.275  gram 
of  pure  nitrite  of  silver  in  pure  distilled  water  and  add  a  dilute  solu- 
tion of  pure  sodium  chloride  until  precipitation  ceases.  Dilute  to  250 
<3C.  and  preserve  in  the  dark  in  an  amber  bottle. 

4.  Standard  Dilute  Sodium  Nitrite  Solution. — Dilute  10  cc. 
of  the  preceding  to  1  liter  with  pure  distilled  water  and  preserve  in  the 
same  way.     One  cc.  equals  0.001  mgr.  of  nitrogen  as  nitrite. 

Process. — To  50  cc.  of  w^ater  in  a  Nessler  tube,  or  to  100  cc.  in  a 
tube  of  larger  diameter,  add  2  cc.  of  each  of  the  two  first-mentioned 
solutions.  If  nitrites  are  present,  a  pink  to  a  garnet  color  is  developed 
\vithin  a  half  hour,  the  intensity  of  color  depending  upon  the  amount 
of  nitrite  present.  If  no  change  is  observable  at  the  end  of  a  half 
hour,  nitrites  may  be  recorded  as  absent ;  if,  on  the  contrary,  a  color- 
ation is  produced,  the  test  may  be  repeated,  and  at  the  same  time  one 
or  more  comparison  cylinders  prepared.  In  similar  tubes,  dilute  to 
the  mark  with  distilled  water  free  from  nitrites  0.25,  0.50,  and  1  cc.  of 
the  dilute  sodium  nitrite  solution,  and  add  to  each  the  proper  amounts 
of  the  test-solutions.  At  the  end  of  half  an  hour,  compare  the  color 
acquired  by  the  water  sample  with  the  standards,  and  multiply  by  the 
j^roper  factor,  to  determine  the  amount  per  liter. 

Since  the  air  of  laboratories  in  which  gas  is  burning  is  very  likely 
to  contain  traces  of  nitrites,  which  are  absorbed  readily  by  water,  it  is 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.   401 

well  to  keep  the  tubes  corked  or  otherwise  protected.  A  tube  left 
open  some  hours  is  almost  sure  to  develop  more  or  less  color. 

The  color  reaction  is  due  first  to  the  action  of  the  nitrite  present  on 
the  sulphanilic  acid,  whereby  a  new  compound  (diazobenzene-sulphonic 
anhydride)  is  produced,  which  is  then  acted  upon  by  the  naphthylamine 
and  converted  into  another  (azo-a-amidonaphthalene-parazobenzene- 
sulphonic  acid)  which  imparts  the  color. 

Permanent  Nitrite  Standards. — Mr.  Jackson  has  proposed  employing 
permanent  standards  for  the  nitrite  determination  also.  They  are  made 
from  two  solutions,  one  made  by  dissolving  24  grams  of  cobaltous 
chloride  in  distilled  water,  adding  100  cc.  of  strong  hydrochloric  acid, 
and  diluting  to  1  liter;  and  the  other  by  dissolving  12  grams  of  dry 
cupric  chloride,  adding  100  cc.  of  strong  hydrochloric  acid,  and  dilut- 
ing likewise  to  1  liter.  The  standards  are  made  up  in  100  cc.  tubes, 
3  cm.  (1|")  in  diameter  and  13.2  cm.  (5:^")  to  the  100  cc.  mark. 
The  following  table  gives  the  proportions  of  each  solution  to  be  made 
up  to  the  100  cc.  mark  : 


1.  solution. 

Cu. 

solution. 

Parts  of  N  as  nitrite 

cc. 

cc. 

per  million. 

1.1 

+ 

1.1 

— 

0.001 

3.5 

+ 

3.0 

:= 

0.003 

6.0 

+ 

5.0 

= 

0.005 

12.5 

+ 

8.0 

= 

0.010 

20.0 

+ 

8.0 

= 

0.015 

The  method  of  determining  nitrites,  as  given  by  Mr.  Jackson,  is  as 
follows  :  Fill  a  100  cc.  Nessler  tube  with  the  water  to  be  tested,  add 
1  cc.  of  hydrochloric  acid  (1  :  4),  then  2  cc.  of  sulphanilic  acid  (8 
grams  per  liter),  and  finally  2  cc.  of  naphthalamine  hydrochlorate  (8 
grams  per  liter  with  10  cc.  of  strong  hydrochloric  acid) ;  allow  to 
stand  twenty  minutes  until  the  full  dev^elopment  of  the  color  appears. 
If  100  cc.  of  water  develop  a  color  corresponding  to  the  second  of 
the  above  standards,  for  example,  it  contains  0.003  part  per  1,000,000 
of  nitrogen  as  nitrite. 

Determination  of  Nitrogen  as  Nitrates. — Solutions  Required. — 1. 
Phexoldisulphonic  Acid. — Heat  together  for  six  hours  in  a  water- 
bath  555  grams  of  strong  sulphuric  acid  and  45  grams  of  pure  phenol. 
Should  the  resulting  compound  solidify  on  cooling,  it  may  be  liquefied 
again  in  the  bath  and  then  poured  into  a  number  of  small  bottles  pro- 
vided with  groinid  stoppers.  Then,  as  needed,  one  of  them  may  be 
placed  in  the  bath  and  the  contents  liquefied. 

2.  Standaed  Solution  of  Potassium  Nitrate. — Dissolve  0.722 
gram  of  pure  potassium  nitrate  in  1  liter  of  pure  distilled  water. 
One  cc.  equals  0.1  mgr.  of  nitrogen  as  nitrates. 

Procehs. — Evaporate  10  cc.  or  more  of  the  water  with  1  drop  of 
sodium  carbonate  solution  to  dryness  in  a  .small  porcelain  dish.  To 
the  residue,  add  1  cc.  of  phenoldisulphonic  acid,  which  should  be 
brought  into  contact  with  every  jiarticle  by  means  of  a  glass  rod. 
Dilute  with  water,  make  strongly  alkaline  with  ammonia  or  caustic 
26 


402  WATEB. 

potash,  and,  fiuallv,  make  up  to  50  or  100  cc.  Avith  water.  Evaporate 
measured  volumes  of  the  standard  nitrate  solution,  treat  the  residnes 
with  a  like  amount  of  the  reagent,  and  proceed  in  the  same  way  to 
make  a  comparison  scale.  The  addition  of  the  alkali  converts  the 
picric  acid,  formed  by  the  action  of  the  nitrate  on  the  phenoldisul- 
phonic  acid,  into  the  corresponding  picrate,  which  imparts  a  bright- 
yellow  color,  the  intensity  of  which  depends  upon  the  amount  of 
nitrate  present.  The  comparison  of  tints  may  be  made  directly  in  the 
porcelain  dishes  or  in  tubes  of  the  same  sort  as  used  in  the  nitrite 
determination. 

The  accuracy  of  the  test  is  diminished  by  the  presence  of  chlorides 
in  notable  amounts,  say  more  than  2  parts  in  100,000,  but  not  by 
nitrites.  On  this  account,  Mason  recommends  the  addition  of  cor- 
responding amounts  of  sodium  chloride  in  the  jjreparation  of  the  color 
scale. 

The  standards  made  as  above  do  not  change  on  keeping,  and  hence 
may  be  made  up  in  sets  and  preserved. 

Determination  of  Chlorine. — Solutions  Required. — 1.  Standard 
SoLUTiox  OF  Silver  Xitrate, — Dissolve  4.797  grams  of  pure 
silver  nitrate  in  1  liter  of  distilled  water.  One  cc.  of  this  solution  is 
the  equivalent  of  1  mgr.  of  chlorine. 

2.  SoLUTiox  OF  Potassium  Chromate. — Dissolve  5  grams  of 
potassium  chromate  in  100  cc.  of  distilled  water,  add  nitrate  of  silver 
solution,  for  the  removal  of  any  traces  of  chlorides  present,  until  a  red 
precipitate  of  chromate  of  silver  is  formed.  Let  stand,  and  separate 
the  precipitate  by  decantation  or  filtration.  This  solution  is  to  be  used 
as  an  indicator. 

Process. — Place  in  each  of  two  beakers  of  similar  size  100  cc.  of 
water  and  5—10  drops  of  the  indicator.  The  beakers  standing  side  by 
side  upon  a  white  surface  of  porcelain  or  filter-paper,  the  silver  nitrate 
solution  is  added  to  one  of  them  from  a  burette  little  by  little  until,  in 
spite  of  stirring  with  a  glass  rod,  a  faint  reddish  tinge  begins  to  be 
perceptible.  This  is  seen  more  easily  by  comparison  with  the  water 
in  the  other  beaker.  The  burette  reading  is  now  taken,  and  then  a 
drop  or  two  more  of  the  reagent  will,  by  intensifying  the  red  color, 
show  that  the  end  point  has  been  reached.  The  process  depends  upon 
the  fact  that  silver  has  a  greater  affinity  for  chlorides  than  for  chrom- 
ates,  and  that,  so  long  as  any  of  the  former  is  present,  no  permanent 
union  will  ■  occur  with  the  latter.  When,  however,  all  the  chlorine 
has  combined  with  the  silver,  the  red  chromate  begins  to  form,  and 
makes  its  presence  known  by  the  change  of  color.  On  completion  of 
the  process,  the  amoimt  of  the  standard  reagent  used  indicates  the 
amoimt  of  chlorine  present,  each  cc.  used  representing  1  milligram. 

Inasmuch  as  a  certain  amount  of  the  reagent  is  required  to  give  the 
beginning  tint  in  100  cc.  of  distilled  water,  a  correction  should  be  made 
before  setting  down  the  result.  This  amount  dififers  somewhat  with 
diiferent  observers,  since  all  eyes  are  not  equally  quick  to  discern  the 
appearance  of  the  reddish  tint,  and  hence  the  best  method  of  fixing 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.   403 

the  amount  to  be  subtracted  is  for  each  one  to  determine  it  himself  hj 
experimenting  with  100  cc.  of  distilled  water  containing  the  requisite 
^amount  of  the  indicator. 

Should  the  amount  of  chlorine  in  a  given  sample  be  so  small  that 
the  end  reaction  appears  on  the  addition  of  but  a  few  drops  of  the 
silver  solution,  it  is  best  to  concentrate  250  or  500  cc.  of  the  water  to 
100  cc,  and  repeat  the  titration. 

Determination  of  Residue. — Evaporate  100  cc.  of  water  to  dry- 
ness in  a  perfectly  clean,  dry,  accurately  weighed  platinum  dish.  When 
completely  evaporated,  transfer  the  dish  from  the  water-bath  to  an  air- 
bath  kept  at  105°  C,  and  leave  it  for  an  hour,  at  the  expiration  of 
which  time,  place  it  in  a  desiccator  to  cool.  Reweigh  and  note  the 
gain  in  weight,  which  represents  the  amount  of  total  solids  in  the  vol- 
ume of  water  taken.  The  number  of  milligrams  gained  represents  the 
number  of  parts  per  100,000.  The  weighing  should  be  done  as  quickly 
as  possible,  in  order  to  avoid  error  due  to  the  absorption  of  atmospheric, 
moisture  by  hygroscopic  matters  in  the  residue. 

In  order  to  determine  the  amount  of  volatile  substances,  the  dish  is 
next  heated  to  dull  redness  on  a  platinum  triangle  over  a  Bunsen 
lamp.  The  organic  matter,  in  the  process  of  burning  off,  gives  rise  to- 
more  or  less  blackening,  and  may  also  evolve  odors  which  often  convey^ 
some  idea  of  its  nature.  The  blackening  may  disappear  quickly  or 
may  persist  for  some  time,  especially  in  the  case  of  woody  matters,  such 
as  are  present  in  brown  swamp  waters.  Animal  matters  cause  an  odor 
like  that  of  burnt  horn  ;  vegetable  substances,  one  suggestive  of  burning 
peat.  The  loss  in  weight  represents  not  only  the  organic  matter,  but 
also  the  nitrates,  nitrites,  ammonium  salts,  combined  carbonic  acid,  and^ 
if  the  temperature  has  been  raised  too  far,  part  of  the  chlorides.  The 
residue  after  ignition  represents  the  "  fixed  solids." 

Determination  of  Hardness. — For  the  determination  of  hardness, 
a  number  of  processes  are  in  use ;  but  for  practical  utility,  that  known 
as  the  "  soap  method  "  is  to  be  preferred. 

Solutions  Required. — 1.  Standard  Solution  or  Calcium  Chlo- 
ride.— Weigh  out  1  gram  of  pure  calcium  carbonate,  dissolve  it  in  as 
little  as  possible  dilute  hydrochloric  acid,  and  evaporate  to  dryness. 
Add  to  the  residue  a  little  distilled  water,  and  again  evaporate  to 
dryness.  Dissolv^e  in  distilled  water  and  make  up  to  1  liter.  One  cc. 
represents  1  milligram  of  calcium  carbonate. 

2.  Standard  Solution  of  Soap. — Scrape  about  10  grams  from 
an  old  dry  piece  of  pure  Castile  soap  free  from  sodium  hydrate  and 
carbonate,  and  dissolve  it  in  1  liter  of  diluted  alcohol.  Let  stand  over 
night  and  filter.  This  should  next  be  standardized  in  the  following 
manner  :  To  100  cc.  of  distilled  water  contained  in  a  glass-stoppered 
bottle  of  about  250  cc.  capacity,  run  in,  from  a  burette,  successive 
small  portions  of  the  soap  solution  until,  on  vigorous  shaking,  a  lather 
is  formed  which  persists  at  least  two  minutes,  and  note  the  amount 
used. 

Repeat  the  operati(jn  with  99  cc.    |    1  cc.  of  tlie  standard  solution  of 


404  WATER. 

calcium  chloride,  and  then  with  2,  3,  4,  5,  6,  7,  8,  9,  and  10  cc.  of  the 
same  solution  made  up  to  100  cc.  with  distilled  water,  and  note  the 
amount  used  in  each  test.  It  will  not  suffice  to  determine  the  amount 
necessary  to  produce  a  lather  with  distilled  water  and  with  10  cc.  of 
the  calcium  chloride  solution,  made  up  to  the  same  volume,  and  divide 
the  difference  bv  10,  since  as  we  go  up  in  the  scale  a  gradual  lessening 
of  the  amount  of  increase  for  each  degree  is  noted.  In  this  way  we 
obtain  a  scale  of  values  for  the  particular  lot  of  soap  solution  made  at 
one  time.  It  will  save  some  trouble  if  one  makes  up  a  number  of 
liters,  but  it  is  necessary  to  make  occasional  tests'  to  see  that  the  strength 
does  not  deteriorate,  or,  if  it  does,  to  correct  the  scale. 

Process. — To  100  cc.  in  the  bottle  above  mentioned,  add  the  soap 
solution  in  the  same  manner  as  employed  in  making  the  scale,  and, 
w^hen  the  end  point  is  reached,  note  the  amount  used,  and,  by  reference 
to  the  scale,  ascertain  the  number  of  degrees  of  hardness.  Should  the 
water  be  harder  than  1 0  degrees,  it  is  best  to  take  a  smaller  amount 
and  make  it  up  to  100  cc.  Avith  distilled  water  and  then  proceed  anew, 
remembering  at  the  end  to  calculate  accordingly. 

The  result  obtained  expresses  the  ''total  hardness."  If  it  be  desired 
to  ascertain  the  tem23orary,  or  removable,  hardness,  100  cc.  of  the  water 
may  be  boiled  five  minutes  and  then  allowed  to  cool.  The  original 
volume  is  restored  by  the  addition  of  the  necessary  amount  of  distilled 
^\'ater,  and  then  the  operation  is  repeated.  The  second  result  indicates 
the  permanent  hardness,  and  the  difference,  if  any,  is  the  temporary 
liardness. 

Determination  of  "  Oxygen  Required." — All  organic  substances 
are  susceptible  of  oxidation  ;  but  as  they  are  widely  variable  in  character, 
they  require  very  different  amounts  of  oxidizing  agents  for  the  attain- 
ment of  tlie  same  result.  The  several  methods  proposed  for  determin- 
ing the  oxygen-consuming  capacity  of  drinking-waters  have,  therefore, 
only  a  limited  value  ;  but,  in  general,  it  may  be  said  that  a  high  require- 
ment indicates  an  amount  of  organic  matter  inconsistent  with  purity 
when  it  cannot  be  accounted  for  by  the  presence  of  ferrous  salts. 
Since  the  amount  of  organic  matter  is  indicated  pretty  fairly  by  the 
ammonia  and  albuminoid-ammonia  determinations,  the  estimation  of 
the  "  oxygen  required  "  serves  only  as  confirmatory  evidence. 

Solutions  Required. — 1.  Standard  Solution  of  Potassium  Per- 
manganate.— Dissolve  0.395  gram  in  1  liter  of  distilled  water.  One 
cc.  is  equivalent  to  0.1  mgr.  of  available  oxygen. 

2.  Standard  Solution  of  Oxalic  Acid. — Dissolve  0.7875  gram 
in  1  liter  of  distilled  water.  One  cc.  corresponds  to  an  equal  measure 
of  the  permanganate  solution. 

3.  Dilute  Sulphuric  Acid,  1:3. 

Process. — The  determination  is  based  on  the  fact  that  potassium 
permanganate  gives  up  its  oxygen  readily  to  organic  matter,  especially 
in  the  presence  of  acid  and  with  the  application  of  heat.  The  reaction 
is  expressed  in  the  following  equation  : 

4KMnO,  +  6H2SO4  =  2K2SO,  +  4MnS04  +  GH^O  +  50.,. 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.   405 

Thus  4  molecules  of  permanganate  will  yield  5  of  oxygen,  or,  differ- 
ently expressed,  632  parts  by  weight  of  the  one  will  yield  160  parts 
by  weight  of  the  other;  hence,  3,950  of  permanganate  equals  1,000 
of  oxygen. 

In  this  operation,  cleanliness  of  vessels  is  of  the  greatest  importance. 
A  porcelain  casserole  or  evaporating  dish  of  sufficient  size  is  made  fit 
for  use  by  boiling  it  in  distilled  water  acidulated  with  sulphuric  acid, 
and  adding  permanganate  solution  until  no  further  decoloration  is 
observed. 

Place  200  cc.  of  the  sample  in  the  dish,  add  10  cc.  of  the  dilute 
sulphuric  acid,  and  heat  to  boiling.  Add  from  a  burette  sufficient  of 
the  permanganate  solution  to  cause  a  very  distinct  redness,  and  boil 
again,  adding  the  permanganate  as  the  color  tends  to  fade,  so  as  to 
retain  as  nearly  as  possible  the  original  color.  When  farther  boiling 
for  five  to  ten  minutes  fails  to  diminish  the  intensity  of  the  color,  oxida- 
tion is  complete.  Add  now  10  cc.  of  the  oxalic  acid  solution,  which 
will  discharge  the  color  if  the  permanganate  has  not  been  added  too 
freely.  Should  the  color  not  be  discharged  by  10  cc,  add  10  more. 
Having  now  a  colorless  solution,  add  more  permanganate  until  a  slight 
pink  color  again  appears.  Note  the  total  amount  of  permanganate 
used,  subtract  from  it  that  used  up  by  the  oxalic  acid,  multiply  the 
number  of  cc.  remaining  by  5,  in  order  to  arrive  at  the  amount  which 
would  be  consumed  by  1  liter,  and  divide  by  10  to  express  the  result  in 
milligrams  of  oxygen.  Inasmuch  as  any  nitrites  present  are  oxidized 
to  nitrates,  a  correction  should  be  made  for  them.  This  can  be  done 
very  readily,  since  16  parts  of  oxygen  are  required  for  14  parts  of 
nitrogen  as  nitrites. 

Since  the  permanganate  solution  is  not  wholly  stable,  it  should  be 
titrated  against  the  oxalic  acid  solution  every  time  it  is  used.  This 
may  be  done  most  conveniently  by  adding,  after  the  operation  is  com- 
pleted and  the  reading  of  the  burette  is  noted,  10  cc.  more  of  the  oxalic 
solution  and  titrating  to  the  same  point  as  before. 

The  oxalic  solution  keeps  better,  if  a  few  cc.  of  strong  sulphuric 
acid  are  added  when  it  is  being  diluted  to  1   liter. 

Determination  of  Color. — The  color  of  water  may  be  observed  by 
viewing  a  sufficient  depth  of  the  specimen  in  a  glass  cylinder  against  a 
white  surface.  Color  may  be  expressed  quantitatively  by  comparison 
with  the  standards  for  the  ammonia  determinations. 

Determination  of  Odor. — Place  about  200  cc.  of  water  in  a  500 
cc.  beaker,  cover  with  a  watch-glass,  and  heat  to  about  40°  C.  Give 
the  beaker  a  rotary  motion,  so  that  the  water  is  set  in  motion,  remove 
the  watch-glass,  and  with  the  nose  well  inside  the  beaker  note  the 
character  of  the  odor.  Some  analysts  prefer  to  heat  the  water  in  a 
glass-stoppered  bottle,  the  use  of  which  permits  a  much  more  thorough 
agitiition  of  the  water  befi)re  applying  the  nose.  The  odor  should  be 
designated  according  to  the  substance  which  its  presence  suggests. 

Determination  of  Reaction. — A  most  delicate  reagent  for  alkalinity 
in  water  is  a  I  per  cent,  solution  of  tohiylene-red.      Fifty  cc.  of  water 


406  WATER. 

distinctly  alkaline  will  become  intensely  yellow  on  the  addition  of  2 
or  3  drops.  A  less  degree  of  alkalinity  will  cause  an  orange  or  pale- 
red  color.  It  is  so  delicate  a  test  that  1  part  of  alkaline  carbonate  in 
1,000,000  is  reyealed  by  it. 

The  presence  of  acids  is  shown  by  another  sensitive  indicator,  lac- 
moid.  This  is  not  aifected  by  carbonic  acid,  nor  by  ferrous  and  other 
metallic  salts  which  are  acid  to  litmus,  but  is  aifected  by  ferric  salts. 
It  may  be  used  as  a  1  per  cent,  solution  in  diluted  alcohol.  Phenol- 
phthalein  solution,  0.5  per  cent.,  is  colorless  in  neutral  and  acid  solu- 
tions, and  pink  in  alkaline.     It  is  affected  by  carbonic  acid. 

In  the  determination  of  reaction,  a  drop  or  two  of  the  indicator  may 
be  added  to  a  volume  of  the  water  in  a  long  glass  tube.  A  very  faint 
change,  due  to  acids  or  alkalies,  is  perceptible  on  looking  down  through 
the  column  against  a  white  background.  If  the  reaction  is  acid,  the 
sample  should  be  boiled,  then  cooled,  and  tested  again  to  ascertain  if 
the  acidity  is  due  wholly  or  in  part  to  carbonic  acid.  Acidity  and  alka- 
linity are  determined  quantitatively  by  titration  with  centinormal  solu- 
tions of  sodium  hydrate  and  hydrochloric  acid,  using  lacmoid  or 
phenolphthalein  and  methyl-orange  as  indicators. 

Determination  of  Turbidity. — For  the  determination  of  the  degree 
of  turbidity,  several  methods  are  in  use,  among  ^vhich  the  following  may 
be  mentioned  :  Mason  ^  recommends  standards  made  by  adding  weighed 
amounts  of  kaolin  to  distilled  water,  each  representing  parts  per 
1,000,000  of  kaolin.  Whipple  and  Jackson^  employ  finely  powdered 
diatomaceous  earth,  instead  of  kaolin,  because  of  the  greater  uniformity 
in  the  size  of  the  particles.  Hazen  ^  measures  it  by  determining  the 
depth  at  which  a  0.1  mm.  platinum  wire  can  no  longer  be  seen. 

Detection  and  Determination  of  Lead. — Many  processes  have 
been  proposed  for  both  qualitative  and  quantitative  determination  of 
this  most  undesirable  contamination.  The  simplest  test,  but  by  no 
means  the  best,  consists  in  adding  a  drop  or  two  of  ammonium  sul- 
phide to  a  volume  of  water  in  a  tall  glass  cylinder,  and  noting  the 
character  of  the  discoloration  produced.  If  darkening  occurs,  due  to 
the  formation  of  a  metallic  suljihide,  the  addition  of  dilute  hydrochloric 
acid  will  distinguish  between  lead  and  iron,  the  sulphide  of  the  latter 
being  soluble.  To  those  who  have  had  practical  experience  in  de- 
tecting minute  amounts  of  metals  in  water,  this  method  is  far  from 
satisfactory.  More  or  less  color  is  imparted  by  the  ammonium  sul- 
phide, and  more  or  less  turbidity  is  produced  commonly  on  the  ad- 
dition of  the  acid.  Moreover,  when  un concentrated  water  is  used  for 
the  test,  no  reaction  may  occur,  although  the  poisonous  metal  is  present 
in  minute  traces. 

Another  simple  test,  depending  upon  the  formation  of  lead  chromate, 
has  been  offered  by  S.  Harvey,*  who  claims  that  water  containing  0.30 

^  Journal  of  the  American  Chemical  Society,  XXI.,  p.  516. 
"^  Technology  Quarterly,  XIII.,  No.  3,  September,  1900. 

*  Journal  of  the  Franklin  Institute,  1899,  p.  177. 

*  The  Analyst,  April,  1890. 


DETERMINATION  OF  FREE  AND  ALBUMINOID  AMMONIA.   407 

milligram  of  lead  in  1  liter  will  show  a  turbidity  from  chrbmate  when 
250  CO.  are  treated  with  0.10  gram  of  potassium  bichromate;  and  that 
in  twelve  hours  the  precipitate  will  settle  and  become  still  more  distinct. 

Since  small  amounts  of  lead  sulphide  remain  in  solution,  and  can 
be  separated  only  with  great  difficulty  when  the  volume  of  water  is 
large,  it  is  best  to  concentrate  the  specimen  to  a  very  small  bulk  before 
attempting  to  precipitate  the  lead.  From  this  point  onward  the 
methods  employed  vary  very  considerably. 

Liebrich  ^  precipitates  the  lead  as  sulphide  in  acid  solution,  converts 
it  to  sulphate  by  treatment  with  nitric  and  sulphuric  acids,  and  dissolves 
this  by  warming  with  a  few  cc.  of  caustic  potash  (1  : 1 0).  The  solution  is 
faltered  and  made  up  to  20  cc,  and  2  cc.  of  ammonium  sulphide  are 
added,  whereby  a  brown  color  is  produced,  which  may  be  compared 
with  the  shades  produced  by  similar  treatment  of  equal  volumes  of 
distilled  water  containing  known  amounts  of  a  solution  of  lead  sulphate 
in  caustic  potash. 

Antony  and  Benelli  ^  recommend  the  addition  of  mercurous  chloride 
before  precipitation  as  sulphides,  believing  that  thereby  no  trace  of  lead 
<3an  escape  complete  separation.  The  combined  sulphides  are  filtered 
and  dried,  then  heated  to  such  an  extent  that  the  mercury  salt  is  driven 
off,  leaving  the  lead  as  a  residue. 

Mr.  H.  W.  Clark,^  after  trying  all  known  methods,  finds  most  satis- 
faction in  the  following  process  devised  in  his  laboratory  :  3,500  cc. 
are  evaporated  to  25  or  30  cc,  10  or  15  cc.  of  ammonium  chloride 
solution  added  to  assist  separation  of  the  sulphides,  and  a  considerable 
excess  of  strong  ammonia.  Hydrogen  sulphide  is  then  added  and  the 
dish  allowed  to  stand  some  hours,  after  which  more  ammonia  and 
hydrogen  sulphide  are  added.  After  boiling  to  expel  the  excess  of  hydro- 
gen sulphide,  the  precipitate  is  filtered  off.  It  contains  any  lead,  iron, 
copper,  or  zinc  as  sulphides,  and  other  suspended  organic  and  mineral 
substances.  It  is  washed  once  with  hot  water,  and  the  paper  is  then 
boiled  in  dilute  nitric  acid  (1  :  5).  It  is  then  filtered,  and  washing  is 
continued  as  long  as  any  acid  is  removed.  The  filtrate  and  the  wash- 
ings are  concentrated  to  about  10  or  15  cc,  cooled,  and  then  mixed 
with  5  cc.  of  concentrated  sulphuric  acid  (specific  gravity  1.84)  and 
heated  until  copious  fumes  of  sulphuric  acid  are  evolved.  In  the 
absence  of  more  iron  than  0.025  in  100,000,  acetic  acid  and  ammonia 
are  added  directly.  The  mixture  is  next  boiled  and  filtered,  all  the 
iron,  dehydrated  silica,  and  insoluble  organic  matter  being  left  on  the 
paper.  The  filtrate  is  then  used  for  the  colorimetric  determination  of 
lead  by  means  of  comparison  of  the  shade  produced  by  the  addition 
of  hydrogen  sulphide  solution  with  a  set  of  standards  containing  known 
amounts  of  lead. 

With  more  than  0.025  iron  in  100,000,  the  process  is  somewhat 
different :  the  lead  sulj^hatc   is  washed  into  a  beaker  with  alcohol  and 

'  •  ClK'mikc-r-Zeitung,  1898,  XXIL,  p.  225. 

^  .Journal  de  phaniiacie  et  de  cheraie,  1898,  No.  7,  p.  72. 
^'  Loco  citato,  p.  582. 


408  WATER. 

water,  and  allowed  to  stand  over  night,  and  then  filtered  off  and  washed 
with  50  per  cent,  alcohol  until  free  from  iron.  The  lead  sulphate  is 
then  dissolved  by  boiling  the  filter  with  ammonium  acetate  in  a  porce- 
lain dish.  Experience  has  demonstrated  that  this  process  is  extremely 
accurate  and  reliable. 

The  author  finds  the  following  process  simple,  rapid,  and  accurate. 
Evaporate  3,000-4,000  cc.  of  water  to  about  15-20  cc.  in  a  porcelain 
dish ;  add,  little  by  little,  and  with  gentle  heat,  sufficient  dilute  hydro- 
chloric acid  to  dissolve  any  incrustation  of  salts  on  the  sides  and  bottom, 
and  to  give  a  slight  acid  reaction ;  then  add  5—10  cc.  of  hydrogen  sul- 
phide water  of  good  strength.  Any  lead  present  is  precipitated  in  a  very 
fine  state,  but  not  so  fine  but  that  the  entire  amount  can  be  collected 
on  a  Swedish  filter.  AYash  twice,  and  then  treat  on  the  filter  with  boil- 
ing dilute  nitric  acid  until  the  black  deposit  is  wholly  dissolved.  Wash 
with  hot  water  as  long  as  the  washings  are  acid,  and  add  them  to  the 
nitric  acid  filtrate.  Evaporate  to  dryness  in  the  original  dish,  add  dis- 
tilled water,  and  again  dry.  Dissolve  the  residue  in  hot  distilled  water 
and  make  up  to  50  cc.  Take  5—10  cc.  and  dilute  to  about  80  cc.  with 
distilled  water  in  a  glass  comparison  tube  of  100  cc.  capacity,  add 
hydrogen  sulphide  water  in  sufficient  amount,  make  up  to  100  cc.  with 
distilled  water,  and  mix  thoroughly  by  inverting  the  tube  a  number  of 
times.  Compare  the  depth  of  color  with  those  of  a  series  of  tubes 
containing  known  amounts  of  lead  as  lead  nitrate,  treated  with  hydro- 
gen sulphide  in  the  same  way. 

The  standard  solution  is  made  by  dissolving  0.160  gram  of  pure  lead 
nitrate  in  1  liter  of  distilled  water :  1  cc.  represents  0.1  milligram  of 
lead.  A  convenient  scale  is  made  with  1,  2,  3,  4,  5,  6,  7,  8,  9,  and 
10  cc.  of  the  solution  in  100  cc.  If  the  hydrogen  sulphide  water  is 
added  after  diluting  to  about  80  cc,  the  result  is  a  series  of  sufficiently 
clear  standards  showing  sharp  and  regular  stages  of  color.  If  the 
reagent  is  added  before  the  lead  salt  has  been  sufficiently  diluted,  the 
standards  are  very  turbid,  and  are  lacking  in  the  very  essential  grada- 
tion of  color. 

Should  the  depth  of  color  obtained  in  the  preliminary  test  be  greater 
than  that  given  by  No.  10,  a  smaller  amount  should  be  taken  and  the 
experiment  repeated.  Should  the  color  be  very  faint,  the  Avhole  of  the 
remainder  may  be  treated  and  compared.  From  the  result  obtained  by 
matching  the  colors,  the  amount  of  lead  in  parts  per  100,000  is  easily 
calculated. 

Example. — Ten  cc.  treated  as  above  gave  a  color  reaction  midway 
between  standards  6  and  7  ;  hence,  one-fifth  of  the  whole  contains  0.65 
milligram  of  lead,  and  the  entire  amount  contains  3.25  milligrams. 
The  amount  of  water  concentrated  was  3  liters.  Hence  1  liter  of  water 
contains  1.08  milligrams,  and  100  cc,  or  100,000  milligrams  of  water^ 
contain  0.108  milligram  of  lead. 

Detection  of  Zinc. — One  is  reasonably  safe  in  assuming  that  water 
which  has  been  in  contact  with  galvanized  iron  will  show  the  presence 
of  zinc.     This  may   be  determined  quantitatively  by   evaporating  a 


INFERENCES  AS  TO   CHARACTER   OF  WATER.  409> 

quantity  of  water  to  a  small  bulk,  heating  the  latter  with  a  sufficient 
amount  of  dilute  hydrochloric  acid  in  order  to  take  up  any  oxide  or- 
carbonate,  and  then  proceeding  to  the  precipitation  of  the  sulphide 
after  making  alkaline  with  ammonia.  For  qualitative  purposes,  a 
volume  of  water  is  made  slightly  alkaline  with  ammonia,  boiled,  and 
filtered.  The  addition  of  a  few  drops  of  test-solution  of  potassium 
ferrocyanide  to  the  filtrate  will,  in  the  presence  of  traces  of  zinc,  cause  a 
white  precipitate,  or  at  least  an  opalescence,  which,  however,  may  not 
be  distinct  within  a  half  hour. 

Detection  of  Tin. — Although,  so  far  as  known,  tin  in  water  has  na 
sanitary  significance,  it  sometimes  is  desirable  to  ascertain  its  presence 
in  water  and  in  other  substances.  For  rapid  testing  for  this  metal,, 
the  method  recommended  by  C.  Deniges  ^  may  be  employed.  This, 
depends  upon  the  fact  that  stannous  compounds  cause  a  reddish-violet 
color  with  nitrate  of  brucine.  The  brucine  solution  is  made  by  dis- 
solving 0.5  gram  of  brucine  in  5  cc.  of  nitric  acid,  diluting  to  250 
cc.  with  distilled  water,  boiling  for  fifteen  minutes,  and,  after  cool- 
ing, making  up  the  volume  to  250  cc.  again.  The  Avater  is  evapo- 
rated to  dryness  with  a  little  hydrochloric  acid.  The  residue  is  dis- 
solved in  a  very  little  water,  and  to  it  is  added  1  cc.  of  the  brucine 
solution.  If  so  little  as  the  twentieth  part  of  a  milligram  of  tin  is 
present,  the  color  change  will  be  distinctly  shown  even  in  the  presence 
of  iron  and  copper. 

Detection  and  Determination  of  Iron. — This  very  common  and 
frequently  troublesome  constituent  of  water  is  detected  very  easily  by 
concentrating  a  sufficient  volume  of  the  sample  to  a  small  bulk,  con- 
verting the  iron  present  from  the  ferrous  to  the  ferric  form  by  boiling- 
with  a  little  nitric  acid,  and  adding  a  few  drops  of  a  solution  of  potas- 
sium sulphocyanate,  which  causes  a  deep-red  coloration.  By  means  of  a 
scale  made  with  known  amounts  of  ferric  iron  treated  with  the  same 
volume  of  test-solution,  the  amount  of  iron  may  be  determined  quite 
accurately.  A  standard  solution  of  iron  may  be  made  by  dissolving- 
0.10  gram  of  pure  metallic  iron  in  aqua  regia  and  diluting  to  1  liter 
with  distilled  water  :  1  cc.  represents  0.10  milligram  of  iron.  The 
comparison  scale  is  made  by  diluting  progressively  increasing  volumes 
with  distilled  water  up  to  nearly  100  cc,  adding  a  few  cc.  of  a  5  per 
cent,  solution  of  potassium  sulphocyanate,  and  then  making  up  ta 
100  cc. 

For  other  determinations  of  a  strictly  technic  character,  the  reader 
is  referred  to  the  many  excellent  treatises  bearing  on  the  subject. 

Inferences  as  to  Character  of  Water  from  the  Results  of 
Sanitary  Chemical  Analysis. 

It  is  impossible  to  fix  any  absolute  standards  by  which  to  pass  upon 
the  potability  of  water  without  reference  to  its  origin,  for  surface- 
waters  cannot  be  judged  by  the  same  standards  as  ground-waters,  and, 

'  iievue  Internationale  des  Fal.sificationH,  VIII.,  p.  98. 


410  WATEB. 

moreover,  those  which  apply  to  waters  of  either  class  from  one  locality 
may  be  wholly  inapplicable  to  those  from  another.  A  surface-water, 
for  instance,  may  without  prejudice  yield  an  amount  of  albuminoid 
4immonia  which  would  be  Inost  suspicious  in  the  case  of  a  ground- 
water ;  while  the  latter  may  contain,  under  some  circumstances,  an 
amount  of  free  ammonia  inconsistent  with  purity  in  the  case  of  the 
former.  Again,  an  amount  of  chlorine  which  in  a  Avater  from  near 
the  sea  would  be  normal,  would  indicate  in  another  from  far  inland  the 
j)resence  of  sewage  matters. 

Ammonia  may  be  expected  in  some  amount  in  any  water ;  it  is 
characteristic  of  decomposition  of  organic  nitrogenous  matter  of  inno- 
cent character  as  well  as  of  sewage,  and  it  may  be  present  in  consider- 
able amounts  in  both  normal  and  polhited  waters.  Furthermore,  it 
may  be  present  in  higher  amounts  in  water  from  an  uncontaminated 
deep-bored  well  or  in  stored  rain,  than  in  polluted  water  that  has 
undergone  chemical  change.  Albuminoid  ammonia  may  be  yielded  in 
equal  amounts  by  a  water  contaminated  by  sewage,  and  by  one  quite 
free  from  it,  but  rich  in  dissolved  vegetable  matter  derived  from  leaves. 
Richness  in  mineral  matter  may  be  present  equally  in  normal  and  pol- 
luted waters.  A  pure  water  may  be  rich  in  nitrates,  while  a  sewage- 
water  may  have  lost  them  by  reduction.  Either  may  be  colored  or 
not,  clear  or  turbid,  and  odorous  or  odorless. 

There  is  one  constituent,  however,  the  presence  of  which  in  more 
than  measurable  quantity  is  a  tolerably  sure  indication  of  pollution, 
that  is  to  say,  the  nitrites ;  but  their  absence  is  not  a  guarantee  of 
puritv,  for  in  grossly  polluted  waters  they  may  be  wholly  wanting.  In 
general,  however,  it  may  be  set  down  as  a  safe  rule,  that  nitrites  and 
high  free  ammonia  together  mean  recent  pollution  ;  occurring  continu- 
ously, they  indicate  constant  pollution  ;  and,  with  chlorine  fairly  above 
the  local  normal,  ordinary  sewage  contamination.  High  ammonia 
with  nitrites,  but  with  no  marked  increase  in  chlorine,  may  indicate 
-contamination  by  matters  from  manured  farming  land. 

The  results  obtained  in  the  chemical  analysis  of  a  specimen  of  water 
are  often  quite  sufficient  for  the  formation  of  an  opinion  of  its  suit- 
ability or  unfitness  for  general  domestic  purposes,  but  more  often  a 
knowledge  of  the  source  and  the  surroundings  thereof  is  necessary 
for  their  intelligent  interpretation.  They  may  be  such  as  to  indicate 
that,  whatever  its  source,  the  water  which  yielded  them  is  very  good 
or  distinctly  bad ;  but,  on  the  other  hand,  they  may  be  such  that  full 
knowledge  of  all  the  facts  is  imperatively  necessary  for  the  formation 
of  a  correct  judgment.  A  water  yielding  the  following  results,  for 
instance,  may  unhesitatingly  be  pronounced  to  be  of  undoubted  purity 
so  far  as  chemistry  can  determine,  quite  irrespective  of  source  (the 
figures  express  parts  per  100,000)  : 

Free  ammonia 0.0002 

Albuminoid  ammonia 0.0018 

Nitrogen  as  nitrates 0.0240 

Nitrogen  as  nitrites .  0.0000 


INFERENCES  AS  TO   CHARACTER   OF   WATER.  411 

Chlorine 0.07 

Volatile  residue 1.25 

Fixed  residue 1.60 

Total  residue 2.85 

Hardness 1.00 

Appearance,  clear  and  bright. 

Color,  absent. 

Odor,  absent. 

Changes  observed  on  ignition  of  residue,  no  blackening. 

In  this  case  the  figures  indicate  almost  total  absence  of  organic  mat- 
ters, and  but  slight  amounts  of  mineral  constituents.  There  is  no 
suggestion  of  contamination  of  any  kind,  and  the  only  conclusion 
that  can  be  drawn  is  that  the  water  is  pure  and  soft,  and  suitable  for 
all  domestic  purposes. 

On  the  other  hand,  the  following  results  may,  in  the  same  way,  be 
sufficient  for  unqualified  condemnation. 

Free  ammonia 0.4750 

Albuminoid  ammonia 0.0585 

Nitrogen  as  nitrates 4.600 

Nitrogen  as  nitrites 0.054 

Chlorine    ._ 4.27 

Volatile  residue 11.10 

Fixed  residue 23.30 

Total  residue 34.40 

Hardness 14.00 

Appearance,  clear  and  bright. 

Color,  absent. 

Odor,  foul  after  heating. 

Changes  observed  on  ignition  of  residue,  slight  blackening. 

These  results,  which  are  actual  ones  obtained  from  a  specimen  sent 
to  the  author  with  no  statement  of  origin,  warranted  a  report  of 
gross  pollution,  regardless  of  source,  for  the  presence  of  sewage  mat- 
ters was  undeniable,  and  under  no  circumstances  of  geographical  loca- 
tion could  any  other  report  be  made.  Inquiry  concerning  the  origin 
of  the  water  brought  the  information  that  the  well  from  which  it 
came  was  located  at  no  great  distance  from  a  leaching  cesspool,  and 
was  used  only  when  the  usual  source  of  supply,  a  spring,  ran  dry. 
Repeated  attacks  of  illness  of  no  great  seriousness  had  been  noticed 
whenever,  during  the  preceding  three  years,  this  water  had  been  used. 

These  two  waters  may  serve  as  good  examples  of  undoubted  purity 
and  extensive  pollution.  Both  are  ground- waters,  and,  what  is  not 
without  interest,  they  came  from  one  and  the  same  small  inland  town. 

Such  results  as  the  above  require  no  long  consideration — they  speak 
for  themselves.  But  it  very  commonly  happens  that  even  a  single 
ingredient  may  cause  suspicion  of  sewage  pollution  to  arise  when 
information  as  to  the  location  of  the  supply  is  withheld.  Thus,  the 
amount  of  chlorine  may  be  very  considerably  higher  than  the  lowest 
normal  commonly  ol)served  inland,  and  yet  well  under  the  amount 
which  f;xcit<;s  no  adverse  comment  in  a  water  from  the  coast.  Thus, 
3.85  parts  in  a  well-water  from  an  island  in  Boston  Harbor,  and  1.35 
in  another  from  the  borders  of  Long  Island  Sound,  may  be  regarded 


412  WATER. 

as  fairly  low ;  while  if  found  in  springs  in  the  Green  Mountain  range, 
they  would  be  most  abnormally  high  and  of  much  significance. 

Again,  such  an  amount  might  come  in  connection  with  fair  yields 
of  the  ammonias,  and  then  under  one  class  of  conditions  the  organic 
matters  Avould  appear  to  be  of  vegetable  origin  and  in  another  to  be  a 
part  of  sewage. 

It  is  also  impossible  to  draw  sharp  dividing  lines  between  small, 
considerable,  and  high  amounts  of  the  ammonias ;  but,  in  general 
terms,  it  may  be  stated  that  up  to  0.005  or  0.006  part  per  100,000 
may  be  regarded  as  low,  from  thereabouts  to  0.015  or  0.020  as  con- 
siderable, and  beyond  as  high.  Measurable  amounts  of  nitrites  are 
most  significant,  while  nitrates  may  run  up  to  several  whole  parts 
per  100,000.  Thus,  it  may  readily  be  understood  that,  in  the  major- 
ity of  cases,  the  results  should  be  considered  in  conjunction  with  all 
material  facts  connected  with  source,  surroundings,  and  opportunity 
for  receiving  pollution. 

Bacteriological  Examination  of  Water. 

The  bacteriological  analysis  of  water  may  be  divided  into  quanti- 
tative and  qualitative  determinations.  The  former  is  commonly  ex- 
tended over  long  periods,  and  has  for  its  object  the  determination  of 
the  normal  bacterial  content  of  a  given  water  supply  and  the  observ- 
ance of  any  unusual  variation  therefrom ;  while  the  latter  is  pursued 
for  the  pur}30se  of  determining  the  nature  of  the  organisms,  and,  more 
particularly,  whether  they  are  such  as  are  to  be  found  in  the  excreta 
of  the  body.  The  finding  of  such  does  not  mean  necessarily  that  the 
use  of  the  water  will  inevitably  produce  disease,  but  it  indicates  the 
possibility  and  probability  that  water  containing  non-pathogenic  organ- 
isms from  this  source  may,  if  not  to-day,  to-morrow,  or  later,  become 
infected  with  others  from  the  same  source,  capable  of  acting  as  the 
exciting  cause  of  grave  disaster. 

As  is  the  case  with  chemical  analysis,  it  is  impossible  to  fix  any 
standard  of  safety  based  on  the  mere  amount  expressed  by  the 
quantitative  results,  since  it  is  the  nature  and  not  the  amount  of 
the  contaminating  matters  which  determines  the  question  of  pota- 
bility. But  sudden  deviations  from  the  seasonal  normal  suggest 
unusual  access  of  contamination,  and  serve  as  warnings  of  possible 
danger. 

The  isolation  and  systematic  study  of  the  various  species  of  bacteria 
in  a  given  water  to  determine  whether  or  not  they  may  be  patho- 
genic, involve  much  labor  and  an  intimate  knowledge  of  bacterio- 
logical technic  which  can  be  acquired  only  by  thorough  training  in 
a  bacteriological  laboratory.  Familiarity  with  the  methods  of  pre- 
paring culture  media  and  making  cultures,  of  isolating  species  and 
studying  their  characteristics,  is,  therefore,  a  necessary  qualification 
for  the  pursuit  of  bacteriological  examination  of  Avater,  and  anything 
more  than  a  brief  outline  of  special  methods  employed  in  this  par- 


BACTERIOLOGICAL  EXAMINATION  OF  WATER.  413 

ticular  field  of  research  would  be  beyond  the  scope  of  a  work  of  this 
character. 

Collection  of  Samples. — In  taking  samples,  it  is,  of  course,  neces- 
.sary  to  observe  the  most  rigid  precautions  against  the  introduction  of 
extraneous  organisms.  All  vessels  should,  therefore,  be  absolutely 
clean  and  sterile.  Collection  may  be  made  either  in  small  bulb  tubes, 
drawn  out  into  a  point  and  sealed  by  closure  in  a  lamp  flame,  or  in 
bottles  of  about  200  cc.  capacity  with  ground  stoppers.  The  bulbs  are 
made  easily  by  anybody  who  has  had  ordinary  experience  in  quali- 
tative analysis.  By  the  application  of  the  heat  of  a  lamp  immediately 
before  sealing,  or  by  vaporizing  a  drop  of  contained  water  by  the  same 
means  and  sealing  just  as  the  last  of  the  steam  is  escaping,  they  will 
contain  but  little  air,  and  when  used  are  filled  easily  through  the  in- 
fluence of  the  partial  vacuum. 

In  taking  the  sample,  the  point  is  introduced  below  the  surface  of 
the  water  and  then  broken  off  with  sterile  forceps.  The  bulb  is  filled 
partly  almost  immediately,  and  then  the  broken  point  is  sealed  as  be- 
fore by  the  application  of  heat  from  a  gas  flame  or  alcohol  lamp.  If 
bottles  are  used,  they  should  first  be  washed  on  the  outside  in  the 
water  to  be  sampled,  and  then  plunged  beneath  the  surface.  The 
stoppers  are  then  withdrawn,  and,  when  filling  is  completed,  they  are 
replaced. 

If  any  considerable  time  must  elapse  before  cultures  can  be  made, 
the  samples  should  be  packed  in  ice,  in  order  to  retard  multiplication 
of  the  contained  bacteria ;  and  since  very  low  temperatures  have  no 
harmful  influence  on  the  vitality  of  the  organisms,  the  addition  of  a 
small  amount  of  salt  to  the  ice  may  be  of  advantage,  although  freezing 
should  not  be  permitted,  on  account  of  the  danger  of  bursting  the  con- 
tainers. 

Planting  the  Samples. — If  possible,  the  planting  should  be  accom- 
plished on  the  spot,  on  account  of  the  multiplication  which  is  inevitable 
with  delay.  If  this  is  not  possible,  no  greater  delay  should  be  per- 
mitted than  is  absolutely  necessary. 

For  qualitative  determinations,  two  sets  of  plates  should  be  made  : 
one  on  gelatin,  to  be  kept  at  18°-22°  C. ;  and  one  on  agar-agar,  to  be 
incubated  at  37°-38°  C.  "When  working  on  a  water  of  unknown  char- 
acter hitherto  unexamined,  different  amounts  of  the  sample — 1,  2,  3, 
and  more  drops — should  be  used,  since  one  can  have  no  definite  idea 
of  its  bacterial  richness. 

In  quantitative  work,  the  amounts  taken  should  be  measured  with 
the  greatest  accuracy,  especially  when  preliminary  determinations  have 
shown  such  a  number  of  organisms  as  to  make  great  dilution  with 
sterile  water  necessary,  for  any  departure  from  absolute  accuracy 
inti-odnces  an  error  which  will  be  multiplied  according  to  the  degree  of 
dilution. 

When  liiill)  tubes  an;  uscid,  their  contents  are  expelled  with  the  aid 
of  gr'Dtlc  hciit,  whicli  causes  the  small  amount  of  contained  air  to 
expand  and  force  the  ]i(pii(l  thi-ongji  the  stem,  which  is  broken  at  the 


414  WATER. 

point  by  pressure  from  sterile  forceps.  The  expelled  water  is  received 
in  a  sterile  tube,  from  which  it  may  be  withdrawn  in  a  sterile  graduated 
pipette. 

Quantitative  Determination. — The  value  of  quantitative  determi- 
nations lies  in  the  comparisons  which  one  is  enabled  to  make  from  a 
series  of  periodical  examinations  of  the  same  water,  for  the  information 
to  be  derived  from  a  single  examination  has  very  limited  utility.  By 
means  of  periodical  counts,  one  is  enabled  to  form  an  idea  of  the  con- 
ditions normally  present  under  different  circumstances,  and  to  note  at 
once  any  disturbing  influence.  Quantitative  determinations  are  of 
special  value  in  noting  changes  in  the  efficiency  of  sand  filtration  of 
public  supplies. 

Knowing  from  preliminary  tests  or  from  past  experience  how  much 
water  should  be  taken  for  each  plate  or  roll,  and  the  degree  of  dilution 
necessary,  two  sets  are  made,  one  on  gelatin  and  one  on  agar-agar,  and 
the  growths  allowed  to  develop.  Gelatin  cultures  are  kept  at  18°— 22° 
C. ;  the  other  are  incubated  at  37°-38°  C.  The  lower  of  these  two 
ranges  of  temperature  is  much  more  favorable  to  the  multiplication  of 
ordinary  water  bacteria  than  the  higher,  and  consequently  it  will  be 
found  that  the  colonies  developing  on  the  gelatin  will  be  decidedly 
more  numerous  than  those  on  the  agar-agar.  In  expressing  results, 
therefore,  mention  should  be  made  of  the  culture  medium  employed ; 
and  in  making  comparisons  of  one  day's  results  with  those  of  another, 
the  importance  of  limiting  them  to  figures  obtained  under  like  condi- 
tions of  culture  medium  and  temperature  is  too  obvious  to  need  farther 
mention. 

The  counting  of  the  colonies  should  be  undertaken  always  at  the 
expiration  of  fixed  intervals  of  time,  since  more  and  more  dev^elop  from 
day  to  day,  particularly  on  agar-agar.  For  assistance  in  counting,  one 
may  employ  the  well-known  Wolff  hiigel  apparatus,  or  one  of  the  sev- 
eral modifications  thereof;  or,  what  is  more  simple,  may  have  the  bot- 
toms of  Petri  dishes  or  under  surfaces  of  the  ordinary  glass  plates, 
whichever  are  used,  ruled  off  in  square  centimeters  by  means  of  a  Merit- 
ing diamond.  The  entire  number  of  colonies  on  the  plate  may  be 
counted,  or  those  falling  within  a  certain  number  of  squares  may  be 
averaged  and  the  result  multiplied  by  the  whole  number  of  spaces 
covered  by  the  culture  medium. 

Drs.  W.  Hesse  and  Niedner  ^  have  proposed  a  method  for  quantita- 
tive determinations  which  obviates  the  use  of  nutrient  gelatin  and  all 
the  attendant  disadvantage  due  to  liquefying  bacteria.  Their  most 
important  recommendations  are  as  follows  : 

The  amount  of  water  planted  per  plate  should  be  such  as  will  pro- 
duce no  more  colonies  than  may  easily  and  accurately  be  counted ;  that 
is  to  say,  not  more  than  a  hundred.  At  least  five  plates  should  be  pre- 
pared, and  if  these  yield  results  fairly  in  agreement,  their  average 
should  be  taken  ;  but  if  any  plate  gives  figures  more  than  100  per 
cent,  removed  from  the  mean,  it  should  be  discarded.  These  should 
^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXIX.,  p.  454. 


BACTERIOLOGICAL  EXAMINATION  OF   WATER.  415 

be  kept  at  room  temperature  and  ia  the  dark  as  long  as  new  colonies 
develop,  that  is,  for  two  to  three  weeks,  at  the  end  of  which  time  one 
may  make  counts  which  will  have  some  claim  to  accuracy.  On  account 
of  the  evaporation  that  occurs  during  this  time,  it  is  necessary  to  use 
for  each  plate  at  least  10  cc.  of  culture  medium.  The  most  suitable 
medium  is  made  with  1.25  parts  of  agar-agar,  0.75  part  of  albumose, 
and  98  parts  of  distilled  water.  Gelatin  should  not  be  used,  on  account 
of  the  rapidity  with  which  plates  made  with  it  become  useless  on  account 
of  the  liquefying  colonies,  which  obstruct  some  growths  and  dissolve  and 
wash  others  away.  The  medium  above  described  possesses  the  advan- 
tage that  it  needs  no  addition  of  acid  or  alkali. 

Qualitative  Determination. — The  chief  interest  in  qualitative  ex- 
amination of  drinking-water  lies  in  the  solution  of  the  question  whether 
or  not  intestinal  bacteria  are  present.  Plates  may  be  prepared  and  pre- 
served in  the  same  manner  as  for  quantitative  work,  except  that  the 
amount  of  water  planted  needs  no  accurate  measurement,  but,  on  ac- 
count of  the  usual  great  preponderance  of  the  common  harmless  bac- 
teria, it  is  rarely  the  case  that  one  can  isolate  the  pathogenic  varieties 
without  recourse  to  special  methods  which  favor  their  growth  and  at  the 
same  time  kill  oif  the  others.  One  such  method  consists  in  incubating 
the  sample  with  bouillon  for  thirty-six  to  forty-eight  hours  at  37°— 38° 
C,  and  then  preparing  plates  in  the  usual  way.  The  common  bacteria 
are  in  this  way  subjected  to  conditions  unfavorable  to  their  growth  and 
vitality,  while  multiplication  of  the  pathogenic  varieties  is  promoted. 
Another  method,  depending  upon  the  resistance  of  the  typhoid  organ- 
ism and  B.  coll  communis  to  the  action  of  dilute  carbolic  and  hydro- 
chloric acids  and  the  powerful  influence  of  these  agents  on  the  common 
water  bacteria,  consists  in  incubating  a  few  drops  of  the  sample  in  10 
cc.  of  bouillon  containing  a  few  drops  of  a  solution  of  5  parts  of  phenol 
and  4  of  hydrochloric  acid  in  100  of  distilled  water.  The  bouillon 
is  incubated  first  with  the  phenol  mixture  for  twenty-four  hours  at 
37°  C,  and  then  receives  the  sample.  After  farther  incubation  for 
twenty-four  hours  or  longer,  plates  are  made  in  the  usual  way  and 
the  resulting  growths  systematically  studied.  Still  another  process  is 
that  of  Professor  Theobald  Smith,^  who  recommends  the  addition  of 
a  few  drops  of  the  water  to  bouillon  containing  2  per  cent,  of  glucose, 
and  incubating  in  fermentation  tubes  at  37°-38°  C.  for  thirty-six  to 
forty-eight  hours,  at  the  end  of  which  time,  if  gas  has  accumulated  in 
the  end  of  the  tubes,  plates  are  prepared  in  the  usual  way.  By  this 
process  it  is  possible  to  secure  pure  cultures  of  the  intestinal  bacteria. 

For  the  detection  of  B.  coll  in  water  supplies,  the  use  of  neutral-red 
has  been  proposed.  Rothberger,^  in  1898,  found  that  this  color  is  re- 
duced by  this  organism,  but  not  by  B.  typhosus,  and  is  changed  to  can- 
ary-yellow with  green  fluorescence.  Later,  he  discovered  that  certain 
anaerobes  have  the  same  power  (B.  tetani,  B.  cedematis  maligni,  B.  an- 
thracis  aymptomatici).     The  majority  of  the  aerobic  pathogenic  bacteria 

^  AmorifiiM  .Joiirriiil  of  tlic  Medical  Srienccs,  September,  1895. 
"^  Centralblatt  fur  Jiakteriologie,  etc.,  XXIV.,  p.  513. 


416  WATEE. 

have  been  tested  with  negative  results.  Scheffler  ^  found  the  reaction 
to  be  constant  in  his  investigation  of  a  large  number  of  races  of  B. 
•coll,  and  concluded  that  organisms  which  give  negative  results  may  be 
excluded  from  the  coli  group. 

MakgilP  found  that  B.  tetani  and  B.  cedematis  maligni  produce  the 
same  eifect  as  B.  coli  in  glucose-agar  even  w^hen  the  surface  of  the 
medium  is  exposed  to  air,  but  in  bouillon  the  anaerobes  produce  the 
reaction  only  when  oxygen  is  excluded.  He  discovered  that  B, 
Qiiesentericus  changes  the  red  to  a  dull  orange  both  in  bouillon  and 
in  glucose-agar.  His  experiments  thus  far  seem  to  indicate  that  a 
Avater  producing  a  typical  canary-yellow  in  neutral-red  media,  within 
forty-eight  hours  in  bouillon,  and  accompanied  in  glucose-agar  by 
green  fluorescence  and  gas  formation,  may  be  considered  to  contain 
B.  coli.  He  finds  that  1  to  5  organisms  per  cc.  will  produce  the  reac- 
tion in  bouillon  within  twenty-four  hours^  and  large  numbers  within 
twelve  hours.  He  concludes  that  neutral-red  affords  a  rapid  and  very 
delicate  test  of  the  presence  of  B.  coli ;  that,  using  varying  quantities 
of  water,  a  rough  estimate  may  be  obtained  of  the  number  present ; 
that  a  negative  result  with  a  fair  sample  is  evidence  of  their  absence ; 
and  that  farther  investigation  is  needed  to  show  that  the  reaction  is 
positive  evidence  of  their  presence,  although  in  his  experiments  it  Avas 
present  whenever  the  reaction  occurred. 

Savage,^  using  glucose  media  (broth  or  agar  containing  0.5  per  cent. 
•of  glucose),  foimd  that  agar  gives  the  best  results.  He  warns  against 
■employing  an  excess  of  neutral-red,  for  it  may  not  be  reduced.  His 
best  results  Avere  from  0.1  cc.  of  an  0.5  per  cent,  aqueous  solution  of 
Griibler's  neutral-red  added  to  10  cc.  of  broth  or  agar.  From  the 
results  of  an  extensiA^e  series  of  experiments,  he  concludes  that  a  posi- 
tiA'e  reaction  is  not  absolutely  diagnostic  of  B.  coli,  but  in  the  A^ast 
majority  of  cases  points  to  its  presence  ;  that  a  negatiA^e  reaction  does 
not  exclude  it,  but  makes  its  presence  highly  improbable ;  and  that  the 
test  is  A^erA'  easy  to  apply,  and  of  great  value  in  the  routine  examination 
of  Avater. 

For  the  detection  of  the  cholera  organism,  Koch  recommends  incu- 
bating 100  cc.  of  the  suspected  water  with  1  gram  each  of  sodium 
chloride  and  peptone  at  37°  C,  and  preparing  therefrom  at  intervals 
of  ten  to  twenty  hours  agar-agar  plates,  from  Avhich,  if  colonies  dcA^elop, 
other  plantings  may  be  made  for  systematic  investigation.  For  the 
detection  of  the  cholera  organism  in  small  numbers  in  the  presence  of 
water  bacteria.  Dr.  Arens  ^  has  found  caustic  potash  of  assistance,  and 
recommends  incubating  175  cc.  of  water  with  25  cc.  of  pancreas  bouillon 
containing  from  0.10  to  0.16  gram  of  the  alkali,  by  means  of  which  the 
growth  of  the  organism  is  faA'ored.  Dr.  Aufrecht,''  Avorking  on  similar 
lines,  found  that  the  development  of  the  organism  is  favored  by  gelatin 
containing  1  per  cent,  of  caustic  soda. 

^  Centralblatt  fiir  Bakteriologie,  etc.,  XXVIII.,  p.  199. 

2  Journal  of  Hygiene,  October,  1901,  p.  430.  »  Jbidem,  p.  437. 

*  Miinchener  medicinische  Wochenschrift,  March  7,  1893. 

*  Centralblatt  fiir  Bakteriologie  und  Pai-asitenkunde,  March  23,  1893. 


COMPARATIVE  VALUE  OF  ANALYSIS  OF  DRINKING-WATER.    411 


Comparative  Value  of  Chemical  and  Bacteriological  Analysis  of 

Drinking-water. 

As  the  science  of  bacteriology  began  to  develop  and  take  the  posi- 
tion to  which  its  importance  gave  it  a  title,  its  disciples  conceived  a 
strong  prejudice  against  and  contempt  for  any  opinion  as  to  the  pota- 
bility of  a  particular  water  based  upon  chemical  analysis,  maintaining, 
quite  correctly,  that  minute  amounts  of  ammonia,  albuminoid  ammonia, 
and  chlorine  are  incapable  of  acting  as  the  exciting  cause  of  infective 
disease,  and  that  not  these  substances,  but  only  specific  organisms  not 
demonstrable  by  chemical  processes,  can  so  act.  It  must  be  conceded 
that,  for  a  time  prior  to  the  discovery  of  the  nature  of  the  infective 
agents,  the  importance  of  the  results  of  chemical  analysis  was  grossly 
exaggerated,  and  that  arbitrary  standards,  such  as  were  established  by 
the  Rivers  Pollution  Commissioners,  upon  which  conclusions  were  based, 
have,  in  the  light  of  farther  experience,  been  abandoned  as  absurd  and 
untrustworthy.  But  it  must  also  be  conceded,  even  by  those  who  were 
most  caustic  in  their  criticism,  that  chemistry  is  to-day  equal,  if  not 
^superior,  to  bacteriology  in  indicating  possible  danger  from  the  use 
of  water  exposed  to  contaminating  influences. 

In  the  earlier  days,  much  capital  Avas  made  by  bacteriologists  of  the 
fact  that  a  sample  of  water,  inoculated  with  a  culture  of  the  bacillus  of 
typhoid  fever,  was  reported  by  a  chemist  of  high  standing  as  of  great 
])urity  and  eminently  suitable  for  domestic  purposes.  Such  a  test, 
however,  is  unworthy  of  the  slightest  consideration,  since  under  natural 
■conditions  a  water  showing  a  high  degree  of  chemical  purity  is  not 
likely  to  be  infected  with  a  pure  culture  of  a  pathogenic  organism,  and 
the  submission  of  a  pure  water  so  treated  is  a  mere  trap,  the  setting 
of  which  is  no  more  praiseworthy  than  would  be  the  sending  of  a 
sterile  solution  of  cyanide  of  potassium  or  of  sulphate  of  strychnine 
to  a  bacteriologist  with  a  request  for  an  opinion  from  the  standpoint 
of  his  specialty  as  to  its  desirability  as  a  beverage. 

Chemical  analysis  can  show  the  presence  of  organic  and  mineral 
impurity  such  as  accompanies  infectious  matters  from  the  intestine  and 
Ijladder.  It  cannot  give  grounds  for  a  positive  assertion  that  the  use 
of  a  water  thus  polluted  will  inevitably  cause  disease,  but  it  can  and 
does  serve  to  point  out  possible  danger.  It  can  detect  the  presence  of 
.sewage  matters,  and  while  it  cannot  prove  the  presence  of  infectious 
mat(!rial  therein,  it  can  at  least  point  out  that  the  occurrence  of  typhoid 
fever  in  the  community  furnishing  the  sewage  is  likely  to  be  followed 
Ijy  other  cases  of  the  disease  in  the  community  which  uses  the  polluted 
water.  It  cannot  distinguish  ty])hoid  pollution  from  any  other  excre- 
mental  contamination,  since  a  healthy  body  yields  the  same  chemical 
substances  as  one  that  is  diseased.  In  the  case  of  waters  containing 
no  evidence  of  contamination,  it  can  supply  the  basis  of  an  opinion  as 
to  safr.'ty,  but  it  cannot  furnish  any  guaranty  that  the  condition  is  per- 
manent. 

27 


418  WATER. 

Bacteriological  analysis  differentiates  between  pathogenic  and  non- 
pathogenic contamination,  but  it  is  only  rarely  that  it  serves  to  point 
out  danger  in  advance.  Even  when  an  outbreak  of  typhoid  fever  has 
occurred  and  attention  is  drawn  thereby  to  the  condition  of  the  water 
supply,  the  results  of  bacteriological  examination  are  generally  negative. 
The  reason  for  this  is  twofold.  In  the  first  place,  the  examination  for 
the  detection  of  the  specific  organism  is  not  ordinarily  begun  until 
attention  is  drawn  to  its  necessity  by  an  outbreak  of  the  disease,  which 
does  not  appear  until  about  two  weeks  from  the  time  contamination 
has  occurred.  Unless  the  contamination  is  continuous,  by  the  time  the 
examination  is  instituted,  the  polluting  materials  have  either  passed  on 
or  the  specific  organisms  have  perished.  In  the  second  place,  even 
although  they  are  present,  with  our  present  methods  it  is  not  an  easy 
matter  to  isolate  them,  and  we  can  determine  in  most  cases  only  the 
probability  of  their  presence. 

It  should  be  borne  in  mind  that  the  organisms  are  particulate  bodies 
in  suspension  in  great  dilution,  and  that  their  distribution  is  not  homo- 
geneous as  is  the  case  with  substances  in  solution,  and  that,  therefore, 
the  amoinit  of  water  taken  for  planting  plates  may  not  contain  them. 
But  in  the  unsuccessful  search,  it  is  not  uncommon  to  find  B.  coli 
communis,  and  where  this  organism  lurks,  the  other  may  have  been 
present. 

As  a  rule,  bacteriological  search  for  the  typhoid  bacillus  has  given 
negative  results.  Laws  and  Andrews  failed  to  find  it  in  the  sewage  of 
London,  although  it  must  have  been  present ;  and  they  had  but  slight 
success  in  the  examination  of  sewage  from  a  hospital  where  forty  cases 
of  the  disease  were  being  treated.  The  reason  for  this  may  be  that 
through  absence  of  suitable  food  material  and  favorable  temperature, 
and  by  reason  of  the  antagonistic  influence  of  the  ordinary  sewage 
bacteria,  the  typhoid  bacilli  had  lost  their  vitality  ;  or  it  may  be  that 
they  were  so  diluted  that  the  volumes  used  for  planting  failed,  as  a 
rule,  to  contain  them.  Examination  of  the  water  supposed  to  be  con- 
cerned in  the  unusual  outbreak  at  Maidstone  yielded  absolutely  nega- 
tive results,  although  no  reasonable  doubt  can  exist  that  at  some  time 
they  had  been  present. 

Professor  Percy  Frankland,  who  has  had  a  large  experience  in 
dealing  with  micro-organisms  in  air  and  water,  says  :  ^  ''  The  detection 
of  specific  pathogenic  bacteria  in  drinking-water  is  now  known  to  be 
almost  beyond  the  range  of  practical  politics,  and  the  search  for  such 
bacteria  is,  in  general,  only  carried  on  in  deference  to  the  special  request 
of  the  layman,  the  uninitiated,  or  the  hopelessly  ignorant,  whilst  it  can- 
not be  repeated  often  enough  that  any  feeling  of  security  which  may 
be  gathered  from  an  unsuccessful  search  for  pathogenic  bacteria  is  wholly 
illusory  and  in  the  highest  degree  dangerous.  .  .  .  By  far  the  most 
important  service  which  has  been  rendered  by  bacteriology  is  the  means 
which  it  affords  of  controlling  the  efficiency  of  filtration  and  other 
purification  processes.  The  slightest  irregularity  or  defect  in  the  proc- 
^  Jouj-nal  of  the  Sanitary  Institute,  October,  1899,  p.  393. 


COMPARATIVE   VALUE  OF  ANALYSIS   OF  DRINKING-WATER.    419 

ess  of  filtration  is  at  once  laid  bare.  Bacteriological  purity  of  well- 
waters  can  also  be  satisfactorily  controlled." 

Professor  W.  H,  Horrocks/  too,  remarking  on  the  fact  that,  if  a 
considerable  time  has  elapsed  since  the  occurrence  of  pollution,  the 
bacteriological  detection  of  the  same,  especially  when  waters  of  great 
original  purity  are  concerned,  becomes  more  and  more  difficult,  adds  : 
"  It  is,  therefore,  evident  that  a  bacteriological  examination  has  its 
limits  of  usefulness,  and  a  slavish  adherence  to  it  under  all  conditions, 
combined  with  neglect  of  the  hints  to  be  obtained  by  chemical  means, 
may  lead  to  a  perfectly  erroneous  judgment.  Still,  there  is  one  branch 
of  hygienic  study  in  which  bacteriology  must  always  reign  supreme ; 
it  is  now  acknowledged  on  all  sides  that  the  working  of  sand  filters 
for  public  water  supplies  cannot  be  properly  kept  under  control  except 
by  appealing  to  bacteriological  methods  of  examination." 

A  positive  result,  the  first  instance  in  which  the  organism  isolated 
responded  to  every  test,  including  growth  on  gelatin,  potato,  litmus 
milk,  bouillon  and  glucose  bouillon,  agglutination,  and  Pfeiffer's  test 
with  animals,  is  recorded  by  Drs.  Kiibler  and  Neufeld.^  In  this  case, 
the  cause  of  the  disease  lay  in  the  use  of  water  from  a  well  infected 
by  the  urine  of  a  person  sick  with  the  disease.  Four  weeks  from  the 
time  of  the  first  examination  when  the  bacillus  was  isolated,  a  second 
analysis  was  made,  which  yielded  bacilli  which  responded  to  all  the 
tests  excepting  Pfeiffer's,  which  exception  was  supposedly  due  to  modi- 
fied virulence.     No  colon  bacilli  were  present  either  time. 

A  second  instance  is  recorded  by  Fischer  and  Flatau,^  who  isolated 
the  organism  from  a  well-water  in  Pellingen.  Similarly,  a  second 
attempt,  made  four  weeks  later,  was  unsuccessful. 

From  what  has  gone  before,  it  may  be  said  that  neither  chemical  nor 
bacteriological  analysis  is  infallible.  Each  has  its  uses,  and  each  may 
be  helped  by  the  other.  The  value  of  either  lies  in  the  skill  displayed 
in  interpreting  the  results,  and  this  requires  as  much  knowledge  as  the 
making  of  the  examination  itself. 

1  Bacteriological  Examination  of  Water,  London,  1901,  p.  3 

^  2^itschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXXI.  (1899),  p.  133. 

^  Centralblatt  fiir  Bakteriologie,  etc.,  XXIX.  p.  329. 


CHAPTER  V. 
HABITATIONS,  SCHOOLS,  ETC. 

Section  1.     GENERAL   CONSIDERATIONS. 

It  is  essential  to  health  that  the  houses  iu  which  we  dwell  shall  be 
built  upon  proper  sites,  free  from  dampness  and  organic  pollution  ; 
they  should  be  provided  with  adequate  means  for  heating,  ventilating, 
and  lighting  ;  they  should  be  well  supplied  Avith  water  for  general 
domestic  purposes,  and  provided  with  a  proper  system  of  plumbing 
for  the  removal  of  sewage ;  they  should  be  constructed  with  proper 
precautions  against  dampness  from  Avithout  or  below.  Heating,  venti- 
lation, lighting,  and  plumbing  are  considered  below  under  their  several 
headings. 

Aspect. — It  is  commonly  directed  that  habitations  should  be  placed 
so  as  to  face  the  south  ;  but,  unfortunately,  one  is  not  always  in  a  posi- 
tion to  be  over-particular  in  the  matter  of  points  of  the  compass,  and, 
indeed,  there  seems  to  be  no  particularly  good  reason  why  that  side  of 
the  house  in  which  is  located  the  main  entrance  should  face  south  and 
the  others  respectively  north,  east,  and  west.  The  southerly  side  of  a 
hill  is  very  much  to  be  preferred  to  the  northerly,  because  of  the 
greater  amount  of  sunlight  and  of  protection  against  the  cold  winds 
from  the  north  ;  but  in  a  plain  and  elscAvhere,  whichever  wall  of  the 
house  faces  south,  there  must  be,  if  the  structure  be  rectangular,  one 
to  the  north.  Far  better  is  a  location  with  the  corners  of  the  house 
pointing  north  and  south,  for  in  that  case  every  window  must  receive 
some  direct  sunlight  at  some  part  of  the  day,  whereas  with  sides  facing 
directly  north  and  south,  the  windows  of  the  former  receive  no  direct 
sunlight  and  the  rooms  are  dull  and  cheerless.  In  large  cities,  aspect 
is  commonly  a  minor  consideration,  the  desirability  of  a  house  being 
determined  mainly  by  other  circumstances.  In  general,  it  may  be  said 
that,  when  possible,  a  house  should  be  so  situated  as  to  insure  an 
abundance  of  light  and  air  with  protection  against  the  cold  winds 
of  winter. 

Construction  and  Arrangement. — Consideration  of  building  ma- 
terials and  the  details  of  arrangement  of  rooms  and  division  of  floor- 
space  are  beyond  the  scope  of  a  work  of  this  nature,  and  it  is  necessary 
only  to  call  attention  to  the  importance  of  insuring  dryness,  light,  and 
air,  and  such  thoroughness  of  construction  as  shall  not  permit  a  too 
generous  amount  of  natural  ventilation  with  consequent  Avaste  of  heat. 

Of  the  very  greatest  importance  is  the  character  of  the  cellar,  that 
part  of  the  house  which  is  most  neglected  during  both  construction  and 
occupancy.      Unless  the  site  is  one  of  unusual  dryness,  the  cellar  floor 

420 


SCHOOLS.  421 

should  consist  of  a  generous  layer  of  cement  impervious  to  moisture 
from  below  and  to  soil-air  and  its  contamination,  such  as  gas  from 
leaking  mains.  The  foundation  walls  should  be  tight  and  dry,  and 
should  contain  in  their  upper  part  a  sufficient  number  of  windows  of  a 
size  to  admit  an  adequate  supply  of  light. 

The  walls  should  be  made  as  far  as  possible  proof  against  wind  and 
weather.  In  exposed  positions,  it  may  be  that  a  clapboarded  wall  is 
far  drier  than  one  of  brick,  for  the  latter  material,  if  very  porous,  is  not 
uncommonly  wet  through  by  driving  rain,  and  does  not  quickly  become 
dry  again.  Sometimes  it  becomes  necessary  to  cover  an  entire  brick 
wall  with  a  protective  coating  of  paint,  or  even  with  a  sheathing  of  tin 
plate.  For  protection  against  dampness  and  cold,  external  walls  may 
be  built  with  an  intervening  air  space,  which  acts  like  that  of  a  double 
window ;  the  outer  and  inner  faces  of  the  wall  are  joined  at  intervals 
by  bonding  bricks  or  ties  of  various  materials,  including  hard  non- 
porous  bricks,  glazed  bricks,  and  iron. 

Roofs  should  be  tight  and  protected  against  the  backing  up  of 
water  from  melting  snow  and  ice  when  the  gutters  are  filled  with  ice. 
As  a  covering,  slate  is  much  to  be  preferred  to  shingles,  though  its 
initial  cost  is  much  greater ;  it  is  permanent  in  character,  impermeable, 
and  requires  but  little  repairing,  while  shingles  wear  out  in  course  of 
time,  and,  by  taking  up  moisture,  lead  to  rotting  of  the  timbers  beneath. 
Tin  is  tight  and  impermeable,  but  is  very  hot  in  summer.  Tar  and 
gravel  are  well  suited  to  nearly  flat  roofs,  the  gravel  protecting  the  tar 
from  the  action  of  the  sun,  and  the  combination  being  very  durable. 

Care  of  Habitations. — The  proper  care  of  a  house  and  its  surround- 
ings is  a  subject  that  can  hardly  be  taught ;  with  many,  it  is  a  natural 
instinct ;  with  more,  very  little  is  required  to  satisfy  the  understand- 
ing of  the  term.  A  large  class  distribute  house  sanitation  with  an 
uneven  hand,  insisting  upon  the  perfection  of  care  of  those  parts  which 
they  inhabit  and  in  which  the  outside  world  is  received,  and  neglect- 
ing those  where  filth  is  most  likely  to  accumulate,  but  to  which,  per- 
haps, the  general  overseeing  eye  never  penetrates.  In  a  way,  the  most 
important  parts  of  a  house  are  the  cellar  and  the  kitchen,  and  these 
should  receive  more  careful  attention  than  the  drawing-room,  where, 
presumably,  organic  filth  can  hardly  gain  access  in  appreciable  amounts. 
The  otherwise  careful  housekeeper,  to  whom  a  burnt  match  on  the 
hearth  of  an  open  fire  is  an  abomination,  will,  perhaps,  view  with  placid 
face  the  boxes,  baskets,  and  even-barrels  of  rotten  fruits  and  vegetables, 
dirty  cans,  and  other  refuse  brought  to  the  surface  from  the  cellar  once 
each  year  at  the  time  given  over  to  "  spring  cleaning."  The  perfectly 
kept  house  knows  no  cleaning  seasons. 

SCHOOLS. 

Schools,  even  more  than  liiil)itations,  require  the  best  of  situations 
with  rcferfncf;  to  ligjit  and  air.  Windows  should  be;  large  and  numer- 
ous, and,  according  to  the  estimates  of  different  autliorities,  their  com- 


422  HABITATIONS,  SCHOOLS,  ETC 

bined  area  should  equal  from  a  tenth  to  a  fourth  of  the  total  floor  area. 
In  the  arrangement  of  school  furniture,  the  main  consideration  lies  in 
the  direction  of  the  light.  The  desks  are  placed  best  so  that  the  light 
comes  from  the  left  of  the  pupils  ;  coming  from  the  right,  it  casts  annoy- 
ing shadows  of  pen  or  pencil  in  exercises  requiring  writing;  cross- 
lighting  may  cause  still  greater  annoyance  by  casting  double  shadows. 
Liight  from  the  front  is  exceedingly  trying,  as  may  readily  be  appre- 
ciated by  attempting  to  read  a  clock  placed  between  two  windows  ; 
from  behind,  it  casts  shadows  of  the  body  upon  the  work  on  the  desk. 

Cloak  rooms  should  be  spacious  and  well  ventilated,  and  provided 
wdth  ample  hanging  facilities  permitting  sufficient  space  between  the 
individual  garments. 

Water-closets  and  urinals  demand  more  than  usual  care,  for  children 
are  prone  to  carelessness  in  their  use  ;  and  since  they  are  commonly 
j)laced  in  the  basement,  they  are  ver}'-  likely,  if  not  kept  in  scrupulously 
clean  condition,  to  pollute  the  air  of  the  rooms  above. 

School  Furniture. — School  furniture  is  well  known  to  be  one  of 
the  most  important  influences  in  the  development  of  lateral  curvature, 
and  much  careful  study  has  been  pursued  in  improving  its  construc- 
tion. Desks  and  chairs  should  not  be  supplied  with  reference  to  age, 
but  according  to  the  size  of  children,  and  should  be  adjustable  to 
each  child.  Common  faults  of  chairs  include  improper  shape  of  back, 
improper  height,  too  great  depth  or  breadth  of  seat,  too  much  slope 
from  front  to  back,  and  improper  horizontal  distance  from  the  desk. 
Common  faults  of  desks  include  insufficient  or  too  great  height,  and 
improper  slope  of  the  surface. 

Chairs  should  be  of  such  a  height  that  when  the  leg  and  thigh  form 
a  right  angle  the  foot  shall  be  squarely  on  the  floor.  If  too  high,  the 
child  cannot  touch  the  floor,  and  fails  to  obtain  the  needed  assistance 
from  the  feet  and  legs  for  the  maintenance  of  an  upright  position  ;  if 
too  low,  the  position  is  cramped  and  awkward  and  the  child  is  forced 
to  extend  the  legs  in  one  direction  or  another,  and  to  contort  the  body 
accordingly.  The  seat  should  be  sufficiently  wide  to  support  both 
thighs  comfortably,  but  not  so  wide  as  to  permit  the  assumption  of  bad 
postures  in  which  the  back  is  not  well  supported.  It  should  not  be 
too  deep  from  front  to  back,  since  then  proper  attitude  is  impossible. 
It  should  slope  very  slightly  from  front  to  back,  or  be  made  slightly 
concave,  in  order  that  the  tendency  to  slip  forward  may  be  counter- 
acted. The  back  should  be  curved  forAvard,  so  as  to  support  the  child's 
back,  and  to  be  comfortable  in  whatever  legitimate  attitude  he  may 
assume,  for  he  requires  changes  in  position  for  the  relief  of  downward 
pressure  and  strain  of  muscle  and  ligaments,  since  any  attitude  long 
maintained  results  in  fatigue.  With  chairs  of  the  best  form  of  con- 
struction, faulty  attitudes  are  less  comfortable  than  proper  ones. 

Desks  should  be  of  such  a  height  that  the  forearms  of  the  child  may 
be  rested  without  causing,  on  the  one  hand,  stooping,  or,  on  the  other, 
raising  of  the  shoulder  and  curving  the  spine.  If  too  high  for  the 
child,  the  work  is  brought  too  near,  and  causes  straining  of  the  eyes. 


VENTILATION  AND  HEATING.  423 

The  top  should  have  a  proper  slope  downward  of  from  ten  to  twenty 
•degrees,  and  its  edge  should  project  slightly  over  the  forward  edge 
of  the  chair,  so  that  the  body  and  head  may  not  be  inclined  forward 
too  far. 

Proper  height  of  seats  and  desks  and  correct  horizontal  distance 
between  the  two  are  attained  by  the  adoption  of  adjustable  furniture, 
of  which  there  are  many  varieties. 

Blackboards  should  be  dull  black,  and  never  shiny,  for  if  they  are 
shiny  they  reflect  light,  and  what  is  written  thereon  is  difficult  to  read 
from  certain  points  in  the  room.  They  should  be  kept  well  cleaned, 
in  order  that  the  contrast  with  the  chalk  shall  be  sharp.  The  chalk 
should  be  white  or  yellow  ;  blue,  green,  and  red  chalk  marks  are  much 
more  difficult  to  read.  Blackboards  should  never  be  placed  between 
windows,  on  account  of  glare.  Copying  from  blackboards  is  very  try- 
ing to  the  eyes,  on  account  of  the  constant  necessary  change  of  focus. 

Legislation  Concerning  Schools. — Many  of  our  States  have  enacted 
laws  providing  for  school  sanitation  in  several  particulars.  Seventeen 
require  expert  examination  of  plans  for  projected  buildings.  Sixteen 
provide  for  fire-escapes  and  other  protection  from  fire.  A  number 
provide  for  proper  ventilation,  but  only  two,  Massachusetts  and  Con- 
necticut, have  established  a  standard  and  require  its  enforcement. 
Kentucky  alone  provides  standards  for  lighting,  for  floor  space  and  air 
space,  for  proper  seating,  and  for  water  supply.  About  one-third  of 
the  States  and  Territories  compel  vaccination,  and  one-fourth  provide 
safeguards  in  the  matter  of  contagious  diseases  in  general. 

Section  2.     VENTILATION  AND  HEATING. 

We  have  seen  how  necessary  it  is  to  life  that  the  CO2  given  off  by 
the  blood  in  the  lungs  to  the  inspired  air  shall  be  discharged  continu- 
ously from  the  body,  and  we  know  that  whatever  other  effects  the  im- 
purities of  vitiated  air  may  produce,  the  effect  of  undue  COj  in  the  air 
is  to  interfere  with  the  function  of  respiration.  Therefore,  it  follows 
that  the  air  which  we  breathe  should  be  as  free  as  possible  from  the 
impurities  which  we  continually  discharge  into  it,  and  that  this  condi- 
tion can  be  obtained  only  by  constant  dilution  of  them  by  a  constant 
supply  of  fresh  air.  In  the  open  air,  this  dilution  goes  on  without 
artificial  assistance  and  requires  no  consideration ;  but  in  confined 
spaces,  we  have  to  a  certain  extent  a  reproduction  of  the  conditions 
that  obtain  in  the  lung ;  namely,  the  presence  of  a  volume  of  vitiated 
air,  separated  from  the  purer  surrounding  air,  and  requiring  to  be  dis- 
charged and  replaced.  In  other  words,  the  air  in  the  first  confined 
space,  the  lung,  is  discharged  into  the  second  confined  space,  the  room, 
and  thence  must  be  removed  to  tlie  outside  and  replaced  by  an  equal 
amount  of  normal  air.  The  constant  dilution  and  removal  of  impuri- 
ties due  to  the  necessities  of  life,  so  that  thcjir  amount  shall  be  so  small 
as  to  be  harmless,  are  the  function  of  ventihition,  wliicli  may  be  re- 
garded as  t})(!  respiration  of  a  l>uil(ling. 


424  HABITATIONS,  SCHOOLS,  ETC. 

It  is,  of  course,  not  to  be  expected  that  the  air  of  an  inhabited  rooni 
can  under  the  usual  conditions  be  maintained  in  a  state  of  purity  like 
that  of  the  outdoor  air,  even  though  but  one  candle  or  one  person  be 
present  to  exchange  carbon  dioxide  and  water  for  oxygen,  but  the 
impurities  can  be  reduced  to  a  minimum  by  the  introduction  of  a  proper 
amount  of  fresh  air.  AVhat  shall  be  considered  a  proper  amount  of 
continuous  air  supply  depends  upon  what  we  adopt  as  a  limit  of  per- 
missible impurity,  measured  by  the  amount  of  COg  present. 

For  the  maintenance  of  a  fair  degree  of  vigor  and  stability  through 
proper  oxidation  of  the  blood  and  dilution  of  the  effete  matters  dis- 
charged, and  for  the  maintenance  of  the  fullest  and  most  perfect  func- 
tional activity,  one  requires  respectively  about  30  and  50  cubic  feet  of 
air  per  minute.  Less  than  30  will  inevitably  produce  impaired  vitality  • 
more  than  50  can  be  productive  of  no  gain  in  improvement,  so  far  as- 
the  eifects  of  the  ordinary  vitiating  matters  are  concerned.  At  the 
latter  rate,  then,  an  hourly  supply  of  3,000  cubic  feet  is  necessary  for 
the  proper  dilution  of  the  respired  air  of  each  individual  present  in  a 
confined  space.  Thus,  a  room  of  3,000  cubic  feet  capacity,  inhabited 
by  one  person,  should  receive  its  full  capacity  of  fresh  air  once  every 
hour.  But  this  renewal  should  be  a  continuous  process,  so  as  ta 
prevent  the  accumulation  of  impurities  which  would  occur  if  the  air 
were  replaced  simply  in  bulk  by  an  hourly  aeration  by  opening  win- 
dows for  the  requisite  few  minutes.  Nor  should  it  be  supposed  that 
even  with  constant  fresh  supply  the  air  of  the  room  can  have  the  same 
composition  as  that  which  enters  from  without,  for  the  impurities  of 
each  respiration  are  not  removed  in  separate,  distinct  lots,  but  are 
mingled  in  the  general  bulk.  If  the  occupant's  head  were  in  a  conduit 
bringing  the  constant  supply  of  fresh  air  and  carrying  away  the 
products  of  respiration,  no  such  amount  of  air  would  be  necessary, 
and  no  contamination  of  the  general  supply  would  occur.  Under 
ordinary  circumstances,  with  an  hourly  supply  of  3,000  cubic  feet  per 
capita,  the  amount  of  CO2  will  not  range  above  6  or  7  volumes  in 
10,000,  and  any  system  of  ventilation  that  will  keep  it  down  to  this 
may  be  called  good. 

Other  impurities  than  those  of  respiration  are  to  be  considered  in  all 
questions  of  ventilation.  The  influence  of  burning  illuminating  mate- 
rial on  the  composition  of  air  is  very  great,  both  as  to  the  consumption 
of  oxygen  and  the  production  of  CO2  and  other  impurities,  and  it 
is  not  insignificant  in  its  relation  to  the  temperature.  The  impurities 
from  1  cubic  foot  of  ordinary  illuminating  gas  are  such  in  amount  as 
to  require,  according  to  various  estimates,  from  500  to  1,800  cubic  feet 
of  air  for  their  proper  dilution.  They  include  not  only  carbon  dioxide 
and  water,  but  carbon  monoxide,  sulphur  acids,  nitrogen  acids,  marsh 
gas,  ammonia  compounds,  unconsumed  carbon,  and  other  matters. 
Different  forms  of  burners  consume  different  amounts  of  gas  to  pro- 
duce the  same  illumination ;  ordinarily  from  3  to  6  cubic  feet  are  used 
per  hour,  requiring  1,500  to  10,000  cubic  feet  of  air-supply  for  proper 
dilution  of  the  impurities  produced  by  each  burner.      Therefore,  on 


AMOUNT  OF  SPACE  REQUIRED  FOR   GOOD    VENTILATION.   425 

both  hygienic  and  economic  grounds,  the  burner  which  produces  the 
maximum  of  light  from  the  minimum  of  gas  is  the  best  for  use,  it  being 
understood  that  a  given  volume  of  gas  will  yield  the  same  amount  of 
impurities,  whatever  the  burner  employed. 

The  impurities  from  candles  and  lamps  are  less  in  number  and 
variety,  but,  measured  by  their  comparative  illuminating  power,  they 
are  larger  in  amount  than  from  gas.  For  example,  the  combustion  of 
an  amount  of  candle  or  kerosene  oil  necessary  to  produce  the  same 
intensity  of  light  as  1  cubic  foot  of  gas  will  produce  from  40  to  160 
per  cent,  more  impurities,  and  requires,  therefore,  proportionately  more 
air  for  their  proper  dilution. 

The  subject  of  ventilation,  involving,  as  it  does,  the  continuous, 
introduction  of  pure  air  to  displace  that  which  has  become  vitiated  by 
whatever  cause  or  heated  to  such  a  degree  as  to  be  inconsistent  with 
comfort ;  having  to  deal  with  buildings  and  rooms  of  various  sizes, 
designed  for  different  uses ;  and,  as  it  is  chiefly  in  the  colder  months, 
that  its  importance  is  greatest,  being  intimately  connected  with  the 
problems  and  cost  of  heating,  is  a  very  complex  one  which  will  not 
permit  the  adoption  of  inflexible  rules  applicable  to  all  cases. 


Amount  of  Space  Required  for  Good  Ventilation. 

If  it  be  agreed  that  for  the  most  perfect  results  an  adult  requires  art 
hourly  supply  of  3,000  cubic  feet  for  the  removal  of  his  own  effete 
matters,  to  say  nothing  of  the  accessory  impurity  dependent  upon 
illumination,  the  next  question  is  as  to  the  amount  of  cubic  space 
necessary  per  capita,  that  is  to  say,  through  how  small  a  space  that 
amount  of  air  can  be  drawn  hourly  without  disagreeably  perceptible 
draughts.  The  sensation  of  draught  is  governed  very  largely  by  the 
temperature  of  the  moving  air,  a  cold  slowly  moving  current  being 
more  perceptible  than  a  warm  one  moving  at  a  greater  rate  of  speed. 
Draughts  which  are  productive  of  discomfort  are  more  dangerous  than; 
the  ordinary  vitiation  of  the  air,  and,  therefore,  complete  ventilation, 
with  draughts  is  worse  than  partial  ventilation  without  draughts. 

It  has  been  shown  by  Pettenkofer  that,  with  the  aid  of  delicate 
apparatus  and  mechanical  power,  about  2,500  cubic  feet  can  be  passed 
without  draughts  through  a  space  of  424  cubic  feet  in  an  hour ;  that  is 
to  say,  through  a  room  8  feet  square  and  6.5  high,  the  air  can  be 
renewed  six  times. 

The  minimum  space  within  which  one  can  receive,  under  artificial' 
conditions,  six  complete  changes  of  air  in  one  hour  is,  therefore,  424 
ciil^ic  feet ;  but  in  order  to  get  3,000  cubic  feet  in  one  hour,  the  air 
would  have  to  be  changed  seven  times,  and  so  the  required  minimum 
space  would  be  500  cubic  feet.  In  large  spaces,  however,  it  is  possible 
U)  obtain  more  frequent  changes  without  danger  from  draughts.  Thus, 
in  a  hall  40  by  20  by  15  feet,  40  persons  may  be  sup])licd  with  3,000 
cubic  feet  each  per  hour,  and  (,'ach  one  will  have  300  cubic  feet  of  air 


426  HABITATIONS,   SCHOOLS,   ETC. 

space.  Therefore,  in  dealing  with  large  spaces,  we  may  assume  300 
cubic  feet  per  capita  rather  than  500. 

In  the  ventilation  of  small  spaces,  there  is,  in  addition  to  the  possi- 
bility and  danger  of  draughts,  the  grave  difficulty  that  the  inlets  and 
outlets  are  necessarily  so  near  together  that  much  of  the  air  will  pass 
directly  from  the  one  to  the  other  without  having  mingled  w'ith  the 
main  body  of  air,  and  without,  therefore,  doing  the  slightest  service  in 
diluting  the  impurities  present.  In  large  air  spaces,  this  objection  does 
not  apply  with  equal  force,  for  the  opportunity  for  diffusion  is  greater, 
the  larger  the  space,  although,  of  course,  here,  too,  the  inlets  and  out- 
lets may  be  so  placed  as  to  favor  the  formation  of  direct  currents. 

In  the  ventilation  of  large  spaces  in  which  large  numbers  of  people 
gather,  as  churches,  theatres,  schools,  and  lecture-rooms,  we  are  at  once 
confronted  by  the  fact  that  300  cubic  feet  of  space  is  a  more  liberal  per 
capita  allowance  than  is  often  practicable,  and  that  this  space  is  incom- 
patible with  a  draughtless  ventilation  by  the  necessary  air  volume.  If, 
then,  the  question  be  asked,  how  to  provide  the  necessary  amount,  there 
is  but  one  answer ;  namely,  that  it  cannot  be  done.  Fortunately, 
however,  the  danger  from  impure  air  is  proportionate  to  the  length  of 
time  of  exposure,  an  occasional  short  time  spent  in  a  crowded  room  or 
public  conveyance  filled  with  bad  air  being  less  harmful  than  prolonged 
and  habitual  occupancy  of  a  room  in  which  the  air  is  less  vitiated,  but 
yet  not  good. 

In  general,  it  may  be  said  that  the  importance  of  ventilation  varies 
with  the  particular  air  spaces ;  those  which  are  used  only  at  intervals 
and  for  short  periods  have  much  less  need  of  it  than  those  which 
are  used  uninterruptedly  ;  those  which  are  not  crowded  demand  less 
than  those  that  are ;  those  used  only  for  the  moment  need  no  consid- 
eration whatever,  the  natural  forces  at  work  at  all  times  being  suffi- 
cient for  their  needs. 

To  insist  upon  thorough  ventilation  of  every  part  of  a  house  at  all 
times,  as  most  amateur  hygienists  do,  is  to  demand  a  needless  waste  of 
energy  and  money,  for  except  in  the  warm  months  when  the  windows 
and  doors  are  left  freely  open  for  the  sake  not  alone  of  ventilation,  but 
of  general  comfort,  ventilation  goes  hand  in  hand  with  heating  and 
divides  the  expense. 

Nor  can  one  successfully  insist  upon  any  rule  that  each  person  must 
have  at  least  1,000  cubic  feet  of  air  space  with  renewal  of  the  contained 
air  once  in  twenty  minutes,  for  to  do  so  is  to  urge  in  the  case  of  the 
poor  of  large  cities  an  impossibility,  since  space  is  costly,  and,  wdth 
ventilation  to  the  proper  extent,  is  beyond  their  means. 

Natural  Forces  in  Ventilation. 

Before  proceedmg  to  the  subject  of  systems  of  ventilation,  we  must 
consider  the  natural  forces  which  are  at  work  in  the  presence  or 
absence  of  all  schemes  and  systems.  These  forces  are  diffusion  and 
gravity. 


NATURAL  FORCES  IN  VENTILATION  427 

Diffusion  and  Gravity. — The  rate  at  which  gases  diffuse  is  by- 
no  means  the  same  for  all,  the  lighter  diffusing  much  more  rapidly 
than  the  heavier.  In  fact,  the  rate  varies  inversely  as  the  square 
roots  of  their  densities.  The  province  of  diffusion  in  ventilation  is 
limited  to  bringing  the  air  to  a  condition  of  more  or  less  complete 
homogeneity  by  causing  the  gaseous  matters  to  become  distributed 
throughout  the  mass  ;  but  in  an  inhabited  room  it  can  do  but  little 
toward  keeping  the  air  at  its  normal  composition.  By  reason  of 
the  law  governing  the  rate  of  diffusion,  there  must  of  necessity  be  a 
constant,  though  slow,  removal  of  gaseous  impurity  into  the  external 
air,  for  wherever  two  gases  are  brought  into  contact,  diffusion  will 
occur,  whether  the  meeting  place  be  large  spaces,  as  rooms,  or  small 
spaces,  as  pores  in  the  plastering,  bricks,  mortar,  stone  or  other 
material  which  forms  the  boundaries  of  that  room.  This  force  is, 
however,  very  inadequate,  and  can  be  of  service  only  as  an  assist- 
ant to  another.  Moreover,  it  can  affect  only  gaseous  and  not  sus- 
pended matters. 

Of  vast  importance,  however,  is  the  other  force,  that  of  gravity. 
Equal  volumes  of  air  at  the  same  temperature  and  under  the  same  press- 
ure will  have  the  same  specific  gravity ;  if  the  temperature  of  one  of 
them  be  raised,  it  expands  a  definite  amount  for  each  degree,  and  thus 
has  less  specific  gravity  than  the  other  the  more  it  is  heated.  Being 
surrounded  by  air  which  is  heavier  than  itself,  it  rises,  or,  more 
properly,  is  forced  upward  by  the  heavier  air,  which  descends  to  occupy 
its  place  in  the  same  way  that  a  volume  of  light  oil  in  a  cylinder  is 
forced  upward  when  water  is  poured  upon  it.  If,  on  the  other  hand, 
it  is  cooled,  its  volume  contracts,  its  specific  gravity  is  increased,  and 
it  sinks  downward  through  the  warmer  lighter  air  below  it.  In  this 
way,  differences  in  temperature  cause  constant  movements  in  bodies  of 
air,  and  currents  are  established.  In  an  inhabited  room  this  force  is 
always  at  work,  for  there  must  necessarily  be  some  source  of  heat,  even 
though  it  be  only  the  body  of  the  occupant.  The  air  in  contact  with 
the  body  becomes  heated,  and  is  then  displaced  by  the  colder  air  about 
it ;  this  in  its  turn  is  subjected  to  the  same  influences,  and  the  whole 
of  the  contained  air  rises  in  temperature  and  is  correspondingly  ex- 
panded. As  it  becomes  lighter  than  the  surrounding  air,  the  latter 
forces  itself  in  and  the  original  air  out  through  all  the  available 
openings,  and  thus  a  certain  amount  of  ventilation  is  accom- 
plished. 

Under  the  ordinary  conditions  of  occupancy  of  a  house  or  room,  we 
have  additional  sources  of  heat  in  the  combustion  of  fuel  and  illumi- 
nating materials,  and  no  matter  how  imperfect  the  applied  system  of 
ventilation  may  be,  and  in  spite  of  all  efforts  to  exclude  the  external 
air,  a  very  considerable  amount  of  interchange  of  air  is  inevitable.  It 
is  only  in  a  chamber  that  is  to  all  intents  and  purposes  hermetically 
sealed  that  no  v<!ntilation  will  occur  when  there  is  a  difference  be- 
twYTMi  the  int(!rnal  and  external  tenii)eratures.  Heated  air  will  escape 
tliron^fli  fines,  tlirougli  cracks  around  windows  and  doors,  between  the 


428 


HABITATIONS,  SCHOOLS,   ETC. 


boards  of  the  floors  aud  of  the  general  structure,  and  even  through  the 
interstices  of  unpainted  plastering  and  mortar,  and  through  the  pores 
of  bricks.  That  a  large  volume  of  air  will  pass  through  cracks,  needs 
no  demonstration  ;  the  passage  of  air  through  bricks,  plaster,  and  mor- 
tar may  easily  be  shown.  If  to  the  opposite  sides  of  a  brick,  we  fasten 
by  means  of  sealing  wax  two  ordinary  glass  funnels,  and  then  smear  its 
entire  exposed  surface  with  a  liberal  coating  of  the  same  material,  all 
of  the  external  pores  excepting  those  within  the  spaces  covered  by  the 
funnels  are  made  impervious  to  air.  If  now  Ave  connect  by  means  of 
a  rubber  tube  the  funnel  on  one  side  with  a  bottle  in  which  air  can  be 
compressed  by  means  of  water  pressure,  and  by  the  same  means  the 


Fig.  38. 


V 


Apparatus  for  demonstrating  the  permeability  of  bricks,  etc.,  to  air. 

Other  funnel  with  an  inverted  test-tube  filled  with  water,  aud  apjAy 
pressure,  the  passage  of  air  through  the  pores  of  the  brick  will  be 
manifested  in  a  few  minutes  by  the  escape  of  bubbles  from  the  outlet 
tube  upward  through  the  water.     (See  Fig.  38.) 

The  passage  of  air  through  plastered  walls  is  much  impeded  by  wall 
paper,  and  may  be  totally  prevented  by  oil  paint  and  moisture. 

Numerous  experiments  have  proved  that  with  varying  differences 
between  the  internal  and  external  temperatures,  the  air  of  a  room  or 
building  will  be  renewed  partly,  wholly,  or  repeatedly  every  hour, 
even  when  efforts  are  m.ade  to  prevent  as  far  as  possible  the  entrance 


NATURAL  FORCES  IN  VENTILATION. 


429 


of  the  outside  air.  The  results  vary  with  the  diiFereuce  in  conditions, 
the  highest  effects  being  produced  when  the  temperature  differences 
are  wide,  the  opportunities  for  leakage  great,  and  the  external  air  in 
active  motion.  With  perfect  calm  and  equal  temperature,  the  result 
will  be  nil. 

Perflation  and  Aspiration. — Inequalities  in  outside  temperatures 
give  rise  to  the  larger  currents  of  air  which  we  know  as  winds.  These 
have  a  very  great  influence  on  ventilation  both  by  their  perflating  action 
and  by  aspiration.  The  highest  results  of  perflation  are  those  obtained 
when  obstacles  to  the  free  admission  and  exit  of  wind  are  removed,  as, 
for  instance,  by  opening  windows  in  its  path.  The  quickness  and  fre- 
quency of  renewal  of  contained  air  by  this  means  will  necessarily  depend 


Fig.  39. 


Fig.  40. 


Fig.  41. 


Common  forms  of  stationary  ventilating  cowls. 


Rotarv  cowl. 


upon  the  size  of  the  openings  and  the  velocity  and  direction  of  the  wind. 
The  least  effects  are  produced,  whatever  the  velocity  and  direction,  when 
the  obstacles  to  entrance  are  greatest. 

The  a.spirating  influence  of  wind  is  shown  by  the  upward  currents 
produced  in  flues  when  the  internal  and  external  temperatures  are 
equal.  A  current  of  air,  moving  swiftly  across  the  outlet  of  a  flue,  has 
the  same  effect  on  the  contents  of  the  flue  as  that  of  a  common  hand 
atomizer  has  on  the  contents  of  the  tube.  The  air  in  the  upper  part 
is  carried  along  mechanically,  a  partial  vacuum  is  formed,  and  that 
which  is  below  rises  to  take  its  ])lace,  and  is  in  turn  carried  away.  In 
the  case  of  the  flue,  air  from  below  is  constantly  drawn  up  and  dissi- 
pated ;  in  the  case  of  the  atomizer,  the  liquid  into  which  the  tube  dips 


430 


HABITATIONS,  SCHOOLS,  ETC. 


is  lifted  and  blown  into  spray.  This  influence  is  utilized  and  assisted 
by  various  forms  of  cowls  placed  over  outlet  flues ;  some  of  these, 
however,  although  they  seem  to  be  an  aid,  are  really  a  hindrance  to 
the  outflow,  as  may  easily  be  demonstrated. 

In  Figs.  39  and  40,  are  shown  forms  of  cowls  which  offer  some 
assistance  to  the  aspiratory  influence  of  winds,  and  in  Fig.  41  is  shown 
another  very  popular  kind,  the  rotary  cowl,  which  offers  an  obstruction 
to  the  passage  of  air.  As  the  wind  causes  the  top  to  revolve,  the  im- 
pression is  made  that  work  is  being  performed  ;  that  in  its  revolutions 
it  is  creating  a  suction  which  causes  an  upward  current  of  air.  As  a 
matter  of  fact,  however,  it  is  doing  no  such  work,  but  is,  on  the  con- 
trary, interposing  an  obstacle  to  the  passage  of  air.  This  may  easily 
be  demonstrated  by  measuring  by  means  of  an  anemometer  the  amount 

Fig.  42. 


Aspirating  cowl  with  vane. 


of  air  discharged  through  the  flue  during  a  given  period  while  the  re- 
volving top  is  in  place,  and  again  during  an  equal  period  while  it  is 
removed.  The  difference  between  the  results  obtained  will  invariably 
be  in  favor  of  the  period  during  which  the  cowl  is  absent. 

Other  forms  of  cowls,  constructed  so  that  their  outlets  are  turned  by 
means  of  a  vane  away  from  the  wind,  are  useful  in  assisting  aspiration. 
Such  a  form  is  shown  in  Fig.  42.  By  reversing  the  position  of  the 
vane,  the  mouth  of  the  cowl  is  turned  toward  the  wind  so  that  the  flue 
is  converted  into  an  inlet  for  fresh  air. 


NATURAL    VENTILATION.  431 

Natural  Ventilation. 

Ventilation  that  proceeds  from  the  operation  of  natural  forces  is 
known  as  "  natural  ventilation."  For  the  attainment  of  the  largest 
results,  these  forces  must  be  assisted  to  the  extent  of  removal  of  ob- 
stacles to  their  action  so  far  as  may  be  advisable.  It  is  not  well  to 
depend  upon  the  chance  cracks  and  upon  the  migration  of  air  through 
the  pores  of  building  materials,  but  necessary  openings,  both  inlets  and 
outlets,  should  be  provided.  The  greater  the  obstacles  to  the  escape  of 
heated  air,  the  less  the  opportunity  for  successful  natural  ventilation. 

The  extreme  of  obstruction  to  the  escape  of  contained  air  may  be 
illustrated  by  an  hermetically  sealed  metallic  box  or  by  a  closed  glass 
bottle.  Suppose  we  provide  one  small  opening  in  the  side  of  the  box 
or  in  the  stopper  of  the  bottle  to  act  as  an  outlet  and  inlet,  and  observe 
the  result.  According  as  the  contained  air  is  warmed  or  cooled,  the 
opening  will  act  as  an  outlet  or  as  an  inlet,  but  only  to  a  limited 
extent.  The  expansion  due  to  heating  will  cause  the  escape  of  a 
portion  of  the  contents  ;  the  contraction  due  to  cooling  will  cause  the 
indrawing  of  some  of  the  outer  air ;  but  in  either  case,  the  movement 
is  all  one  way,  and  there  is  no  real  interchange.  Suppose,  however^ 
two  openings  are  supplied  ;  then  one  may  act  as  an  outlet,  the  other 
as  an  inlet,  and  a  constant  inward  and  outward  current  may  be  main- 
tained. 

The  more  tightly  fitting  we  make  our  windows  and  doors,  and  the 
more  impervious  to  air  we  make  our  walls  by  means  of  paint  and 
sheathing  paper,  the  more  do  we  oppose  natural  ventilation.  On  the 
other  hand,  the  intelligent  placing  of  inlets  and  outlets  furthers  the 
object  to  be  achieved. 

In  addition  to  permanently  installed  inlet  and  outlet  flues,  tempo- 
rary openings  may  be  utilized  whenever  desirable.  The  most  avail- 
able of  these  is  the  opened  window,  which  may  be  utilized  so  as  to 
avoid  too  voluminous  exchange  and  unbearable  draughts.  The  area 
of  the  opening  may  be  very  simply  regulated,  and  the  air  may  be 
deflected  upward  or  the  current  may  be  broken  up  by  the  interposition 
of  fine  wire  gauze,  flannel,  or  other  pervious  material. 

A  very  common  plan  is  to  place  a  board  lengthwise  under  the  lower 
sash,  so  as  to  fill  completely  the  opening  made  by  raising  the  window, 
and  thus  establish  an  inlet  or  outlet  where  the  sashes  overlap  each 
other,  for  the  barrier  to  the  movement  of  air,  formed  by  the  juxtaposi- 
tion of  the  lower  border  of  the  upper  sash  and  the  upper  border  of  the 
lower  one,  no  longer  exists,  and  the  entering  current,  moreover,  is 
given  an  upward  direction.  Instead  of  a  board,  a  frame,  over  which 
a  diaphragm  of  flannel  is  fastened,  may  be  used.  This  arrangement 
is  pervious  to  air  but  impervious  to  dirt,  which,  therefore,  is  filtered 
out.  Movable  j)ancs,  either  sliding  or  swinging  by  the  side  or  end,, 
arc  frccjucntly  employed,  especially  in  double  windows.  There  are 
also  nimi(;rous  patented  dcvi(!es  for  window  ventilation,  all  designed 
with  tiie  idea  of  dividing  or  deflecting  the  current  of  admitted  air. 


432  HABITATIONS,  SCHOOLS,  ETC. 

As  has  been  remarked  above,  the  most  important  force  in  natural 
ventilation  is  that  dependent  upon  unequal  temperatures  of  bodies  of 
air ;  in  a  perfect  calm  and  with  equal  temperatures,  natural  ventilation 
Avould  have  to  depend  wholly  on  the  force  of  diifusion. 

The  enormous  influence  exerted  by  the  heating  and  lighting  of  a 
building  or  room  on  its  ventilation  becomes,  then,  self-evident,  but  it 
is  not  simply  as  a  motive  force  that  the  relation  between  heat  and  ven- 
tilation is  so  close  and  important,  for  the  incoming  air  must  be  raised 
to  an  agreeable  temperature  in  order  that  the  space  may  be  habitable. 
Thus,  a  very  large  share  of  the  cost  of  heating  is  chargeable  to  venti- 
lation, whatever  the  system  of  ventilation  be.  In  the  matter  of 
•expense,  the  amount  of  leakage  through  cracks  and  other  small  open- 
ings is,  in  a  certain  class  of  cases,  of  very  great  importance.  In  our 
■dwellings,  it  is  important  that  the  interchange  of  air  shall  proceed 
•continuously  in  the  inhabited  parts,  but  in  buildings  which  are  used 
•only  by  day,  and  perhaps  for  only  a  few  hours  daily  (schools,  etc.), 
it  is  not  essential  that  the  air  shall  be  renewed  constantly  at  other 
times ;  and  here  it  is  wise  to  obstruct  the  leakage  as  much  as  possible 
by  perfect  construction  and  by  dampers  in  the  flues,  so  that  waste  of 
ieat,  fuel,  and  money  may  be  prevented. 

For  the  promotion  of  the  process  of  natural  ventilation,  a  number 
of  "  systems "  have  been  devised,  many  of  which  can  be  productive 
of  no  results  other  than  incomes  for  their  promoters.  As  a  rule, 
most  of  those  noticed  in  works  of  this  character  are  either  ill-adapted 
to  the  conditions  of  our  climate  or  incompatible  with  our  methods  of 
building,  and  will,  therefore,  not  be  considered  here. 

The  onlv  svstem  of  natural  ventilation  worthy  of  advocacy  is  that 
"which  provides  proper  inlets  and  outlets  and  a  suitable  means  of 
heating. 

Inlets  and  Outlets. — As  to  the  size,  location,  and  number  of  in- 
lets and  outlets,  no  hard-and-fast  rules  can  be  applied  for  all  cases, 
since  the  conditions  are  Avidely  varying,  and  many  different  circum- 
stances have  to  be  taken  into  account.  But  general  rules  may  be  laid 
■down. 

If  several  inlets  are  to  be  provided  in  a  room,  it  is  essential  that 
they  should  be  distributed  in  such  a  manner  as  to  insure  a  thorough 
blending  of  the  admitted  air.  They  should  not  be  so  placed,  with 
reference  to  outlets,  as  to  favor  the  forming  of  direct  currents  between 
them,  whereby  a  large  proportion  of  the  inflowing  air  is  discharged 
Avithout  having  fulfilled  its  function — a  not  unusual  condition,  which 
illustrates  that  the  amount  of  air  admitted  is  not  by  any  means  a 
measure  of  thoroughness  of  ventilation.  Their  location  is  not  such 
an  important  matter  as  the  placing  of  the  outlets,  but,  in  general,  an 
inlet  is  placed  best  on  an  inner  wall  where  it  shall  be  most  nearly 
central  in  relation  to  the  outside  walls. 

With  reference  to  the  floor,  if  the  incoming  air  is  heated,  inlets 
may  be  placed  high  or  low  ;  but  if  it  is  admitted  cold,  they  should 
be  at  a  higher  level  than  the  heads  of  the  occupants,  and  provided 


NATURAL   VENTILATION.  433 

with  arrangements  for  deflecting  the  current  toward  the  ceiling. 
This  may  be  accomplished  by  causing  the  current  to  impinge  upon 
a  surface  slanting  upward.  The  results  of  this  deflection  are  that  the 
fresh  air  becomes  mixed  with  the  warmer  air,  and  that  more  time  is 
required  for  it  to  reach  the  lower  parts  of  the  room,  when  it  will  have 
become  sufficiently  warmed  not  to  cause  discomfort.  The  interposi- 
tion of  the  deflecting  surface  also  spreads  the  current  radially  and 
.reduces  its  velocity.  The  incoming  air  becomes  mingled  with  the 
general  supply  and  joins  the  currents  which  are  constantly  in  motion. 
That  which  comes  in  contact  with  cooling  surfaces,  such  as  windows 
and  outside  walls,  is  cooled,  and,  therefore,  falls  toward  the  floor, 
and  that  which  takes  its  place  as  it  falls  is  cooled  in  its  turn  and  fol- 
lows after,  so  that  currents  are  established,  which  tend  to  keep  the  whole 
bulk  in  more  or  less  rapid  motion.  As  these  currents  reach  the  floor, 
their  natural  trend  is  across  that  surface  toward  the  inner  warmer 
walls,  where  they  become  heated  and  are  inclined  toward  the  ceiling, 
reaching  which,  they  are  pushed  by  the  force  behind  and  dra^rn  by 
the  one  in  front  toward  the  outer  walls  and  windows  again.  In  the 
meantime,  some  of  the  air  is  escaping  through  outlets,  and  diffusion 
of  the  impurities  is  proceeding,  so  that  a  more  or  less  even  character 
is  brought  about  throughout  the  air  of  the  room. 

Outlets  may  be  placed  at  the  level  of  the  floor,  in  the  ceiling,  or  at 
any  height  in  the  walls,  according  to  the  conditions  of  each  individual 
case.  If  the  incoming  air  is  not  heated,  the  outlets  should  be  placed 
high  up,  for  where  only  unheated  air  is  admitted,  the  warmest  air  must 
be  the  oldest  and  its  location  will  be  in  the  upper  air  space.  If,  on  the 
other  hand,  the  air  is  heated,  the  outlets  may  be  anywhere  so  far  as 
height  is  concerned,  but  there  is  some  choice  in  locations  with  respect 
to  inner  and  outer  walls.  Outlets  placed  beneath  windows  or  near 
outer  walls  will  withdraw  the  falling  currents  of  the  only  recently  in- 
troduced air  before  it  has  had  an  opportunity  to  become  well  mixed  by 
passage  across  the  floor  to  the  other  side,  and  before  it  has  in  any 
proper  degree  fulfilled  its  functions ;  but  if  its  passage  through  the 
lower  strata  is  not  interrupted  in  this  manner,  it  is  enabled  to  mix  with 
and  dilute  the  impurities  of  the  air  already  vitiated,  and  thus  effect  a 
large  measure  of  work,  and  so  when  it  reaches  the  other  (inner)  side 
and  finds  an  outlet  for  its  escape,  there  is  no  objection  to  its  withdrawal, 
and,  indeed,  its  removal  then  is  highly  desirable.  Hence,  and  for 
another  reason  as  will  appear,  outlets  should  be  placed  in  inner  walls 
rather  than  near  or  in  outer  cooler  ones,  and  near  the  floor  where  they 
may  intercept  the  air  before  it  may  again  become  a  part  of  the  ceiling 
currents. 

If  but  one  outlet  is  to  be  provided,  it  should  be  placed  with  reference 
to  tlu!  most  even  movement  of  the  current  over  the  whole  area,  having 
in  mind  the  fiict  that  the  air  movement  toward  it  is  convergent,  and 
the  dirfjct  reverse  of  the  flow  from  the  deflecting  and  diffusing  surface 
at  the  inlet. 

As  to  size,  it   may  l)e  said,  in    general,  that  a   single  outlet,  or   the 

28 


434  HABITATIONS,  SCHOOLS,  ETC. 

aggregate  if  there  be  more  than  one,  should  be  of  such  size  as  to  insure 
the  possibility  of  removal  of  such  an  hourly  air  supply  as  the  space  is 
likely  to  require  under  the  ordinary  conditions  of  its  usual  occupancy ; 
that  it  should  not  materially  exceed  this  limit ;  and  that  the  final  velocity 
of  the  outflowing  current  should  not  be  productive  of  the  sensation  of 
disagreeable  draughtiness. 

As  to  the  shape  of  inlets  and  outlets,  it  is  self-evident  that,  with 
equal  areas,  that  which  has  the  smallest  periphery  will  offer  the  least. 
frictional  resistance,  and  is,  therefore,  best  adapted.  Thus,  a  circle  en- 
closing an  area  equal  to  a  square  foot  has  a  smaller  periphery  than  a 
square  enclosing  the  same  area,  and  a  square  has  a  smaller  one  than 
an  oblong  rectangle.  Take,  for  instance,  a  square  foot ;  it  may  be  in- 
cluded within  boundaries  : 

12  X  i2  inches,  a  square. 
16  X    9       " 


18  X 

24  X  6 

36  X  4 

48  X  3 

72  X  2 

144  X  1 


oblong  rectangles. 


With  these  boundaries,  the  periphery  ranges  from  4  feet  (the  smallest) 
to  24  feet  2  inches.  The  frictional  resistance  will,  therefore,  be  greater 
in  proportion  as  the  shape  varies  from  the  circle  and  square. 

The  shafts  communicating  wdth  the  inlets  and  outlets  should  be  so 
disposed  in  the  general  plan  as  to  offer  the  least  resistance  to  the  inflow 
and  outflow  of  air.  Unless  they  are  heated  artificially,  inlet  flues 
should  not  be  located  in  outer  walls,  on  account  of  the  likelihood  of 
the  formation  of  down  draughts  due  to  cooling  of  the  air  column. 
Their  inner  surface  should  be  as  smooth  as  possible,  in  order  to  bring 
to  a  minimum  the  loss  of  movement  due  to  friction,  and  they  should 
be  cylindrical,  if  possible,  for  the  same  reason.  They  should  be  as 
free  as  possible  from  angles,  and  esj)ecially  right  angles,  because  of  the 
very  serious  loss  of  motion  which  these  cause,  each  right  angle  dimin- 
ishing the  current  about  half;  thus,  after  passing  one  right  angle,  the 
flow  would  be  half;  after  a  second  angle,  the  half  would  be  reduced 
to  a  quarter,  and  after  a  third,  to  an  eighth.  The  neglect  to  take  into 
account  the  loss  of  flow  by  friction,  bends,  and  angles  is  responsible 
for  the  failure  of  many  a  plan  for  ventilation. 

"What  has  been  said  concerning  the  impossibility  of  making  general 
rules  for  the  sizes  of  inlets  and  outlets  applies  with  equal  force  to  the 
fixing  of  sizes  of  flues,  for  these  depend  upon  the  many  and  varied 
conditions  which,  even  under  the  best  favoring  circumstances,  affect 
the  rate  of  flow. 

In  planning  inlet  and  outlet  shafts,  it  is  to  be  borne  in  mind  that 
something  more  is  necessary  for  their  proper  working  than  the  dictum 
that  this  one  is  for  fresh  air  and  that  one  for  foul,  for  natural  forces 
have  no  respect  for  mere  names  and  plans,  and  the  current  in  a  flue 
will  be  upward  or  downward,  inward  or  outward   according  to  natural 


ARTIFICIAL  HEATING  IN  ITS  RELATIONS  TO    VENTILATION.   435 

laws.  Outlet  shafts  may  become  considerably  cooled  by  low  external 
temperatures  ;  they  may  be  invaded  by  rain  and  snow,  the  evaporation 
of  which  causes  cooling  and,  therefore,  increase  in  gravity ;  or  there 
may  be  an  insufficiency  of  inlet  air,  so  that  a  partial  vacuum  is  formed 
by  the  current  of  one  large  outlet  flue,  which  thereby  causes  a  reversal 
of  that  of  a  smaller  one,  so  that  one  flue  draws  against  another.  It  is 
from  any  one  of  these  causes  that  a  chimney  may  fail  to  discharge 
smoke  upward — a  circumstance  noticed  more  often  in  summer  than  in 
winter. 

Mechanical  Ventilation. 

Mechanical  ventilation  consists  in  the  propulsion  or  extraction  of  air 
by  means  of  blowers  or  exhaust  fans  driven  by  steam  or  electricity. 
That  in  which  the  air  is  propelled  by  the  action  of  a  blower  is  known 
as  the  "  plenum  "  system,  and  the  other,  in  which  it  is  withdrawn  by  an 
exhaust  fan,  is  known  as  the  "  vacuum  "  system. 

In  the  plenum  system,  the  air  is  drawn  into  a  box,  in  which  the 
revolving  blades  of  a  fan  are  located,  and  it  is  then  driven  into  a  cen- 
tral conduit,  and  from  there  through  appropriate  shafts  to  the  spaces  for 
which  it  is  intended.  When  it  is  desired,  the  air  may  be  received  from 
or  blown  first  into  a  chamber  where  it  may  be  heated.  The  air  suj)ply 
may  be  regulated  very  easily  by  diminishing  or  increasing  the  number 
of  revolutions  per  minute,  but  it  should  always  be  in  slight  excess  of 
the  real  need,  in  order  to  produce  a  slight  outward  pressure,  which  will 
prevent  inward  leakage. 

In  the  vacuum  system,  the  air  is  extracted  from  the  various  rooms 
through  pipes  leading  to  a  central  shaft,  where  it  is  drawn  into  the  fan 
and  discharged  outwardly.  This  system  has  among  other  disadvan- 
tages that  of  great  inequalities  in  draught  in  the  different  discharge 
tubes,  and  that  the  vacuum  condition  favors  the  inward  leakage  of  cold 
air  through  cracks,  walls,  and  about  windows,  and  tends  to  cause  cold 
floors  and  disagreeable  small  draughts  about  windows.  In  consequence, 
more  fuel  is  needed  for  the  maintenance  of  a  proper  temperature,  and 
the  system  is,  therefore,  a  source  of  greater  expense. 

The  advantages  of  mechanical  ventilation  lie  in  the  fact  that  the 
object  sought  is  attainable  in  any  and  all  conditions  and  variations  of 
weather,  and  that  less  space  is  required  for  shafts  than  in  the  case  of 
natural  methods. 

Mechanical  ventilation  on  a  comparatively  small  scale  is  employed 
commonly  in  crowded  offices  and  other  spaces  by  means  of  small  ex- 
tracting fans  run  by  the  aid  of  electricity  (connection  being  made  with 
the  electric  light  system)  in  specially  provided  locations  connected  with 
outlet  flues,  or  directly  in  a  space  made  by  removing  window  panes. 

Artificial  Heating-  in  Its  Relations  to  Ventilation. 

First,  for  the  prr)por  understanding  of  the  subject  of  heating  in  its 
bearings  on  ventilation,  it  is  necessary  to  consider  the  different  ways 


436  HABITATIONS,  SCHOOLS,  ETC. 

in  which  heat  is  imparted.  These  are  three  in  number  :  radiation, 
conduction,  and  convection. 

Radiation. — Radiant  heat  passes  from  its  source  through  the  air  to 
bodies  by  which  it  may  be  absorbed,  transmitted,  or  reflected.  Air, 
being  "  transparent "  to  heat,  is  not  materially  aifected,  and  the  drier 
the  air,  the  less  heat  it  will  retain.  It  passes  directly  from  its  source 
in  waves,  like  the  waves  of  light,  to  the  object  upon  which  it  falls,  and 
the  amount  reflected  or  absorbed  varies  with  the  nature  of  the  object, 
its  color,  the  character  of  its  surface,  and  its  temperature.  Its  in- 
tensity varies  inversely  as  the  square  of  the  distance  between  the 
source  and  the  object  upon  which  it  falls  ;  thus,  the  amount  received 
by  two  objects  1  and  5  feet  respectively  distant,  will  be  inversely  as  1 
and  25  ;  at  1  and  10  feet,  inversely  as  1  and  100 ;  at  5  and  10  feet, 
inversely  as  25  and  100 ;  that  is,  the  nearer  will  receive  in  the  first  in- 
stance 25  times  ;  in  the  second,  100  times ;  and  in  the  third,  4  times 
as  much  as  the  farther  object. 

As  an  instance  of  radiant  heat,  we  may  take  that  which  proceeds 
from  an  open  fire.  The  heat  passes  in  direct  lines  through  the  air  to 
the  walls,  floor,  ceiling,  furniture,  and  other  objects  in  its  path,  and 
these  absorb  some  and  reflect  the  rest  to  other  parts  of  the  room.  It 
directly  warms  only  that  surface  of  an  object  that  is  directly  opposed 
to  it.  The  objects  by  which  it  is  opposed  then  disseminate  it  in  two 
ways  :  by  conduction  and  convection. 

Conduction. — Conducted  heat  is  that  which  passes  from  one  par- 
ticle of  matter  to  another  in  direct  contact ;  that  is,  from  one  particle  to 
another  of  the  same  object,  or  from  one  object  to  another  which  it 
touches.  Conduction  acts  through  all  solid  substances,  but  by  no 
means  to  the  same  extent,  some  being  good,  some  indifferent,  and 
others  bad  conductors.  The  best  conductors  are  metals,  and  these 
vary  within  very  wide  limits ;  copper,  for  instance,  is  a  very  much 
better  conductor  than  iron  or  zinc.  Wood  is  a  poor  conductor,  and 
woven  and  felted  materials  and  asbestos  are  very  poor.  Through 
liquids  and  gases,  heat  is  conducted  to  only  a  very  limited  extent,  but 
there  is  no  substance  known  that  is  absolutely  non-conducting. 

Good  conductors  permit  a  rapid  flow  of  heat  through  their  substance  ; 
poor  ones,  only  a  slow  transmission.  Good  conductors  relinquish  their 
heat  rapidly  to  their  colder  surroundings,  whether  air  or  anything  else, 
and  withdi^aw  heat  from  bodies  which  are  warmer  than  themselves. 

Convection. — Convection  is  the  process  by  which  heat  is  communi- 
cated to  gases  and  liquids,  acting  through  their  mobility,  which  jjermits 
those  parts  that  have  been  expanded  by  reason  of  becoming  heated  to 
be  displaced  upward  by  cooler  portions,  which,  in  their  turn,  receiving 
heat,  give  way  to  others,  until  the  whole  mass  becomes  raised  in  tem- 
perature by  continued  application  of  heat  and  consequent  maintenance 
of  circulation.- 

Every  warm  body  with  which  air  comes  in  contact  communicates  its 
heat  to  those  portions  in  its  immediate  vicinity  ;  these  expand  and  are 
forced  onward  bv  the  cooler  heavier  parts  nearest  them ;  these  in  their 


ARTIFICIAL  HEATING  IN  ITS  RELATIONS  TO    VENTILATION.  437 

turn  give  way  to  others,  and  convection  currents  are  established  to 
such  au  extent  that  the  air  of  a  room  takes  on  a  very  complicated  state 
of  activity. 

Convection  currents  are  established  by  every  person  in  a  room  so 
long  as  the  temperature  is  below  that  of  the  body.  They  are  estab- 
lished by  the  warmer  walls,  floor,  furniture,  hot-water  pipes,  steam 
radiators,  close  stoves,  and  other  warm  objects,  and  in  this  way  the  air 
becomes  heated.  The  air  which  enters  rooms  through  shafts  com- 
municating with  the  air  chambers  of  furnaces  and  "  indirect  radiation  '* 
apparatuses  are  convection  currents  in  the  largest  sense.  The  direct 
rays  of  the  sun,  passing  through  windows  and  absorbed  by  the  floor, 
walls,  and  other  objects  which  they  strike,  also  cause  upward  con- 
vection currents. 

Methods  of  Warming'. — The  principal  methods  of  heating  houses 
and  rooms  are  :  1.  Open  fires.  2.  Stoves.  3.  Furnaces.  4.  Hot- 
water  pipes.  5.  Steam  pipes.  The  method  most  applicable  in  any 
particular  case  will  depend  upon  the  size  of  the  room  and  the  number 
of  rooms  in  the  building.  In  general,  it  may  be  stated  that  the  smaller 
the  space,  the  more  simple  the  method.  For  a  single  room,  an  open  fire 
or  a  stove  will  be  sufficient ;  for  a  small  house,  stoves  or  a  furnace ; 
for  a  large  one,  one  or  more  furnaces  or  hot-water  or  steam  apparatus ; 
and  for  large  buildings — office  buildings,  for  instance — "  direct "  or 
"indirect"  steam. 

1.  Open  Fires. — Practically  the  whole  of  the  heat  supplied  by  an  open 
fire  is  radiant.  If  the  fuel  is  held  in  a  grate,  there  is,  of  course,  a  cer- 
tain amount  of  conduction  from  the  bars,  and  of  convection  currents 
in  the  air  in  its  immediate  vicinity.  But  this  heat  does  not  get  out 
into  the  room,  because  it  is  immediately  carried  up  the  flue  by  the 
draught  of  the  chimney.  The  radiant  heat  is  absorbed,  reflected,  and 
distributed  in  the  manner  already  described,  but  reaches  directly  only 
those  surfaces  which  are  opposed  to  its  source — which  accounts  for  the 
saying  that,  in  a  cold  room  with  an  open  fire,  "  one  side  roasts  while 
the  other  freezes."  Only  a  small  part  of  the  total  heat  of  the  fuel 
consumed  is  available  for  heating,  since  most  of  it — about  seven- 
eighths — is  carried  at  once  up  the  chimney.  An  open-fire  stove,  such 
as  the  old-fashioned  "  Franklin,"  which  stands  out  in  the  room,  and  is 
connected  with  the  flue  by  stove  piping,  yields  a  large  amount  of  its 
heat,  since  the  material  of  its  construction  is  heated  by  conduction  and 
then  gives  it  off  to  the  air  by  convection. 

Open  fires  cause  the  introduction  and  removal  of  large  volumes  of 
air,  but  these  are  by  no  means  always  well  mixed  with  the  whole  mass 
of  contained  air.  Nevertheless,  a  large  measure  of  ventilation  is  ac- 
complished, a  certain  amount  of  heat,  perhaps  sufficient  for  immediate 
needs,  is  giv(;n  off,  and  there  is  also  an  unmeasurable  addition  to  the 
general  cheerfulness.  They  may  cause  too  much  draught,  and  they  are 
certainly  not  economical,  but  as  accessories  to  other  heating  methods 
they  may  be  most  useful. 

2.  Stoves. — Close  st(;ves  have  more  direct  results  in  heating  and  less 


438 


HABITATIONS,  SCHOOLS,  ETC. 


in  ventilating  than  the  open  fire,  for  more  of  the  heat  produced  is 
available,  and  they  discharge  into  the  chimney  only  the  air  volumes 
that  have  passed  through  them.  The  materials  used  in  their  construc- 
tion, iron,  soapstone,  brick  and  fireclay,  conduct  the  heat  and  give  it 
otf  to  the  air  with  varying  rapidity  ;  cast  iron  yields  it  about  as  rapidly 
as  it  is  received,  soapstone  and  brick  give  it  olF  only  gradually,  but 
for  a  longer  period. 

When  cast-iron  becomes  red  hot,  it  may  be  decidedly  objectionable 
for  two  reasons  :  first,  that  the  organic  dust  particles  in  its  immediate 
vicinity  become  charred  and  yield  odors  ;  and  second,  that  it  absorbs 
and  transmits  considerable  carbon  monoxide  from  burning  coal.  Stoves 
may  be  so  arranged  as  to  act  not  alone  as  heaters,  but  as  ventilating 
apparatuses,  and  this  fact  is  of  very  great  value  in  tlie  case  of  small 
school  buildings  in  country  districts.      The  stove,  standing  out  in  the 

Fig.  43. 


Datnper 


Wire     N;  ^^^^^^"T--"f"-^--X 


F-resfv  Air' 


M        M 


Jacketed  ventilating  stove. 

room,  may  be  surrounded  by  a  cylindrical  jacket  from  the  floor  up- 
ward, leaving  a  sufficient  air  space  between  the  two.  Through  the 
floor  within  the  enclosure,  is  an  opening  into  an  air  duct  comnmnicat- 
iuff  with  the  outdoor  air.  The  heat  of  the  stove  is  communicated 
to  the  air  between  the  latter  and  the  jacket  and  an  upward  current  is 
formed,  which  draws  upon  the  fresh-air  conduit,  so  that  a  constant 
current  of  warmed  pure  air  is  thrown  into  the  room.  (See  Fig.  43.) 
It  goes  without  saying,  that  here,  as  elsewhere,  the  incoming  air  must 
be  taken  from  points  where  its  purity  cannot  be  interfered  with  by 
local  conditions. 

Gas  stoves  and  oil  stoves  have  the  advantage  over  others  that  they 
are  more  prompt  in  results,  more  easily  controlled,  and  more  quickly 
put  out  of  use.  They  have  the  disadvantage,  however,  that  the  prod- 
ucts of  their  fuel  combustion  are  discharged  directly  into  the  air  of  the 
room.     In  the  case  of  the  oil  stove,  this  is  not  such  a  serious  matter, 


ARTIFICIAL  HEATING  IN  ITS  RELATIONS  TO    VENTILATION.   439 

since  the  perfect  combustion  of  good  oil  results  in  carbon  dioxide  and 
water ;  but  with  gas  the  products  are  more  numerous  and  varied,  and 
include  some  that  are  irritating  and  poisonous.  With  proper  ventilation, 
however,  in  the  case  of  both^  no  harm  will  be  done. 

3.  Furnaces. — Hot-air  furnaces  are  not  only  of  very  great  importance 
as  heaters,  but  of  enormous  influence  in  ventilation.  In  their  use,  the 
cold  outdoor  air  is  brought  in  by  a  conduit,  the  "cold- air  box/'  to  a 
chamber  in  the  upper  part  of  the  furnace,  above  and  surrounding  the 
''dome,"  where  it  comes  in  contact  with  the  very  hot  surface  and  is 
heated  by  convection.  Thence  it  passes  upward  through  separate  tin 
tubes  to  the  several  places  for  its  discharge.  In  a  house  which  is 
unprovided  with  special  inlet  and  outlet  flues  for  ventilation — and  most 
of  our  houses  are  so  constructed^a  furnace  of  ordinary  heating 
capacity  performs  an  amount  of  ventilating  work  quite  sufficient  for  all 
needs,  and  for  which  it  rarely  receives  credit.  It  discharges  into  the 
various  rooms  a  constant  supply  of  warmed  fresh  air.  Where  and  how 
it  all  escapes  is  a  matter  of  secondary  interest  and  importance,  for  it 
gets  out  wherever  it  may  find  its  way. 

4.  Hot-water  Pipes. — Hot- water  heating  depends  upon  the  circulation 
of  water  by  convection  currents  through  a  system  of  pipes  which  may 
extend  all  through  a  large-sized  building.  The  water  is  heated  in  a 
boiler  below  and  passes  through  a  main,  leading  from  the  upper  part 
thereof.  As  one  portion  of  water  comes  in  contact  with  the  heating 
surface  and  expands,  it  is  moved  along,  and  the  circulation  becomes 
established  just  as  with  air.  The  "main"  gives  oif  branches  where 
needed,  and  these  at  their  extremities  turn  back  and  become  "  returns," 
which  eventually  connect  with  each  other  and  form  the  "  main  return," 
Avhich,  conveying  the  cooled  water,  enters  the  boiler  at  its  lowest  point. 
The  first  part  of  this  system  may  be  compared  with  the  arteries,  and 
the  "  returns,"  with  the  veins  of  the  body.  Vents  are  provided  for  the 
■escape  of  dissolved  air  liberated  from  the  water,  and  "  cut-ofPs "  are 
inserted  for  the  shutting  out  of  any  part  of  the  system  as  desired.  It 
is  very  necessary  that  air  should  not  be  allowed  to  accumulate  in  the 
pipes,  since  it  will  stop  the  flow.  In  low-pressure  systems,  a  small 
cistern  is  provided  to  allow  for  the  expansion  of  the  water  and  to  pre- 
vent its  overflow.  The  hot- water  system  may  be  of  either  high  or  low 
pressure.  With  high  pressure,  the  pipes  are  smaller  and  necessarily 
.stronger,  and  the  water  is  heated  to  a  considerably  higher  temperature 
(300°  F.),  and  hence  circulates  more  rapidly.  With  the  low-pressure 
system,  the  water  does  not  go  much,  if  any,  above  212°  F, 

With  the  hot-water  system  of  heating,  the  air  is  heated  mainly  by 
convection,  though  from  polished  pipes  a  certain  amount  of  radiation 
occurs.     With  high  ])rt'ssure,  the  air  may  easily  be  overheated. 

o.  Steam  Pipes. — In  steam  heating,  the  system  is  very  like  that  of 
hot-wat<3r  heating,  except  that  steam  is  the  circulating  medium  instead 
of  water.  With  steam,  and,  indeed,  with  hot  water,  heat  may  be  dis- 
tril)Mtcd  by  the  "  dire(^t  "  or  "  indirect "  methods.  In  the  "direct" 
method,  the  pipes  are  distributed  within  the  space  to  be  heated,  and  the 


440  HABITATIONS,  SCHOOLS,   ETC. 

air  of  each  room  is  heated  separately.  In  the  "  indirect "  method,  the 
heating  surfaces  are  all  concentrated  in  the  basement,  and  are  enclosed 
in  galvanized  iron  conduits,  which  receive  and  conduct  the  air  just  as 
in  the  case  of  the  hot-air  furnace.  The  two  methods,  it  will  be  noticed, 
vary  widely  in  the  matter  of  assisting  ventilation ;  the  direct  brings 
in  no  air,  but  heats  that  which  is  at  hand ;  the  indirect  brings  in  large 
volumes  of  heated  fresh  air,  and  thus  insures  change  of  air. 

In  conclusion,  may  be  mentioned  the  considerable  heating  and 
circulating  influence  of  burning  illuminating  gas.  By  means  of  suit- 
able outlets  above  the  burners,  gas  may  be  made  not  only  to  discharge 
the  products  of  its  own  combustion,  but  to  send  out  large  volumes  of 
otherwise  vitiated  air  as  well.  Nor  is  the  heat  of  the  sun  so  insignifi- 
cant that  it  may  be  passed  by  without  notice  in  the  planning  of  sys- 
tems of  ventilation.  Inasmuch  as  the  difference  in  temperature  of  the 
outside  air  on  the  north  and  south  sides  of  a  house  averages  about  5, 
and  may  reach  10,  degrees  F.,  just  that  amount  of  advantage  may  be 
gained  by  taking  the  air  for  ventilation  from  the  warmer  side.  In 
gravity  ventilation,  the  inlets  should  be  where  they  may  face  the  pre- 
vailing winds. 

Regulation  of  Temperature. 

In  carrying  out  any  scheme  of  efficient  ventilation,  it  is  necessary 
to  guard  against  overheating,  which  may  not  be  noticed  until  it  be- 
comes so  marked  that  it  cannot  help  attracting  attention.  When  such 
is  the  case,  the  common  practice  is  to  cause  a  lowering  of  the  tem- 
perature to  the  desired  point  as  soon  as  possible  by  opening  windows  to 
admit  the  colder  air.  The  consequence  is  the  production  of  a  distinctly 
cold  atmosphere,  more  so  than  ordinarily  is  shown  by  the  thermometer^ 
which  does  not  react  very  promptly  to  sudden  changes.  This  produces 
chilly  sensations  which  call  for  a  return  to  the  original  condition.  In 
the  meantime,  a  lot  of  heat  has  been  wasted  and  the  foundation  for  a 
cold  has,  perhaps,  been  laid.  If  windows  are  left  open  in  the  upper 
stories,  as  often  happens  in  overheated  buildings,  there  are  constant 
outflow  and  waste  of  heated  air,  with  a  corresponding  inflow  of  un- 
warmed  air  below,  which  requires  the  expenditure  of  additional  fuel  in 
order  that  the  lower  stories  shall  be  properly  warmed.  In  overheated 
buildings,  there  is  also  the  additional  loss  from  outward  leakage  through 
all  possible  outlet  channels. 

To  prevent  waste  of  heat  in  properly  heated  buildings,  we  have 
recourse  to  double  glazing  and  double  windows.  Double  glazing  is 
accomplished  by  fitting  two  panes  into  each  space,  instead  of  one,  with 
a  space  of  a  quarter  or  a  half  inch  between  them.  By  this  means, 
the  loss  of  heat  occurring  through  ordinary  windows  is  reduced 
about  one-third,  which  means  a  saving  of  considerable  fuel,  since  the 
loss  of  heat  by  conduction  through  glass  windows  is  very  considerable. 
Double  windows  are  still  more  efficient  as  heat-savers.  Here  the 
outer  window  is  made  to  fit  as  accurately  and  closely  as  possible  by 


NECESSITY  OF  PROVIDING  MO  IS  TUBE.  441 

the  use  of  listing,  and  we  have  between  the  two  windows  a  fairly  deep 
space  filled  with  air,  which  is  a  very  poor  conductor  of  heat.  It  is  on 
the  same  principle  that  we  use  loosely  woven  woollen  goods  and  furs, 
which  hold  within  their  meshes  and  between  the  hairs  a  large  amount 
of  this  poor  conductor.  The  loss  of  heat  through  walls  is  lessened 
when  a  similar  air  space  exists  within  them ;  a  solid  wall  will  con- 
duct a  very  large  amount  of  heat  and  waste  it,  while  the  same  amount 
of  building  material,  or  considerably  less,  may  be  so  disposed  as  to 
bring  this  loss  down  to  a  minimum. 

Loss  of  heat  is  caused  also  by  dampness  of  walls,  for  a  continual 
evaporation  goes  on  from  their  surface,  and  this  requires  heat  and  pro- 
duces cooling.  Every  ounce  of  moisture  so  vaporized  requires  the 
consumption  of  extra  fuel. 

Necessity  of  Providing  Moisture. 

Concerning  the  need  of  insuring  a  normal  amount  of  moisture  in  the 
air  of  heated  buildings,  there  is  more  or  less  difference  of  opinion,  but 
the  weight  of  evidence  from  a  medical  standpoint  and  from  our  own 
sensations  points  to  the  advisability  of  introducing  an  amount  of 
moisture  sufficient  to  bring  the  relative  humidity  of  the  air  to  50  or 
55  per  cent. 

The  lower  the  temperature  of  a  body  of  air,  the  less  the  amount  of 
moisture  it  can  hold,  and  what  would  be  saturation  at  a  low  tempera- 
ture would  be  but  a  very  low  relative  humidity  at  a  high  one.  For 
instance,  a  volume  of  air  at  0°  F.,  containing  its  fullest  possible  amount 
of  aqueous  vapor,  admitted  to  the  cold-air  box  of  a  furnace  and  then 
heated  to  85°  F.  before  being  conducted  to  the  rooms  of  a  house,  will 
have  at  its  new  temperature  but  a  very  small  relative  humidity.  It 
will  be  so  much  drier  than  any  outside  air,  that  that  of  the  driest 
climate  in  the  world  will  be  moist  in  comparison.  The  great  majority 
of  U.  S.  Signal  Service  Stations  have  a  mean  relative  humidity  of  65 
to  75  per  cent.  ;  only  twenty-four  show  below  60  or  over  80,  and  the 
very  lowest  is  in  the  hottest  part  of  Arizona,  where  newspapers  crack 
when  handled,  glued  furniture  falls  apart,  and  the  skin  becomes  hard 
and  dry.  At  this  place.  Fort  Yuma,  the  mean  relative  humidity  is  35 
per  cent. 

When  outdoor  air  is  heated  so  as  to  maintain  an  even  temperature 
of  70°  F.,  but  with  no  addition  of  watery  vapor,  its  capacity  for  ab- 
sorbing moisture  is  very  much  increased,  and  it  will  take  it  up  from 
all  moist  objects  with  which  it  comes  in  contact.  It  will  take  it  from 
the  skin,  from  the  mucous  membranes  of  the  mouth,  nose,  and  respir- 
atory tract ;  from  furniture  made  from  wood  which,  in  the  process 
of  kiln-drying,  was  never  brought  to  such  dryness ;  from  the  leather 
bindings  of  b(joks,  causing  them  to  crack  and  fall  to  pieces  ;  and  from 
plants,  which,  in  cons('<|u<'iice,  wither  and  die.  It  thus  causes  more  or 
less  (]ryn(!ss  of  the  skin,  irritation  of  the  throat,  and  cough.  It  causes 
also  need  of  a  higher  temperature  to  give  tlie  same  sensation  of  warmth 


442 


HABITATIONS,   SCHOOLS,   ETC. 


and  comfort  than  is  the  case  with  air  containing  a  normal  amount  of 
moisture.  It  is  on  account  of  the  disagreeable  and  destructive  eifects 
of  extreme  dryness  that  water-holders  are  attached  to  furnaces  and 
stoves  so  as  to  give  moisture  to  the  heated  air.  But  even  when  atten- 
tion is  paid  to  keeping  them  full,  which  is  not  often,  they  are  very 
inadequate  for  the  purpose. 

Air  at  25°  F.,  saturated  with  moisture  and  then  heated  to  70°  F., 
would  need  more  than  0.5  pint  of  water  in  every  1,000  cubic  feet  to 
give  it  a  humidity  of  65  per  cent.,  and  this  is  far  in  excess  of  the 
capacity  of  the  ordinary  waterpot  of  the  furnace,  as  is  seen  when  we 
reckon  what  0.5  pint  per  1,000  cubic  feet  means  in  the  course  of  a 
day. 

Moisture  may  be  imparted  to  the  air  by  exposing  pans  or  porous 
vessels  of  water  to  the  heated  current,  or  by  means  of  the  "humidi- 
fier," which  exposes  to  the  air  passing  through  the  registers  a  surface 
of  cotton  wicking  communicating  with  the  reservoir  of  water.  (See 
F'ig.   44.)     With  this  device.  Dr.  H.  J.  Barnes,  of  Boston,  reports 

Fig.  44. 


Humidifier. 


that  he  is  able  to  keep  his  office  at  53  per  cent,  relative  humidity  by 
■evaporating  an  average  of  4.5  quarts  of  water  per  day.  At  the  same 
time,  he  finds  a  temperature  of  65°  to  be  perfectly  comfortable  where 
before  he  had  required  70°  or  71°, 

On  a  larger  scale,  water  may  be  vaporized  into  the  air  in  the  form 
of  steam  from  a  boiler.  In  the  building  of  the  American  Bell  Tele- 
phone Co.,  in  Boston,  a  building  having  a  capacity  of  450,000  cubic 
feet  and  a  day-time  population  of  more  than  450  persons,  the  air, 
which  is  distributed  by  the  mechanical  system,  is  drawn  into  the 
building  at  the  rate  of  26,000  cubic  feet  per  minute,  heated  to  about 
100°  F.  in  the  stack  room,  and  moistened  so  as  to  contain  about  50 
per  cent,  relative  humidity.  For  the  production  of  this  condition, 
no  less  than  675  gallons  of  water  in  the  form  of  steam  are  given  to 
the  air  in  ten  hours,  or  about  one  and  a  half  barrels  per  hour.  Certain 
parts  of  the  building  which,  before  the  adoption  of  this  process,  had 


DETERMINATION  OF  RATES  OF   VENTILATION.  443 

been  heated  with  some  difficulty,  are  now  made  more  comfortable,  and 
in  the  whole  building  3  degrees  less  heat  are  required  for  the  mainten- 
ance of  an  agreeable  temperature.  According  to  Mr.  C.  J.  H.  Wood- 
bury,^ under  whose  direction  the  plant  was  installed,  "another  feature 
indicating  the  greater  comfort  of  the  building  was  the  absence  in  win- 
ter of  the  coughing  by  those  employed  there,  a  cough  of  the  bronchial 
kind  or  from  the  larynx,  a  cough  which  ends  with  a  squeal,  which  is 
so  prevalent  in  New  England  during  the  winter,  especially  in  those 
employed  in  offices." 

Filtration  of  Air. — Here  may  be  given  an  instance  of  the  benefit 
derived  from  filtering  large  volumes  of  air  introduced  into  a  building 
for  purposes  of  ventilation.  In  the  building  above  mentioned,  the 
air  is  drawn  into  and  through  a  system  of  large  cotton  bags  30  feet 
in  length,  in  which  all  dirt  and  dust  is  retained.  About  a  peck  per 
month  is  separated  in  this  way  from  the  air,  which  is  drawn  not  from 
the  street  level,  but  far  above  it.  An  analysis,  chemical  and  micro- 
scopical, made  in  April,  1897,  showed  22.67  per  cent,  of  organic  and 
77.33  of  inorganic  matter.  The  material  consisted  of  all  manner  of 
animal,  mineral,  and  vegetable  substances  ordinarily  present  in  the  dust 
of  large  cities. 

Determination  of  Rates  of  Ventilation. 

The  estimation  of  the  amount  of  air  entering  and  leaving  a  room 
through  inlet  and  outlet  flues  is  a  very  simple  matter,  but  the  results 
may  not  be  accepted  as  an  indication  of  the  efficiency  of  ventilation, 
since  it  so  often  happens  that  much  of  the  effluent  air  has  failed  to  per- 
form its  full  duty  in  diluting  the  impurities  arising  from  respiration 
and  combustion.  Nevertheless,  such  a  determination  may  yield  im- 
portant indications. 

In  order  to  ascertain  the  volume  of  air  passing  through  an  opening, 
whether  inlet  or  outlet,  it  is  necessary  to  know  the  area  of  the  opening 
and  the  velocity  of  the  current.  The  former  is  easily  calculated  arith- 
metically ;  the  latter  can  be  found  only  by  the  use  of  an  anemometer, 
an  instrument  of  very  delicate  construction,  which  registers  the  distance 
travelled  by  a  current  of  air  in  any  period  during  which  it  is  ex- 
posed. 

A  current  of  air,  passing  through  an  opening,  has  not  the  same 
velocity  at  all  points  of  its  cross-section.  It  moves  in  the  same  manner 
as  a  river — faster  at  its  center,  where  it  is  least  subject  to  the  influence 
of  friction.  Therefore,  the  velocity  should  be  taken  at  different  points, 
and  the  mean  of  the  results  accepted  as  its  true  rate  of  movement. 
The  anemometer  is  held  for  a  given  time,  say  half  a  minute,  at  a  point 
at  tlie  periphery  of  the  opening,  and  then  moved  along  a  short  distance 
and  held  for  an  equal  period,  and  so  on,  from  ])oint  to  point,  until  the 
whole  area  has  fairly  been  traversed.  The  reading  of  the  instrument 
is  then  noted,  and  the  distance  indicated  is  divided  by  the  number  of 

'  TransactioriH  of  the  New  J<>iiglaii(J  Cotton  Manufaeturerw'  Association,  Vol.  03. 


444  HABITATIONS,  SCHOOLS,  ETC. 

points  where  stops  have  been  made.  The  quotient  equals  the  distance 
travelled  by  the  whole  current  during  the  unit  of  time  employed.  It 
will  be  found  most  commonly  that  the  movement  at  the  periphery  is 
very  slow,  aud  that,  as  the  center  is  approached,  the  velocity  becomes 
greater  and  greater,  the  maximum  being  attained  at  the  center.  Know- 
ing the  average  movement  in  feet  or  meters,  the  volume  is  calculated 
by  multiplying  this  by  the  area  in  square  feet  or  square  meters,  the 
product  being  the  volume  in  cubic  feet  or  cubic  meters  passing  during 
the  unit  of  time.  From  this  result,  the  volume  per  hour  is  easily  made 
known. 

Example. — The  size  of  the  opening  is  2  by  3  feet ;  the  area  is, 
therefore,  6  square  feet.  The  anemometer,  held  at  twenty-four  points 
for  fifteen  seconds  each,  registers  228  feet.  The  mean  of  this  is  9.5 
feet,  and  the  current  is  moving,  therefore,  at  the  rate  of  38  feet  per 
minute.  The  cross-section  of  the  current  being  6  square  feet,  the 
volume  discharged  in  a  minute  equals  6  X  38,  or  228  cubic  feet,  and, 
in  an  hour,  13,680  cubic  feet. 

By  determining  the  rate  of  discharge  through  all  iulets  and  outlets 
in  this  manner,  an  idea  is  obtained  of  the  amount  of  ventilation  occur- 
ring through  means  provided,  but,  as  has  been  stated,  not  of  its  effi- 
ciency. The  sum  of  the  inlet  discharge  will  almost  never  agree  with 
that  of  the  outlet,  since  much  air  enters  aud  leaves  a  room  through 
other  openings.  Knowing  the  capacity  of  the  room,  we  learn  from  the 
amount  of  inlet  air  the  number  of  times  the  air  of  the  room  has  been 
replaced. 

The  full  measure  of  ventilation  and  its  efficiency  may  be  determined 
very  closely  by  methods  originated  by  Pettenkofer.  One  of  these  con- 
sists in  first  creating  an  unusual  degree  of  impurity  either  through 
respiration  of  a  large  number  of  persons,  as,  for  instance,  by  children 
occupying  a  schoolroom,  or  by  burning  a  number  of  candles,  or  by 
other  chemical  processes,  then,  after  taking  a  specimen  of  the  air  for 
analysis,  keeping  the  room  closed  for  an  hour  or  two.  At  the  expira- 
tion of  the  allotted  time,  a  second  sample  is  taken,  and  from  the  results 
of  the  two  analyses,  the  rate  of  ventilation  is  ascertained  by  means  of 
SeideFs  formula,  which  is  as  follows  : 

G  =-.  2.303  m.  log  &-— 5- 
P2  -a 
in  which  C  =  amount  of  air  which  has  entered. 

2.303  is  a  constant. 
m  =  capacity  of  the  room. 
I  j3j  =  amount  of  CO2  originally  present. 
p^  =  amount  of  CO2  at  the  end  of  the  experiment. 
a  =  amount  of  COj  in  the  external  air. 

Example. — The  air  of  a  schoolroom  of  500  cubic  meters  capacity, 
accommodating  34  children,  contains  at  the  end  of  the  session  18.5  cc. 
of  CO2  in  10,000,  or  0.00185  :  1.  At  the  end  of  an  hour,  a  second 
analysis  shows  8.5  cc.  of  CO,  in  10,000,  or  0.00085  :  1.  The  outer 
air  contains  3.5  cc.  of  COg  in  10,000,  or  0.00035  :  1. 


LIGHTING,  445 

Then 

/>   ^  QHQ  v/  r:nn  v/  1   0.00185  —  0.00035 
(7  -  2.303  X  500  X  log  o.oo085  -  0.00035 

=  1151.5  X  log  ^-^ 
^  ^  0.0005 

=  1151.5  X  log  3 

=  1151.5  X  0.4771213 

=  549.4  cubic  meters  of  air  in  an  hour. 

Thus,  the  air  of  the  room  is  renewed  but  once  and  a  tenth  per  hour, 
and  the  result  shows  that  the  per  capita  ventilation  is  about  a  fifth  of 
what  it  should  be. 

The  other  method  consists  in  imparting  to  the  air  of  a  room  a  contin- 
uous supply  of  carbon  dioxide  by  means  of  burning  candles,  and  making 
periodical  analyses  of  the  contained  air.  Candles  of  pure  stearin,  1 
gram  of  which  yields  1.404  liters  of  the  gas,  are  employed.  A  prelimi- 
nary analysis  of  the  air  is  made,  and  then  a  number  of  the  candles,  the 
combined  weight  of  which  is  noted,  are  placed  about  the  room  and 
lighted.  At  stated  intervals,  the  room  is  entered,  and  after  the  air 
has  been  well  mixed  by  vigorous  fanning,  samples  are  taken  for  anal- 
ysis. At  the  end  of  the  experiment,  the  candles  are  put  out  and  re- 
weighed,  and  from  their  loss  in  weight  and  the  results  of  the  analyses, 
the  amount  of  ventilation  is  calculated  by  means  of  a  most  complicated 
formula  devised  by  Hagenbach. 

Other  methods  have  been  proposed  by  Recknagel,  Petri,  and  others, 
but  they  present  no  advantages,  and  are,  in  general,  so  complicated 
that  in  the  hands  of  other  than  expert  physicists  they  are  quite  useless. 

Section  3.     LIGHTING. 

Natural  Lighting. — In  natural  lighting,  the  light  enters  the  room 
directly  or  by  reflection  through  the  windows,  and  is  then  reflected  to 
different  parts  of  the  interior,  which  receive  diiferent  amounts  of  light 
according  to  circumstances.  Thus,  white  and  light-colored  walls,  floors, 
and  articles  of  furniture  reflect  and  disperse  the  light,  while  dark  walls, 
draperies,  and  other  objects  absorb  it.  Large  rooms  having  but  small 
window  area  and  all  rooms,  however  generously  provided  therewith, 
looking  on  narrow  alleys  or  streets  in  which  the  opposite  buildings  are 
so  high  that  the  sky-angle  is  small,  cannot  be  illuminated  uniformly  by 
diffused  daylight  without  some  assistance. 

The  means  employed  are  exceedingly  simple,  and  the  discovery  of 
their  utility  for  this  purpose  was  due  to  chance.  In  order  to  obstruct 
the  view  into  factory  workrooms  from  the  outside,  and  to  lessen  the 
temptation  to  operatives  to  waste  time  in  looking  out,  ribbed  glass 
was  introduced  instead  of  ordinary  glass  for  use  in  windows,  and  it 
was  noticed  that  not  only  was  the  desired  end  attained,  })ut  that  the 
light  from  the  windows  was  projecited  fartlujr  into  the  rooms,  and  to  such 
an  extent  in  some  instances,  that  artificial  h'ghts,  required  before  in 
the  brightest  part  of  the  day,  could  l)e  dispcsnsed  with.  Attention 
being  tlius  drawn  to  the  great  advantage  and  saving  of  expense^  a  num- 


446 


HABITATIONS,  SCHOOLS,   ETC. 


ber  of  diiferent  kinds  of  glass  with  uneven  surface  have  been  placed 
upon  the  market  and  have  come  into  very  extensive  use.  The  best  of 
these,  which  is  the  most  expensive,  is  known  as  "  prismatic  glass  "  from 
the  fact  that  one  surface  consists  of  a  series  of  prisms  running  horizon- 
tally.    The  entering  light,  instead  of  falling  directly  to  the  floor,  is 


Fig.  45. 


Fig.  46. 


Action  of  prismatic  glass  in  projecting  light. 

tipped  up  and  projected  toward  the  opposite  sides  of  the  room,  as  shown 
in  Fig.  45.  Vertical  section  of  a  sheet  of  the  glass  is  shown  at  A  in 
Fig.  46.  By  varying  the  angle  of  the  prisms,  the 
conditions  obtaining  in  any  situation  can  be  met 
and  light  may  be  projected  in  any  desired  direc- 
tion. Naturally,  the  prisms  cannot  be  used  indis- 
criminately, for  a  series  adapted  to  light  the  entire 
lower  part  of  the  room  with  a  certain  sky  angle 
might,  when  applied  to  another,  throw  the  light 
toward  the  ceiling  instead  of  to  the  parts  where 
it  is  required.  Therefore,  to  meet  all  conditions, 
the  glass  is  made  with  a  great  range  of  angles, 
and  the  particular  kind  needed  in  any  situation  is 
determined  by  measurement.  Where  the  sky  angle 
is  very  small,  canopies,  hung  at  the  proper  angle 
above  the  windows,  serve  to  throw  inward  a  flood 
of  light.  The  disadvantage  of  prismatic  glass  is 
its  great  cost. 

Ribbed  glass  is  very  efficient  and  much  less 
expensive.  This  is  made  with  4,  5,  7,  11,  and  12 
ribs  to  the  inch,  and  of  difl^erent  thickness  and  weight,  since  the  fcAver 
the  ribs,  the  deeper  they  must  be  cut,  and  the  thicker,  therefore,  the 


Vertical  section  of  pris 
matic  and  ribbed  glass. 


LIGHTING.  447 

glass.     Vertical  section  of  a  sheet  of   ribbed  glass  is  shown  at  B  in 
Fig.  46. 

Artificial  Lighting. — The  methods  of  artificial  illumination  com- 
prise electric  lighting  aud  those  dependent  upon  the  combustion  of  oils, 
gases,  and  hard  fats.  The  oils  employed  are  chiefly  of  mineral  origin, 
but  animal  and  vegetable  oils  are  used  to  some  extent,  although  not 
very  much  in  this  country.  Hard  fats  in  the  form  of  candles  are  useci 
very  extensively  in  all  countries,  on  account  of  safety,  cheapness,  and 
general  availability.  The  gases  in  common  use  are  derived  from 
coal  and  hydrocarbons.  Of  late,  acetylene  gas,  obtained  by  the  action 
of  moisture  on  calcium  carbide,  has  come  into  extensive  use. 

Luminosity  of  Flame. — In  the  combustion  of  a  candle,  it  will  be  ob- 
served that  the  flame  consists  of  four  parts,  the  lowest  of  which,  blue 
in  color,  gives  out  practically  no  light ;  the  middle  portion,  dark  in 
color,  consists  of  hydrocarbon  gas  generated  from  the  substance  of  the 
candle ;  next  is  the  luminous  yellow  portion ;  and  outside  of  this,  is  an 
almost  invisible  envelope.  The  atmospheric  oxygen,  moving  toward 
the  inner  portion  of  the  flame,  unites  with  the  carbon  escaping  outward 
from  the  luminous  portion,  and  forms  carbon  dioxide ;  more  oxygen 
passes  onward  and  inward,  meets  the  hot  gas  from  the  central  part  of 
the  flame,  and,  being  insufficient  in  amount  to  unite  with  both  the- 
hydrogen  and  carbon  constituents,  combines  by  reason  of  greater  affin- 
ity with  the  hydrogen,  leaving  the  carbon  free,  but  so  much  raised  in 
temperature  that  it  becomes  incandescent,  thus  furnishing  light  during 
the  extremely  slight  interval  elapsing  in  its  passage  to  the  outermost 
portion  of  the  flame,  where,  as  has  been  stated,  it  is  oxidized  to  carbon 
dioxide.  The  same  process  goes  on  in  the  combustion  of  illuminating 
gas  and  oils,  the  luminosity  of  the  flame  being  due  to  the  incandescent 
particles  of  carbon  in  the  breaking  up  of  the;  hydrocarbon  compounds 
into  their  elements.  A  mixture  of  gas  and  air,  such  as  occurs  in  the 
use  of  the  Bunsen  burner,  gives  off  little  or  no  light,  since  each 
particle  of  carbon  is  provided  with  sufficient  oxygen  to  convert  it  at 
once  into  carbon  dioxide,  and  so  incandescence  cannot  occur.  If  the 
air  supply  to  the  interior  of  the  flame  is  shut  off,  luminosity  is  produced 
at  once. 

If  the  area  of  the  outer  surface  of  an  ordinary  gas  flame  is  so  small 
that  atmospheric  oxygen  cannot  be  taken  up  sufficiently  fast  to  unite 
with  all  the  carbon  arriving  at  the  outer  part  of  the  flame,  the  nnoxi- 
dized  carbon  becomes  cooled  below  the  ignition  point  and  is  given  off'  in 
the  form  of  smoke.  Defects  in  the  burner  or  excessive  richness  in 
hydrocarbons  may  cause  smoking  during  combustion,  the  supply  of  air 
being  too  small  to  consume  the  carbon.  The  introduction  of  a  cool 
surface  into  the  luminous  j)ortion  of  the  flame  causes  deposition  of  soot 
thereon.  If  the  area  of  tlie  flame  is  made  too  large  by  turning  on  a 
large  volume  of  gas  under  high  j)ressure,  the  gas  is  projected  so  far  that 
it  comes  in  contact  with  suffici(!nt  atinosphciric  oxygcsn  to  burn  a  large 
part  of  its  carl^on  and  iiydrog(!n  simiiltaiicously,  and,  as  a  result,  the 
excess  of  gas  is  consumed  without  himinosity  and  wasted. 


448  HABITATIONS,   SCHOOLS,   ETC. 

G-as  Burners. — The  best  of  the  burners  in  most  common  use  is  known 
as  the  bafs-idng,  from  the  shape  of  the  flame.  The  tip  is  hemispher- 
ical, and  is  provided  with  a  single  straight  slit,  through  which  the  gas 
emerges  in  a  thin  flat  sheet.  Another,  known  as  the  fish-tail,  contains 
in  its  tip  two  small  orifices,  through  which  the  gas  issues  and  then 
spreads  out  into  a  flat  flame,  shaped  as  the  name  indicates.  This  burner 
is  inferior  to  the  bat's-wing  in  that  its  flame  is  less  luminous  with  the 
same  amount  of  gas,  and  the  orifices  are  much  more  easily  fouled  and 
occluded. 

The  Ar-gand  burner  consists  of  a  hollow  ring,  provided  with  a  circle 
of  small  holes  and  attached  by  hollow  arms,  through  which  the  gas  is 
supplied,  to  a  socket  screwed  to  the  pipe.  The  gas,  issuing  from  the 
holes,  forms  a  circular  flame,  which  is  provided  with  an  abundant  air 
supply  which  passes  upward  through  the  perforations  of  the  holder  for 
the  chimney,  which  is  an  essential  part  of  the  a]3paratus,  and  through 
the  central  hole  of  the  burner  as  well.  The  chimney  should  be  of 
proper  diameter  and  height  to  insure  an  air  supply  adequate  for  com- 
plete combustion  of  the  gas. 

The  Wckbach  burner,  which  may  be  taken  as  a  good  representative 
of  the  class  of  incandescent  lamps,  consists  of  a  modified  Bunsen  burner, 
over  which  is  suspended  a  mantle  composed  of  incombustible  material, 
which  becomes  intensely  luminous  when  heated  in  the  Bunsen  flame, 
and  thus  transforms  non-luminous  heat  energy  into  luminous  light 
radiation.  The  mantles  are  made  in  different  ways,  of  different  mate- 
rials, and  are  exceedingly  fragile.  One  of  the  most  common  and  best  sorts 
is  made  by  saturating  a  delicate  network  of  cotton  in  a  strong  solution 
of  several  earthy  oxides  (cerium,  zirconium,  lanthanum,  thorium),  then 
baking,  and  finally  heating  it  until  the  cotton  fibers  are  destroyed,  thus 
leaving  a  gauze  composed  of  the  oxides  alone.  No  single  earth  is  effi- 
cient by  itself.  The  flame  and  mantle  are  protected  by  a  cylindrical 
glass  chimney,  M^hich  serves  also  to  steady  the  flame,  and  the  whole  is 
enclosed  commonly  in  some  form  of  globe  or  shade  to  modify  the 
intensity  of  the  light.  By  j)roviding  a  suitable  burner  to  insure  the 
requisite  degree  of  heat,  any  kind  of  combustible  gas  or  oil  vapor  may 
be  used.  Lamps  are  made  on  the  same  principle  for  kerosene  burning. 
The  incandescent  mantle  not  only  gives  out  much  more  light  than  an 
ordinary  or  Argand  flame,  but  does  so  at  a  much  smaller  expenditure 
of  gas. 

Objection  is  often  made  that  the  Welsbach  light  is  very  trying  to 
the  eyes. '  This  is  true ;  but  the  same  objection  may  be  urged  against 
the  sun  and  other  intensely  bright  objects  when  looked  at  directly. 
The  lights  should  be  so  placed  that  they  will  illuminate  those  parts 
where  light  is  needed ;  and  if  they  are  likely  to  try  the  eyes,  they 
should  be  enclosed  in  globes  designed  to  soften  the  glare  and  diffuse 
the  rays  uniformly. 


VARIETIES  OF  ILLUMINATING   GAS.  449 

Varieties  of  Illuminating  Gas. 

Coal-gas  is  made  by  heating  bituminous  coal  in  fire-clay  retorts,  in 
which  process  the  compounds  of  hydrogen  and  carbon  are  transformed 
into  gaseous  and  other  products.  The  gas  is  conducted  by  pipes  to 
condensers  and  purifiers,  where  it  is  freed  from  ammonia,  hydrogen  sul- 
phide, tarry  matters,  and  other  impurities,  and  then  is  carried  to  storage 
tanks.  The  purified  product  consists  of  about  50  parts  of  hydrogen,  35 
of  marsh-gas,  6  or  7  of  carbon  monoxide,  and  the  remainder  of  ethylene 
and  other  hydrocarbons,  and  nitrogen. 

Water-gas  is  made  from  coke  or  anthracite  coal,  steam,  and  petroleum. 
The  coke  or  coal  is  placed  in  an  air-tight  cylinder  lined  with  fire  clay, 
and  then  is  ignited  and  blown  up  to  a  white  heat  by  means  of  a  blast 
of  air.  The  air  is  then  shut  off  and  a  current  of  steam  is  blown 
through.  This  is  decomposed  by  the  great  heat  into  hydrogen  and 
oxygen,  the  former  passing  on  unconibined,  and  the  latter  uniting  with 
carbon  to  form  carbon  monoxide.  The  resulting  mixture  is  then  car- 
ried to  a  gas-holder,  from  which  it  is  conducted  to  the  "  carburetter," 
where  it  is  enriched,  in  order  that,  when  burned,  it  shall  joroduce  a 
luminous  flame.  This  is  a  chamber  of  fire-brick  kept  at  red  heat. 
Here,  vaporized  petroleum  is  injected  with  the  hot  gas  until  the  requis- 
ite percentage  of  carbon  in  the  mixture  is  attained.  The  final  product 
has  much  the  same  odor  as  coal-gas,  but  is  of  very  different  composi- 
tion, and  much  more  poisonous  in  character,  containing  about  30  per 
cent,  of  carbon  monoxide,  35  of  hydrogen,  20  of  marsh-gas,  and  the 
remainder  of  etliylene  and  nitrogen.  Water-gas  may  also  be  made  by 
pumping  crude  petroleum  in  a  small  stream  into  a  red-hot  gas  retort, 
where  it  is  converted  at  once  into  vapor,  which,  with  a  current  of 
superheated  steam,  is  then  driven  through  a  long  coil  of  pipe  heated  to 
a  high  temperature.  The  chemical  reaction  is  the  same,  the  carbon 
uniting  with  the  oxygen  of  the  steam  to  form  carbon  monoxide,  leaving 
the  hydrogen  free. 

The  poisonous  properties  of  both  coal-gas  and  water-gas  are  due 
solely  to  the  contained  carbon  monoxide,  which,  as  shown  originally  by 
Claude  Bernard,  makes  a  definite  compound  with  the  oxygen  carrier 
of  the  blood,  the  haemoglobin,  which  then  becomes  incapable  of  per- 
forming its  function.  This  being  the  case,  the  vastly  greater  clanger 
attending  the  use  of  water-gas  is  self-evident.  The  odor  of  the  two 
gases  is  practically  the  same  in  kind,  but  not  in  degree,  so,  in  order  to 
have  the  same  value  as  a  warning  of  danger  from  leaks,  that  of  water- 
gas  should  be  much  more  pronounced,  since  so  much  less  of  the  gas  is 
rcrjuircd  to  bring  the  air  into  a  poisonous  condition. 

Usually  about  0.4  per  cent,  of  carbon  monoxide  in  the  air  is  required 
to  ])roduce  fatal  n^snlts,  l)ut  less  may  be  fatal  after  long  exposure.  In 
recovery  from  poisoning,  tin;  carbon  monoxide  is  not  oxidized  in  the 
body,  but  is  driven  out  of  its  combination  by  the  oxygen  of  the  in- 
spired air  ;  but  although  after  a  few  hours  the  blood  may  nearly  be  freed 
from  the  j)oison,  the  damage  already  done  to  the  brain  and  other  tissues 
29 


450  HABITATIONS,  SCHOOLS,  ETC. 

through  the  temporary  partial  deprivation  of  oxygen  may  be  severe  and 
lasting.  Recovery  is  accompanied  commonly  by  severe  headache, 
persisting  for  a  long  time,  often  with  nausea  and  vomiting. 

The  increased  danger  of  gas-poisoning  when  coal-gas  is  supplanted 
by  water-gas  with  its  high  carbon  monoxide  content  is  well  shown  by 
the  statistics  bearing  on  the  subject  at  Boston,  Massachusetts.  In 
1888,  when  but  1  per  cent,  of  the  gas  sold  was  water-gas,  there  were 
no  deaths,  suicidal  or  accidental,  from  gas-poisoning.  In  the  following 
year,  there  was  but  1.  In  1890,  the  percentage  of  water-gas  rose  to 
8,  and  there  were  6  deaths,  4  accidental  and  2  suicidal.  In  1892,  as 
a  result  of  permissive  legislation,  52  per  cent,  of  the  gas  sold  was 
water-gas,  and  the  deaths  rose  to  15.  In  1897,  the  percentage  rose 
to  93,  and  the  deaths  to  47,  32  of  which  were  accidental  and  15 
suicidal.  In  the  five  years  ended  September  1,  1899,  169  deaths  had 
occurred. 

On  account  of  the  danger,  a  commission  appointed  in  England  in 
1899,  reported  adversely  on  all  illuminating  gas  containing  more  than 
20  per  cent,  of  carbon  monoxide,  which  proportion  corresponds  approxi- 
mately to  a  mixture  of  equal  volumes  of  coal-gas  and  water-gas. 

Acetylene  gas,  Callj,  is  an  unstable  compound  of  carbon  and  hydro- 
gen. It  has  a  strong,  disagreeable  odor.  Mixed  with  air  in  the  pro- 
portion of  1  to  19,  it  is  violently  explosive.  It  is  poisonous,  but  not 
to  the  same  extent  as  ordinary  coal-gas ;  an  animal  exposed  to  an 
atmosphere  containing  it  becomes  unconscious  after  a  time,  with  no 
manifestations  of  nervous  or  respiratory  excitement,  and,  if  removed 
at  once,  recovers  in  a  very  short  time.  Prolonged  exposure  is  fatal. 
Blood  will  absorb  about  0.8  per  cent,  of  its  volume  of  acetylene,  but 
the  solution  gives  no  characteristic  spectroscopic  appearance.  If  any 
compound  is  formed  with  haemoglobin,  it  must  be  very  unstable.  If  a 
high  percentage  of  oxygen  be  present,  animals  may  survive  its  action 
many  hours. 

Acetylene  is  made  from  calcium  carbide,  a  reddish-brown  or  gray 
material  prepared  by  subjecting  a  mixture  of  lime  and  coke  to  very 
intense  heat.  When  this  substance  is  wet  with  water,  a  double  decom- 
position occurs,  the  calcium  uniting  with  the  oxygen  of  the  water  to 
form  quicldime,  and  the  carbon  Avith  the  hydrogen  to  form  acetylene. 
Between  four  and  five  cubic  feet  of  the  gas  are  yielded  by  a  pound  of 
the  ordinary  commercial  carbide. 

Burned  in  ordinary  gas-burners,  the  flame  cannot  secure  a  sufficient 
supply  of  oxygen  for  the  complete  combustion  of  the  carbon,  and  in 
consequence  it  smokes  and  fails  to  exert  its  full  power  of  illumination. 
By  using  a  tip  with  an  exceedingly  thin  slit,  and  forcing  the  gas 
through  under  heavy  pressure,  the  Hame  is  greatly  enlarged  and  is  of 
great  brilliancy.  Its  illuminating  power  is  about  1 5  times  greater  than 
that  of  ordinary  gas. 

Acetylene  is  liquefied  at  a  temperature  of  64°  F.  by  a  pressure  of 
1,200  pounds  to  the  square  inch,  and  may  be  stored  in  cylinders  of 
steel.     Apparatus  for  its  use  should  not  be  made  of  copper  or  silver^ 


VARIETIES  OF  ILLUMINATING  GAS.  451 

since  these  metals  are  attacked  by  it,  and  the  resulting  compounds  are 
very  explosive. 

In  some  apparatuses  in  use,  the  water  is  dropped  on  to  the  carbide 
by  an  automatic  arrangement,  so  that  the  yield  of  gas  is  regulated, 
but  the  gas  continues  to  be  evolved  after  the  water-supply  is  shut  off, 
since  the  moistened  carbide  cannot  be  prevented  from  undergoing 
decomposition.  In  others,  the  carbide  is  introduced  into  10  times  its 
volume  of  water  in  a  vessel  connected  with  a  gas-holder  of  sufficient 
capacity. 

Whether  acetylene  is  likely  to  have  a  great  field  in  the  future, 
cannot  in  the  present  state  of  development  be  predicted,  but  many 
changes  and  improvements  are  necessary  before  it  can  be  looked  upon 
as  having  any  great  practical  value. 

Gasolene  gas  is  a  mixture  of  gasolene  vapor  and  air,  the  function  of 
the  latter  being  to  dilute  the  former  until  the  proportion  of  carbon  in 
the  mixture  is  equivalent  to  that  in  common  gas.  Gasolene  is  a  mixt- 
ure of  light  hydrocarbons,  a  product  of  the  distillation  of  crude  petro- 
leum. Its  specific  gravity  ranges  from  0.629  to  0.667.  It  volatilizes 
slowly  at  low  temperatures  and  rapidly  at  70°  F.  and  above.  It  is 
exceedingly  inflammable. 

Gasolene  gas  is  generated  and  forced  through  supply  pipes  to  the 
burners  by  special  forms  of  apparatus  which  require  but  little  atten- 
tion. It  is  well  suited  to  single  houses  and  small  groups  of  houses 
where  no  public  supply  exists. 

Impurities  Given  off  in  Lighting. — In  the  combustion  of  illumi- 
nants  of  all  kinds,  considerable  amounts  of  decomposition  products 
are  given  off  to  the  air,  and  their  removal  by  means  of  efficient  venti- 
lation is  important.  These  products  are  least  in  amount  and  impor- 
tance in  lighting  with  candles  and  oil  lamps,  being  chiefly  carbon 
dioxide  and  watery  vapor.  The  impurities  given  off  in  the  combus- 
tion of  gases  include  sulphur  dioxide,  very  variable  in  amount  accord- 
ing to  the  extent  of  purification ;  carbon  monoxide,  also  variable 
according  to  the  completeness  of  combustion;  carbon  dioxide;  ammo- 
nium compounds,  and  aqueous  vapor. 

Gas  Pipes. — Street  mains  are  commonly  made  of  cast-iron  pipes  of 
rather  light  weight,  which  vary  much  in  texture  and  density,  and  not 
infrequently  are  perforated  with  blow-holes  of  varying  diameter  or 
otherwise  defective.  On  account  of  the  dangers  of  extensive  leakage 
and  of  the  financial  loss  due  to  waste  of  gas  and  the  cost  of  making 
repairs,  all  pipes  should  be  tested  thoroughly  before  being  laid.  Pipes 
which  show  no  leaks  when  new  may  soon  be  corroded  in  the  soil  at 
points  whore  biibbk^s  occur  in  the  walls  with  but  a  thin  layer  of  metal 
on  either  side.  Wrought-iron  pipes  are  corroded  more  quickly  in  the 
soil,  but  are  more  uniform  in  density  and  texture  than  cast-iron  and 
rcfjuii-e  fc^wcr  joints  in  a  given  distance.  Both  kinds  should  be  pro- 
tected by  a  generous  coatnig  of  aspljultum  or  otlusr  suitable  material. 

Mouse  ))ipes  are  most  commonly  of  wrought  iron,  though  sometimes 
softer  materials  are  employed.     The  latter  are  more  ex2)ensive,  and 


452  HABITATIONS,  SCHOOLS,   ETC. 

possess  the  additional  disadvantage  of  being  easily  punctured  by 
nails  and  gnawed  by  rats  and  mice.  The  entire  system  of  distribut- 
ing pipes  should  be  joined  most  carefully,  in  order  that  no  leaks  shall 
occur.  When  they  do  occur,  the  search  for  their  location  should  be 
conducted  with  all  possible  precautions  against  risk  of  explosions, 
since  mixtures  of  gas  and  air  in  the  proportion  of  about  8  per  cent,  of 
the  former  are  violently  explosive  if  brought  in  contact  with  a  flame. 
The  gas  should  be  shut  olf  at  the  meter,  and  the  apartments  where 
the  smell  is  perceived  should  be  aired  thoroughly.  The  examination 
should  then  be  begun  at  the  meter  and  its  connections,  and  if  defects 
are  there  found,  the  meter,  if  at  fault,  should  be  removed,  or  the  con- 
nections put  in  proper  condition  with  new  wasliers.  The  fixtures 
should  next  receive  attention,  every  joint  and  cock  being  tested,  the 
gas  being  turned  on  again  at  the  meter.  Smearing  the  joints  with 
some  viscid  material,  such  as  strong  soapsuds,  will  show  small  leaks 
by  formation  of  bubbles.  The  examination  of  the  joints  of  the  dis- 
tributing pipes  is  a  matter  of  considerable  difficulty,  and  may  require 
much  disturbance  of  structural  parts. 

Fixtures  should  be  so  located  as  to  avoid  hot-air  currents  from  reg- 
isters in  the  floor  and  walls,  on  account  of  the  great  annoyance  caused 
by  flickering  of  the  flame.  Flickering  is  caused  also  by  the  presence 
of  condensed  moisture  in  sags  in  the  pipes  and  bends  in  the  fixtures, 
which  causes  the  gas  to  issue  in  a  series  of  bubbles  with  consequent  un- 
steadiness of  the  flame.  The  remedy  consists  in  interposing  drip  cups 
and  draining  off  the  water. 

The  proper  arrangement  of  fixtures  is  frequently  a  difficult  problem, 
particularly  in  large  rooms.  In  general,  it  may  be  said  that  they 
should  be  well  distributed  rather  than  clustered  in  central  chandeliers. 
Pairly  uniform  diffusion  may  be  secured  by  the  use  of  globes  of  pris- 
matic glass,  which  act  in  the  same  way  as  the  ribbed  and  prismatic 
window  glass  described  above. 

Electric  Lighting". — Incandescent  electric  lighting  possesses  cer- 
tain notable  advantages  over  all  other  systems  of  artificial  illumina- 
tion. It  requires  no  oxygen  and  produces  no  decomposition  com- 
pounds, and  hence  in  no  way  alters  the  composition  of  the  air.  It 
imparts  but  little  heat  to  the  surrounding  air,  and  hence  has  but  a 
limited  influence  in  causing  convection  currents  and  raising  room 
temperature. 

Section  4.     PLUMBING. 

Whether  we  view  the  subject  from  the  standpoint  of  possible  danger 
of  infection  through  inhalation  of  sewer  air  or  from  that  of  eesthetics, 
we  should  recognize  the  great  importance  of  the  removal  of  all  sewer 
wastes  from  the  habitation  through  a  system  of  plumbing  that  is  so 
perfect  that  it  shall  leak  neither  liquid  nor  solid  matters,  nor  foul  air 
and  smells.  For  the  attainment  of  the  best  results,  all  large  commu- 
nities adopt  plumbing  ordinances  designed  to  prevent  faulty  construc- 
tion and  the  admission  of  the  dreaded  "  sewer  gas,"  which,  to  the  lay 


PLUMBING.  453 

mind,  and  very  generally  to  the  professional  mind  as  well,  is  a  most 
potent  cause  of  disease.  While  the  weight  of  evidence  is  against  the 
acceptance  of  the  doctrine  of  the  transmission  of  disease  through  this 
agency,  it  must  be  conceded  that  foul  odors,  besides  being  disagree- 
able, exert  on  the  sensitive  individual  a  decidedly  injurious  action 
through  the  imagination,  and,  more  particularly,  through  their  effects 
on  the  appetite  and  digestion.  Most  of  the  foul  smells  coming  from 
plumbing  fixtures  are  not  from  the  sewer  at  all,  and  hence  may  not 
properly  be  called  sewer  gas  or  sewer  air ;  they  are  due  to  decomposing 
organic  matters  within  the  pipes  or  traps,  or  in  some  other  part  of  the 
fixture,  which,  with  ordinary  use,  does  not  become  thoroughly  cleansed. 
Thus,  it  is  often  found  that  the  odor  from  a  wash-basin  is  due  to 
decomposing  soapy  matters  and  other  deposits  in  the  horn  leading 
from  the  overflow  holes,  but  it  is  difficult  to  convince  the  timid  that 
such  is  the  fact,  except  by  ocular  and  other  demonstration. 

The  most  perfect  system  of  plumbing  needs  careful  supervision,  for 
no  pipe  or  other  part  subjected  to  frequent  contact  with  filthy  matters 
can  be  kept  permanently  clean  unassisted ;  and  any  such  surface  not 
cut  off  from  contact  with  the  free  air  of  the  room  must  inevitably, 
under  certain  conditions,  give  rise  to  a  certain  amount  of  nuisance. 
The  reduction  of  these  possibilities  for  nuisance  to  the  lowest  limits  is 
one  of  the  main  objects  of  the  many  ingenious  plumbing  appliances  of 
one  kind  and  another  that  are  almost  daily  increasing  in  number  and 
variety. 

Broadly  speaking,  plumbing  may  be  divided  into  two  classes  :  good 
plumbing  and  bad  plumbing.  The  former  costs  more  in  the  begin- 
ning ;  the  latter,  in  the  end ;  the  former  is  installed  by  the  capable  and 
honest  plumber ;  tte  latter,  by  the  trickster  who  has  given  his  calling 
such  a  bad  name  that  he  finds  it  more  to  his  liking  to  hide  behind  the 
more  pretentious  title  of  "  sanitary  plumbing  engineer,"  just  as  some 
barbers  become  "  tonsorial  artists." 

The  better  class  of  plumbers,  in  undertaking  the  installation  of  a 
system  of  plumbing,  attempt  to  attain  such  a  degree  of  perfection  that 
repairs  are  only  occasionally  necessary ;  the  other  class,  either  inten- 
tionally or  because  of  inability  to  do  good  work,  produce  a  system 
requiring  constant  repairs  and  consequent  expenditure.  This  class 
of  workmen  also  are  quick  to  take  every  advantage  of  loosely  drawn 
or  ambiguous  specifications,  whereby  the  owner  suffers  eventually  more 
than  the  original  financial  injustice.  But  the  responsibility  for  poor 
plumbing  is  not  by  any  means  always  to  be  placed  upon  the  plumber, 
for  an  owner  unwilling  to  pay  the  price  of  good  work  can  hardly 
blame  the  plumber  for  unwillingness  to  provide  labor  and  first-class 
material  at  less  than  cost,  and  so  gets  cheap  material  and  cheap  work- 
manship in  return  for  his  inade({uate  appropriation. 

A  good  system  of  pluml)ing  calls  for  sound  materials,  absolutely 
tight  joints,  thorough  ventilation,  and  a  plentiful  water  supply  to  in- 
siiiv  llioroiigli  Hiisliing  without  wastefulness.  It  should  be  so  planned 
that  the  various   fixtures  on  each  floor  shall   be  in  relatively  the  same 


454  HABITATIONS,  SCHOOLS,  ETC. 

locations,  thus  avoiding  unnecessary  and  expensive  extensions  of  waste 
and  supply  pipes.  The  wastes  should  be  easily  accessible,  and  are  best 
run  in  full  view,  so  that  any  leakage  may  be  detected  at  once.  When 
hidden  from  view,  leaks  may  exist  undetected  until  much  damage  has 
resulted.  Open  plumbing,  furthermore,  insures  good  workmanship, 
and  makes  repairs  simpler  and  much  less  expensive.  The  pipes  need 
not  be  a  disfigurement  to  a  room,  for  they  may  be  neatly  painted  or 
bronzed,  and  will  then  have  no  worse  appearance  than  those  used  in 
steam  heating.  If  they  must  be  placed  in  recesses  or  within  walls, 
they  may  be  concealed  by  boards  or  panels  fastened  by  screws,  and 
easily  removable. 

The  important  fixtures,  such  as  bathtubs  and  water-closets,  should 
be  placed  where  ventilation  can  be  secured  and  where  dependence  upon 
artificial  light  is  not  altogether  necessary.  The  ideal  place  is  in  an 
outer  room  with  a  window  through  which  the  sun's  rays  and  fresh  out- 
door air  may  enter. 

The  Soil-pipe  and  Main  Drain. — The  soil-pipe  receives  at  various 
points,  through  the  several  waste-pipes,  the  contents  of  wash-bowls, 
sinks,  bathtubs,  urinals,  water-closets,  and  other  fixtures,  and  conducts 
them  to  the  drain,  by  which  they  are  carried  on  to  the  sewer  or  cess- 
pool, as  the  case  may  be.  In  this  country,  the  material  almost  univer- 
sally used  for  soil-pipe  is  cast  iron  ;  but  in  England  lead  is  preferred. 
The  advantages  of  iron  over  lead  are  many ;  it  is  lighter,  stiffer, 
stronger,  cheaper,  and  more  durable,  and  is  not  subject  to  accidental 
perforation  by  driven  nails  and  gnawing  rats.  Lead  pipe  of  large 
diameter  sags  by  reason  of  its  weight,  and  it  is  difficult  to  secure  it 
strongly  wherever  its  Aveight  is  borne  by  the  fastenings.  It  is  very 
easily  corroded,  dented,  flattened,  and  perforated. 

Cast-iron  soil-pipe  is  made  in  two  grades  ;  light,  or  "  standard,"  and 
*'  extra  heavy."  Only  the  latter  should  be  employed,  the  former  being 
much  too  thin  and  flimsy.  The  walls  of  the  extra  heavy  grade  should 
not  be  less  than  an  eighth  of  an  inch  in  thickness.  The  pipe  is  made 
in  lengths  of  five  feet,  exclusive  of  the  socket,  or  hub,  which  is  an 
enlargement  of  one  end  for  the  reception  of  the  spigot  end  of  the  next 
length,  so  that  no  irregularities  shall  be  caused  in  the  caliber  of  the 
pipe  where  joints  occur,  but,  on  the  contrary,  that  the  inner  surface  shall 
be  flush  throughout.  Each  length  should  be  of  uniform  wall  thickness 
throughout  and  free  from  flaws,  sand  holes,  and  other  imperfections, 
and  should  be  subjected  to  strength  tests  at  the  place  of  manufacture. 
The  inner  surface  should  be  perfectly  smooth. 

In  joining  the  lengths  together,  the  spigot  end  of  one  is  inserted  as 
straight  as  possible  into  the  hub  of  the  next,  and  a  gasket  of  oakum  is 
inserted  into  the  intervening  space  by  means  of  a  caulking  tool,  and 
rammed  hard  so  as  to  fill  about  half  the  depth  of  the  hub.  The  object 
of  the  gasket  is  to  prevent  the  entrance  to  the  bore  of  the  pipe  of  any 
of  the  molten  lead  used  in  the  next  process.  The  next  step  is  the 
filling  of  the  rest  of  the  space  with  molten  lead  from  a  ladle.  Since 
this  metal  shrinks  on  cooling,  and  since  moisture  and  dirt  prevent  its  ' 


PLUMBING.  455 

adherence  to  the  iron,  it  is  necessary  next  to  expand  it  and  drive  it 
down  by  mechanical  means.  This  process  requires  care  and  involves 
much  risk  of  fracture,  since  the  blows  of  the  caulking  tools  must  be 
quite  heavy  ;  in  fact,  much  heavier  than  the  lighter  grade  of  pipe  can 
withstand.  Against  this  form  of  pipe  and  its  jointing,  certain  objec- 
tions are  urged,  not  the  least  of  which  is  the  opportunity  given  for 
botch-work  and  fraud.  Instances  of  filling  the  space  with  mortar, 
sand,  putty,  and  other  material  have  been  not  uncommon.  Some- 
unscrupulous  plumbers  gloss  over  the  fraud  with  a  thin  layer  of  lead ; 
some  make  the  joint  properly  and  neglect  to  caulk  it ;  some  make  as 
perfect  a  joint  as  possible  in  places  where  ocular  inspection  is  easy  and 
probable,  and  omit  to  caulk,  or  even  to  insert  the  oakum,  where  the 
joints  are  hidden,  but  without  forgetting  to  make  the  usual  charge. 

Another  objection  to  this  form  of  joint  is  the  possibility  of  its  be- 
coming loose  through  alternate  expansion  and  contraction  due  to  changes 
in  temperature.  The  expansion  is  unequal,  especially  when  due  to  hot 
water  in  the  pipe,  and  the  spigot  expands  more  than  its  surrounding 
socket  and  compresses  the  interposed  lead,  which,  when  equilibrium 
becomes  reestablished,  does  not  resume  its  original  shape,  but  remains 
in  its  new  form.  In  this  way,  it  is  possible,  but  not  very  probable,  that 
a  minute  space  may  be  created  all  about  the  spigot,  and  that  through 
this  space,  leakage  of  liquid,  but  more  especially  of  air,  may  occur.  In 
an  upright  pipe,  leakage  of  liquid  is  most  unlikely  to  occur,  since  the 
hub  end  of  each  joint  is  uppermost. 

Still  another  objection  is  the  great  difficulty  encountered  in  unjoint- 
ing,  when,  for  any  reason,  it  is  necessary  to  remove  a  length  of  pipe  in 
making  repairs  and  alterations.  The  usual  and  easiest  course  to  pursue 
in  such  a  case  is  to  break  the  pipe  and  remove  it  in  pieces. 

To  meet  the  several  objections  to  this  form  of  pipe,  the  Sanitas 
flanged  pipe  was  devised  by  Mr.  J,  Pickering  Putnam,  of  Boston. 
This  makes  a  joint  which  is  described  as  an  adjustable  flanged  joint 
with  lead  washers  or  gaskets  for  packing.  The  gaskets,  which  are 
star-shaped  in  cross-section,  are  squeezed  between  the  flanges  of  the  two 
adjoining  pipes  and  crushed  to  half  their  original  thickness  by  screw- 
ing up  the  bolts  set  in  square  recesses  in  the  flange  ears.  These  are 
screwed  simultaneously,  so  that  the  pressure  on  either  side  is  equalized 
and  the  gasket  is  compressed  uniformly.  The  gasket  for  a  four-inch 
pipe  weighs  a  half  pound.  For  this  joint,  are  claimed  cheapness  and 
security.  The  time  required  to  make  it  is  reckoned  in  seconds  as 
against  minutes,  the  amount  of  lead  consumed  is  much  less,  and  the 
unjointing  is  simple  and  involves  no  breakage. 

The  diameter  of  a  soil  pipe  should  ordinarily  not  exceed  four  inches, 
but  in  very  large  buildings,  in  which  are  numerous  water-closets  and 
oth(!r  fixtures,  five-inch  pipe  is  sometimes  used. 

Soil  pipes  should  run  as  nearly  vertically  and  with  as  few  deviations 
from  a  straight  line  as  practicable.  When  these  are  necessary,  right- 
angled  l)ends,  such  as  are  shown  in  Fig.  47,  should  be  avoided,  and 
instead  thereof,  obtuse-angled   elbows,  as    in   Fig.  48,  should  be  em- 


456 


HABITATIONS,  SCHOOLS,   ETC. 


ployed.     Where  waste-pipes  and  branches  connect,  the  junctions  should 
be  made  with  Y-branches  and  not  at   right   angles.     (See  Fig.  49.) 


Fig.  48. 


Fig.  47, 


Improper  bends  in  soil-pipe. 


Proper  bends  in  soil-pipe. 


Y-branch  to  soil-pipe. 


Fig.  50. 


These  junctions  are  made  differently  when  a  lead  pipe  is  to  be  con- 
nected with  an  iron  one.  The  lead  pipe  is  first  "wiped"  on  to  a 
brass  ferrule  by  means  of  solder,  and  then  the  ferrule  is  caulked  into 

the  hub.  With  the  flanged  Sanitas  pipe,  the 
connection  is  obtained  more  easily  and 
cheaply ;  here  the  lead  pipe  is  flanged  out 
and  bolted  to  the  iron  by  means  of  cast-iron 
rings  with  ears  and  bolt-holes  corresponding 
to  those  on  the  pipe. 

Each  soil-pipe  should  be  extended  in  full 
size  through  the  roof  for  about  two  feet,  and 
its  outlet  should  not  be  obstructed  by  a  cap 
or  cowl,  as  is  commonly  done.  The  cap 
serves  no  useful  purpose,  and  the  passage 
for  air  is  so  narrow  that,  in  winter,  when  the 
warm,  moist  air  ascends,  a  coating  of  frost  is 
formed  all  over  the  inner  surface  of  the  ex- 
posed pipe,  and  this  may  grow  in  thickness 
so  as  to  occlude  the  outlet  completely,  as  is 
shown  at  A  in  Fig.  50.  In  all  cases,  one 
should  make  provision  for  the  expansion  and 
contraction  of  the  column  of  metal,  for  while 
the  movement  either  way  is  slight,  its  force  is 
very  great ;  therefore,  the  fastenings  should 
not  be  too  rigid,  but  should  allow  a  little  play. 
The  soil-pipe  should  be  very  firmly  supported  at  the  bottom,  and 


Occlusion  of  outlet  of  soil-pipe 
by  frost. 


PLUMBING. 


457 


its  junction  with  the  main  drain  should  be  made  with  a  bend  of  as 
large  a  radius  as  possible.  The  best  support  is  either  a  brick  pier 
or  a  wooden  post,  or  other  firm  and  unyielding  structure.  The  con- 
nection should  under  no  circumstances  be  at  a  right  angle,  but  with 
an  elbow  bend  supported  on  a  foot,  as  in  Fig.  51.  If  the  pipe  must 
be  carried  along  a  cellar  wall,  it  should  be  supported  either  by  a  shelf 
or  by  wrought-iron  pipe-hooks. 

From  the  point  where  the  soil-pipe  departs  from  the  perpendicular 
and  tends  toward  the  sewer  or  cesspool,  it  is  commonly  known  as  the 
drain,  whether  other  soil-pipes  enter  it  or  not.  The  drain  should  con- 
sist of  iron  as  far  as  a  point  well  away  from  the  foundation  of  the 
house  and  from  all  danger  of  fracture  due  to  settling.  Under  no  cir- 
cumstances should  an  earthenware  drain-pipe  be  employed  within  the 
house  or  beneath  the  foundation,  or  through  a  soil  in  which  a  well  of 
drinking-water  is  situated.  The  main  drain  may  be  carried  along  the 
wall  of  the  cellar  in  the  manner  above  described,  or  it  may  be  suspended 
by  wrought-iron  hangers  from  the  joists  of  the  floor  of  the  first  story ; 


Fig.  51. 


Fig.  52. 


Elbow  bend  and  support. 


Intercepting  trap.    (Running  trap.) 


or,  if  there  are  water-closets  or  other  fixtures  in  the  cellar,  it  may  run 
below  the  floor.     In  the  latter  case,  it  should  be  easily  accessible. 

The  drain  should  have  all  the  fall  that  can  conveniently  be  given, 
and  this  should  be  as  nearly  uniform  as  possible  throughout  its  length. 
No  part  of  it  should  run  flat  or  sag.  The  greater  the  pitch,  the  more 
completely  the  pipe  is  scoured  out  by  each  passage  of  water.  It  should 
have  a  fall  of  at  least  a  quarter  of  an  inch  to  the  foot,  or,  preferably, 
more. 

Before  the  drain  passes  beneath  the  foundation  wall,  or,  if  this  is 
impossible,  at  a  point  outside  in  a  manhole,  an  intercepting  trap  is 
placed,  provided  with  clean-out  holes  covered  with  air-tight  covers. 
This  trap,  known  sometimes  as  the  running  trap  and  main  trap,  is  of 
the  same  diameter  throughout  as  the  drain  itself.  This  kind  of  trap 
is  manufactured  in  an  immense  variety  of  forms,  one  of  the  best  of 
which  is  shown  in  Fig.  52.  This  has  an  inlet  and  an  outlet  for  sew- 
age, an  inlet  for  fnjsh  air,  and  a  clean-out  and  inspection  hole  on  the 


458 


,„,«wimm.rm 
Tiwmiii'inwkii 


HABITATIONS,  SCHOOLS,  ETC. 
Fig.  53. 

JL 


«S  U.--'-\.^  ;>?-'V'V;_-/o-v.-- - 


Objectionable  arrangement  of  intercepting  trap  and  ventilating  pipe. 

outfall  side.      The  sewage  enters  by  the  inlet  at  the  left,  which  is 
slightly  higher  than  the  outfall  at  the  right.     The  uppermost  opening 

Fig.  54. 


Preferable  arrangement  of  intercepting  trap  and  ventilating  pipe. 

is  for  the  fresh-air  inlet.  The  latter  is  for  the  purpose  of  insuring  a 
complete  circulation  of  fresh  air  throughout  the  entire  length  of  the 
drain  and  soil-pipe,  and  communicates  with  the  external  air  by  means 


PLUMBING. 


459 


of  a  pipe  of  the  full  diameter  of  the  drain,  running  from  the  house  side 
of  the  trap  to  some  point  outside. 

In  Fig.  53  is  shown  an  arrangement  very  commonly  adopted,  but 
open  to  serious  objections.  Here,  the  filth  may  be  thrown  up  against 
the  entrance  of  the  fresh -air  pipe  F  oi  A  and  form  an  accumulation. 
The  floor  of  the  drain  and  of  the  outlet  S  are  at  the  same  level,  as  is 
shown  by  the  two  sides  of  the  water  seal  L,  and  there  will  be,  there- 
fore, not  head  enough  to  force  all  light  solids  easily  beneath  the  dip 
of  the  trap. 

A  much  better  arrangement  is  that  shown  in  Fig.  54.  In  this,  the 
inlet  of  the  fresh-air  pipe  F  is  situated  at  a  point  some  distance  away 
from  and  on  the  house  side  of  the  trap,  where  splashing  and  accumu- 
lation of  filth  cannot  occur.  At  A,  the  entering  sewage  falls  through 
a  distance  of  about  two  inches  at  L,  and  can  force  any  solid  matter 
under  the  dip  and  onward  through  8.  It  will  be  noted  by  the  direc- 
tion of  the  arrows  in  both  figures  that  the  normal  direction  of  the  air 
current  is  inward,  but  under  some  conditions  of  internal  and  external 
temperatures,  as,  for  example,  in  summer,  the  direction  is  likely  to  be 
reversed.  In  winter,  owing  to  the  higher  temperature  of  the  house,  the 
movement  in  the  soil-pipe  is  naturally  upward  and  outward,  and  in  the 
pipe  F  is  downward  and  inward. 

Waste-pipes. — The  pipes  connecting  fixtures  with  the  soil-pipe  are 
known  as  waste-pipes.  They  are  made  commonly  of  lead,  although 
cast-iron,  wrought  iron,  and  galvanized  iron  are  employed  also.     The 

Fig.  55. 


in  an  improperly  laid  pipe. 


advantage  of  using  lead  is  that  it  is  more  easily  run,  especially  in  places 
where  bends  and  angles  are  necessary,  and  requires,  therefore,  a  smaller 
number  of  joints.  The  disadvantages  are  the  liability  to  perforation 
by  nails  carelessly  driven  and  by  gnawing  rats,  and  the  possibility  of 
the  formation  of  air-locks  through  sagging  of  a  pipe  improperly  laid. 
These  occur  sometimes  when  a  pipe  is  not  properly  supported  or  where 
high  points  and  low  points  occur  in  a  crooked  run.  This  is  shown  in 
exaggerated  form  in  Fig.  55.  Here  we  see  a  series  of  low  points,  in 
which  water  will  stand  and  where  sediment  may  accumulate,  and  a  cor- 
responding number  of  high  points  containing  air.  These  impede  the 
flow  of  water  onward,  and  if  the  pressure  is  low,  a  series  of  them  in  a 
sing](!  run  may  stoj)  it  altogether. 

Iron  pipes  possess  whatever  advantage  attaches  to  rigidity,  and 
while  they  are  not  so  easily  adapted  to  crooked  runs  and  require  more 
joints,  it  must  be  said  that  the  latter  are  made  quickly  and  easily 
when  screw  coiijiliDgs  are  employed.     Some  joints  are  made  by  screw- 


460 


HABITATIONS,  SCHOOLS,   ETC. 


ing  directly  into  hubs  and  some  by  means  of  ordinary  couplings,  the 
result  in  either  case,  as  shown  in  Fig.  56,  being  perfectly  flush 
fittings. 

Ordinarily  waste-pipes  need  not  be  larger  than  1,5  inches  in  diameter, 
nor  heavier  than  three  pounds  to  the  foot.  In  those  cases  where  the 
supply  pipes  deliver  a  heavy  stream  of  water  under  high  pressure,  it 
may  be  necessary  to  use  a  larger  size,  in  order  to  insure  the  removal 
of  all  the  water  without  danger  of  overflow.     Too  large  pipes  and  toa 

Fro.  56. 


Flush  fittings  with  screw  couplings. 


small  pipes  are  equally  bad.  If  too  small,  the  overflow  is  retarded 
and  they  are  choked  easily ;  if  too  large  for  the  fixture  from  which 
they  lead,  they  cannot  possibly  be  flushed  thoroughly,  but  are  soon 
coated  with  grease  and  other  filth,  and  eventually  become  completely 
occluded.  Thus,  a  2-inch  waste-pipe,  attached  to  a  fixture  by  a  1.25- 
inch  joint,  would  be  quite  too  large  and  out  of  place. 

Lead  waste-pipes  may  be  joined  to  iron  soil-pipes  in  the  manner 
already  described,  and  to  wrought  iron  by  brass  screw  nipples  wiped 
on  to  the  lead  with  solder  and  screwed  with  red  lead  into  the  thread 
of  the  fitting.  Lead  should  always  be  joined  to  lead  by  wiped  solder 
joints,  and  never  by  cup  or  "copper  bit"  joints,  excepting  when  the 
operation  of  wiping  is  clearly  impossible. 

Traps. — Each  separate  fixture  connected  with  the  soil-pipe,  that  is 
to  say,  each  water-closet,  wash-bowl,  bathtub,  etc.,  should  be  provided 


Fig.  57. 


Running  trap. 


with  some  form  of  trap  situated  as  near  it  as  possible.  A  good  trap 
will  wholly  prevent  the  passage  of  all  air  or  gas  or  odor  from  the 
waste-pipe  or  soil  pipe  backward  into  the  air  of  the  house,  while  per- 


PLUMBING. 


461 


mitting  the  free  passage  of  liquids  and  suspended  solids  toward  the 
sewer.  It  should  be  of  such  construction  as  will  admit  of  ready- 
inspection  and  cleaning,  and  under  ordinary  circumstances  should  be 
self-cleansing.  Improperly  trapped  or  untrapped  fixtures  are  as  much 
to  be  avoided  as  leaks,  the  result  in  either  case 
as  the  passage  of  oifensive  odors  is  concerned. 


being  the  same  so  far 


Fig.  58. 


Forcing  of  seal  of  running  trap. 


The  simplest  form  of  trap,  called  running  trap,  consists  of  a  down- 
ward bend  in  a  horizontal  pipCj  as  shown  in  Fig.  57.  When  water  is 
discharged  through  such  a  pipe,  the  depressed  portion  will  be  found  to 
stand  full  of  water  when  the  discharge  ceases,  and  this  body  of  water 


Fig.  59. 


VV 


Forms  of  round-pipe  traps. 


will  prevent  the  passage  of  air  in  cither  direction  ;  but  if  sufficient 
pressure  is  exerted  on  either  side  to  force  the  level  of  the  water  on  that 
side  down  to  tlic;  lowest  point  of  the  bend,  air  may  bo  forced  through, 
as  is  shown  in  Fig.  58.     The  water  between  the  water  level  and  the 


462 


HABITATIONS,  SCHOOLS,  ETC. 


lowest  point  of  the  upper  internal  surface  of  the  bend  is  known  as  the 
seal,  and  this  should  never  be  less  than  1.5  inches  in  depth.  In  Fig. 
57,  the  seal  is  that  which  lies  between  the  dotted  lines.  This  form  of 
trap  is  one  of  a  class  called  round-pipe  traps,  and  to  this  class  belong 
a  number  of  forms,  five  of  which  are  shown  in  Fig.  59.  These  are 
the  S-trap  {A),  the  Ha/f-S  (5),  the  Three-quarter  S  (C),  the  Running 
(D)  already  described,  and  the  Double-S  or  Hunchback  (jE").  These 
several  forms  are  in  all  cases  of  the  same  size  throughout  and,  there- 
fore, will  pass  anything  that  can  gain  entrance.  With  proper  flush- 
ing, they  are  easily  kept  clean,  but  they  are  quick  to  lose  their  seal  by 
a  sudden  flow  of  water  through  them  or  by  disturbance  of  atmospheric 
pressure  produced  by  the  sudden  discharge  of  water  through  pipes 
with  which  their  own  pipes  are  connected.  The  means  for  the  preven- 
tion of  this  occurrence  are  considered  below. 

Another  class  of  simple  traps  includes  all  those  known  as  Bottle  or. 
JPot  traps.  In  one  form  of  the  bottle  trap,  the  principle  of  which  is 
shown  in  Fig.  60,  the  end  of  the  inlet-pipe  dips  several  inches  into  the 
pool  of  water.  In  order  to  drive  air  backward  through  the  inlet-pipe 
A,  it  would  be  necessary  to  exert  pressure  sufficient  to  force  the  water 
within  the  chamber  B  upward  through  A  until  its 
level  is  brought  down  to  the  lower  end  of  A.  Under 
ordinary  circumstances,  such  a  pressure  would  be 
quite  impossible.  To  drive  air  in  the  other  direction 
through  A  into  B  is  less  difficult,  but  this  will  require 
a  pressure  sufficient  to  depress  the  water  standing 
within  A  down  to  the  outlet  of  the  pipe. 

In  Fig.  61  is  shown  a  tra])  of  this  kind,  in  which 
there  are  two  inlets ;  the  principal  one,  the  pipe  /, 
and  the  second,  which  connects  with  the  overflow  of 
the  fixture,  the  pipe  B.  The  arrows  indicate  the 
direction  of  movement  of  the  sewage  through  the  pot. 
As  the  level  rises,  the  excess  runs  off  through  the 
outlet  0  and  discharges  downward.  The  upper 
portion  of  the  pipe  marked  V  connects  with  the 
ventilating  pipe,  in  which  free  circulation  of  air  is 
maintained.  The  object  of  this  is  explained  below.  This  form  of 
trap  is  made  to  lose  its  seal  only  with  great  difficulty,  although  a  part  of 
it  may  be  lost  by  siphonage.  The  objection  to  this  form  of  trap  is  the 
likelihood  of  the  accumulation  of  filth,  for,  unlike  the  round-pipe  trap, 
they  are  not  self-cleansing,  since  the  whole  contents  are  not  set  in 
motion  each  time  the  fixture  is  used. 

Another,  simpler,  form  of  pot-trap  is  that  shown  in  Fig.  62.  Here 
the  inlet-tube  /  is  not  immersed  in  the  liquid,  but  communicates 
directly  with  the  lower  part  of  the  chamber ;  the  outlet  O  starts  from 
the  upper  part  of  the  chamber,  and  the  communication  with  the  ven- 
tilating pipe  has  its  exit  at  the  crown.  It  will  be  observed  that  in 
both  these  forms  the  seal  is  quite  deep.  The  undue  accumulation  of 
fiilth  in  these  traps  should  be  guarded  against,  and  for  this  purpose 


F 

1g.  6( 

). 

B 

A 

r-"r"- 

^^ 

:EIHr 

W- 

5>: 

^ 

PLUMBING. 


46? 


clean-out  holes,  closed  with  metallic  screw-caps,  are  provided.  A  large 
accumulation  of  filth  in  one  of  these  traps  makes  siphonage  of  the 
seal  more  easily  brought  about.  This  class  of  trap  is  used  only  under 
sinks,  basins,  baths,  and  washtubs  ;  never  under  any  circumstances 
under  water-closets. 


Fig.  61. 


Fig.  62. 


Two  forms  of  ventilated  bottle  traps. 


Among  the  traps  depending  upon  mechanical  devices  to  assist  the 
water-seal,  the  Ball-trap  may  be  taken  as  a  type.  In  this  form  (shown 
in  Fig.  63),  the  up-cast  limb  of  the  trap  consists  of  a  chamber  con- 
siderably broader  than  the  inlet  branch,  and  contains  a  ball,  the  specific 
gravity  of  which  is  slightly  greater  than  that  of  water.     This,  when. 


Fig.  63. 


Ball-trap. 


the  contents  of  the  trap  arc  at  rest,  rests  on  its  seat  and  makes  a  gas- 
tight  joint.  Wh(3n  liquid  is  discharged  into  the  trap,  the  ball  B  is 
thrown  upward  into  the  position  iudicated  by  the  dotted  line ;  and 
when  the  flow  ceases,  it  drops  into  its  original  posititm.  It  cannot 
escape  from  the  chamber,  since  there  is  not  space  enough  for  it  to 


464 


HABITATIONS,  SCHOOLS,  ETC, 


pass  between  the  lip  of  the  pot  and  the  top  of  the  cover.  This  form 
of  trap  cannot  be  siphoned  out,  because  of  the  size  of  the  pot,  but, 
with  disuse,  it  may  lose  its  seal  by  evaporation.  In  such  an  event, 
however,  the  ball  retains  its  seal  and  closes  the  joint.  The  great  objec- 
tion to  this  trap  is  that,  even  although  nothing  which  should  otherwise 
be  disposed  of  is  thrown  into  the  fixture,  as,  for  instance,  matches  and 
other  objects,  the  seat  of  the  ball  is  likely  to  become  the  point  of 
deposit  for  hair,  bits  of  cotton,  linen  fiber,  and  sponge,  and  then  a  gas- 
tight  joint  cannot  be  made  with  the  ball.  As  a  matter  of  fact,  indeed, 
all  mechanical  devices  in  traps  are  much  inferior  to  the  ordinary  water- 
seal. 

Another  form  of  trap,  much  used  in  kitchen  sinks,  is  known  as  the 
Bell  trap.     (See  Fig.  64.)     In  this,  the  delivery  pipe  D  projects  for 

Fig.  64. 


Bell  trap. 


some  distance  upward  into  the  reservoir ;  the  inlet  consists  of  a 
strainer,  S,  to  which  is  attached  the  bell  B,  which  dips  into  the  pool 
of  water  in  the  reservoir  and  encloses  the  outlet  of  the  pipe  D.  There 
is,  it  will  be  seen,  no  direct  communication  between  the  air  contained 
within  the  bell  and  that  above.  The  waste  reaches  the  reservoir 
through  the  holes  in  the  strainer,  and  as  the  level  of  the  liquid  rises, 
it  escapes  through  D.  This  form  of  trap  is  quite  likely  to  be  choked 
by  deposits  of  small  bits  of  food  material  and  other  substances  forced 
through  the  holes  of  the  strainer  with  the  aid  of  a  sink  brush.  It 
is  also  easily  siphoned,  and,  furthermore,  being  easily  removed,  it 
happens  very  commonly  that  the  fixture  is  utilized  by  lazy  servants 
for  the  disposal  of  waste  matters  which  should  be  deposited  else- 
where. 

Grease  traps  are  devices  for  preventing  the  choking  of  drains  by 


PLUMBING. 


465 


"L^ 


grease,  which,  discharged  in  the  liquid  state  with  hot  water,  solidifies 
when  it  comes  in  contact  with  the  cold  surface  of  the  waste-pipe  and 
adheres  thereto  with  great  ten- 
acity. The  coating  which  it  Fig.  65. 
forms  becomes  thicker  and 
thicker  through  successive  ap- 
plications, and  eventually  may 
occlude  the  pipe  so  completely 
that  the  trouble  must  be  at- 
tacked from  the  outside,  the 
remedy  requiring  sometimes 
the  removal  and  incidental  de- 
struction of  an  entire  length 
of  pipe.  Grease  traps  may  be 
located  beneath  the  sink  or, 
preferably,  in  a  place  provided 
therefor  outside  the  house. 

A  common  type  of  this  de- 
vice is  shown  in  Fig.  65.  The 
greasy  water  runs  into  the  res- 
ervoir through  the  inlet  /,  and 

the  liquid  grease,  being  lighter  than  the  water,  rises  to  the  surface  and 
forms  a  scum,  which,  when  cold,  solidifies  into  a  cake.  The  outlet  O 
of  the  trap  dips  far  beneath  the  surface,  and  so  discharges  none  of  the 


Grease  trap. 


Fig.  66. 


Jacketed  grease  trap. 

accumulated  grease.     Air  is  admitted  through  V,  and  can  circulate 
thencf!  through  the  inlet  pipe  J,  as  indicated  by  the  arrows.     The  accu- 
mulated grease  should  be  removed  periodically  through  the  clean-out, 
30 


466 


HABITATIONS,  SCHOOLS,   ETC. 


which  is  closed  by  the  cover  C.  A  larger  and  more  complicated  appa- 
ratus is  shown  in  Fig.  66.  Here  the  chamber  is  enclosed  in  a  jacket, 
A  B,  through  which  cold  water  is  allowed  to  circulate.  The  dirty 
water  enters  through  I  and  discharges  from  the  upper  branch  0,  which 
is  vented  through  V.  The  grease  accumulates  at  G,  and  is  removed 
through  the  top,  which  is  closed  by  the  hinged  cover  C. 

There  are  many  other  forms  of  grease  interceptors,  but  none  is  per- 
fect, for  under  the  most  favoring  circumstances  some  grease  will  escape 
and  may  congeal  on  the  surface  of  the  waste-pipe  or  drain.  All  grease 
traps  should  be  attended  to  at  short  intervals,  else  they  may  become 
almost  completely  filled  with  solid  grease. 

Loss  of  Seal. — Traps  may  lose  their  seal  in  various  ways  :  by 
siphonage,  by  evaporation,  by  back  pressure,  by  leakage,  by  accumu- 
lation of  sediment,  and  by  capillary  attraction.     The  most  important 

Fig.  67. 


Effects  of  veutilation  and  non-ventilation  of  traps. 

of  these  is  siphonage,  for  the  prevention  of  which  two  methods  com- 
monly are  employed.  In  one,  the  up-cast  limb  of  the  trap  is  widened 
so  that  it  becomes  a  pot  or  reservoir.  A  large  reservoir  will  resist 
siphonic  action  much  more  successfully  than  a  small  one ;  an  8-inch 
pot  cannot  be  siphoned  through  a  pipe  of  ordinary  size,  a  4-inch  pot 
resists  only  when  its  seal  is  unusually  deep,  and  anything  less  than  4 
inches  is  inadequate. 

This  form  of  trap,  however,  offers  decided  objection.  In  the  first 
place,  it  is  likely  to  accumulate  much  sediment;  and  in  the  second,  it 
constitutes  a  miniature  cesspool,  the  presence  of  which  in  a  system  of 
plumbing  should  not  be  countenanced,  since  sewage  matter  should  be 
discharged  in  as  fresh  a  condition  as  possible,  and  not  in  a  state  of 
putrefaction,   which,    if  cesspools   are   employed,   will    inevitably    be 


PLUMBING. 


467 


brought  about.  Moreover,  tliis  form  of  trap  is  very  expensive  and 
bulky.  In  the  other  method,  the  up-cast  branch  is  connected  with  a 
ventilating  pipe  by  a  branch  from  its  upper  portion.  Unless  one  or 
the  other  of  these  two  methods  is  adopted,  the  contents  of  the  trap, 
particularly  in  the  case  of  a  round-pipe  trap,  are  likely  to  be  siphoned 
over  when  its  fixture  is  used  or  when  a  large  volume  of  water  is  dis- 
charged from  some  other  fixture  into  the  soil-pipe,  and  in  its  descent 
causes  a  partial  vacuum.  In  the  former  case,  the  trap  is  self-siphoned ; 
in  the  latter,  the  partial  vacuum  draws  the  water  over  and  breaks  the 
seal.  If  the  trap  communicates  with  a  ventilating  pipe,  this  disturb- 
ance of  equilibrium  cannot  occur,  since  the  descending  mass  of  water 
causes  a  downward  suction  of  air  through  the  vent  pipe  to  satisfy 
what  would  otherwise  be  a  partial  vacuum.     In  Fig.  67,  the  diagram 


Fig. 


Improper  and  proper  positions  of  vent  pipes. 

on  the  right  shows  the  condition  after  siphonage  has  occurred ;  the 
greater  part  of  the  water  has  been  drawn  over  until  air  can  be  sucked 
through,  and  that  which  remains  has  fallen  back  into  place.  The 
result  is  that  a  free  communication  exists  between  the  fixture  above 
and  the  soil-pipe  below.  The  diagram  on  the  left  shows  the  condition 
of  the  seal  if  the  trap  is  connected  with  a  ventilating  pipe  through  V. 

In  venting  traps  in  this  way,  the  position  of  the  vent  pipe  is  of 
considerable  importance.  Ordinarily,  it  is  placed  as  shown  in  the 
figure.  The  objection  to  this  procedure  and  the  proper  method  are 
shown  in  Fig.  68.  If  the  pipe  enters  in  the  middle  of  the  bend,  each 
discharge  of  sewage  into  the  trap  causes  a  projection  of  the  liquid 
upward  into  the  pipe  V,  and  after  a  time  an  accumulation  is  likely 
to  occur  at  A.  If  the  pipe  is  situat('<l  fiirther  to  th(!  right,  as  in  the 
drawing  on  the  right,  this  afcuiniulatiou  is  not  likely  to  occur,  and 


468 


HABITATIONS,  SCHOOLS,  ETC. 


the  sewage  and  the  air  take  the  directions  indicated  by  the  arrows. 
The  vent  pipe  is  more  easily  joined  to  the  trap,  however,  in  the  man- 
ner to  which  objection  is  made. 

The  ventilating  pipes  from  the  different  traps  of  a  system  of 
plumbing  connect  with  a  main  ventilating  pipe,  which  may  be  joined 
to  the  soil-pipe,  alongside  of  which  it  runs,  at  a  point  in  its  upper 
part,  before  its  projection  through  the  roof.      It  is  important  that  the 

junction  of  each  vent  pipe  with  the 
Fig.  69.  main  shall  be  at  a  point  above  the 

fixture,  since,  in  case  of  an  ob- 
struction in  the  soil-pipe  below,  the 
water  may  back  up  through  the 
trap  and  discharge  through  the  vent 
pipe  iuto  the  main  vent,  as  shown 
in  Fig.  69.     Here,  the  soil-pipe  S 

Fig.  70. 


Improper  junction  of  vent  pipe  with  main  vent. 


Sanitas  trap  (taken  apart). 


has  been  obstructed  at  a  point  just  below  the  entrance  of  the  waste- 
pipe  from  the  fixture,  and  water  has  accumulated  throughout  the 
entire  length  of  waste-pipe  and  is  discharging  into  the  main  venti- 
lating pipe  at  V.  If  the  point  V  were  higher  than  the  upper  margin 
of  the  bowl,  this  could  not  occur,  since  the  bowl  itself  would  fill  and 
overflow  into  the  room,  and  thus  call  attention  to  the  obstruction. 

Non-siphoning  Traps. — A  number  of  traps  known  as  non-siphoning 
have  been  devised  to  obviate  the  necessity  of  back-venting.     Among 


PLUMBING. 


469 


these  may  be  mentioned  the  "  Sanitas,"  invented  by  Mr.  J.  Pickering 
Putnam,  and  the  "  Hydric." 

The  Sauitas  trap,  shown  in  Fig.  70,  is  made  proof  against  siphonic 
action  by  a  deflecting  partition  within  the  chamber,  which  permits  the 
passage  of  air  above  the  water  and  throws  back  a  volume  of  water 
sufficient  to  maintain  a  seal  over  three  inches  in  depth,  which  resists 
evaporation  for  a  long  time  and  cannot  be  destroyed  by  capillary  at- 
traction. When  attached  to  fixtures  with  large  outlets  and  quick  dis- 
charge, it  is  also  self-cleansing,  even  when  ashes  and  similar  unusual 
constituents  of  sewage  are  thrown  into  it.  In  the  figure,  the  several 
parts  are  shown  separately  :  the  main  structure,  the  chamber,  and  the 
deflecting  partition.  . 

The  Hydric  trap,  shown  in  Fig.  71,  contains  no  deflecting  partition 
or  other  mechanical  device,  but  depends  upon  the  action  of  the  upper 
surface  of  the  body  of  the  trap  in  deflecting  and  throwing  back  the 
water  during  the  sucking  of  the  air  through  the  chamber  and  over  the 

Fig.  71. 


Hydric  trap. 


water.  When  the  siphoning  action  is  finished,  a  sufficient  volume  of 
water  remains  to  form  a  permanent  seal. 

Evaporation  of  the  seal  does  not  commonly  occur  except  after  long 
disuse.  It  is  favored  by  trap  ventilation,  since,  when  a  current  of  air 
comes  in  constant  contact  with  a  body  of  water,  constant  absorption 
is  in  process.  In  order  to  prevent  loss  by  evaporation  in  case  of  long 
disuse,  two  processes  are  in  vogue.  One  is  to  employ  a  trustworthy 
person  to  visit  the  premises  weekly  during  the  absence  of  the  occupants 
and  flush  each  fixture.  The  other,  and,  on  the  whole,  the  more  eco- 
nomical, is  to  pour  into  each  fixture  a  sufficient  amount  of  glycerin, 
which,  being  hygroscopic,  will  take  water  from  rather  than  yield  it  to 
the  atmosphere,  or  of  oil,  which  will  float  on  the  surface  of  the  water 
and  prevent  its  absorption  by  the  air. 

Back  pressure  is  a  force  which  is  not  much  to  be  feared.  In  former 
times,  v/hen  it  was  not  customary  to  ventilate  the  soil-pipe,  back  press- 
ure was  caused  not  uncommonly  by  winds  and  the  action  of  tides,  so 
that  thf  air  in  the  whole  plumbing  system  was  compressed  and  the  seal 


470  HABITATIONS,  SCHOOLS,  ETC. 

forced  backward.  Sometimes,  a  trap  situated  near  the  bottom  of  a  tall 
stack  is  forced  by  back  pressure,  brought  about  by  the  descent  of  a 
column  of  water  pressing  the  contained  air  ahead  of  it. 

Leakage  as  a  cause  of  loss  of  seal  is  too  evident  to  require  explana- 
tion. Accumulation  of  sediment  may  be  so  extensive  as  to  replace  the 
water  in  great  part,  and  thus  render  siphoning  much  easier.  Capillary 
attraction  is  a  not  infrequent  cause  of  loss  of  seal  when  accumulations 
of  hair,  threads,  and  other  like  substances  occur  in  a  non-scouring  trap 
at  the  outlet  and  drain  away,  little  by  little,  the  fixture  side  of  the  seal 
into  the  outfall. 

It  is  hardly  necessary  to  say  that  nothing  should  be  thrown  into 
traps  excepting  those  matters  which  are  recognized  as  constituents  of 
normal  sewage,  that  is  to  say,  neither  matches,  nor  rags,  nor  broken 
china,  nor  wads  of  newspaper,  nor  stiif  writing  paper  not  easily  dis- 
integrated by  the  action  of  water.  All  such  substances  are  likely  not 
only  to  clog  traps  and  break  the  seal,  but  also  to  form  obstructions  in 
soil-pipe,  particularly  where  bends  occur. 

The  extremists  who  cling  to  the  sewer-air  theory  of  transmission  of 
disease  are  not  always  satisfied  with  ordinary  trapping,  feeling  sure 
that  the  water  in  one  branch  of  the  trap  will  absorb  disease  germs 
from  the  sewer  air  and  discharge  them  on  the  fixture  side.  To  avoid 
this,  a  system  of  double  trapping  has  been  advocated,  with  which  assur- 
ance is  made  doubly  sure.  With  this  arrangement,  we  have  two  traps 
in  immediate  succession,  so  that  the  waste  from  the  first  must  pass 
through  the  second ;  thus  we  have  two  seals,  and  any  poison  absorbed 
from  the  farther  one  and  disengaged  backward  will  then  meet  with  a 
second  obstruction.  Besides  the  manifest  absurdity  of  such  extreme 
precaution,  there  is  a  decided  objection  to  this  arrangement,  since  solid 
matters  are  likely  to  lodge  in  the  second  trap  and  cause  it  to  be  ob- 
structed. While  the  head  of  water  may  be  sufficient  to  drive  the  waste 
through  one  trap,  it  is  by  no  means  certain  that  it  will  be  strong 
enough  to  drive  it  through  two,  and,  as  a  matter  of  fact,  it  usually 
is  not.  Moreover,  between  the  two  traps  an  air  lock  is  likely  to 
form,  and  that  in  itself  is  a  decided  objection,  as  has  been  explained. 

Water-closets. — By  reason  of  the  fact  that  their  general  employ- 
ment is  a  matter  of  comparatively  recent  times,  it  is  believed  very  com- 
monly that  water-closets  are  the  invention  of  the  last  half  century. 
They  date  back,  however,  many  centuries,  for  in  a  somewhat  simpler 
form  they  were  in  use  in  ancient  Rome  and  Pompeii,  and  probably 
even  earlier  in  Asia  and  Africa.  These  primitive  forms,  however,  were 
devoid  of  the  mechanical  appliances,  flushing  tanks,  etc.,  of  the  closets 
of  the  present  day.  It  is  said  that  the  prototype  of  the  present  closet 
was  in  use  in  France  and  Spain  before  the  sixteenth  century,  but,  so 
far  as  is  known,  no  diagrams  of  their  construction  are  extant.  In 
England,  the  first  water-closet  with  a  flushing  apparatus  was  constructed 
under  the  direction  of  Sir  John  Harington,  at  his  country  seat  at  Kel- 
ston,  near  Bath,  and  described  by  him  in  a  satirical,  semi-political 
work,  "An  Anatomy  of  the  Metamorphosed  Ajax,"  printed  in  1596, 


PLVMBING. 


471 


from  which  work  Figs.   72  and  73  are  taken.     Fig.    72   shows   the 
details  of  the  apparatus  described  by  him  as  follows  : 


Fig.  72. 


.te^\V\\\\\\^vvv\v\vvv\vvv\\v^^^O^^ 


Reduced  facsimile  of  the  oldest  known  (1596)  drawing  showing  details  of  a  water-closet. 

"  Here  are  the  parts  set  down  with  a  rate  of  the  prices,  that  a  builder 
may  guess  what  he  hath  to  pay. 

s     d 

"  A  the  cistern  ;  stone  or  brick.      Price 6     8 

b,  d,  e  the  pipe  that  comes  from  the  cistern,  with  a  stopple  to 

the  washer 3     6 

c  a  waste-pipe 1     0 

/,  g  the  stem  of  the  great  stopple,  with  a  key  to  it 1     6 

h  the  form  of  the  upper  brim  of  the  vessel  or  stool-pot  .    .    . 

m  the  stool-pot,  of  stone 8    0 

n  the  great  brass  sluice,  to  which  is  three  inches  current  to 

send  it  down  a  gallop  into  the  Jax 10    0 

i  the  seat,  with  a  peak  devant  for  elbow-room.  The  whole 
charge  thirty  shillings  and  eight  pence  ;  yet  a  mason  of  my 
masters  was  offered  thirty  pounds  for  the  like.  Memoran- 
dum.    The  scale  is  about  half  an  inch  to  a  foot." 

Fig.  73  shows  the  apparatus  set  up  and  during  flushing.  "  Here  is 
the  same  all  put  together  ;  that  the  workman  may  see  if  it  be  well.  A 
the  cistern.  B  the  little  washer,  c  the  waste-pipe.  D  the  seat  board. 
e  the  pipe  that  comes  from  the  cistern.  /  the  screw,  g  the  scallop 
shell,  to  cover  it  wh(!n  it  is  shut  down.  lithe  stool  pot.  i  the  stopple. 
k  tlu;  current.  I  the  sluice,  m,  N  th(!  vault  into  whi(^h  it  falls  ;  always 
remember  that  (  )  at  noon  and  at  night  empty  it,  and  leave  it 


472 


HABITATIONS,  SCHOOLS,  ETC. 


half  a  foot  deep  in  fair  water.     And  this  being  well  done,  and  orderly- 
kept,  your  worst  privy  may  be  as  sweet  as  your  best  chamber." 

We  have  evidence  that  even  among  peoples  not  classed  among  the 
highly  civilized,  the  use  of  water-closets  is  by  no  means  of  recent  date. 
Thus,  Ogilby  in  his  elaborate  work  on  Africa,  published  in  1670,  de- 
scribing the  city  of  Fez,  says,  on  page  187  :  "The  River  Fez  which 
Paulus  Jovius  calls  Rhasalme,  passes  through  the  City  in  two  Branches  ; 
one  runs  Southward  towards  New  Fez,  and  the  other  West ;  each  of 
these  subdividing  into  many  other  clear  running  Channels  through  the 
Streets,  serving  not  onely  each  private  House,  but  Churches,  Inns, 

Fig.  73. 


Companion  to  Fig.  72,  showing  parts  put  together. 


Hospitals,  and  all  other  publick  Places  to  their  great  conveniences. 
Round  about  the  Mosques  are  a  hundred  and  fifty  Common-Houses  of 
Easement,  built  Four-square  and  divided  into  Single-Stool-Rooms,  each 
furnished  with  a  Cock  and  a  Marble  Cistern,  which  scoureth  and  keeps 
all  neat  and  clean,  as  if  these  places  were  intended  for  some  sweeter 
Employment." 

The  water-closets  of  the  present  day  may  be  divided  into  two  classes  : 
those  having  movable  internal  mechanism,  and  those  having  none.  To 
the  former  class  belong  the  plunger,  or  plug,  closet,  the  pan  closet,  and 
a  number  of  others ;  to  the  latter  belong  the  hopper  closet,  the  various 
w^ash-out  closets,  the  siphon  closets,  and  the  siphon  jet  closets.  To 
attempt  to  describe  all  the  different  forms  on  the  market  would  be  a 
tedious  and  useless  task,  for  the  patented  devices  alone  run  up  into  the 


PLUMBING. 


473 


hundreds.  Therefore,  in  the  following  pages,  only  those  which  may- 
be taken  as  types  of  the  worst  and  best  will  be  described.  First  will 
be  described  those  of  distinctly  objectionable  construction.  These  in- 
clude a  number  which,  while  they  are  no  longer  introduced  in  com- 
munities having  modern  plumbing  regulations,  exist  in  thousands  of 
houses,  into  which  they  were  introduced  at  a  time  when  they  were  re- 
garded as  absolutely  perfect. 

The  Pan  Closet. — The  principle  of  this  apparatus  is  shown  in  Fig. 
74,  which  is  a  vertical  section  of  the  working  part  of  the  closet,  free 
from  the  cabinet  work  in  which  it  is  usually  enclosed.  It  consists  of 
a  hopper  H,  provided  with  a  flushing  rim  and  closed  at  its  outlet  by 
means  of  a  hinged  pan  P,  which  is  released  by  a  mechanism  which  it 


Fig.  74. 


Pan  closet. 


is  unnecessaiy  to  illustrate  or  explain.  When  the  pan  is  in  the  hori- 
zontal position,  it  is  partly  filled  with  water,  into  which  the  excreta 
are  discharged,  although  ordinarily  they  come  in  contact  first  with  the 
surface  of  the  hopper  above  the  water  level.  The  closet  is  emptied 
by  pulling  a  knob  or  handle  which  releases  the  pan,  which  then  takes 
the  position  shown  in  the  figure  by  the  dotted  lines.  The  contents 
are  thus  thrown  into  the  lower  chamber,  and  fall  into  the  trap  below. 
The  mechanism  which  releases  the  pan  also  starts  a  flush  of  water 
through  the  flushing  rim  over  the  surface  of  the  hopper.  This  flush 
is  supposed  to  scour  the  interior  and  to  be  sufficiently  voluminous  to 
drive  the  excreta  over  the  bend  of  the  trap  and  forward  toward  the 
soil-pipe.  When  the  pan  is  brought  back  to  its  original  place,  the 
flush  continues  until  the  pan  is  filled  to  the  same  level  as  before. 

As  a  matter  of  fact,  the  flush  of  these  closets  is  ordinarily  little 


474 


HABITATIONS,  SCHOOLS,  ETC. 


better  than  a  mere  dribble.  The  front  wall  of  the  receiving  chamber, 
against  which  the  excreta  are  thrown  by  the  pan  in  its  descent,  is 
invariably  in  a  filthy  condition,  which  cannot  be  improved  by  any 
amount  of  such  flushing  as  the  apparatus  is  capable  of  giving.  The 
consequence  is  that  each  time  the  pan  is  dropped,  a  volume  of  foul 
air  is  displaced  upward  into  the  room.  The  inlet  side  of  the  trap  is 
commonly  a  miniature  cesspool,  since  the  flush  has  so  little  head  that 
it  is  unable  to  drive  objects  of  lighter  specific  gravity  than  that  of 
water  through  the  trap.  In  the  illustration,  8  represents  what  is 
known  as  a  "  safe  "  to  catch  all  drippings  from  any  source,  and  from 
this,  the  pipe  s  conducts  them  to  the  bend  of  the  trap.  This  whole 
contrivance,  formerly  the  pride  of  the  plumber's  craft,  is  now  gener- 
ally and  justly  regarded  as  an  abomination. 

The  Plunger,  or  Plug,  Closet. — This  apparatus,  shown  in  Fig.  75,  is 
far  less  objectionable  than  the  pan  closet.     It  consists  of  a  receiver  B, 

Fig.  75. 


Plunger  closet. 

in  which  a  large  volume  of  water  can  be  retained  when  the  plunger,  or 
plug,  A,  is  in  place.  When  A  is  lifted,  the  contents  of  B  escape 
downward  into  the  trap,  which  is  vented  at  V.  The  plunger  A  not 
only  controls  the  emptying  of  the  receiver,  but  also  acts  as  a  standing 
overflow,  for  should  the  water  in  the  reservoir  rise  higher  than  the 
upper  level  of  the  plunger,  it  will  flow  over  into  A,  and  from  it 
through  G  into  the  trap.  This  fixture  requires  a  large  amount  of 
water  in  order  to  obtain  a  proper  flush,  for  unless  the  flush  is  gener- 
ous, bits  of  paper  and  other  material  may  adhere  to  the  edge  of  the 
outlet,  so  that  when  the  plunger  is  in  place  the  valve  is  not  tight. 
Naturally,  with  a  loose  joint,  the  contents  of  the  receiver  will  ooze 
away  and  leave  it  in  a  dry  condition. 

These  two  forms  sufiice  as  illustrations  of  the  objectionable  class  of 


PLUMBING.  ^"ib 

closets,  and  it  may  be  said,  in  general,  that  all  closets  depending  upon 
internal,  mechanical,  movable  parts  are  objectionable,  and  all  of  them 
are  likely  to  become  exceedingly  foul. 

A  properly  constructed  water-closet  should  have  a  flush  of  water 
that  will  wash  the  whole  of  the  interior  surface  of  the  bowl  most 
thoroughly,  carry  onward  all  the  filth  and  other  material  beyond  the 
trap,  and  leave  the  bowl  filled  to  the  proper  height  with  clean  water. 
It  should  be  cleaned  so  thoroughly  every  time  it  is  used,  that  no  filth 
may  remain  deposited  at  any  point,  and  it  should  be  free  from  dis- 
agreeable odor. 

Hopper  Closet. — The  simplest  form  of  non-mechanical  closets  is 
known  as  the  Hopper,  which  is  shown  in  Fig.  76.  The  illustra- 
tion hardly  needs  explanation,  the  device  consisting  of  a  hopper  con- 
nected with  a  simple  S-trap,  ventilated  in  the  usual  way.  Hoppers 
are  known  variously  as  short  and  long.  The  long  variety  presents  no 
advantage  over  the  short,  and  is  kept  much  less  easily  in  proper  con- 
dition. The  long  hopper  has  its  trap  beneath  the  floor  ;  the  short  hop- 
per, above  it.     The  short  hopper  is 

less  likely  to  become   foul,   on  ac-  Fig.  76. 

count  of  the  smaller  surface  pre- 
sented, and  because  the  level  of  the 
water  in  the  trap  is  nearer  the  seat. 
The  hopper  should  be  provided  with 
a  generous  flush  from  a  flushing  rim, 
for  otherwise  it  is  likely  to  become 
foul,  since,  from  the  shape  of  the 
receiver,  fouling  of  its  posterior 
interior  surface  is  inevitable.  This 
is  more  marked  with  the  long  than 
with  the  short  hopper.  Unless  the 
flush  is  a  generous  one,  it   is  neces-  Hopper  closet. 

sary  to  pour  down  an  occasional 
pailful  of  water,  and  also  to  apply  the  closet  brush  at  least  daily. 

Open  Wash-out  Closets.— The  open  wash-out  closet  is  designated 
variously  as  front  or  back  or  side  wash-out,  according  to  the  direction 
which  the  contents  of  the  bowl  take  toward  the  trap.  In  Fig.  77  is 
shown  a  front  wash-out  in  vertical  section.  The  bowl,  provided  with 
a  flushing  rim  F  fed  by  the  supply  pipe  P,  holds  a  pool  of  water,  into 
which  the  excreta  are  projected.  The  greatest  depth  of  this  volume 
should  not  exceed  1.75  inches.  In  use,  the  contents  of  the  bowl  are 
swept  by  the  water  from  the  flushing  rim  into  the  trap  S,  which  is 
ventilated  at  V  in  the  usual  manner,  and  the  flow  is  sufficiently  volu- 
minous to  force  the  excreta  down  and  under  the  partition. 

W  the  volume  of  water  in  the  bowl  is  deeper  than  above  stated,  it  is 
possible  that  the  flush  may  sweep  beneath  any  floating  excreta,  which, 
in  consequence,  may  be  retained.  If  no  pool  at  all,  or  only  a  very 
much  shallower  one,  be  kept,  the  excreta  may  adhere  to  the  basin  with 
such  tenacity  that  they  are  not  easily  dislodged  by  a  single  flush.     For 


476 


HABITATIONS,  SCHOOLS,  ETC. 


the  wash-out  closet,  it  was  intended  to  secure  the  combined  advantages 
of  the  hopper  and  the  phinger  closets,  that  is,  the  advantage  of  a  large 
surface  of  water  in  the  bowl  in  addition  to  that  in  the  trap,  without 
the  intervention  of  any  mechanical  contrivance.  The  objections  to  the 
wash-out  closets  are  :  (1)  that  the  principal  office  of  the  flush  is  the 
cleansing  of  the  basin ;  (2)  that  after  each  using,  the  excreta  and  paper 
are  Ukely  to  remain  in  the  inlet  side  of  the  trap  until  the  fixture  is 
used  again ;  and  (3)  that  the  surface  against  wdiich  the  excreta  are 
thrown  during  the  flushing  is  likely  to  become  fouled  and  remain  so 
until  cleaned  mechanically  by  means  of  a  brush  or  other  appliance. 

Another  form  of  wash-out  closet  has  the  basin  so  constructed  as  to 
form  a  trap.     Closets  of  this  class  are  much  like  the  hopper,  but  hold 

Fig.  77. 


Open  wash-out  closet. 

a  much  greater  depth  of  water.  They  are  known  more  commonly  as 
"wash-down"  closets.  In  both  the  wash-out  and  the  wash-down 
closets,  the  lip  of  the  trap  should  dip  not  less  than  1.5  inches  beneath 
the  water  level ;  less  than  that  increases  the  risk  of  loss  of  seal  by 
evaporation,  and  more  requires  a  larger  flush  than  is  ordinarily  obtain- 
able to  force  the  excreta,  etc.,  downw^ard  and  onward. 

Siphon  Closets. — Another  type  of  wash-down  closet  is  known  as  the 
siphon  jet  In  this,  the  contents  of  the  receiver  are  drawn  out  by 
siphonage,  and  at  the  same  time  are  propelled  by  a  jet  of  water  from 
the  front.  In  Fig;.  78,  one  of  these  closets  is  shown.  Here  the 
chamber  is  divided  into  two  sides  of  a  trap  by  the  partition  S.  As 
the  flush  is  brought  into  play,  a  jet  of  water  comes  down  with  some 
force  through  A  and  pushes  the  contents  of  B  over  into  the  chamber 
C,  and,  as  the  flush  continues,  the  chamber  C  becomes  the  long  leg  of 


PLUMBING. 


477 


a  siphon,  so  that  when  the  flush  ceases  to  act,  the  siphon  continues  to 
suck  out  the  contents  of  the  receiver  until  the  water  level  is  brought 
down  to  the  point  ^S',  when  air  is  admitted  and  the  siphon  becomes 
thereby  broken.     The  after-flush   raises  the  water  level  again  to  its 

original  point. 

Fig.  78. 


(mm^ 


Siphon  jet  closet. 


Another  form  of  siphon  closet,  which  acts  without  the  assistance  of  a 
jet  is  known  as  the  Dececo.  This  is  a  very  simple  and  efficient  fixture, 
invented  by  the  late  Colonel  George  E.  Waring,  Jr.  The  receiver  is 
very  deep,  and  maintains  several  inches  of  seal.  The  apparatus  is 
shown  in  Fig.  79,     To  assist  in  charging  the  siphon,  a  weir-chamber, 


Fig.  79. 


Fig.  80. 


Dececo  closet. 


Sanitas  closet. 


situated  below  the  receiver  and  just  beneath  the  floor,  is  employed. 
When  the  flush  is  set  in  action,  the  water  in  the  basin  overflows  and 
falls  into  the  weir-chamber  below.  This  has  a  constricted  outlet, 
which  is  closed  very  quickly  by  the  descending  water,  and  thereby  the 


478 


HABITATIONS,   SCHOOLS,    ETC. 


entrance  of  air  from  the  soil-pij)e  side  is  prevented.  As  the  water 
rushes  into  the  long  leg  of  the  siphon,  it  pushes  the  contained  air 
onward,  the  leg  is  soon  filled  with  water,  and  the  siphon  is  completed. 
AVhen  the  contents  of  the  bowl  have  been  sucked  down  to  the  lower 
border  of  the  partition,  the  siphon  it  broken  by  the  admission  of  air  at 
that  point,  and  the  bowl  is  then  refilled  by  the  after-flush. 

Still  another  efficient  form  of  closet  is  the  Sanitas,  shown  in  Fig.  80. 
In  this  apparatus,  invented  by  Mr.  J.  Pickering  Putnam,  the  flush  is 
accomplished  by  the  pressure  of  water  in  the  supply  pipe.  This  pipe 
enters  the  bowl  below  the  normal  water  level  and  stands  permanently 
full  through  its  entire  length  up  to  the  cistern.  The  water  is  held  in. 
the  pipe  by  atmospheric  pressure.  The  upper  end  of  the  pipe  is  closed 
by  the  cistern  valve,  and  the  lower  end  by  the  water  beneath  the  water 
level  of  the  receiver.  The  lower  portion  of  the  supply  pipe  is  perfo- 
rated at  two  different  points,  through  the  first  of  which,  water  is  sup- 
plied to  the  flushing  rim,  and  through  the  second,  a  jet  is  set  in  action, 
as  in  the  ordinary  siphon  jet  closet.  When  the  flush  is  set  in  opera- 
tion, the  cistern  valve  is  opened,  and  the  water  descends  and  escapes 
through  the  two  outlets ;  through  the  upper,  the  passage  leading  to  the 
flushing  rim  is  filled,  and  through  the  lower,  the  water  is  projected 
from  the  bottom  of  the  receiver  up  into  the  siphon.  The  action  is 
very  quick  and  practically  without  noise.  "When  the  cistern  valve 
is  again  closed,  the  water  ceases  to  escape  through  the  openings, 
and  that  in  the  flushing  rim  and  passages  leading  thereto  falls  back 
into  the  bowl  and  restores  the  normal  level. 

Flushing  Apparatus. — The  object 
of  a  flushing  apparatus  is  the  thorough 
removal  of  all  adhering  excreta  from 
the  sides  of  the  fixture,  and  its  propul- 
sion through  and  beyond  the  trap.  The 
flushing  rim  is  connected  with  a  supply 
pipe  of  about  1.25  inches  diameter, 
connected  with  the  cistern.  Through 
this  pipe,  the  water  is  delivered  with  a 
rush,  and  is  spread  out  by  the  flushing- 
rim  in  small  jets  against  the  sides  of 
the  bowl.  With  some  forms  of  flushing 
cisterns,  the  flush  continues  as  long  as 
the  lever  which  opens  the  valve  is  held 
down  or  until  the  cistern  is  emptied 
completely. 

Another    form    of    flushing    cistern 
is    known    as    the    siphon    tank,    the 
valve  of  which   is  shown  in  Fig.  81. 
This    consists    of    a    double    tube,    A 
Valve  of  siphon  tank.  and   B,  the   inner  tube   A   being  the 

longer,  and   the  two  tubes   forming  a 
siphon.       The  lower  end  of  the  long  leg  of  the  siphon  A  rests  on 


Fig 


PLUMBING. 


479 


a  rubber  ring  at  C,  and  forms  the  valve.  The  siphon  is  started  in 
operation  by  lifting  the  valve  off  its  seat  by  means  of  a  chain  fastened 
to  the  ring  in  the  cap  E.  The  water  rushes  downward  through  the  flush 
pipe  F,  sucks  the  air  out  of  A,  and  fills  the  siphon  with  water.  The 
valve  is  then  dropped  back,  and  the  discharge  continues  flowing  into 
the  siphon  at  D,  and  downward  through  A,  as  indicated  by  the  arrows. 
The  discharge  continues  until  the  level  of  the  water  is  brought  down 
to  the  point  D,  when,  air  being  sucked  in,  the  siphon  is  broken.  With 
this  apparatus,  the  flush  tank  is  emptied  every  time  the  fixture  is  used, 
and  the  valve  needs  to  be  opened  only  long  enough  to  start  the  siphon 
in  motion,  which  object  is  accomplished  in  a  few  seconds. 

Still  another  form  of  flushing  apparatus  is  shown  in  Fig.  82.  This 
is  employed  to  furnish  a  large  flush  and  a  small  after-flush,  by  means 
of  which  the  bowl  of  the  fixture  may  receive  water  after  the  main 


Fig.  82. 


Flushing  tank. 

flushing  has  been  accomplished.  The  tank  is  divided  into  two  cham- 
bers, A  and  B.  The  valve  F,  worked  by  chain  and  lever,  is  4  inches 
in  diameter.  When  opened,  it  discharges  water  more  rapidly  than  it 
can  flow  through  the  pipe  E,  and,  in  consequence,  the  surplus  fills  the 
chamber  B.  When  the  valve  is  closed,  the  main  flush  ceases,  and  a 
smaller  flow  continues  until  the  chamber  B  is  emptied.  At  the  point 
0,  is  the  overflow  for  the  chamber  A  into  B. 

A  flushing  tank  should  contain  not  less  than  4  gallons,  and,  except 
in  the  case  of  the  Sanitas  closet,  should  be  not  less  than  6  feet  above 
the  closet  bowl. 

Water-closet  Connections. — The  ordinary  method  of  connecting  a 
modern  water-closet  with  the  soil-pipe  branch  is  by  means  of  what  is 
known  as  a  brass  floor-plate  joint.  The  soil-pipe  branch  is  fastened  l)y 
means  of  solder  to  a  brass  flange,  which  is  screwed  to  the  floor.  The 
closet  flange  is  set  upon  an  intervening  rubber  gasket,  and  the  two  are 
then  screwed  or  bolted  together.     The  common  putty  joint  should  not 


480 


HABITATIONS,   SCHOOLS,   ETC. 


he  used,  for  although  it  may  not  leak  water,  it  is  usually  pervious  to 
air  and  odors.  In  screwing  up  the  porcelain  branch,  great  care  should 
be  taken  to  avoid  breakage.  Some  closets  are  made  in  two  pieces,  the 
bowl  being  of  porcelain,  and  the  trap  of  iron  or  other  metal  with  a 
porcelain  lining.  With  these,  the  danger  of  breakage  is  reduced  to  a 
minimum. 

Urinals. — The  urinal  is  a  fixture  which  should  not  be  tolerated  in  a 
private  house,  since,  with  the  best  of  care,  they  are  almost  inevitably 
offensive  and,  with  ordinary  care,  are  sure  to  be  a  decided  nuisance. 
They  are  necessary  only  in  large  buildings,  and  there  they  require 
abundant  and  frequent  flushing  and  constant  care.  The  waste-pipe  is 
commonly  coated  on  the  interior  as  far  as  the  trap  with  a  deposit  de- 
rived from  the  urine,  and  does  not  yield  it  readily  to  flowing  water. 
The  application  of  washing  soda  or  of  solution  of  ordinary  potash  is 
ineffective,  but  hydrochloric  acid  in  10  per  cent,  strength,  followed 
shortly  by  a  generous  flush  of  water,  will  remove  it.  Weak  sulphuric 
acid,  about  2.5  per  cent.,  is  also  efficient. 

Wash  Basins. — Wash  basins  are  made  of  metal,  as  copper,  enam- 
elled and  galvanized  iron,  and  of  earthenware  and  porcelain.  Most 
commonly,  they  are  of  glazed  earthenware.  In  shape,  they  are  either 
circular  or  oval.  The  latter  form  is  generally  preferred,  as  it  affords 
more  space  for  free  action  of  the  arms  than  a  circular  one  of  the  same 


Fig.  83. 


Fig.  84. 


Wash  basin  with  overflow  horu  discharging 
beueath  plug. 


Wash  basin  with  overflow. 

capacity.  Some  bowls  are  made  with 
a  flushing  rim  at  the  top,  through 
which  hot  and  cold  water  are  intro- 
duced together  on  all  sides,  and  thus 
the  entire  surface  of  the  bowl  is  more 
easily  kept  clean.  In  the  upper  part  of  the  commonest  form  of  basin 
(see  Fig.  83)  a  number  of  perforations  (8)  communicate  with  the  over- 
flow horn  (iJ)  connected  with  the  waste-pipe.  Ordinarly,  these  outlet 
holes  are  unable  to  deliver  water  as  rapidly  as  it  enters  through  a  faucet 
with  moderate  head,  and  consequently  too  much  dependence  should 
not  be  placed  on  them  in  the  prevention  of  overfilling  of  the  basin. 
In  some  bowls,  the  entire  overflow  horn  is  an  integral  part  of  the  fixt- 
ure, opening  just  beneath  the  plug,  as  shown  in  Fig.  84.  Where 
the  horn  does  not  so  extend,  its  junction  with  the  waste-pipe  is  not  in- 
frequently wrongly  made ;  sometimes,  it  is  connected  below  the  trap  ; 
sometimes,  at  the  crown  of  the  trap,  into  or  near  the  vent  pipe.     The 


PLUMBING. 


481 


overflow  horn,  especially  with  long  use  of  the  fixture,  is  very  likely  to 
become  foul,  on  account  of  the  soap  and  filth  which  become  deposited 


Fig.  85. 


Wash  basin  with  standpipe  plug  and  overflow. 

along  its  inner  surface.  In  fact,  the  odor  which  is  ascribed  commonly 
to  "  sewer  gas  "  comes  from  the  horn  and  from  the  waste-pipe  between 
the  bowl  of  the  trap.     Another  source  of  odor  of  much  less  importance 

Fig.  86. 


Improved  standpipe  overflow. 


is  the  chain  attached  to  the  plug.     This  gradually  collects  within  its 
links  the  same  kind  of  deposit,  which  is  removed  completely  only  with 


31 


482  HABITATIONS,  SCHOOLS,  ETC. 

some  difficulty  and  much  scrubbing  with  a  brush.  On  account  of  the 
fouling  of  the  chain  and  the  inconvenience  of  having  it  in  the  way  of 
the  hands,  some  forms  of  basins  are  equipped  with  a  standpipe,  which 
acts  as  plug  and  overflow  at  the  same  time.  In  Fig.  85  such  an 
arrangement  is  shown ;  the  bowl  presents  no  irregularities  of  surface, 
not  even  a  plug.  The  standpipe  jj,  enclosed  in  the  pipe  P,  acts  as  a 
valve  when  it  is  dropped  into  place,  and  the  surplus  water,  rising 
between  P  and  p,  escapes  through  the  holes  in  the  upper  extremity  of 
p.  The  device  is  lifted  by  a  knob,  and  is  kept  off  the  seat  by  means 
of  a  bayonet  catch.     In  the  illustration,  the  plug  is  off  the  seat. 

The  principal  objection  to  this  form  of  waste-valve  is  that  the  outlet 
is  situated  at  a  considerable  distance  from  the  outlet  of  the  bowl,  and 
the  entire  surface  between  these  two  points  is  certain  to  become  foul. 
Furthermore,  small  bits  of  lint  and  hair  are  likely  to  be  deposited  near 
the  seat  and  cause  it  to  leak  so  rapidly  that  the  bowl  cannot  hold  water 
for  any  length  of  tinie.  A  better  form  is  shown  in  Fig.  86.  Here 
the  standpipe  overflow  has  its  seat  directly  in  the  outlet  of  the  basin, 
and  may  easily  be  got  at  and  cleaned. 

Bathtubs. — Bathtubs  are  made  of  various  materials  in  a  number  of 
forms.  The  finest  grade  of  tubs  are  made  of  porcelain  or  of  fine 
earthenware  with  a  heavy  enamel  of  porcelain.  They  are  made  in 
various  shapes  and  very  commonly  are  decorated  somewhat  ornately. 
They  are  very  heavy  and  quite  expensive.  The  plainest  varieties  have 
most  commonly  the  shape  shown  in  Fig.   87.     They  are  usually  set 

Fig.  87. 


Porcelain  or  iron  bathtub. 

upon  slabs  of  marble.  Tubs  of  iron  with  a  lining  of  porcelain  enamel 
also  are  made  in  this  form.  These  are  open  to  the  objection  that  the 
enamel  is  chipped  off  very  easily.  Within  recent  years,  a  cheap  form 
of  tub  in  this  shape,  made  of  ordinary  tin  plate,  has  been  introduced. 
In  spite  of  the  iron  frame  with  which  it  is  surrounded,  it  is  constructed 
very  flimsily. 

The  commonest  form  of  bathtub  used  in  this  country  is  made  of 
tinned  and  planished  copper,  weighing  from  10  to  24  ounces  to  the 
square  foot.  In  Fig.  88,  this  form  of  tub  is  shown  in  vertical  section. 
Inasmuch  as  the  copper  is  to  all  intents  and  purposes  the  lining  of  a 
box,  it  is  necessary,  for  the  sake  of  appearances,  to  have  an  outside 


PL  UMBING. 


483 


casing  of  cabinet  work.  The  ordinary  tub  is  provided  with  a  waste 
plug,  chain,  and  overflow,  as  shown  in  the  figure.  Not  uncommonly,  the 
chain  and  plug  are  supplanted  by  an  ordinary  pipe  of  the  desired  length. 


Fig. 


E^ 


Vertical  section  of  commonest  form  of  bathtub. 


which  fits  into  the  outlet  of  the  tub,  and  thus  acts  both  as  plug  and 
overflow.  In  some  of  the  tubs  of  more  elaborate  construction,  a  stand- 
ing overflow  and  waste-pipe,  shown  in  Fig.  89,  is  used.      In  this,  the 


Fig.  89. 


Standing  overflow  and  waste-pipe. 


overflow  passes  over  and  into  the  pipe  7>  and  escapes  through  the 
bottom.  When  the  tub  is  to  be  emptied,  the  tube  is  lifted,  and  thereby 
the  perforations  at  the  bottom  of  the  inner  tube  A  are  exposed.     On 


484  HABITATIONS,   SCHOOLS,   ETC. 

the  whole,  this  form  is  in  no  way  superior  to  the  ordinary  standing 
overflow,  but  possesses  certain  disadvantages  which  do  not  apply  to 
that  device,  which  can  be  removed  completely  from  the  outlet  each  time 
the  tub  is  emptied. 

Other  forms  of  baths,  including  the  sitz-bath,  foot-bath,  shower- 
bath,  douche,  and  needle-bath,  and  bidets  are  found  ordinarily  only 
in  the  very  elaborately  fitted  bath-rooms  of  the  very  wealthy.  As 
plumbing  appliances  pure  and  sun  pie,  they  possess  no  special  hygienic 
interest,  the  matter  of  waste-pipes,  trapping,  etc.,  differing  in  no  essen- 
tial respects  from  what  has  been  described  in  connection  with  other 
fixtures.  The  shower-bath,  which  consists  mainly  of  a  large  sprinkler 
from  which  water  is  delivered  downward  in  fine  streams,  is  very  com- 
monly set  above  the  ordinary  bathtub,  with  a  screen  of  wood  or  cur- 
tain of  rubber  cloth  or  other  suitable  material  to  prevent  splashing  the 
floor.  Smaller  arrangements,  consisting  of  a  sprinkler,  such  as  is  at- 
tached to  the  nozzle  of  a  watering-pot  and  a  rubber  tube  to  connect 
with  the  faucet  of  the  bathtub,  are  very  commonly  used.  If  desired, 
the  rubber  tube  may  be  attached  to  a  mixing  pipe,  which  in  its  turn  is 
attached  to  both  cold  and  hot  water  faucets,  and  thus  the  temperature 
of  the  shower  may  be  regulated. 

Sinks. — Under  sinks  are  included  pantry  sinks,  kitchen  sinks,  and 
slop  sinks.  These  are  made  of  various  metals,  including  cast-iron, 
enamelled  iron,  steel,  and  copper,  and  of  soapstone,  slate,  earthenware, 
and  porcelain. 

Cast  iron  is  easily  kept  clean  with  ordinary  care,  but  on  account  of 
danger  of  the  breaking  of  dishes  and  other  articles  which  are  washed 
or  otherwise  handled  in  them,  a  grating  of  wood  not  uncommonly  is 
laid  on  the  bottom.  This  easily  becomes  foul,  particularly  if  it  is  al- 
lowed to  stand  in  the  wet  sink  when  not  in  actual  use.  All  such  grat- 
ings should  be  kept  scrupulously  clean,  and  when  not  actually  needed 
in  the  sink,  should  be  hung  up  in  the  air. 

Enamelled  iron  is  much  more  desirable  than  plain  iron,  and  presents 
a  much  better  appearance.  Unfortunately,  however,  the  enamel  is  very 
easily  cracked  and  detached. 

Steel  sinks  are  not  so  durable  as  ordinary  cast  iron,  but  they  are 
light  and  cheap.  They  are  very  commonly  enamelled,  and  then  they 
are  necessarily  open  to  the  objection  above  mentioned. 

Tinned  and  planished  copper  is  much  used  for  pantry  sinks,  which 
are  made  commonly  with  rounded,  but,  better,  with  perfectly  flat  bot- 
toms. The  copper  should  have  a  weight  of  not  less  than  18  to  24 
ounces  per  square  foot. 

In  some  quarters,  soapstone  is  the  favorite  material  for  kitchen  sinks. 
Ordinarily,  it  is  quite  durable,  particularly  if  it  has  been  subjected  to 
a  preliminary  oiling,  but  some  specimens  show  a  tendency  to  disinte- 
grate very  rapidly,  and  to  become  so  pitted  as  to  present  a  honeycombed 
appearance. 

Earthenware  sinks  are  thick  and  heavy,  and  present  no  advantages 
over  soapstone. 


PLUMBING.  485 

Porcelain  is  expensive,  and,  if  thin,  is  easily  broken.  It  is  not 
extensively  used  in  ordinary  sinks. 

All  sinks  should  be  provided  with  a  not  too  fine  strainer  over  the 
outlet.  Kitchen  and  pantry  sinks  are  connected  best  with  a  grease 
trap.  The  common  practice  of  constructing  cupboards  or  closets  be- 
neath sinks  should  be  discouraged,  since  these  spaces  are  commonly 
maintained  as  clutter-holes  in  which  to  store  unwashed  pots,  kettles, 
and  other  utensils,  which,  in  unclean  condition,  would  not  be  tolerated 
in  positions  where  they  are  open  to  inspection. 

House-maids'  sinks,  commonly  known  as  slop  sinks,  are  located 
generally  in  small,  dark,  unventilated  closets  in  the  upper  story. 
This  form  of  fixture  is  made  rather  deeper  than  an  ordinary  sink,  and 
is  sometimes  shaped  like  a  hopper.  They  are  made  best  with  a  flush- 
ing rim,  which  will  assist  in  keeping  the  entire  surface  clean  and  free 
from  odor.  On  account  of  the  nature  of  the  refuse  poured  into  these 
receptacles,  and  because  of  the  great  probability  of  the  occurrence  of 
splashing  when  vessels  are  emptied,  these  sinks  are  often  extremely 
foul,  and  the  closets  in  which  they  are  placed  are  then  always  neces- 
sarily offensive.     The  greatest  care  is  necessary  to  insure  cleanliness. 

Laundry  Tubs. — Laundry  tubs  are  made  of  practically  the  same 
materials  as  sinks.  The  cheapest  kind  is  made  of  stout  planking^ 
with  well-fitting  joints  drawn  tight  by  iron  bolts.  This  form  is  not 
very  durable,  since  the  alternate  drying  and  wetting  soon  ruins  the 
joints  and  causes  the  wood  to  decay.  Those  made  of  porcelain  and 
earthenware  are  heavy  and  expensive,  but  are  very  durable  and  readily 
kept  clean.  The  soapstone  tub  is  regarded  generally  as  the  most  satis- 
factory, but  it  should  be  made  of  material  of  the  best  quality,  since 
otherwise  it  is  liable  to  chip  and  crack  off  from  constant  contact  with 
hot  water.  All  enamelled  tubs  are  likely  to  lose  their  enamel,  which 
is  separated  easily  from  the  metal  and  chipped  off. 

House  Service  Tanks. — With  most  plumbing  systems,  it  is  essen- 
tial that,  in  the  upper  part  of  the  building,  above  the  highest  fixture, 
there  shall  be  a  service  tank  to  feed  the  hot-water  boiler  and  the  vari- 
ous flushing  cisterns  connected  with  water-closets  and  other  fixtures. 
These  tanks  are  commonly  placed  in  positions  where  access  to  them  is 
not  easy,  and,  in  consequence,  they  are,  as  a  rule,  examined  very  infre- 
quently. No  matter  how  carefully  they  are  covered  and  regardless  of 
the  kind  of  water  that  enters  them  for  storage,  they  accumulate  more 
or  less  dust,  dirt,  organic  matter,  and  other  sediment.  All  this  adheres 
to  and  accumulates  on  the  bottom,  forms  a  slimy  coat  uj)on  the  sides, 
and  there  remains  until  removed  by  some  external  force.  It  is  hardly 
necessary  to  say  that  this  condition  should  Aot  be  permitted.  The  tank 
should  be  inspected  periodically  and  thoroughly  cleaned.  Fortunately, 
it  is  neither  necessary  nor  customary  in  ordinary  dwellings  to  use  water 
from  the  service  tank  either  for  drinking  or  for  cooking,  since  the  cold- 
water  service  pipes  connect  directly  with  the  street  main,  and  are  tapped 
at  intervals  with  faucets  and  terminate  at  tlie  tank,  where  their  delivery 
is  regulated  by  means  of  ball-oocks.     Inasmuch  as  the  water  from  the 


486  HABITATIONS,  SCHOOLS,  ETC. 

tank  is  not  used  for  drinking  and  cooking,  excepting  in  houses  not  con- 
nected with  the  public  supply,  but  served  from  a  tank  filled  periodically 
by  pumping,  it  makes  no  very  great  difference  from  a  hygienic  stand- 
point of  what  material  the  tank  is  built.  A  very  good  tank  is  made 
of  riveted  iron  plates  lined  with  cement  of  proper  quality.  Wooden 
tanks  are  much  used,  and  give  satisfaction  if  they  are  kept  full  and 
clean.  The  tank  which,  on  the  whole,  is  most  satisfactory  is  constructed 
of  wood,  with  the  sides  secured  to  the  ends  by  long  bolts,  and  lined 
with  tinned  copper  of  good  weight.  Lead  forms  a  poor  lining,  for  it  is 
coiroded  easily  by  water.  Gralvanized  iron  and  sheet  zinc  also  make 
poor  lining  material.  In  large  office  buildings  in  which  all  the  fixtures, 
including  those  from  which  water  for  drinking  is  obtained,  are  supplied 
from  a  main  tank  in  the  upper  story,  it  is  advisable  that  the  lining  of 
the  tank  should  be  of  tinned  copper,  and  under  no  circumstances  should 
it  be  of  lead. 

Service  Pipes. — The  method  of  installing  the  water  service  is  of 
slight  interest  to  the  hygienist  and  requires  no  discussion,  the  nature 
of  the  pipes  having  been  considered  in  another  chapter ;  but  there  is 
one  minor  trouble  connected  with  them  which  may  be  a  cause  of 
great  annoyance,  especially  to  persons  of  nervous  or  irritable  nature. 
This  trouble  is  commonly  known  as  v-cder-hammer,  and  is  something 
more  than  an  annoyance,  since  its  occurrence  has  a  weakening  eifect 
on  the  entire  pipe  system.  This  is  the  quivering  and  rattling  that 
occur  from  eud  to  end  when  the  current  of  water  within  them  is 
checked  suddenly  by  the  quick  closure  of  a  cock  or  valve.  In  order 
to  prevent  this,  it  is  necessary  to  make  some  provision  for  a  cushion, 
particularly  where  the  water  pressure  is  very  great.  This  not  infre- 
quently runs  as  high  as  a  hundred  pounds  to  the  square  inch,  and 
even  higher.  To  cushion  the  blow,  an  air  chamber,  commonly  made 
bv  turning  the  pipe  upward  for  a  foot  or  two  above  the  cock,  is  used. 
This  extension  will  at  the  outset  contain  a  volume  of  air,  which, 
on  being  compressed  by  the  force  of  the  water,  makes  an  elastic 
cushion.  Sometimes,  however,  the  air  originally  contained  becomes 
gradually  absorbed  by  the  water  which  is  driven  into  the  chamber, 
and  thus  it  becomes  replaced  by  water  and  the  cushion  is  destroyed. 
In  such  an  event,  it  is  well  to  shut  off  the  ^^^ater  and  empty  the  pipes 
so  that  air  may  again  fill  the  chamber.  Another  form  of  air  chamber 
recommended  is  made  by  extending  the  pipe  with  a  piece  of  larger 
diameter,  covered  at  the  top  with  a  tightly  fitting  screw  cap.  Within 
this  extension,  may  be  placed  two  or  more  rubber  balls,  upon  which 
the  force  of  the  blow  of  the  water-hammer  may  be  expended. 

Water-hammer  of  a  most  annoying  and  persistent  kind  is  occasioned 
often  by  the  too  easy  movement  of  a  light  ball-cock  controlling  a 
current  of  high  pressure  in  a  small  tank.  For  example,  the  water  in 
the  tank  becomes  lowered  through  the  use  of  some  fixture  below,  the 
ball,  floating  on  the  surface,  opens  the  valve  of  the  cock,  and  water  is 
admitted  to  take  the  place  of  that  which  has  been  drawn  off.  The 
water,  entering  with  much  force,  sets  the  whole  contents  in  motion. 


PLUMBING.  487 

The  ball  is  thrown  up  and  shuts  off  the  water  with  great  suddenness 
and  falls  again  ;  another  jet  of  water  is  thrown  in,  and  thus,  with  alter- 
nate quick  jets  and  movement  of  the  ball,  the  hammering  continues, 
until  finally  the  level  of  the  water  has  been  restored  to  its  original 
point. 

Testing"  Plumbing. — Tightness  of  joints  throughout  a  system  of 
plumbing  may  be  determined  in  several  ways.  For  testing  the  joints 
of  soil-pipes  and  main  drains,  a  most  important  and  searching  test  is 
that  known  as  the  water-pressure  test.  This  is  applied  before  any 
fixtures  have  been  joined  to  the  wastes  and  soil-pipe.  All  outlets  are 
closed  with  appropriate  plugs,  made  for  the  purpose  and  kept  in  place 
by  means  of  bolts,  and  then  the  entire  pipe  with  its  branches  is  filled 
with  water.  Should  there  be  leaks  in  any  part  of  the  system,  the 
fact  will  be  made  manifest  by  the  sinking  of  the  water,  and  the  points 
of  escape  may  easily  be  found  on  inspection. 

The  other  methods  applicable  to  the  entire  system  include  the  smoke 
test  and  the  peppermint  test.  In  the  smoke  test,  the  system  is  filled 
with  smoke  by  means  of  a  device  known  as  an  asphyxiator.  If  leaks 
€xist,  the  fact  will  be  made  evident  in  two  Avays  :  first,  to  the  sense  of 
smell ;  second,  to  the  sense  of  sight.  Besides  the  asphyxiator,  a 
number  of  other  devices,  including  the  smoke  rocket,  have  been  in- 
vented. The  common  method  of  testing  plumbing  in  this  country 
is  known  as  the  peppermint  test.  For  this  test,  the  presence  of  two 
persons  is  necessary ;  one  to  apply  the  peppermint,  and  the  other  to 
detect  its  presence  in  the  air  of  the  building.  About  two  ounces  of 
oil  of  peppermint  are  used  for  each  stack  of  soil-pipes.  This  very 
pungent  oil  should  be  carried  through  the  house  in  very  tightly  corked 
vials,  in  order  that  no  odor  shall  be  given  off  in  transit.  The  vent 
openings  are  closed  first  with  plugs,  and  the  oil  of  peppermint  is  then 
poured  into  the  soil-pipe,  and  is  followed  by  a  quart  or  two  of  hot 
water,  to  assist  its  volatilization.  The  outlet  is  then  closed  securely. 
On  account  of  the  clinging  quality  of  the  odor,  the  person  who  emp- 
ties the  peppermint  should  remain  on  the  roof,  with  the  scuttle  closed, 
until  thorough  inspection  of  the  premises  has  been  made.  The  vapor 
of  the  oil  permeates  all  parts  of  the  soil-pipe  and  its  connections,  and 
in  case  of  defective  seal  or  any  other  imperfection  in  the  system,  it 
escapes  and  makes  its  presence  known  in  the  rooms  through  its  effect 
on  the  sense  of  smell.  During  the  examination,  it  is  important  that 
no  water-closet  be  pulled  and  that  no  bowl,  bath,  or  sink  be  used, 
since  thereby  the  whole  of  the  peppermint  may  be  driven  out  of  the 
system  into  the  sewer. 


CHAPTER  VI. 

DISPOSAL  OF  SEWAGE. 

The  composition  of  sewage  varies  according  to  the  character  of  the 
community  by  which  it  is  produced.  To  the  lay  mind,  the  word  con- 
veys the  idea  of  a  mixture  of  urine  and  faeces,  paper  and  burnt  matches, 
with  waste  from  baths,  wash-stands,  laundries,  and  kitchen-sinks  ;  this 
is  ordinary  domestic  sewage,  and  may  be  taken  as  the  type  of  sewage 
of  districts  that  are  purely  residential.  But  the  sewage  of  a  large  com- 
munity in  which  all  manner  of  manufacturing  is  carried  on  is  neces- 
sarily of  a  most  complex  character,  containing,  as  it  does,  in  addition 
to  domestic  waste,  that  which  is  inseparably  connected  with  the  various 
industries.  Moreover,  it  is  ever  changing  with  increase  and  diminution 
and  changes  of  all  kinds  in  manufacturing  activity. 

Establishments  like  paper  mills,  tanneries,  dye-houses,  and  woollen- 
mills  produce  enormous  amounts  of  sewage.  In  fact,  a  single  one  is 
quite  capable  of  producing  as  much  as  that  of  a  fairly  large  town,  and 
such  manufacturing  sewage  often  contains  much  more  organic  and  other 
matters  than  domestic  sewage,  which,  in  purely  residential  districts,  is 
of  fairly  constant  composition,  and,  where  the  water  supply  is  abun- 
dant, contains  but  a  small  fraction  of  1  per  cent,  of  organic  matter. 
But  it  is  in  this  very  small  percentage  that  the  capacity  for  producing 
mischief  resides,  for  the  most  important  constituents  of  sewage  are 
those  which  in  any  Avay  may  be  the  cause,  direct  or  indirect,  of  injurious 
effects  on  health — that  is,  organic  matters  connected  with  infective 
diseases,  and  hence  mostly  to  be  found  in  ordinary  domestic  wastes. 
Industrial  sewage  is  of  secondary,  but,  nevertheless,  in  many  ways,  of 
great,  importance,  for  its  nature  may  be  such  as  to  make  separate  treat- 
ment necessary,  because  of  its  action  on  the  life  of  fish  in  rivers,  and 
on  that  of  the  organisms  which  bring  about  purification  by  methods 
to  be  described.  It  may  contain  all  manner  of  chemicals,  dyestuffs, 
and  other  matters,  and  be  repugnant  to  sight  and  smell. 

The  importance  of  removal  and  disposal  of  filth  needs  no  elucida- 
tion. Kemoval  should  be  speedy  and  final  disposal  so  thorough  as  to 
remove  completely  the  possibility  of  injuriously  affecting  health.  It 
should  not  be  stored  on  the  premises  in  cesspools,  as  is  so  commonly 
the  practice  both  in  small  and  in  many  large  and  densely  populated 
places,  whether  these  be  of  the  leaching  sort  which  drain  their  contents 
constantly  into  the  subsoil,  or  the  far  less  objectionable,  but,  neverthe- 
less, objectionable,  tight  pits  with  cemented  sides  and  bottoms,  in  which 
the  contents  are  always  in  a  condition  of  putrefaction.  The  use  of  this 
sort  necessitates  more  or  less  frequent  emptying,  which,  unless  done  by 

488 


DISPOSAL   OF  SEWAGE.  489 

the  "  odorless  excavation  "  suction  apparatus  (and  sometimes  even  then)^ 
gives  rise  to  intolerable  stench,  not  confined  to  the  immediate  neighljor- 
hood,  but  disseminated  over  a  wide  area. 

As  will  be  shown  later,  fresh  sewage  may  be  disposed  of  so  as  to  lose 
its  character  completely,  without  undergoing  the  processes  which  we 
designate  collectively  as  putrefaction.  Its  organic  constituents  are 
seized  upon  by  micro-organisms  which  work  in  the  presence  of  air,  and 
they  are  converted  to  inoffensive  harmless  products  which  possess  the 
additional  property  of  being  invaluable  plant  foods,  such,  for  instance, 
as  the  nitrates  of  potassium  and  sodium.  But  when  filth  is  conserved 
in  pits  so  that  only  its  upper  surface  is  exposed  to  the  oxygen  of  the 
air,  its  decomposition  is  effected  by  a  variety  of  organisms  of  a  differ- 
ent class,  which  work  without  air  and  produce  entirely  different  chem- 
ical compounds,  including  hydrogen  sulphide  and  other  noisome  bodies. 
Although  sewage  which  has  undergone  putrefactive  changes  may  yet  be 
acted  upon  by  the  beneficent  nitrifying  organisms,  it  is  best  to  get  rid 
of  it  before  such  changes  become  advanced. 

Before  proceeding  to  the  consideration  of  the  various  methods  of 
disposal  of  excreta  and  other  wastes,  it  may  be  well  to  look  into  the 
matter  from  an  economic  standpoint.  It  is  very  commonly  the  case 
that  the  question  of  methods  to  be  adopted  is  influenced  largely  by  the 
hope  of  gain,  for  it  is  axiomatic  in  the  minds  of  many  that  municipal 
sewage  is  possessed  of  such  immense  manurial  value  that  its  disposal 
without  previous  treatment  for  the  purpose  of  reclaiming  its  valuable 
constituents  is  sinful  wastefulness.  This  idea  has  doubtless  never 
been  more  forcibly  expressed  than  by  Victor  Hugo,  in  the  following 
passage  :  ^ 

"  Paris  casts  twenty-five  millions  of  francs  annually  into  the  sea ;  and 
we  assert  this  without  any  metaphor.  How  so,  and  in  what  way  ?  By 
day  and  night.  For  what  object  ?  For  no  object.  With  what  thought  ? 
Without  thinking.  With  what  object?  None.  By  means  of  what  organs? 
Its  intestines.  What  are  its  intestines?  Its  sewers.  Twenty-five 
millions  are  the  most  moderate  of  the  approximative  amounts  given 
by  the  estimates  of  modern  science.  Science,  after  groping  for  a  long 
time,  knows  now  that  the  most  fertilizing  and  effective  of  manures  is 
human  manure.  The  Chinese,  let  us  say  it  to  our  shame,  knew  this 
before  we  did ;  not  a  Chinese  peasant — it  is  Eckeberg  who  states  the 
fact — who  goes  to  the  city  but  brings  at  either  end  of  his  bamboo  a 
bucket  full  of  what  we  call  filth.  Thanks  to  the  human  manure,  the 
soil  in  China  is  still  as  youthful  as  in  the  days  of  Abraham,  and  Chi- 
nese wheat  yields  just  one  hundred  and  twenty  fold  the  sowing.  There 
is  no  guano  comparable  in  fertility  to  the  detritus  of  a  capital,  and  a 
large  city  is  the  strongest  of  stercoraries.  To  employ  the  town  in 
manuring  the  plain  would  be  certain  success ;  for  if  gold  be  dung,  on 
the  other  hand,  our  dung  is  gold. 

"What  is  done  with  this  golden  dung?  It  is  swept  into  the  gulf. 
We  send  at  a  great  expense  fleets  of  sliips  to  collect  at  the  southern 
'  Les  Miserables,  pfirt  5,  book  2. 


490  DISPOSAL   OF  SEWAGE. 

pole  the  guano  of  petrels  and  penguins,  and  cast  into  the  sea  the  incal- 
culable element  of  wealth  which  we  have  under  our  hand.  All  the 
human  and  animal  manure  which  the  world  loses,  if  returned  to  land, 
instead  of  being  thrown  into  the  sea,  would  suffice  to  nourish  the  world. 
Do  you  know  what  those  piles  of  ordure  are,  collected  at  the  corners 
of  streets,  those  carts  of  mud  carried  off  at  night  from  the  streets,  the 
frightful  barrels  of  the  night-man,  and  the  fetid  streams  of  subterra- 
nean mud  which  the  pavement  conceals  from  you  ?  All  this  is  a  flow- 
ering field,  it  is  green  grass,  it  is  mint  and  thyme  and  sage,  it  is  game, 
it  is  cattle,  it  is  the  satisfied  lowing  of  heavy  kine  at  night,  it  is  per- 
fumed hay,  it  is  gilded  wheat,  it  is  bread  on  your  table,  it  is  warm 
blood  in  your  veins,  it  is  health,  it  is  joy,  it  is  life. 

"  So  desires  that  mysterious  creation,  which  is  transformation  of 
earth  and  transfiguration  in  heaven  ;  restore  this  to  the  great  crucible, 
and  your  abundance  will  issue  from  it,  for  the  nutrition  of  the  plains 
produces  the  nourishment  of  men.  You  are  at  liberty  to  lose  this 
wealth  and  consider  me  ridiculous  into  the  bargain ;  it  would  be  the 
masterpiece  of  your  ignorance.  Statistics  have  calculated  that  France 
alone  pours  every  year  into  the  Atlantic,  a  sum  of  half  a  milliard. 
Note  this  ;  with  these  five  hundred  millions,  one  quarter  of  the  expenses 
of  the  budget  would  be  paid." 

Concerning  the  fertilizing  value  of  human  excreta,  there  can  be  no 
doubt ;  but  when  these  are  diluted  to  such  an  extent  that  their  organic 
constituents  amount  to  less  than  a  thousandth  part  of  the  whole,  it  nat- 
urally follows  that  to  reclaim  them  in  concentrated  form  involves  an 
expense  which  may  be  far  in  excess  of  their  value.  A  substance  which, 
in  hand,  is  of  intrinsic  value,  may  be  so  situated  that  its  acquisition 
by  ordinary  known  means  cannot  be  justified  because  of  the  attendant 
pecuniary  risk,  and  then,  and  until  other  better  means  are  devised,  it 
is  practically  worthless.  For  example,  many  districts  abound  in  rocks 
containing  silver,  gold,  and  other  metals,  but  in  such  small  amounts 
that  they  cannot  be  worked  with  profit ;  therefore,  so  far  as  increasing 
material  wealth  is  concerned,  these  ores  might  as  well  be  at  the  bottom 
of  the  sea.  But  in  the  case  of  sewage,  the  difficulty  is  increased  still 
farther  by  the  fact  that  the  manurial  product  is  not  usable  on  the  spot, 
but  must  undergo  transportation,  which  is  costly  in  proportion  to  the 
distance. 

A  fair  estimate  of  the  value  of  the  manurial  matters  contained  in  a 
ton  of  crude  sewage  of  average  composition  places  it  at  somewhat  less 
than  four  cents,  an  amount  so  small  as  to  appear  worse  than  ridiculous 
when  we  consider  that  it  is  diluted  by  a  volume  of  water  equal  to  about 
six  barrels.  The  value  of  the  sewage  of  cities  with  a  very  abundant 
water  supply  is  even  less  than  this.  Thus,  that  of  Boston  has  been 
estimated  by  the  Massachusetts  State  Board  of  Health  to  be  about  one 
cent  per  ton,  and  that  of  New  York  is  said  to  be  even  smaller.  To 
separate  this  small  amount,  the  employment  of  some  chemical  is  neces- 
sary. The  resulting  compound,  known  as  sludge,  has  a  certain  value 
in  agricultural  operations,  but  that  that  value  is  not  such  as  to  warrant 


METHODS  OF  SEWAGE  DISPOSAL.  491 

the  cost  of  handling  and  transportation,  is  most  evident  when  it  is 
stated  that  as  a  rule  it  finds  no  market  at  any  price.  In  London,  for 
instance,  thousands  of  tons  of  wet  sludge  are  produced  every  day,  more 
than  2,000,000  yearly,  and  anybody  who  wants  it  can  have  it  free  of 
charge ;  but  nobody  cares  enough  for  it  to  transport  it,  and  hence  it 
has  to  be  carried  far  out  to  sea  to  Barrow  Deep,  fifty  miles  away,  and 
dumped. 

In  considering  sewage  disposal,  it  should  be  borne  in  mind,  therefore, 
that  it  is  a  positive  public  necessity  as  much  as  police  and  fire  patrol, 
that  it  costs  money,  and  that  it  cannot  be  a  source  of  income  over  ex- 
penditure. No  community  expects  a  pecuniary  return  on  an  invest- 
ment for  steam  fire-engines  and  hose  carriages,  or  for  revolvers  and 
police  stations  :  such  are  needed  for  the  protection  of  life  and  property. 
So,  too,  a  system  of  sewerage  and  sewage  disposal  is  necessary  for  the 
protection  of  health,  and  is  not  to  be  treated  as  though  primarily  in- 
tended as  a  source  of  public  revenue,  although,  of  course,  any  return 
which  may  be  possible,  either  from  sale  of  sludge  or  crude  sewage,  may 
be  regarded  as  a  welcome  diminution  in  the  cost  of  maintenance. 


METHODS  OF  SEWAGE  DISPOSAL. 

The  methods  of  disposal  of  excreta  and  sewage  include  : 

1.  Discharge  into  the  sea  or  other  bodies  of  water. 

2.  The  "  dry  method,"  or  pail  system. 

3.  Chemical  treatment. 

4.  Irrigation,  or  "  sewage  farming." 

5.  Filtration. 

6.  Other  biological  systems. 

1.  Discharge  into  the  Sea. — In  communities  on  and  near  the  coast, 
it  is  a  comparatively  easy  niatter  to  get  rid  of  sewage  by  discharging 
it  into  the  ocean  and  having  it  carried  away  by  the  outgoing  tide.  If 
it  be  discharged  in  a  fresh  condition,  it  becomes  so  enormously  diluted 
in  a  very  short  time  that  only  under  exceptional  circumstances  can  it 
ever  be  a  nuisance  in  any  way.  This,  of  course,  presupposes  a  reason- 
able rise  and  fall  of  the  tide,  and  does  not  contemplate  such  slight  dif- 
ferences as  a  foot  or  so.  With  slow  movement,  less  than  one  and  a 
half  miles  per  hour,  deposits  are  more  than  likely  to  be  formed,  and 
nuisance  thus  caused  must  of  necessity  increase  with  time,  and  espe- 
cially with  increase  of  sewage  due  to  growing  population.  Thus  it 
happens  that,  even  on  the  seaboard,  it  may  be  necessary  to  purify  sewage 
Ixifore  discharging  it,  and  the  problem  of  successful  and  economical 
])in-ilication  may  be  one  of  the  most  difficult  and  important  in  the  whole 
range  of  sanitary  science. 

In  inland  communities  situated  on  rivers  of  considerable  size,  delivery 
at  a  point  below  the  outskirts  is  the  easiest  method  of  sewage  disposal ; 
l)Ut  other  communities  farther  down  may  pro])erly  object  on  more  than 
one  groiuid  to  such  action,  for  the  sewage  itself  may  be  a  nuisance,  and 


492  DISPOSAL    OF  SEWAGE. 

the  river  may  be  the  source  of  the  public  water  supply.  Here,  again, 
and  where  the  flow  is  sluggish  and  the  volume  small,  treatment  before 
discharge  is  necessary.  Where  the  water  into  which  the  sewage  is 
delivered  is  to  be  used  below  for  the  public  drinking  supply,  the  process 
of  purification  should  be  such  as  to  give  the  most  perfect  results  pos- 
sible ;  that  is,  should  give  an  effluent  which  will  not  aifect  the  quality 
of  the  water  injuriously. 

In  both  rivers  and  harbors,  in  order  to  prevent  nuisance  from 
untreated  sewage,  the  current  should  be  sufficiently  voluminous  and 
strong  to  afford  large  dilution  and  prevent  deposition. 

2.  The  Pail  System. — This  is  limited  in  its  application  to  the 
disposal  of  excreta  in  pails  containing  dry  earth,  peat  powder,  or 
other  material,  and  although  it  is  in  operation  in  several  places  of 
considerable  size  in  England  and  on  the  Continent,  it  is  better  adapted 
to  the  needs  of  isolated  houses  and  small  villages.  It  was  the 
natural  outgrowth  of  the  very  extensive  adoption  of  the  earth-closet, 
a  device  invented  by  the  Rev.  Henry  Moule,  in  which  the  solid 
excreta  are  discharged  into  a  receptacle  of  suitable  size  and  covered 
after  each  addition  with  dry  earth,  peat  powder,  or  ashes.  As  often  as 
necessary,  the  pails  are  collected  and  emptied,  and  their  contents  are 
removed  to  a  distance,  treated  or  not  with  chemicals,  according  to  cir- 
cumstances, and  buried  or  used  as  manure.  From  the  fact  that  the 
collection  is  made  at  night,  arose  the  common  term  night-soil,  and 
later,  from  this  one,  another  to  designate  an  important  part  of  house 
plumbing,  the  soil-pipe. 

It  is  a  primitive  sort  of  system,  but  it  has  points  in  its  favor  as 
well  as  against.  It  is  not  expensive,  there  is  no  pollution  of 
streams,  and  the  manurial  value  of  fseces  is  not  wasted.  But  it 
requires  the  collection,  drying,  and  storage  of  a  large  amount  of  earth, 
or  other  material,  not  always  easy  to  obtain ;  the  emjjtying  of  the  pails 
is  necessarily  accompanied  by  the  escape  of  more  or  less  odor ;  it 
may  possibly  give  rise  to  a  nuisance  at  or  near  the  place  of  final 
disposal ;  and  additional  provision  must  be  made  for  the  removal  of 
liquid  refuse. 

The  materials  used  in  the  pails  are  chiefly  dry  earth  and  peat,  both 
of  which  substances  are  very  absorbent.  The  earth  is  ordinarily  either 
simply  dried  or  thoroughly  baked,  but  drying  is  preferable  to  bakings 
because  the  influence  of  the  saprophytic  bacteria  of  the  soil  is  not 
destroyed.  The  late  Colonel  Waring  demonstrated  most  convincingly 
the  very  great  power  of  air-dried  soil  to  dispose  of  the  organic  constit- 
uents of  fffical  matter  so  nearly  completely  that  but  an  insignificant 
amount  remains.  He  kept  two  tons  of  dry  earth  for  a  long  time,  using- 
it  repeatedly  in  earth-closets  and  storing  it  after  each  period  of  use  in  a 
dry  well-ventilated  cellar.  It  was  estimated  that  by  the  time  it  had 
been  used  ten  times,  no  less  than  230  pounds  of  nitrogen  had  been 
added  to  it,  but  analysis  showed  that  but  8  pounds  remained,  the  rest 
having  been  restored  in  gaseous  form  to  the  atmosphere.  The  same 
fact  has  been  observed  by  Professor  Vollcker,  who  found  that  earth 


METHODS  OF  SEWAGE  DISPOSAL.  493 

after  being  dried  and  used  three  times  contained  practically  no  more 
nitrogen  than  it  did  originally. 

Peat  has  not  only  remarkable  power  of  absorption,  but  also  very 
marked  bactericidal  properties.  It  will  absorb  and  retain  from  nine 
to  eighteen  times  its  weight  of  water,  it  acts  as  a  deodorant  in  the  same 
manner  as  charcoal,  and  it  retains  ammonia  in  apparently  unchanged 
condition.  The  resulting  manure  is  found  to  decompose  rapidly,  and 
to  be  especially  suited  to  sandy  and  light  loamy  soil.  Experiment  has 
shown  that  neither  the  typhoid  nor  cholera  organisms  retain  their  vital- 
ity in  contact  with  peat  longer  than  a  very  few  hours,  and  the  same  is 
true  of  many  other  varieties  of  bacteria. 

Sawdust  also  is  recommended  for  use  in  earth-closets,  and  as  an 
absorbent  for  urinals  where  there  is  no  water  supply.  Experiments 
conducted  by  Dr.  G.  V.  Poore  ^  with  various  materials  proved  its  value 
for  the  latter  purpose  and  yielded  interesting  results.  A  flannel  bag, 
two  and  a  half  feet  long  and  a  foot  broad  at  the  bottom,  containing  6 
pounds  of  dry  sawdust,  received  in  the  course  of  two  months  39  pounds 
of  urine  ;  after  about  a  year,  45  pounds  more  were  added  during  a 
period  of  three  months.  jS'otwithstanding  that  the  bag  had  become 
so  rotten  as  hardly  to  hold  together,  the  contents  were  not  in  the  least 
offensive,  and  had  never  given  off  any  offensive  odor.  Of  the  84 
pounds  of  urine  added,  only  6  pounds  had  filtered  through,  while  the 
rest  had  evaporated  or  had  been  retained.  The  filtrate  was  dark  brown 
in  color,  thick,  and  of  high  specific  gravity,  but  never  offensive  ;  nor  had 
it  shown,  after  lying  about  for  months,  any  tendency  to  putrefy  or  be- 
come offensive.  Filtration  through  earth,  old  stucco,  and  peat  moss 
gave  identical  results.  With  fresh  earth,  fresh  stucco,  and  fresh  ashes, 
the  filtrate  was  almost  colorless  and  odorless,  but  the  power  of  ashes  to 
give  this  result  is  short-lived. 

The  pail  system,  whatever  may  be  said  in  its  favor,  has  had  its  day 
in  large  communities,  and  where  it  still  obtains,  it  is  being  superseded 
gradually  by  systems  more  suitable  and  satisfactory. 

3.  Chemical  Treatment. — Sewage  disposal  by  chemical  treatment 
has  for  its  object  the  separation  of  the  suspended  matters  and  the  pre- 
cipitation and  consequent  separation  of  the  putrescible  matters  in. 
solution.  The  larger  masses  of  the  suspended  substances  may,  of 
course,  be  removed  by  being  entangled  in  the  coagulum  produced  from 
the  soluble  matters  by  the  addition  of  chemical  precipitants.  The 
effluent  should  be  clear,  and  should  contain  a  minimum  of  organic 
matter  capable  of  undergoing  putrefaction.  Whatever  the  precipitant 
used,  the  process  requires  constant  and  careful  supervision,  in  order  to 
achieve  the  best  results  and  to  keep  the  expenditure  down  to  as  low  a 
figure  as  is  consistent  with  efficiency.  The  screened  sewage,  deprived 
of  its  coarser  matters,  is  treated  and  thoroughly  mixed  with  the  chemi- 
cals in  large  tanks,  and  is  then  passed  into  other  tanks,  where  the  pre- 
cipitate is  allowed  to  separate  by  subsidence.  The  sludge  is  removed 
and  then  disposed  of  in  its  natural  state  or  after  treatment  in  hydraulic 
»  British  Medical  .Journal,  Aug.  31,  1895. 


494  BISPOSAL   OF  SEWAGE. 

presses  for  removal  of  the  water.  The  sewage  should  be  treated  iu  as 
fresh  condition  as  possible  and  before  putrefactive  processes  have  begun, 
since  when  the  latter  have  got  well  under  way,  the  results  are  never 
satisfactory. 

The  substances  most  used  as  precipitants  are  alum,  lime,  and  ferrous 
sulphate,  but  which  of  these  and  others  is  the  best  suited  for  the  work, 
is  a  question  concerning  which  there  is  no  general  agreement.  Alum 
and  other  soluble  salts  of  aluminum  have  moderate  disinfectant  prop- 
erties, are  not  poisonous  in  the  general  sense  of  the  word,  and  when 
used  in  excess  impart  no  color  to  the  effluent.  In  the  presence  of  lime 
or  ammonia,  they  yield  a  very  bulky  gelatinous  precipitate,  which 
entangles  the  suspended  matters  and  bacteria  present,  and  carries 
them  down,  leaving  a  clear  supernatant  fluid,  which  is  without  color 
or  odor  and  practically  sterile. 

With  excess  of  alum,  the  effluent  is  acid  in  reaction,  and  is  thus  capable 
of  injuring  aquatic  life  ;  but  it  does  not  form  unsightly  compounds  with 
sulphur  as  do  iron  and  other  substances  which  form  black  sulphides. 
Lime  in  the  form  of  milk  of  lime  is  used  extensively  both  alone  and 
in  connection  with  ferrous  sulphate  or  alum.  When  used  alone,  it 
gives  a  much  more  bulky  sludge,  which  has  but  slight  value  as  a 
fertilizer.  The  amount  necessary  for  treatment  of  a  million  gallons  of 
sewage  is  generally  stated  at  one  ton,  but  may  be  much  less.  At  the 
precipitation  works  at  Worcester,  Mass.,  for  instance,  during  the  year 
ended  Nov.  30,  1895,  the  average  daily  amount  of  sewage  treated  was 
16,000,000  gallons,  and  the  average  amount  of  lime  used  per  million 
gallons  was  but  a  trifle  over  1,200  pounds,  while  the  sewage  of 
Lawrence,  Mass.,  was  found  in  the  experiments  conducted  by  the 
State  Board  of  Health,^  to  require  1,800  pounds  for  the  same  amount. 
As  a  matter  of  fact,  the  amount  necessary  depends  upon  the  character 
of  the  sewage,  that  is,  upon  the  amount  of  carbon  dioxide  in  it,  for  it 
is  this  which  acts  upon  the  lime  to  cause  a  precipitate  to  be  formed. 
Hence  it  may  be  said  that  the  amount  necessary  is  that  which  will 
exactly  neutralize  the  contained  carbon  dioxide. 

Ferrous  sulphate  is  very  rarely  employed  alone,  but  generally  with 
lime,  the  two  being  used  in  such  amounts  that  no  great  excess  of  either 
is  left  in  the  effluent ;  and  these  amounts  can  only  be  determined  by 
actual  experiment  with  the  sewage  to  be  treated.  On  this  account, 
precipitation  by  ferrous  sulphate  is  likely  to  be  somewhat  complicated, 
but  when  it  is  carried  out  properly,  it  appears  to  give  very  good  results. 
The  experiments  conducted  by  the  State  Board  of  Health  at  the  station 
at  Lawrence  led  to  the  conclusion  that  sulphate  of  iron  alone  acts  best 
among  chemical  precipitants.  According  to  Mr.  W.  J.  Dibdin,-  how- 
ever, who,  as  is  well  known,  has  made  extensive  experiments  on  this 
subject,  the  combination  with  lime  constitutes  the  most  economical  and 
most  efficient  agent.     An  excess  of  iron  in  the  effluent  may  lead  later 

^  Keport  on  Purification  of  Sewage  and  Water,  1890. 
^  Journal  of  State  Medicine,  January,  1895. 


METHODS  QF  SEWAGE  D'ISPOSAL.  495 

to  an  unsightly  deposit  of  ferrous  sulphide  along  the  banks  of  the  stream 
into  which  it  is  eventually  discharged. 

Certain  other  chemical  processes  have  been  exploited  in  this  country 
and  elsewhere,  but  none  of  them  appears  likely  to  be  adopted  extensively. 
Among  them  may  be  mentioned  the  "Amines"  process,  in  which  the 
sewage  is  treated  with  lime  and  amines,  chiefly  trimethylamine,  in  the 
form  of  herring-brine.  While  this  process  gives  satisfactory  results, 
it  has  certain  drawbacks,  among  which  are  the  difficulty  of  securing  a 
sufficient  supply  of  the  brine,  the  offensive  odor  of  the  same,  deteriora- 
tion on  storage,  and  possible  influence  on  fish  life.  Another,  some- 
times known  as  the  "  Woolf,"  and  sometimes  as  the  "  Hermite," 
process,  depends  upon  the  action  of  chlorine  compounds  produced  by 
electrolysis  of  salt  in  sea-water  or  in  the  sewage  itself.  The  organic 
matters  are  attacked  and  somewhat  diminished  in  amount,  but  the 
principal  influence  is  exerted  in  the  direction  of  sterilization.  The 
precipitating  agent  is  ferrous  hydrate,  formed  by  the  action  of  the 
electric  current  on  iron  plates  in  the  tanks.  In  the  so-called  A.  B.  C. 
process  (alum,  blood,  and  clay),  a  mixture  of  clay  and  charcoal  is  first 
added  to  the  sewage,  and  next  a  solution  of  alum  and  sulphate  of  mag- 
nesium. It  is  an  expensive  and  troublesome  process,  and  yields  a  largo 
amount  of  sludge.  Blood  was  employed  originally,  but  was  found  to 
be  unnecessary. 

In  all  processes  of  chemical  treatment,  a  more  or  less  complete  tem- 
porary sterilization  is  effected,  and  this  of  itself  is  often  a  very  serious 
objection,  since,  although  the  effluent  when  discharged  may  be  sterile, 
this  condition  is  not  lasting,  and  the  organic  matter  still  present  will 
certainly,  sooner  or  later,  decompose,  and,  perhaps,  become  a  serious 
nuisance.  The  objection  to  sterilization  of  sewage  does  not  extend, 
of  course,  to  the  pathogenic  bacteria  of  infected  fseces  and  urine, 
which  should  be  destroyed  before  entrance  to  the  main  body  of  sew- 
age, but  wholly  to  the  saprophytic  organisms,  which  eventually  de- 
stroy the  organic  matters  and  convert  them  to  simple,  harmless 
compounds. 

There  is  always  more  or  less  organic  matter  in  the  effluent,  however 
clear  this  may  be,  and,  being  putrescible,  it  is  certain  to  undergo 
change.  This  has  been  demonstrated  wherever  chemical  treatment  has. 
been  adopted,  and  it  is  admitted  generally  that  the  effluent  cannot  be 
admitted  to  water  courses  without  injury  to  the  quality  of  the  water,, 
both  so  far  as  fish  life  and  wholesomeness  for  drinking  are  concerned, 
unless  it  is  first  further  treated  by  some  biological  process,  and  thereby 
made  clean  and  harmless.  In  the  words  of  Professor  L.  P.  Kinni- 
cutt,'  who  has  made  an  exhaustive  study  of  chemical  purification  at 
Worcester,  Mass.,  and  elsewhere  in  America  and  in  Europe,  "  We 
believe  we  have  proved  in  America  .  .  .  that  by  chemical  pre- 
cipitation alone,  even  with  the  greatest  care,  and  at  an  excessively  high 
cost,  a  filtrate  cannot  be  obtained  sufficiently  pure  to  turn  into  a  water 
course  unless  the  minimum  dry  weather  flow  of  tliat  water  course  is  at 

'  Jonniiil  (if  the  Sanitary  rnstitiite,  Jan.,  1900,  p.  662. 


496  DISPOSAL  OF  SEWAGE. 

least  ten  times,  and,  better,  fifteen  times  the  average  flow  of  the 
sewage." 

Action  of  Sewage  Effluents  on  Fish  Life. — It  may  be  stated  -  broadly 
that  "  purified  "  sewage,  when  discharged  into  a  water  course,  will  cause 
more  harm  to  fish  than  will  ordinary  crude  sewage,  for  while  all  chemical 
precipitants  will  either  cause  the  water  to  act  as  a  poison  or  withdraw 
its  dissolved  oxygen  so  that  it  will  not  sustain  life,  the  elements  of  crude 
sewage  may  be  taken  up  greedily  by  the  fish  as  valuable  food  material. 
Much  depends,  of  course,  upon  the  nature  of  the  precipitant  (some 
of  them  being  more  poisonous  than  others),  and  also  upon  its  amount ; 
Lut  even  when  extensively  diluted,  its  action  is  distinctly  harmful. 
Lime  is  supposed  to  act  by  being  precipitated  in  the  gills  as  car- 
bonate, thus  diminishing  the  respiratory  area.  Chlorine,  in  a  free 
state  or  as  chlorinated  lime  or  soda,  exerts,  even  in  extremely  dilute 
condition,  as  less  than  1  part  in  100,000  of  water,  a  very  fatal  influ- 
euce.  Iron  salts  act  not  only  as  poisons,  but  the  ferrous  forms  take 
up  the  dissolved  oxygen  and  become  ferric ;  then  these  become  reduced 
and  again  absorb  it,  and  continue  in  this  way  to  rob  the  water  of  its 
power  to  sustain  the  respiratory  function.  But,  on  the  other  hand, 
while  fresh  sewage  of  ordinary  composition  is  sought  for  by  many 
species  of  fish  as  a  desirable  food,  putrefying  sewage  will  either  act 
injuriously  on  fish  or  make  the  water  so  repugnant  to  them  as  to  drive 
them  away. 

4.  Sewage  Irrig-ation. — In  the  "  broad  irrigation  "  or  "  sewage 
farming"  system,  sewage  is  utilized  in  the  growing  of  crops  which 
take  up  and  dispose  of  much  of  the  water  and  dissolved  solids,  while, 
at  the  same  time,  oxidation  processes  in  the  interstices  of  the  soil  destroy 
the  bacteria  and  convert  the  remaining  organic  matter  to  simple,  harm- 
less products.  For  the  disposal  of  large  volumes  by  this  method, 
very  large  sewage  farms  are  required.  The  necessary  area  will  depend 
upon  the  nature  of  the  soil,  its  permeability  and  water  capacity,  and 
upon  the  amount  of  annual  rainfall. 

This  method  has  been  adopted  very  extensively  in  England,  where 
there  are  hundreds  of  sewage  farms,  and  in  Germany,  France,  India, 
America,  and  elsewhere  ;  and  everywhere  it  has  been  found  that  no  hard 
and  fast  rules  as  to  area  per  thousand  of  population  can  be  followed. 
In  England,  the  idea  obtains  very  generally  that  every  hundred  of 
population  will  require  one  acre  of  sewage  farm,  but  this,  it  should  be 
remarked,  while  it  may  apply  in  England,  which  is  a  rainy  country, 
-and  one  where  domestic  sewage  is  likely  to  amount  to  many  more  gallons 
per  capita  than  on  the  Continent,  owing  to  the  more  general  habit  of 
daily  bathing,  is  much  in  excess  of  actual  need  where  the  soil  is  more 
suitable  for  the  purpose,  where  the  rainfall  is  less  in  amount,  and 
where  domestic  sewage  per  capita  is  jaroduced  in  smaller  quantities. 
According  to  Waring,  each  acre  of  a  well-regulated  plant  will,  under 
ordinary  conditions,  absorb  and  purify  the  sewage  of  250  to  500  per- 
sons, and  if  the  soil  be  of  porous  fine  sand  and  the  question  of  crops 
be  put  in  the  background,  that  of  1,000  to  1,500.     As  the  population 


METHODS  OF  SEWAGE  DISPOSAL.  497 

grows,  the  plant  must  be  enlarged,  and  hence  it  is  necessary  to  hold 
land  in  reserve  to  meet  future  demands. 

Of  the  very  first  importance  is  the  selection  of  a  suitable  tract  of 
land  for  the  establishment  of  the  plant.  This,  of  course,  is  not  always 
possible,  for  sometimes  no  land  is  available,  and,  again,  such  as  is 
at  hand  may  be  unsuited  to  the  purpose.  It  should  be  neither  too 
permeable  nor  too  close.  If  too  coarse,  it  will  permit  the  passage  of 
the  sewage  so  rapidly  that  no  purification,  or  at  most  imperfect  purifi- 
<?ation,  will  occur,  and  the  effluent  will  be  unfit  to  be  discharged  from 
the  underdrains  into  a  water  course ;  if  too  close,  as  will  be  the 
case  with  a  very  dense  clay,  the  imbibition  of  water  will  be  so  slow 
that  it  will  fall  far  below  the  amount  of  loss  by  evaporation.  The 
very  best  soil  for  the  purpose  is  one  of  sandy  loam  with  fine  inter- 
stitial spaces,  which  will  permit  not  too  rapid  percolation,  and  wherein 
the  processes  of  nitrification  may  go  on  most  thoroughly.  Very  dense 
clays  may  be  rendered  suitable  by  the  admixture  of  sand  or  lime  and 
by  tile  underd raining,  and  then  will  perform  its  office  in  a  satisfactory 
manner.  With  a  proper  plant  and  intelligent  supervision,  the  purified 
sewage  makes  a  clear,  bright,  and  practically  sterile  effluent. 

In  order  to  carry  out  the  scheme  so  as  to  achieve  the  best  results, 
the  farm  should  be  divided  into  three  parts,  not  necessarily  of  equal 
area  but  of  equal  absorbability,  each  of  sufficient  capacity  for  the  dis- 
posal of  the  entire  sewage  of  a  single  day.  Then  each  third  may  be 
worked  in  its  turn,  receiving  sewage  one  day  and  resting  two,  but  the 
capacity  of  none  should  be  overtaxed,  lest  the  soil  become  swampy  and 
filthy,  and  cease  the  work  of  oxidation. 

The  farm  is  laid  out  in  broad  ridges  and  furrows,  the  latter  receiving 
the  sewage  at  regular  intervals  ;  the  crops  grow  on  the  broad  ridges 
between.  It  should  be  underdrained  naturally  or  artificially  at  a  dis- 
tance of  about  six  feet,  so  that  the  purified  filtered  water  may  be 
removed  and  allowed  to  discharge  into  any  convenient  water  course. 

The  amount  of  daily  dose  per  acre  varies  very  widely  according  to 
pore-volume,  permeability,  and  rankness  of  vegetation.  On  a  close 
soil  in  a  cold  climate,  but  a  few  thousand  gallons  per  acre  can  be  dis- 
charged, while  on  an  open  soil  in  a  hot  country  with  rank  vegetation, 
as  in  Madras,  for  instance,  as  much  as  75,000  gallons  daily  will  not  be 
excessive.  The  chief  crops  grown  are  cabbages,  mangolds,  timothy, 
rye,  and  other  grasses ;  in  short,  such  as  can  bear  heavy  flooding  of 
the  soil. 

As  regards  ]:)rofit,  it  may  be  said  that  this  system  is  the  only  one 
which  can  possibly  yield  a  revenue,  but  this  is  not  due  to  the  supposed 
value  of  the  manurial  constituents  of  the  sewage,  but  to  the  water  itself, 
which  puts  the  crops  outside  the  danger  of  drought  and  beyond  the 
need  of  rain.  In  some  climates,  crop  follows  cro]i  the  year  round,  and 
the  annual  yield  is  large  ;  in  others,  the  season  is  so  short  in  comparison 
that  the  yield  is  much  less.  At  the  Berlin  farms,  a  yearly  yield  of  25 
tons  of  grass  per  acre,  equal  to  5  of  hay,  is  regarded  as  large  and 
satisfactory,  while  at  Krishnampett  in  Madras,  where  eight  crops  per 


498  DISPOSAL   OF  SEWAGE. 

year  are  harvested,  the  output,  according  to  Dr.  J.  N,  Cook,^  was  iq 
one  year  69  tons  per  acre,  equal  to  about  23  of  hay,  and  worth  nearly 
200  dollars.  The  city  of  Berlin  purchased  and  set  aside  20,000  acres 
of  land  for  its  sewage  farms,  and,  notwithstanding  an  outlay  of  more 
than  13,000,000  dollars  for  the  entire  plant,  receives  a  yearly  profit  of 
60,000  dollars  from  its  operation,  the  labor  costing  nothing  except  for 
maintenance  of  the  men  engaged,  these  being  condemned  thereto  for 
various  minor  misdemeanors. 

Whether  there  be  a  profit  or  not,  this  aspect  of  the  question  should 
ever  be  kept  in  the  background  and  the  primary  object  ever  in  view. 
When  the  farms  are  let  out  to  contractors,  it  is  always  advisable,  and 
even  necessary,  that  they  be  under  the  supervision  of  municipal 
authority,  to  insure  that  the  public  good  is  not  subordinated  to  private 
gain. 

It  is  not  to  be  supposed  that,  even  in  very  cold  weather,  the  use  of 
the  system  must  be  suspended,  for  when  vegetation  ceases,  the  soil  con- 
tinues the  process  of  purification.  At  St.  Laurent  College,  near  Mon- 
treal, for  example,  the  small  sewage  farm  was  found  to  act  efficiently 
in  disposing  of  the  usual  amount  of  sewage  in  a  January  (1898)  tem- 
perature of  —20°  F. 

Influence  of  Sewage  Irrigation  on  Health. — Concerning  the  influence 
of  sewage  farms  upon  the  health  of  those  dwelling  on  and  near  them^ 
the  evidence  is  entirely  on  one  side,  and  in  opposition  to  what  would 
naturally  be  supposed  to  be  the  case.  It  is  the  same  from  Berlin, 
Paris,  Edinburgh,  and  the  hundreds  of  other  places  where  the  system 
is  in  use,  and  all  to  the  effect  that  in  no  way  is  it  injurious.  It  is  true 
that  not  infrequently  the  sewage  gives  rise  to  more  or  less  disagreeable 
odor,  especially  if  it  be  stored  too  long ;  bat  the  fields  themselves  are 
generally  quite  free  from  nuisance,  and  even  though  odor  be  present,  it 
produces  no  harm.  At  the  Berlin  works,  in  a  population  of  more  than 
1,500,  there  was  one  death  from  typhoid  fever  in  five  years,  the  gen- 
eral death-rate  was  very  low,  and  the  zymotic  death-rate  exceedingly 
so ;  in  fact,  during  one  year  it  was  7iil. 

Complete  freedom  from  infectious  disease  is  by  no  means  unique,  but 
is,  indeed,  a  common  condition  in  the  experience  of  sewage  farming. 
At  the  farms  at  Gennevilliers,  where  the  sewage  of  Paris  is  received, 
the  population  is  constantly  increasing,  the  general  health  is  excellent, 
and  the  general  death-rate  is  low  and  continually  decreasing.  An  ex- 
tensive epidemic  of  typhoid  fever  in  Paris  would  be  supposed  to  be  the 
forerunner  of  another  of  greater  comparative  severity  where  its  sewage, 
containing  all  the  bowel  discharges  and  urine  of  sick  and  well  alike,  is 
treated,  but  experience  has  demonstrated  that  such  is  by  no  means  the 
case,  for  in  1882,  for  instance,  when  Paris  suffered  from  an  unusually 
extensive  outbreak  of  that  disease,  there  was  not  a  single  case  at 
Gennevilliers. 

So  far  as  is  known,  there  is  as  yet  no  proof  that  sewage  irrigation 
has  ever  been  responsible  in  any  way  for  the  occurrence  of  extensive 
^  Indian  Medico-chirurgical  Eeview,  Dec,  1895,  p.  676. 


METHODS  OF  SEWAGE  DISPOSAL.  499 

outbreaks  of  typhoid  fever,  dysentery,  or  cholera,  or,  indeed,  of  entozoic 
trouble.  Nor  is  there  reason  to  look  askance  upon  the  products  of 
the  farms,  despite  assertions  to  the  contrary  based  on  surmise  and 
inexperience,  for  the  facts  show  that  grass  and  other  crops  are  of  good 
quality,  make  good  fodder,  and  bring  good  results  in  milk  and  butter 
when  fed  to  cows. 

Ferre^has,  it  is  true,  reported  an  outbreak  of  typhoid  fever  in  a  girls^ 
boarding-school  at  Juranjon,  which  was  presumably  due  to  vegetables 
from  a  garden  watered  with  the  contents  of  an  infected  cesspool ;  and 
another  localized  outbreak  of  the  same  disease  due  to  infected  celery 
has  been  reported  by  the  State  Board  of  Health  of  Massachusetts. 
This  occurred  in  September,  1899,  at  the  Insane  Asylum  at  North- 
ampton, in  which,  prior  to  September  10th  of  that  year,  but  4  cases 
had  occurred  during  ten  years.  Then  cases  began  to  appear,  and  in 
fifteen  days  the  number  had  reached  39,  and  later  a  few  more.  Inves- 
tigation proved  beyond  reasonable  doubt  that  the  outbreak  was  due  ta 
celery  grown  in  beds  which  received  the  sewage  of  the  institution.  The 
method  of  banking  employed  in  the  cultivation  of  the  plants  made  them, 
a  favorable  medium  for  transmitting  the  disease.  If  should  be  noted,, 
however,  that  neither  of  these  outbreaks  was  due  to  produce  from  a, 
large  farm  receiving  the  diluted  sewage  of  a  distant  municipality. 

Aside  from  local  considerations  of  health,  what  are  the  results  at- 
tained ?  This  question  can  be  answered  in  a  fevv  words.  The  organic 
matters  of  the  sewage  are  destroyed  completely  by  the  saprophytic  bac- 
teria, which  also  dispose  of  their  pathogenic  brethren  ;  the  greater  part 
of  the  water  is  taken  up  by  growing  vegetation  and  evaporated  into  the 
atmosphere,  and  the  remainder  in  practically  sterile  condition  sinks  into 
the  subsoil  or  is  carried  away  by  the  underdrains  and  discharged  into  a 
stream.  The  effluent  at  Gennevilliers,  for  example,  is  organically  purer 
than  the  original  water  before  it  becomes  sewage. 

The  Waring  System  of  Irrigation. — Irrigation  on  a  small  scale,  known 
in  this  country  as  the  "  Waring  system,"  is  resorted  to  very  commonly 
for  the  treatment  of  sewage  of  single  houses  and  small  settlements. 
As  begun  by  the  Rev.  Mr.  Moule,  the  inventor  of  the  earth-closet,  it 
was  a  scheme  for  the  disposal  of  the  liquid  wastes  which  could  not  be 
cared  for  by  earth-closets.  The  plant  consisted  of  an  open-jointed  tile 
drain  laid  a  little  below  the  surface  of  the  ground,  parallel  with  and 
close  to  a  row  of  grapevines.  It  was  next  enlarged  by  Mr.  R.  Field 
by  the  addition  of  a  reservoir  or  flushing  tank,  shown  in  Fig.  90,  by 
means  of  which  the  whole  drain  could  be  flooded  throughout  and  inter- 
mittently. Brought  to  the  notice  of  Colonel  Waring,  he  adopted  the 
system  for  his  own  house,  and  proceeded  to  improve  it  in  several  direc- 
tions and  to  bring  it  into  common  use.  Under  him,  the  system  was 
brought  to  its  present  state  of  perfection. 

The  plant  consists  of  a  reservoir  into  which  the  sewage  runs,  a  wire 
scrr-ening  basket  to  separate   the   paper   and  other   matters  not  easily 
oxidizable,  an  automatic  siphon  by  which  complete  discharge  is  secured 
'  Annales  d'Hygiene  et  de  Medecine  l(5gale,  Jan.,  1899,  p.  23. 


600 


DISPOSAL   OF  SEWAGE. 


as  often  as  the  reservoir  becomes  filled,  and  a  gate-chamber  by  means 
of  which  the  flow  is  diverted  to  anj  of  the  three  outlets,  which  lead  to 
a  miniature  sewage  farm.  The  drain  pipes  are  laid,  with  open  joints, 
not  more  than  ten  inches  below  the  surface,  and  the  ground  where  they 
discharge  may  be  used  for  grassplots  or  gardens.  The  results  are  most 
satisfactory  in  every  way  ;  the  organic  wastes  are  oxidized  by  the  soil 
bacteria,  and  the  water  which  sinks  into  the  subsoil  is  incapable  of 
causing  pollution  such  as  occurs  when  cesspools  with  open  bottoms  below 
the  zone  of  saprophytic  bacteria  are  employed. 

Within  recent  years,  the  tendency  has  been  to  do  away  with  the 
■drains  where  sufficient  land  is  available,  and  to  discharge  the  sewage 
directly  upon  the  surface.  Fresh  sewage  thrown  upon  grass  is  inoffensive, 
except  to  the  sight,  unless  deposited  in  such  amounts  in  the  same  place 

Fig.  90. 


Field  flushing  tank. 

as  to  cause  miring  of  the  ground,  cessation  of  oxidation,  and  consequent 
putrefaction.  It  is,  of  course,  necessary  that  the  screened  matters  be 
removed  frequently  and  buried  or  burned,  and  that  the  reservoir  be 
cleansed  at  regular  intervals. 

5.  Sewage  Filtration. — The  method  of  intermittent  filtration  of 
sewage  is  the  same  in  principle  as  the  process  described  in  the  chapter 
on  Water.  Like  that,  it  is  more  than  a  mechanical  separation  of  sus- 
pended matters  :  it  is  a  process  of  screening,  oxidation,  and  eventually 
almost  complete  purification,  much  like  sewage  irrigation.  As  early  as 
1836,  Bronner,  of  Heidelberg,  endeavoring  to  learn  the  reason  why 
the  constituents  of  fertilizers  in  solution  failed  to  reach  the  deeper 
layers  of  the  soil,  filled  a  bottle,  having  a  small  hole  in  the  bottom, 
with  sifted  garden  soil  and  poured  in  gradually  a  thick  stinking  manure 
juice,  and  observed  the  character  of  the  effluent,  which  he  found  to  be 
almost  odorless  and  colorless,  and  devoid  of  fertilizing  properties. 


METHODS  OF  SEWAGE  DISPOSAL.  501 

But  the  system  of  sewage  purifioation  by  this  means  had  its  begin- 
ning within  recent  years  at  the  experiment  station  at  Lawrence  under 
the  direction  of  the  Engineering  Department  of  the  State  Board  of 
Health  of  Massachusetts,  and  is  now  in  actual  use  by  many  munici- 
palities in  this  country  and  abroad.  The  filter  beds  are  made  best  of 
sand,  not  finer  than  0.2  mm.  grain  size,  and  gravel.  Ordinary  loams, 
clays,  and  peat  are  practically  useless  as  filtering  materials,  on  account 
of  the  difficulty  with  which  water  passes  through  them.  The  purifying 
agents  are  the  bacteria  which  are  soon  established  within  the  interstices, 
and  these  include  both  anaerobic  and  aerobic  varieties.  In  order  that 
both  kinds  may  perform  their  office,  the  application  of  the  sewage 
should  alternate  with  thorough  aeration  of  the  bed.  Unless  the  appli- 
cation be  intermittent,  the  anaerobic  action  alone  is  encouraged  and  the 
process  fails.  Where  sand  of  the  right  sort  is  not  obtainable,  many 
other  materials  as  coke,  burnt  clay,  coal  dust,  and  cinders,  have  been 
used  as  substitutes. 

It  is  unnecessary  to  disturb  the  main  body  of  the  filter  after  the 
process  has  been  started ;  but  on  account  of  the  tendency  of  solid  ma- 
terials, such  as  paper,  etc.,  to  accumulate  in  the  upper  layers,  it  is  found 
necessary  to  rake  or  dig  over  the  surface  as  often  as  the  indications 
point  out.  According  to  Mr.  X.  H.  Goodnough,^  of  the  Engineering 
Department  of  the  State  Board  of  Health  of  Massachusetts,  the  beds 
of  four  of  the  filters  at  the  Lawrence  station,  after  ten  years'  continu- 
ous operation,  required  only  a  weekly  raking  and  a  semi-annual  spad- 
ing to  a  depth  of  six  to  eight  inches.  In  five  years,  it  had  not  been 
necessary  to  remove  any  of  the  clogged  sand  for  renewal  of  the  sur- 
face. During  the  tenth  year,  more  than  90  per  cent,  of  the  organic 
matter  of  the  very  strong  Lawrence  sewage  was  removed,  and  also  more 
than  99  per  cent,  of  the  contained  bacteria. 

It  has  been  shown  by  the  experiments  at  Lawrence  that  100,000 
gallons  of  crude  sewage  per  day  may  be  purified  during  all  but  the 
colder  months  of  the  year  by  each  acre  of  filter  underdrained  at  a  depth 
of  three  to  five  feet.  And  even  in  winter,  there  is  no  great  difficulty 
in  disposing  of  almost  as  large  volumes  if  the  beds  are  properly  looked 
after,  and  provided  the  sewage  is  delivered  in  large  volumes  at  a  time. 
With  delivery  of  small  quantities,  there  is  more  danger  of  freezing. 

It  should  be  borne  in  mind  that  the  sewage  of  many  kinds  of  manu- 
facturing establishments  is  not  suited  to  sand  filters  or  other  processes 
which  depend  for  their  efficiency  on  micro-organisms,  because  of  con- 
taining chemicals  which  will  destroy  the  life  of  these  necessary  agents. 
Thus,  in  the  single  industry  of  tanning,  at  least  two  substances  are 
used  which  interfere  with  bacterial  growth.  In  the  first  place,  green 
skins  are  quite  likely  to  be  preserved  by  means  of  chemical  disinfec- 
tants (sulfonaphtol),  and,  in  the  second  place,  when  the  skins  are  soaked 
preparatory  to  having  the  hair  removed,  large  quantities  of  chemicals, 
such  as  arsenic  sulj)hide  and  lime,  mixed  together,  are  used  to  facilitate 
the  process.  Sewage  containing  these  substances  in  sufficiently  large 
'  Journal  of  the  Massachusetts  Association  of  Boards  of  Health,  July,  1898. 


502  DISPOSAL   OF  SEWAGE. 

amount,  if  applied  directly  to  a  sand  filter,  will  quickly  interfere  with 
its  efficiency  by  destroying  the  nitrifying  organisms.  Sewage  from  this 
industry  contains,  in  addition,  such  a  very  large  amount  of  organic  matter 
in  suspension,  that  if  applied  directly  to  a  sand  filter,  it  will  cause 
clogging  very  quickly.  Hence  this  and  other  industrial  sewage  of  ob- 
jectionable character  should  be  submitted  to  sedimentation  or  other 
treatment,  according  to  its  nature,  as  a  preliminary  to  sand  filtration. 
It  has  been  found  that  arsenic,  for  instance,  may  be  removed  completely 
by  passing  the  sewage  through  coke  breeze.  "  The  removal  is  probably 
due  to  a  combination  of  the  arsenic  with  the  iron  in  the  coke,  and  the 
formation  of  an  insoluble  double  salt  of  iron  and  arsenic,  which  is 
retained  in  the  coke."  ^  Filtration  through  coke  has  also  been  found 
efficient  in  removing  the  organic  matters,  even  when  the  sewage  is 
applied  at  the  rate  of  250,000  to  300,000  gallons  per  acre  daily. 
Other  kinds  of  industrial  sewage  may  contain  other  objectionable  sub- 
stances which  may  tend  to  clog  the  filter,  as  grease,  soap,  and  other 
materials,  and  these  may  require  special  treatment.  The  importance 
of  guarding  against  injury  to  the  nitrifying  organisms  by  special  sew- 
ages should  be  borne  in  mind,  and  also  that  if  the  process  be  stopped 
in  winter,  it  cannot  be  renewed  until  the  return  of  warm  weather. 

6.  Other  Biological  Processes:  Dibdin's  "Bacteria  Bed." 
Cameron's  "  Septic  Tank,"  etc. — As  an  outcome  of  experiments  in 
the  farther  purification  of  the  effluent  of  chemically  treated  sewage, 
sprang  the  method  known  as  that  of  Dibdin's  Bacteria  Filter.  With 
the  idea  that  purification  in  a  filter  bed  is  not  brought  about  wholly  at 
the  surface,  but  that  the  whole  bulk  of  the  filter  is  concerned  therein, 
experiments  were  made  to  determine  the  result  of  filling  a  bed  and 
restraining  the  outflow  for  different  periods,  thus  giving  the  organ- 
isms throughout  the  bed  the  same  opportunity  for  action.  When 
the  contents  were  allowed  to  run  off  through  the  underdrains,  the  in- 
terstices of  the  bed  became  filled  with  air  by  inspiration,  and  after 
standing  thus  for  a  time,  the  process  of  filling,  standing,  and  emptying 
was  repeated  continuously  for  six  days,  and  then  an  interval  of  twenty- 
four  hours  was  allowed  for  complete  aeration.  The  results  obtained 
were  most  promising.  During  the  first  month,  running  at  the  rate  of 
half  a  million  gallons  daily,  the  purification,  measured  by  the  albumi- 
noid ammonia,  ran  between  70  and  80  per  cent.,  and  after  a  full  month 
reached  83  per  cent.  The  effluent  was  then  so  pure  that  fish,  placed 
in  it,  lived  many  weeks.  Later  on,  the  plan  adopted  comprised  two 
hours  for  filling,  one  for  standing  full,  and  five  for  emptying,  so  that 
the  cycle  was  completed  in  eight  hours.  Passing  filtrate  at  the  rate  of 
a  million  gallons  a  day  for  eight  weeks,  the  bed  was  found  to  show  78 
per  cent,  of  purification.  The  good  results  were  observed  to  be  yielded 
even  when  the  weather  was  so  cold  that  ice  formed  on  the  surface. 
From  these  experiments  it  appears,  therefore,  that  the  purifying 
capacity  of  a  filter  may  be  expressed  in  terms  of  cubic  as  well  as 
of  surface  measure. 

^  Report  of  the  State  Board  of  Health  of  Massachusetts  for  1896,  p.  430. 


METHODS  OF  SEWAOE  DISPOSAL.  503 

In  consequence  of  the  favorable  results  of  these  experiments,  Mr. 
Dibdin  recommended  similar  treatment  for  crude  sewage,  and  in  No- 
vember, 1896,  the  process  was  iustituted  at  Sutton.  An  average  of 
29,165  gallons  per  day,  equal  to  773,000  gallons  per  acre  per  day, 
was  treated  with  good  results,  the  purification  amounting  to  66  per 
cent.  The  effluent  was  treated  farther  on  other  beds,  and  thus  a  total 
reduction  of  86.5  per  cent,  was  brought  about.  The  effluents  were 
nearly  inodorous  ;  the  slight  odor  suggested  freshly  turned  garden  soil. 
During  the  76  days  of  observation,  the  suspended  solids  disposed  of 
by  bacterial  agency  amounted  to  the  equivalent  of  more  than  a  ton  of 
sludge  daily,  so  that  not  only  was  purification  eifected  much  more 
simply  and  cheaply  than  by  chemical  treatment,  but  the  annoying 
and  expensive  matter  of  sludge  disposal  was  done  away  with  entirely. 

For  the  disjaosal  of  a  million  gallons  of  sewage  per  day,  Mr.  Dib- 
din ^  recommends  as  follows  :  Before  being  passed  on  to  the  beds,  the 
sewage  should  be  screened,  in  order  to  remove  mechanically  as  much 
of  the  suspended  matters  as  possible,  and  these  may  be  burned  or 
buried.  The  finer  solids  "  if  placed  upon  a  filter  constructed  in  the 
ordinary  manner  with  a  stratum  of  fine  material  upon  the  surface,  will 
at  once  form  a  layer  of  slimy  mud,  impeding  the  progress  of  the  water 
into  the  pores  of  the  filter,  and  preventing  the  entrance  of  air  so  neces- 
sary for  the  healthy  life  processes  of  the  bacteria,  with  the  result  that 
in  a  short  time  the  whole  mass  becomes  putrid,  and  the  '  filter '  is  a 
faihire. 

"  The  first  set  of  bacteria  beds  should,  to  be  on  the  safe  side, 
have  a  collective  capacity  of  160,000  cubic  feet,  divided  into,  say, 
nine  partitions.  These  beds  should  be  filled  with  either  coke,  burnt 
ballast,  or  other  suitable  substance  which  has  been  rejected  by  a  half- 
inch  mesh,  in  order  to  exclude  dust  and  small  stuff,  and  thus  lessen  the 
ohance  of  clogging  from  the  accumulation  of  sludge  and  the  zooglea 
form  of  bacteria,  which,  by  its  gelatinous  character,  under  favorable 
conditions  might  develop  to  a  sufficient  extent  to  assist  materially  in 
rendering  the  filter  water-logged.  ...  In  addition  to  this  set  of 
beds  filled  with  coarse  stuff,  a  second  series  of  the  same  capacity  should 
be  constructed  at  such  a  level  that  they  can  be  filled  without  pumping 
from  the  first.  These  should  be  filled  with  the  fine  coke  or  ballast 
passed  by  the  sifting  in  the -first  instance,  but  the  fine  dust  should  be 
rejected. 

"  If  it  should  be  desired  to  obtain  a  still  more  perfect  effluent,  and 
thus  to  realize  the  ideal  of  perfection,  namely,  an  approach  to  drinking- 
water,  another  set  of  filter  beds  of  the  same  area  as  the  foregoing  may 
be  provided  in  those  cases  where  the  levels  permit,  and  filled  with 
very  fine  breeze  or  fine  sand,  such  as  that  used  by  the  water  com- 
panies." The  beds  of  each  series  are  to  be  filled  in  order,  and  when 
No.  8  is  filled.  No.  1  is  ready  for  its  second  charge,  and  so  on.  Allow- 
ing one  hour  for  filling,  two  for  resting  full,  one  for  emptying,  and 
three  for  resting  empty,  each  bed  can  receive  three  changes  in  twenty- 
'  Purification  of  Sewage  and  Water,  London,  1S97,  p.  129. 


504  DISPOSAL   OF  SEWAGE. 

four  hours.  The  ninth  bed  is  to  be  held  in  reserve  to  replace  any  one 
which  may  be  thrown  out  of  action,  and  "  it  would  be  a  useful  arrange- 
ment to  systematically  throw  one  tank  out  of  action  each  day,  thus 
giving  them  all  a  day's  rest  once  in  nine  days."  The  efficiency  of  the 
various  beds  may  be  determined  occasionally  by  testing  the  filtrate  for 
nitrates,  the  presence  of  which  in  fairly  regular  amount  is  evidence  of 
unimpaired  activity. 

According  to  Dr.  Clowes,^  the  first  effluent  of  the  experimental  coke 
beds  at  Crossness  for  the  treatment  of  London  sewage  is  of  such  a 
character  that  fish  can  live  in  it  for  months.  The  whole  of  the  sus- 
pended matter  and  51.3  per  cent,  of  oxidizable  and  putrescible  matters 
are  removed  by  a  single  treatment.  Double  treatment  raises  the  per- 
centage from  51.3  to  69.2.  The  deposition  of  cellulose  in  various 
forms,  as  cotton,  paper,  woody  matters,  straw,  and  chaff,  which  matters 
do  not  appear  to  be  acted  upon  to  any  extent  by  bacteria,  causes  con- 
siderable clogging  of  the  interstices,  and  hence  reduces  the  capacity  of 
the  filter.  It  was  estimated  that  the  reduction  amounted  to  about  a 
third  in  ten  months. 

At  Sutton,  it  should  be  said,  there  is  a  catchpit  to  intercept  the 
heavier  matters,  and  also  a  very  efficient  screening  machine  ;  and  since 
the  sewage  comes  down  in  so  fresh  a  condition  that  neither  the  paper 
nor  the  solid  faeces  have  had  a  chance  to  disintegrate,  a  very  large  per- 
centage of  organic  matter  never  reaches  the  filter  at  all. 

The  Cameron  "  Septic  Tank  "  process  is  one  in  which  the  anaerobic 
bacteria  are  first  utilized  for  the  purpose  of  hastening  decomposi- 
tion of  the  organic  matters.  Contrary  to  the  general  opinion  that 
sewage  ought  always  to  be  treated  before  the  beginning  of  putrefac- 
tion, in  this  system  the  sewage  is  kept  in  storage  tanks  out  of  contact 
with  light  and  air  until  the  organic  matter  is  broken  down,  and  then 
is  passed  on  to  bacteria  beds,  where  the  aerobic  forms  continue  the 
work. 

The  first  attempt  at  purification  of  town  sewage  by  this  system 
was  instituted  at  St.  Leonard's,  a  suburb  of  Exeter,  England,  by 
Mr.  Donald  Cameron,  whose  initial  plant  consisted  of  an  under- 
ground covered  tank,  sixty-four  feet  long,  eighteen  feet  deep,  and  of 
an  average  depth  of  a  little  more  than  seven  feet,  and  five  Dibdiii 
bacteria  beds  filled  with  coke  breeze  and  clinkers.  The  crude  sewage,, 
before  entering  the  tank,  passes  first  into  a  grit  chamber,  which  is 
three  feet  deeper  than  the  tank,  and  in  this  the  heavy  matters  fall  and 
are  detained,  but  may  be  removed  without  interruption  of  the  process 
in  operation  within  the  tank.  The  sewage  is  not  screened  in  any  way, 
and  enters  the  tank,  after  passing  the  grit  chamber,  by  inlets  placed 
five  feet  below  the  surface.  These  are  so  placed  for  several  reasons  : 
the  scum  floating  on  the  surface  is  not  disturbed,  gases  from  the  tank 
cannot  escape  backward,  and  air  cannot  enter  the  sewage.  In  the 
tank,  the  sewage  undergoes  putrefaction,  the  organic  matters  being- 
broken  up  into  simpler  soluble  forms  and  in  great  part  converted  to 

^  Bacterial  Treatment  of  Sewage.     Second  Repoit.     London  County  Council,  1899. 


METHODS  OF  SEWAGE  DISPOSAL.  505 

carbon  dioxide,  sulphuretted  hydrogen,  ammonia,  nitrogen,  and  other- 
gases.  The  flow  through  the  tank  is  continuous,  and  the  effluent 
passes  off  through  outlets  located  at  the  farther  end  at  the  same  level 
as  the  inlets.  In  the  center  of  the  tank,  an  inspection  chamber  of 
brick  and  thick  plate  glass  is  constructed,  and  from  this  the  processes, 
going  on  may  be  observed.  At  the  surface  of  the  liquid,  a  scum 
about  two  inches  in  thickness,  consisting  of  flocculent  matter  in 
various  stages  of  decomposition,  is  formed,  much  of  it  brought  up 
from  the  bottom  by  gases  formed  in  the  process  of  decomposition. 
Throughout  the  tank,  countless  small  masses  are  seen  rising  through 
generation  of  gases  and  falling  by  their  own  weight.  Every  time  a 
particle  rises  or  falls,  it  loses  in  volume,  and  finally  it  disappears.  The 
effluent  from  the  tank,  brownish  yellow  in  color  and  offensive  in  odor,, 
is  next  admitted  to  the  bacteria  beds,  where  the  nitrifying  organisms, 
perform  their  share  of  the  work.  In  its  journey  to  these  beds,  it 
passes  in  a  thin  layer  over  the  sides  of  troughs  closed  at  both  ends^ 
and  thus  becomes  aerated  by  contact  with  the  air.  By  an  automatic 
arrangement  which  regulates  the  flow,  one  bed  remains  full  while 
another  is  being  filled,  and  after  a  certain  time  is  allowed  to  empty. 
Four  beds  are  kept  in  use,  the  fifth  resting  for  a  week.  Each  bed, 
then,  is  in  operation  four  weeks  out  of  every  five,  and  after  its  week 
of  rest,  takes  the  place  of  the  one  which  has  been  longest  in  use.  The 
accmnulation  of  sludge  in  the  tank  is  very  slight.  It  amounted  to  but 
fifteen  inches  at  the  end  of  ten  months'  trial,  during  which  time  more 
than  17,000,000  gallons  of  sewage  were  treated. 

Analysis  has  shown  that  the  organic  matters  in  solution  are  reduced 
in  amount  nearly  a  third  and  the  suspended  matters  more  than  a  half 
by  bacterial  action  within  the  tank,  and  that,  after  passing  througk 
both  the  tank  and  the  bacteria  beds,  the  sewage  loses  practically  all 
of  the  suspended  matters,  and  more  than  80  per  cent,  of  the  oxidizable 
organic  substances  in  solution.  The  effluent  from  the  beds  is  fairl}^ 
clear  and  sufficiently  pure  to  warrant  its  discharge  into  a  water  course. 
It  is  claimed  even  that  it  is  fit  to  drink. 

The  advantage  of  the  tank  lies  in  the  reduction  in  the  amount  of 
suspended  matters,  whereby  less  clogging  of  the  surface  of  the  bed 
occurs,  and  in  relieving  the  beds  of  much  of  the  work  of  disposing^ 
of  organic  matter  by  nitrification.  The  cost  of  working  is,  moreover,, 
very  slight,  inasmuch  as  the  apparatus,  by  reason  of  its  ingenious, 
system  of  automatic  gears,  requires  little  supervision.  It  is  said  that,, 
with  this  system,  as  much  as  363,000  gallons  per  acre  of  bacteria 
beds  can  be  disposed  of  daily  without  nuisance. 

The  Scott-Moncrieflf  System,  introduced  in  1896,  at  Caterham,  Eng- 
land, consists  of  a  tank  filled  with  bn»ken  flints  and  other  coarse  mate- 
rial resting  on  a  perforated  bottom,  and  a  filter  consisting  of  a  series- 
of  trays  containing  coke.  The  sewage  enters  the  tank  continuously 
beneath  the  perforated  bottom,  passes  upward  through  the  flints,  and 
in  its  passage;  is  subjected  to  the  influence;  of  the  anaerol)ic  species  of 
bacteria  alone,  excepting  that,  at  the  surfiice,  the  action  is  aerobic  ta 


506  DISPOSAL   OF  SEWAGE. 

a  slight  extent.  It  passes  thence  to  the  upper  trays  of  the  filter, 
where  the  action  is  wholly  aerobic,  and  flows  continuously  downward 
from  tray  to  tray,  becoming  more  and  more  oxidized  and  nitrified, 
the  resulting  effluent  showing  a  very  high  degree  of  purification. 
The  system  possesses  no  advantage,  however,  over  the  septic  tank, 
which,  by  reason  of  the  absence  of  filling  material  (flints,  etc.),  has 
greater  capacity  for  sewage,  and  which,  therefore,  may  be  operated  at 
lower  cost. 


CHAPTER    VII. 
DISPOSAL  OF  GARBAGE. 

Garbage  comprises  all  manner  of  waste  material,  and  its  disposal 
is  of  very  great  economic  and  sanitary  importance.  The  daily  accumu- 
lation in  towns  and  cities  is  enormous,  and  its  removal  at  regular 
intervals  is  a  matter  of  great  concern  to  municipal  administration. 
From  a  hygienic  standpoint,  the  proper  disposal  of  kitchen  waste  and 
other  decomposable  material  far  outweighs  in  importance  the  removal 
of  such  matters  as  waste  paper,  ashes,  discarded  boots  and  shoes,  tin 
cans,  bottles,  and  other  rubbish,  which  in  no  way  can  aiFect  the  public 
health,  but  which  for  various  reasons,  may  not  be  allowed  to  accumulate 
in  the  household.  In  rural  districts,  the  disposal  of  garbage  in  general 
is  exceedingly  simple ;  but  in  crowded  communities  it  entails  great  ex- 
pense, and  is  usually  a  very  complicated  problem.  Since  this  work  is 
concerned  solely  in  matters  of  sanitary  interest,  and  not  in  economics, 
the  consideration  of  this  subject  will  be  restricted  to  the  methods  of 
disposal  of  those  matters,  the  retention  of  which  on  occupied  premises 
may  be  regarded  as  detrimental  to  health,  namely,  those  known  as 
kitchen  refuse,  or  swill. 

The  methods  of  disposal  of  these  matters  comprise  those  which 
may  be  carried  out  by  the  individual  householder  on  the  spot, 
and  those  adopted  by  municipal  authority  after  house-to-house  col- 
lection. 

In  many  households,  refuse  is  disposed  of  by  burning  in  the  kitchen 
fire  with  or  without  a  preliminary  process  of  drying,  for  which  a  num- 
ber of  simple  apparatuses  have  been  devised.  A  very  efficient  arrange- 
ment in  common  use  consists  of  an  enlargement  in  the  lower  part  of  the 
vStovepipe,  forming  a  chamber  into  which,  through  a  doorway  in  the  end  or 
side,  the  refuse,  in  a  suitable  metallic  holder  with  perforated  sides  and 
bottom,  is  introduced.  Through  this  the  hot  air,  gases,  and  smoke 
from  the  fire  pass  on  their  way  to  the  chimney  flue,  and  thus  complete 
drying  and  partial  carbonization  are  brought  about.  The  dried  residue 
is  disposed  of  finally  by  burning  in  the  stove,  where  it  serves  a  useful 
purpose  as  fuel. 

In  country  and  suburban  districts,  kitchen  waste  is  advantageously 
disposed  of  by  feeding  it  in  a  fresh  and  sweet  condition  to  swine  and 
poultry,  and  depositing  in  the  soil  such  matters  as  they  will  not  eat. 
Burying  in  the  soil  is  a  simple  and  effective  method  of  disposal,  entail- 
ing but  little  labor,  since  it  is  best  not  to  deposit  it  very  deeply.  Near 
the  surface,  decomposition  occurs  rapidly,  and  so  a  covering  of  earth 
a  few  inch(;s  in  depth  is  sufficient  to  prevent  contamination  of  the 
atmosphere  with  noisome  odors. 

507 


508  DISPOSAL   OF  G  ABB  AGE. 

The  methods  adopted  by  municipal  authorities  comprise  dump- 
ing into  the  sea,  disposal  to  farmers  for  swine-feeding,  utilization 
as  food  for  herds  of  swine  kept  for  the  purpose,  and  reduction  and 
incineration  in  furnaces  of  special  construction,  known  as  destructors. 

Dumping  into  the  sea  is  open  to  the  objection  that,  under  favoring 
conditions  of  winds,  tides,  and  currents,  much  material  may  be  washed 
ashore,  and  become  a  nuisance  and  eyesore  to  the  immediate  neigh- 
borhood. 

Disposal  to  farmers  involves  cartage  over  miles  of  road  in  wagons, 
which,  if  not  leaky  for  liquid  matters,  at  least  permit  the  escape  of 
nauseous  odors,  to  the  annoyance  of  dwellers  and  travellers  along  the 
route.  It  involves,  also,  storage  for  at  least  a  short  time  after  collec- 
tion, unless  the  garbage  wagons  can  themselves  be  sent  into  the  coun- 
try— a  proceeding  which  can  hardly  be  regarded  by  taxpayers  as 
consistent  with  the  proper  management  of  municipal  revenues.  This 
period  of  storage  is,  in  effect,  a  continuation  of  that  which  has,  perhaps, 
extended  already  through  several  days  or  a  week  before  collection, 
during  which  time,  various  fermentative  processes  have  been  active  in 
the  production  of  compounds  of  offensive  character. 

Incineration  at  special  stations  for  the  destruction  of  swill  and  all 
other  combustible  rubbish  is  being  widely  adopted  by  large  communi- 
ties, and,  in  many  places,  has  proved  to  be  not  only  the  most  econom- 
ical method  of  disposal,  but  even  a  source  of  gain.  To  such  a  station 
are  brought  the  daily  collections  of  garbage,  which  at  once  undergo  a 
process  of  sorting.  Paper  and  pasteboard  are  utilized  in  the  furnaces 
as  fuel  or  are  sold  to  be  used  in  the  manufacture  of  the  cheaper  grades 
of  paper  and  cardboard  ;  old  shoes  and  boots  are  disposed  of  to  makers 
of  artificial  leather,  and  rubbers  and  overshoes  to  manufacturers  of 
rubber  goods ;  tin  cans  are  heated  to  recover  the  solder ;  pieces  of  un- 
consumed  coal  are  collected  and  used  or  sold  for  fuel ;  broken  furni- 
ture, boxes,  barrels,  and  other  wooden  objects  are  split  up  into  kindling, 
and  excelsior  stuffing  is  utilized  in  the  furnaces.  In  short,  almost 
every  kind  of  rubbish  may  be  utilized  in  some  way  to  advantage. 
The  late  Colonel  George  E.  Waring,  Jr.,  experimenting  in  New  York 
with  a  long  travelling  belt,  on  which  the  combustible  waste  from  a 
district  containing  200,000  people  was  deposited  and  picked  over, 
found  that  90  per  cent,  of  it  was  salable,  and  but  10  per  cent,  remained 
to  be  destroyed  by  fire.  In  some  establishments  now  in  operation,  a 
long,  travelling,  endless  belt  of  steel  plates  is  employed,  the  carts 
dumping  upon  it  at  one  place.  As  the  material  passes  along,  it  is 
sorted  over  quickly  by  men  on  either  side,  and  what  is  left  is  conveyed 
onward  to  a  bin,  from  which,  in  time,  it  passes  to  the  furnace,  to  serve 
to  destroy  the  kitchen  waste. 

It  would  be  impossible,  even  if  it  were  not  unnecessary,  to  give 
in  detail  a  description  of  the  many  varieties  of  machines  and  fur- 
naces Avhich  have  been  invented  for  the  incineration  of  refuse.  In 
general,  it  may  be  said  that  a  destructor  consists  of  a  furnace  with  a 
chamber,  provided  with  grate-bars,  in  which  the  dry  or  partially  drieql 


DISPOSAL   OF  GARBAGE.  509 

offal  is  burned  ;  and  a  second  chamber,  in  which  it  is  subjected  to  a 
preliminary  process  of  drying.  This  second  chamber  is  placed  behind 
the  front  compartment,  which  receives  the  dried  garbage  and  other 
combustible  material  serving  as  fuel.  In  the  best  forms,  two  fires  are 
maintained  :  one  at  the  forward  end,  and  the  second  at  the  stack  end 
of  the  furnace,  the  latter  being  designed  to  insure  complete  combustion 
of  vapors  and  dust  before  entrance  to  the  chimney,  from  which,  other- 
wise, they  might  issue  in  such  a  form  as  to  create  serious  nuisance,  not 
alone  to  the  immediate  neighborhood,  but  even  at  considerable  dis- 
tances. 

The  burning  of  the  smoke  and  fumes  is  very  essential,  and  failure 
to  provide  therefor,  or  the  unsuccessful  operation  of  the  fume  cremator, 
has  caused  the  abandonment  of  many  plants,  which,  with  better  instal- 
lation, should  have  worked  successfully  and  to  public  satisfaction. 
In  many  English  cities,  destructor  furnaces  have  been  in  operation  for 
years  in  close  proximity  to  dwellings,  schools,  and  hospitals  without 
causing  offence.  At  Ealing,  for  example,  the  furnace  is  located  at  a 
distance  of  180  yards  from  two  hospitals;  in  Whitechapel,  within  a 
very  few  yards  of  dwelling  houses  in  the  midst  of  a  very  populous 
district ;  at  Leicester,  but  a  very  few  yards  from  a  large  school  and 
immediately  adjoining  a  considerable  number  of  dwellings. 

The  fume  cremator  consists  of  a  reverberatory  arch  with  rings  of 
firebrick,  placed  in  the  direction  taken  by  the  gases.  Projecting  ribs 
deflect  the  vapors  to  the  top  of  an  intensely  hot  fire,  in  which  they  are 
destroyed.  Provision  is  made  for  rapid  removal  of  ashes,  and  for 
drafts  of  air  at  needed  points  to  maintain  a  continuous  temperature 
above  2.000°  F.  The  heat  produced  is  commonly  utilized  in  the  pro- 
duction of  steam  for  the  engine  which  does  the  necessary  hoisting  and 
other  work,  and  drives  the  shafting  connected  with  the  endless  belt  and 
other  appliances.  Another  most  useful  and  economical  application  is 
the  utilization  of  the  great  store  of  energy  for  maintaining  electric- 
light  plants  for  lighting  the  premises,  and  even  the  public  streets.  In 
New  York  and  Boston,  the  surplus  energy  is  utilized,  but  at  most 
other  plants  in  the  54  cities  and  towns  of  this  country  which,  in  1899, 
were  using  the  process,  the  heat  is  wasted. 

At  the  beginning  of  1899,  81  communities  in  Great  Britain  were 
employing  incineration  as  the  chief  means  of  disposal  of  refuse,  and  76 
of  them  turned  the  developed  heat  to  some  usefiil  purpose.  About  a 
third  of  the  number  use  the  power  for  electric  lights  for  the  works  or 
streets,  or  both  together  ;  nearly  two-thirds  maintain  mills  for  grinding 
materials  for  mortar  and  clinkers  for  pathways  ;  six  employ  the  steam 
for  the  purpose  of  juiblic  disinfection  ;  several,  for  pumping  sewage,  and 
others,  for  various  useful  purposes.  In  one  city,  3,000,000  gallons  of 
sewage  arc  pumped  through  a  twenty-foot  lift,  the  works  are  lighted 
by  electricity,  the  shops  and  forges  of  the  municipal  service  are  sup- 
plied with  power,  and  other  work  also  is  jierformed. 

Reduction. — In  the  reduction  ])i-(jcess,  the  kitchen  garbage  is  stored 
in  laiiks  \vhi(;h   pcnnit  the  draining  away  of  most  of  the  water,  which 


510  DISPOSAL   OF  GARBAGE. 

is  conducted  directly  to  a  sewer.  Next  it  is  dried  in  cylindrical 
steam-jacketed  chambers,  into  which  hot  air  and  superheated  steam  are 
conducted,  the  process  requiring  about  six  hours.  The  material  loses 
about  three-fourths  of  its  weight,  which  passes  oif  in  the  form  of  aque- 
ous vapor  and  is  condensed  and  discharged  into  the  sewer ;  the  non- 
condensible  stinking  vapors  are  disposed  of  in  the  vapor  cremator 
connected  with  the  boilers  in  which  the  steam  is  generated.  The  dried 
residue  is  next  introduced  into  tanks  of  naphtha,  and  the  whole  is  heated 
by  steam  coils  until  all  grease  has  been  removed,  when  the  naphtha 
solution  is  separated.  This  is  then  distilled,  the  naphtha  passing  over 
and  being  reclaimed  for  repeated  use,  and  the  fat  remaining  behind  as 
a  valuable  product.  The  extracted  residue  is  dried  again  and  worked 
up  into  fertilizer. 

Reduction  methods  are  applicable  only  to  large  cities,  and  since  it  is 
almost  impossible  to  conduct  the  works  without  creating  a  nuisance, 
these  should  be  located  at  such  a  distance  from  a  community  that  the 
value  of  property  may  not  be  impaired,  and  the  daily  enjoyment  of 
life  may  be  in  no  way  sensibly  abridged.  If  the  amount  of  collectable 
kitchen  waste  is  sufficiently  large,  say  that  from  a  population  of  at 
least  150,000,  and  if  the  works  can  be  so  placed  as  to  cause  no  nuisance 
and,  at  the  same  time,  not  to  necessitate  a  long  and  expensive  haul  of 
the  material,  reduction  has  been  found  to  fulfil  both  the  sanitary  and 
the  economic  requirements,  the  yield  of  grease  and  fertilizer  having 
considerable  value,  thus  reducing  materially  the  cost  of  disposal.  But, 
as  in  the  case  of  sewage,  it  should  be  borne  in  mind  that  the  removal 
and  disposal  of  waste  are  sanitary  measures,  and  should  not  be  viewed 
too  much  from  the  standpoint  of  profit-making. 

If  the  quantity  of  garbage  collected  is  too  small  to  warrant  treatment 
by  reduction  processes,  it  may  be  burned  to  advantage  in  destructors. 
A  combination  of  the  two  methods,  reduction  and  cremation,  would 
seem  to  be  the  most  advantageous  for  communities  producing  a  very 
large  daily  amount  of  general  wastes.  But  the  possibility  of  nuisance 
from  all  reduction  works,  a  nuisance  which  has  caused  the  abandon- 
ment of  the  great  majority  of  the  plants  which  have  been  installed  in 
this  country,  should  ever  be  borne  in  mind,  even  though  the  nuisance 
be  limited  to  a  small  percentage  of  the  population,  who,  if  they  com- 
plain, are  regarded  by  the  rest  as  unduly  sensitive,  prone  to  magnify 
small  discomforts  and  give  them  a  factitious  importance,  and  incon- 
siderate of  the  general  w^elfare,  which,  even  if  true,  can  not  deprive 
them  of  their  right  to  appeal  to  the  courts  for  the  abatement  of  the 
cause  of  their  discomfort. 


CHAPTEK    VIII. 

DISINFECTANTS  AND  DISINFECTION. 

Disinfectants,  or  germicides,  are  agents  which  bring  about  the 
destruction  of  bacteria  in  general,  and,  more  particularly,  of  those  that 
act  as  the  exciting  causes  of  disease.  While  they  are  all  to  be  classed 
as  antiseptics,  the  latter,  as  a  class,  are  by  no  means  necessarily  disin- 
fectants, since  many  of  them  act  simply  to  delay  or  prevent  the  action 
of  fermentative  agents,  without  exerting  any  destructive  influence  upon 
them.  Cold,  for  example,  is  a  most  efficient  antiseptic ;  but  while  it 
may  inhibit  growth  and  activity  of  micro-organisms,  it  does  not  neces- 
sarily deprive  them  of  vitality. 

Deodorants  are  agents  which  remove  or  mask  disagreeable  odors,  but 
they  are  not  necessarily  disinfectants.  Some  deodorants  are  efficient 
disinfectants,  but  not  all  disinfectants  are  efficient  deodorants.  The 
latter  are  largely  substances  which,  being  of  strong,  peculiar  odor,  are 
used  to  overcome  or  supersede  disagreeable  odors,  but  without  exerting 
any  influence  upon  the  causes  thereof.  Odors  may  or  may  not  be  a 
concomitant  of  infectious  matter  according  to  circumstances  ;  and  when 
so,  the  mere  fact  of  their  being  overwhelmed  by  a  more  powerful  rival 
smell  has  no  influence  on  the  vitality  of  the  bacteria  present.  Some 
deodorants  remove  smells  without  the  creation  of  another,  and  without 
exerting  any  action  upon  their  causes  ;  such  are  charcoal  and  ordinary 
earth. 

The  function  of  disinfectants  is  the  destruction  of  morbific  agents  so 
that  they  shall  not  spread  infective  diseases.  They  are  not  curative  of 
the  infected  person,  but  are  preventive  of  the  spread  of  the  disease 
from  that  person  to  others.  An  efficient  disinfectant  for  general  pur- 
poses should  possess  the  property  of  killing  not  this  and  that  species  of 
bacteria,  but  one  and  all,  and  their  spores  as  well.  Some  pathogenic 
bacteria  have  a  tolerance  for  certain  disinfectants,  and  may  acquire  one 
gradually  for  certain  others.  Such  agents  cannot,  therefore,  be  in- 
cluded among  the  efficient  class  for  general  use.  For  special  work  in 
destroying  the  infective  agents  of  certain  diseases,  disinfectants  which 
have  been  proved  to  exert  a  destructive  influence  on  the  particular  or- 
ganisms may  be  used,  although  they  have  failed  to  show  an  equal  power 
against  other,  more  resistant,  varieties.  Disinfectants  may  be  divided 
into  two  classes,  namely  :  1.  Physical  agents.     2.  Chemical  agents. 

PHYSICAL  AGENTS. 

The  physical  agents  are  :   1.  Light.      2.  Heat. 

Light. — Direct  sunlight  is  one  of  the  most  important  disinfectants 
known.     It  retards  the  growth  of  many  organisms,  and,  after  a  vary- 

611 


•512  DISINFECTANTS  AND  DISINFECTION. 

ing  number  of  hours  of  exposure,  completely  destroys  the  vitality  of 
a  number  of  the  most  important  pathogenic  bacteria,  including  some 
generally  recognized  as  highly  resistant.  Diifused  daylight  and  electric 
light  also  are  effective,  but  in  a  much  diminished  degree. 

Koch^  announced,  in  1890,  that  the  bacillus  of  tuberculosis  is  killed 
by  direct  sunlight  in  from  a  few  minutes  to  several  hours,  according  to 
the  thickness  of  the  layer  of  material  in  which  it  is  exposed,  and  by 
diffused  light  in  from  5  to  7  days.  Dr.  Franz  Migneco  ^  exposed  tuber- 
culous sputum  on  linen  and  woollen  fabrics  to  direct  suulight,  and 
found  that,  provided  the  layer  was  not  too  thick,  the  bacilli  could  not 
resist  longer  than  from  24  to  30  hours.  The  virulence  was  observed 
to  diminish  gradually  after  10  to  15  hours,  and  to  disappear  completely 
after  24  to  30  hours. 

Janowski,^  experimenting  with  the  typhoid  fever  bacillus,  discovered 
that  that  organism  failed  to  grow  when  planted  in  bouillon  and  exposed 
for  6  hours  to  direct  sunlight ;  and  that,  in  bouillon,  exposed  8  hours 
out  of  every  day  to  diffused  light  and  kept  in  the  dark  the  rest  of  the 
time,  its  development  was  much  delayed,  but  in  the  same  medium,  kept 
wholly  in  the  dark,  cloudiness  was  observed  in  from  16  to  20  hours. 
That  this  action  is  not  due  to  increase  in  temperature,  was  shown  first 
by  Saverio,*  who  exposed  gelatin  cultures  of  the  organisms  of  typhoid 
fever,  anthrax,  and  cholera,  and  SkiphyloGoccus  pyogenes  aureus,  to  sun- 
light and  electric  light  for  from  2  to  47  hours,  and  made  careful  obser- 
vations of  the  temperatures  within  the  tubes.  He  discovered  that  the 
most  energetic  action  was  not  coincident  with  high  temperatures, 
although  the  latter  hastened  the  beginning  of  the  process.  The  action 
of  electric  light  was  much  less  energetic  than  that  of  direct  sunlight. 
Anthrax  spores  were  destroyed  almost  as  quickly  as  the  bacilli,  and 
after  a  certain  length  of  time  their  virulence  progressively  diminished. 
The  red  and  infra-violet  rays  appeared  to  exert  no  bactericidal  proper- 
ties. 

Geissler  ^  found  that  direct  sunlight  exerts  a  more  powerful  influence 
on  cultures  of  the  bacillus  of  typhoid  fever  than  an  electric  light  of  a 
hundred-candle  power  at  a  distance  of  a  meter,  and  advanced  the  prop- 
osition that  the  effects  on  the  bacteria  are  due  in  part  to  changes 
brought  about  in  the  character  of  the  culture  media.  That  the  action 
of  sunlight  is  chemical,  is  shown  by  the  differences  in  the  capacity  of 
the  different  rays  for  producing  results,  the  ultra-violet  being  endowed 
with  the  greatest  power. 

This  change  in  the  character  of  the  culture  media  has  been  noted  also 
by  Kruse,^  who  found  that  liquid  media,  containing  complex  nitrogenous 
substances,  are   so  altered  by  the  influence  of  light  that  they  acquire 

'  Vortrag  auf  dem  zehnten  internatioiialen  medicinisclien  Congresse,  1890. 

^  Archiv  fiir  Hygiene,  XXV.,  p.  361. 

^  Centralblatt  fiir  Bakteriologie,  VIII.,  p.  6. 

*  Annali  delFistituto  d'igiene  sperimentale  della  reale  universita  di   Eoma,   II., 
Serie  2,  p.  121. 

*  Centralblatt  fiir  Bakteriologie,  XL,  Nos.  6  and  7. 

°  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XIX.,  p.  313. 


PHYSICAL  AGENTS.  513 

antiseptic  properties  against  the  bacteria,  and  that  the  change  is  pro- 
portionate to  the  intensity  of  the  light  and  the  duration  of  the  exposure. 
It  is  due  directly  to  the  atmospheric  oxygen,  which,  according  to 
Moment,^  is  simply  assisted  by  the  light,  which  by  itself  would  have 
but  little  effect  But  it  is  not  alone  through  changes  in  the  media  that 
bacteria  are  killed,  but  through  changes  brought  about  within  them- 
selves as  well  And,  indeed,  it  has  been  demonstrated  that  not  alone 
bacteria,  but  their  toxins  also,  are  affected.  According  to  Fermi  and 
Celli,^  the  toxin  of  tetanus,  diluted  with  distilled  water  and  exposed  to 
direct  sunlight  at  temperatures  between  40°  and  50°  C,  is  rendered 
inert  in  8  hours,  and  at  37°  C,  in  15  hours.  In  dried  condition,  it 
loses  its  power  after  4  hours. 

Moisture  and  access  of  air  are  also  important  factors,  as  has  been 
shown  by  Momont,  who  found  that  anthrax  bacilli  in  a  moist  state 
were  killed  in  2.5  hours  with  free  access  of  air,  and  survived  more 
than  50  hours  when  air  was  excluded.  Dry  bacilli  were  killed  with 
access  of  air  in  5  hoars  ;  dry  spores,  exposed  in  glass  without  air,  were 
virulent  after  110  hours,  and  proved  to  be  more  resistant  than  others  in 
a  moist  state. 

The  rapidity  of  action  of  sunlight  is  influenced  also  by  the  number 
■of  bacteria  present  —  the  greater  the  number,  the  longer  the  time 
required  for  the  bactericidal  effect  to  be  instituted. 

The  sterilizing  influence  of  sunlight  on  the  bacteria  of  drinking- 
water  and  sewage  has  been  demonstrated  by  Procaccini,  Buchner  and 
Minck,  and  others  to  be  very  considerable,  especially  at  and  near  the 
surface.  Procaccini^  obtained  positive  results  at  a  depth  of  from  26 
to  30  centimeters.  Minck  and  Buchner  *  found  that  water  containing 
100,000  B  coll  communis  to  the  cubic  centimeter  was  rendered  sterile 
m  an  hour.  The  bacilli  of  typhoid  fever  and  cholera,  and  B.  pyo- 
cyaneus  also  were  found  to  be  destroyed.  Cultures  of  B.  ty2:)hosus, 
exposed  at  a  depth  of  about  5  feet,  were  sterilized  in  4^  hours,  but  at 
twice  that  distance  beneath  the  surface  the  action  virtually  ceased. 
Buchner^  found,  farther,  that  diffused  light  has  a  strong  influence, 
even  as  late  in  the  year  as  November,  on  B.  coli  communis  and  B. 
pyocyaneus.  The  action  of  light  is  considerably  interfered  with  by 
particles  in  suspension,  but  with  fairly  clear  water  the  effects  are  per- 
ceptible at  a  depth  of  about  6  feet.  The  action  of  sunlight  on  bacteria 
in  the  presence  of  water  is  believed  by  many  to  be  due  to  the  produc- 
tion of  hydrogen  peroxide. 

The  obvious  disadvantages  of  relying  upon  sunlight  for  practical 
disinfection  are  that  its  supply  is  beyond  control,  and  that,  even  on 
the  brightest  days,  it  is  impossible  to  apply  it  to  all  parts  of  a  house. 
Nevertheless,  its  beneficent  action  may,  under  favoring  conditions,  be 

'  Annales  rle  I'lnstitut  Pasteur,  1892,  p.  28. 
2  Centralblatt  fiir  Bakteriologie,  XII.,  No.  18. 

■''  Annali  dell'iHtituto  d'icriene  sneriraentale  della  reale  universita  di  Roma,  IIL. 
p.  437  b  1  -^        » 

*  Centr.ilhlaU,  fiir  Bakteriologie,  etc.,  XI.,  p.  781. 

*  Archiv  fur  Hygiene,  XVIL,  p.  177. 

.33 


514  -     DISI^'FECTANTS  AND  DISINFECTION. 

taken  advantage  of  in  the  treatment  of  furniture,  hangings,  and  deco- 
rations, often  the  most  troublesome  objects  to  disinfect,  especially  in  a. 
country  practice. 

Heat. — For  purposes  of  disinfection,  heat  is  employed  as  "  dry 
heat,"  i.  e.,  hot  air,  and  "  moist  heat,"  i.  e.,  steam  and  boiling  water. 
Steam  is  employed  under  various  pressures  in  both  the  saturated  and 
superheated  conditions.  In  both  conditions  it  is  actually  dry,  although, 
as  very  commonly  understood,  saturated  steam  is  associated  with  the 
idea  of  moisture.  "Wet"  steam  is  partially  condensed  saturated 
steam,  and  contains  suspended  particles  of  water.  The  temperature  at 
which  steam  is  formed  depends  upon  the  pressure ;  and  whatever  the 
temperature  and  pressure,  as  ebullition  begins  and  proceeds,  the  M'ater 
is  maintained  at  that  temperature,  and  is  converted  constantly  into 
steam,  in  which  the  heat  employed  becomes  latent.  Until  all  the 
water  has  become  converted,  the  resulting  steam  is  said  to  be  saturated^ 
since  any  vapor  in  the  presence  of  the  liquid  from  which  it  originates 
and  in  thermal  equilibrium  is  necessarily  saturated.  In  the  saturated 
state,  it  can  neither  do  work  by  expansion  nor  be  cooled  without 
undergoing  partial  condensation. 

When  saturated  steam  is  farther  heated,  its  temperature  rises,  and  it 
is  then  known  as  superheated;  and  then,  having  a  temperature  higher 
than  the  condensing  point  corresponding  to  its  actual  density  and 
volume,  it  may  be  cooled  and  can  do  work  by  expansion  without  being 
condensed.  When  very  much  superheated,  it  behaves  more  and  more 
like  a  perfect  gas,  while  saturated  steam  differs,  as  a  rule,  considerably. 
If  water  at  the  temperature  of  superheated  steam  be  mixed  with  the 
latter,  some  of  it  will  be  vaporized  and  taken  up ;  but  mixed  with 
saturated  steam  at  the  same  temperature,  no  such  action  will  occur. 

According  to  Rideal,^  the  first  recorded  experiments  in  the  sterilizing 
of  organic  matter  by  the  application  of  heat  were  those  of  Needham, 
made  prior  to  and  during  the  year  1743,  and  the  first  application  of 
this  agent  to  disinfection  on  a  large  scale  was  made  in  1831  by  Dr. 
Henry,  F.R.S.,  who  treated  infected  clothing  with  hot  air,  and  showed 
that  the  clothing  of  scarlet  fever  patients,  subjected  to  a  temperature 
of  200°  F.  for  two  to  four  hours,  would  not  propagate  the  disease  if 
worn  by  healthy  persons.  The  first  use  of  direct  steam  as  a  dis- 
infectant was  made  under  the  direction  of  Dr.  A.  N.  Bell,  U.S.N., 
in  the  case  of  the  steamer  Vixen  and  schooner  Mahones,  which  were 
infected  with  yellow  fever  while  on  service  in  the  Mexican  war  in 
1848.  Knowing  of  this  use  and  its  observed  results,  at  the  Quaran- 
tine and  Sanitary  Convention  held  in  Boston,  Mass.,  in  June,  1860, 
the  committee  recommended  that  "  steam  generators  and  steam  jackets 
or  vats  be  provided  for  the  disinfection  of  all  personal,  hospital,  and 
ship's  clothing  and  bedding,  together  with  such  other  infected  goods  or 
things  as  may  properly  be  subjected  to  high  steam  heat."  ^ 

In  1862,  according  to  Dr.  Bell,  the  U.  S.  Transport  Delaware  was 

^  Disinfection  and  Disinfectants,  London,  1898,  p.  20. 
^  The  Sanitarian,  June,  1897. 


PHYSICAL  AGENTS.  515 

disinfected  by  steam  at  the  New  York  Quarantine  Station  on  account 
of  yellow  fever,  this  being  the  first  disinfection  of  a  vessel  at  that 
station,  and  probably  the  first  at  any  of  the  port  quarantines.  Accord- 
ing to  the  same  authority,  Commander  Ralph  Chandler,  of  the  U.  S.  S. 
Don,  from  Santa  Cruz,  W.  I.,  reported  to  the  Navy  Department  that 
his  vessel  had  been  infected  with  yellow  fever  in  its  worst  form  (23 
cases  with  7  deaths),  and  that  he  had  disinfected  the  ward  room  and 
berth  deck  successfully  by  means  of  steam.  He  recommended  that 
vessels  destined  for  service  in  the  West  Indies  be  provided  with  means 
of  steaming  the  lower  decks  and  holds. 

Dry  Heat. — Dry  heat  is  much  less  effective  than  moist  heat,  even  at 
much  higher  temperatures  and  with  longer  exposure.  Thus,  air  at 
300°  F.  requires  three  or  four  times  as  long  to  accomplish  the  same 
work  as  steam  at  212°,  and  possesses  the  additional  disadvantage  of 
injuring  fabrics  and  other  objects  exposed  to  it.  Most  fabrics  of  cot- 
ton, linen,  and  silk  will  withstand  an  exposure  of  several  hours  to  dry 
heat  at  230°  F.,  but  beyond  this  point,  evidence  of  impaired  tensile 
strength  is  soon  manifested.  Even  at  302°  F.  (150°  C),  dry  heat  was 
found  by  Koch  and  WoliFhiigel  to  be  not  always  effective,  even  after 
two  hours,  while  boiling  water  and  streaming  steam  at  212°  F.  were 
found  to  produce  the  desired  results  in  a  very  short  time.  But  Schura- 
burg^  has  shown  that  air  heated  to  212°  F.  will  destroy  the  common 
non-sporing  pathogenic  bacteria  if  it  contains  55  to  65  relative  humid- 
ity. This  condition  can  be  secured  by  placing  pans  of  water  within 
the  space  where  the  infected  objects  are  treated. 

Steam. — Although  steam  had  been  recommended  and  used  for  pur- 
poses of  disinfection  as  early  as  1848,  and  although  Pasteur,  Tyndall, 
Cohn,  and  others  had  demonstrated  in  a  number  of  extensive  scientific 
investigations  the  sterilizing  action  of  moist  heat  on  putrefactive  bac- 
teria and  other  micro-organisms,  and  Tyndall  had  shown  the  necessity 
of  discontinuous  boiling  for  the  sterilization  of  spore-bearers,  the  first 
investigation  of  the  action  of  steam  on  the  vitality  of  the  bacteria  asso- 
ciated with  infective  diseases  was  that  conducted  by  Koch,  Wolflfhiigel, 
and  their  associates,  the  results  of  which  were  published  in  1881. 
They  demonstrated  the  very  great  superiority  of  steam  over  much 
hotter  air,  and  showed  that  the  most  resistant  spores  are  destroyed 
within  a  few  minutes.  They  studied  its  effects  on  the  different  kinds 
of  articles,  such  as  clothing,  bedding,  furniture,  and  other  objects, 
which  in  sanitary  practice  may  require  to  be  disinfected,  showed  its 
applicability  to  all  excepting  a  limited  number,  such  as  furs,  leather, 
and  veneered  furniture,  and  led  the  way  to  the  installation  of  public 
disinfecting  plants  for  municipalities,  hospitals,  and  quarantine  stations. 

A  variety  of  apparatuses,  both  fixed  and  portable,  have  been  devised^ 
and  their  use  is  steadily  on  the  increase,  not  alone  in  large  communities, 
but,  especially  in  Europe,  in  thinly  settled  districts  as  welL  For  the 
latter,  the  portable  apparatus  on  wheels  is  especially  adapted,  for  it  is 

^  Mitthcilungen  aus  dem  kaiserlichen  Gesundheitsanite,  I.,  p.  301. 
^Zeitschrift  fiir  Plygiene  und  Infectionskrankheiten,  XLT.,  p.  167.  . 


616  DISINFECTANTS  AND  DISINFECTION. 

beyond  the  limits  of  reason  to  expect  small  towns  in  which,  perhaps, 
infective  diseases  of  the  kinds  that  call  for  thorough  disinfection  are 
only  occasional  visitors,  to  establish  and  maintain  public  stations, 
whereas  a  number  of  such  communities  may  have  joint  ownership  in  a 
portable  machine  which  may  be  despatched  on  demand  to  the  point 
where  its  services  are  required. 

The  general  plan  of  the  stationary  and  portable  machines  is  essen- 
tially the  same.  They  consist  of  one  or  more  chambers  of  sufficient 
size  to  admit  objects  as  large  as  or  larger  than  a  rolled  mattress  ;  and 
a  boiler  for  the  generation  of  steam,  which  is  admitted  through  pipes 
controlled  by  valves.  The  most  approved  machines  are  so  constructed 
that,  after  the  objects  have  been  introduced  and  the  doors  closed,  the  con- 
tained air  may  be  withdrawn  and  a  partial  vacuum  of  about  20  inches 
produced,  the  object  of  which  will  be  explained  later.  This  is  pro- 
duced best  through  the  agency  of  a  steam  jet  rather  than  by  a  pump, 
since  the  latter  is  much  slower  in  achieving  the  same  result  and  exerts 
110  disinfecting  action  on  the  germs  that  are  contained  in  the  air  with- 
drawn. The  best  machines  are  provided  also  with  a  steam  jacket, 
which  assures  a  more  uniform  diftusion  of  heat  in  the  chamber  walls 
and  a  lessened  opportunity  for  condensation,  and  a  non-conducting 
outside  casing  of  asbestos  or  asbestos-magnesia  composition,  to  prevent 
loss  of  heat. 

The  apparatus  in  use  at  the  Xew  York  Quarantine  Station  may  be 
taken  as  a  type  of  the  most  approved  construction.  It  consists  of  a 
chamber  of  steel,  the  inside  dimensions  of  which  are  4  feet  by  3  feet 
3  inches  by  7  feet  2  inches,  with  an  outer  shell  of  the  same  material, 
and  an  intervening  space  of  2  inches.  The  outer  shell  is  encased  in 
a  layer  of  asbestos-magnesia,  1.5  inches  in  thickness,  for  the  prevention 
of  loss  of  heat.  At  each  end  is  a  door,  made  to  fit  air-tight,  swung 
on  a  crane,  and  fastened  to  the  chamber  by  means  of  turn-buckles. 
Within  the  chamber  is  a  movable  track  so  arranged  that  the  car, 
made  of  1.5  inch  angle-iron  and  No.  6  galvanized  iron  netting,  for  the 
reception  of  articles  to  be  disinfected,  may  be  withdrawn  at  either  end. 

The  steam  from  the  boiler  enters  the  chamber  through  a  2.5  inch 
pipe  at  a  pressure  of  15  pounds  to  the  square  inch,  or  at  such  other 
pressure  as  may  be  desired.  By  means  of  a  steam  exhauster,  con- 
trolled by  valves,  a  vacuum  may  be  produced  in  one  minute  either  in 
the  chamber  or  in  the  space  between  the  two  steel  shells,  A  fresh-air 
inlet,  consisting  of  a  1.5  inch  pipe  provided  with  a  valve  by  which  it 
is  opened  and  closed,  and  with  a  fine  brass  netting  for  the  exclusion 
of  matters  which  otherwise  might  gain  entrance,  connects  the  chamber 
at  its  upper  part  with  the  external  air. 

The  apparatus  is  so  disposed  that  the  ends  of  the  chamber  open 

into  rooms  having  no  communication  Avith  each  other,  one  being  for 

the  reception  of  infected  articles,  and  the  other  for  their  delivery  after 

they  have  been  disinfected.^  .  The  articles  to  be  treated  are  placed  in 

^  The  foregoing  description  of  the  apparatus  and  the  following  account  of  the 
method  of  operation  are  abstracted  from  Assembly  document  No.  58,  "  Disinfection  by 
Steam,"  by  Dr.  A.  H.  Doty,  Health  Officer  of  the  Port  of  New  York. 


PHYSICAL  AGENTS.  517 

the  car  in  the  special  room  for  their  reception,  the  door  is  then  bolted, 
and  a  vacuum  of  20  inches  is  obtained  by  the  steam  exhauster.  This 
removes  the  air  from  the  chamber,  and  also  the  air  and  moisture  from 
the  material  to  be  treated,  which,  forming  a  cushion,  would  prevent 
the  proper  entrance  of  the  steam.  Steam  is  then  admitted  very  rapidly, 
and  a  temperature  of  230°  to  240°  F.  is  attained  within  3  or  4  min- 
utes. After  15  minutes'  exposure,  the  steam  exhauster  is  again 
brought  into  play,  and  a  vacuum  of  20  inches  is  again  secured.  The 
fresh-air  inlet  is  then  opened,  and  by  means  of  the  steam  exhauster 
a  current  of  air  is  drawn  through  the  chamber  and  its  contents  for  8 
or  10  minutes.  The  door  communicating  with  the  second  room  is 
then  opened  and  the  articles  are  removed,  unrolled,  and  exposed  for 
3  or  4  minutes,  at  the  expiration  of  which  time  they  are  completely 
dry,  and  may  be  taken  away. 

According  to  Dr.  Doty,  "  The  degree  of  improvement  in  the  drying 
process,  which  is  the  result  of  the  combined  action  of  the  steam  ex- 
hauster and  the  fresh-air  inlet,  can  only  be  appreciated  by  one  who 
has  waited  two  or  three  hours  or  more  for  this  same  result.  .  .  . 
The  importance  of  the  rapidity  with  which  this  work  is  now  performed 
and  the  material  dried  is  especially  appreciated  in  the  treatment  of 
mail,"  in  which  a  letter  unsealed  or  partly  unsealed  is  very  rarely, 
and  with  the  superscription  aifected  is  never,  found.  This  satisfac- 
tory result  is  due  to  the  rapid  action  of  the  heat,  the  rapid  drying, 
and  the  prevention  of  the  spreading  of  the  ink  and  of  the  unsealing 
of  the  package. 

The  value  of  the  vacuum  in  steam  disinfection  lies  in  the  fact  that 
confined  air  in  the  chamber  causes  great  delay  in  the  attainment  of  the 
desired  temperature  and  interferes  much  with  the  penetrating  action 
of  the  steam.  In  Doty's  experiments  with  and  without  the  assist- 
ance of  the  vacuum,  self-registering  thermometers,  placed  within  pack- 
ages of  newspapers,  sheets,  blankets,  and  rugs,  showed  differences 
ranging  from  nothing  to  a  100  degrees  (F.)  after  3  minutes'  exposure, 
the  higher  temperature  in  each  case  being  reached  in  the  experiment 
with  vacuum,  and  the  smaller  differences  occurring  when  the  articles 
were  loosely  wrapped.  With  longer  exposure,  the  differences  were 
considerably  smaller. 

When  no  appliance  for  securing  a  vacuum  is  a  part  of  a  steam  dis- 
infector,  the  contained  air  may  be  driven  out  through  a  vent  controlled 
by  a  valve,  which  is  opened  for  a  time,  while  the  steam  is  being  ad- 
mitted, and  then  closed. 

Another  point  in  favor  of  the  vacuum  is  the  lessened  opportunity 
for  condensation  of  the  steam  in  the  interior  of  bundles  and  in  the 
interstices  of  fabrics.  It  has  been  found  to  be  advantageous  to  fill  the 
chamber  several  times  at  sliort  intervals  with  a  fresh  charge  of  steam, 
and  when  the  vacuum  appliance  is  at  hand,  the  time  required  for  this 
series  of  operations  is  lessened  materially. 

The  penetrating  power  of  steam  is  greatly  dependent  upon  the 
amount  of  pressure;  tlie  hjwcr  the  pressure,  the  less  the  penetration. 


518 


DISINFECTANTS  AND  DISINFECTION. 


With  machines  in  which  low-pressure  steam — a  pound  or  two,  for 
instance — is  employed,  penetration  is,  therefore,  very  slow  and  un- 
certain ;  and  when  bulky  articles,  such  as  rolled  carpets  and  bedding, 
are  treated,  the  results  are  likely  to  be  unsatisfactory.  For  such 
articles,  it  is  agreed  generally  that  a  pressure  of  at  least  20  pounds 
is  none  too  great.  With  whatever  pressure  employed,  penetration 
may  be  much  assisted  by  arranging  the  contents  of  the  chamber  so 
that  too  solid  packing  is  avoided.  This  is  secured  by  the  interposi- 
tion of  wooden  slats  and  gratings,  which  leave  spaces  between  the 
different  layers,  through  which  the  steam  is  distributed  more  readily. 
With  low-pressure  steam,  condensation  is  much  more  likely  to  be 
troublesome  than  when  high  pressures  are  employed  ;  but  ordinarily 
€ven  then  but  little,  if  any,  injury  is  suiFered  by  the  most  delicate 
fabrics,  beyond  a  slight  impairment  of  gloss  or  the  imparting  of  a 
slight  yellowish  tinge. 

Fig.  91. 


Ground  plan  of  public  disinfecting  station. 

In  the  arrangement  of  public  disinfecting  stations,  it  is  essential 
that  infected  and  disinfected  articles  shall  be  kept  strictly  apart,  and 
that  means  shall  be  at  hand  for  the  proper  treatment  of  articles  not 
suited  to  disinfection  by  steam.  As  an  example  of  simple,  conve- 
nient, and  efficient  arrangement,  may  be  cited  the  first  public  station 
installed  in  Berlin,  the  ground  plan  of  which  is  shown  in  Fig.  91.^ 
Here  the  infected  articles  are  unloaded  at  the  platform  L  and  stored 
in  the  room  J,  from  which  they  are  carried  into  the  room  G^,  between 
which  and  the  room  G^,  the  steam  disinfectors  are  installed.  They 
are  loaded  into  the  trucks  6,  6,  6,  which  are  pushed  into  the  steam 
chambers  a,  a,  a,  the  doors  of  which  are  then  securely  closed.     Steam 

1  Taken  from  H.  Merke's  description  in  Vierteljahrsschrift  fiir  gerichtliche  Medicia 
und  offentliches  Sanitiitswesen,  XLV.,  p.  137. 


PHYSICAL  AGENTS.  519 

is  admitted  from  the  boilers  in  room  B,  and  after  the  proper  interval 
of  time,  the  doors  of  the  chambers  opening  into  the  room  G^  are 
opened  and  the  trucks  withdrawn.  The  disinfected  articles  are 
removed  and  carried  into  the  store-room  A,  from  which  they  are  sent 
to  the  platform  M  for  shipment,  in  special  wagons,  back  to  their 
owners.  J.  is  a  repair  shop  and  store-room  for  coal,  C  and  D  are 
bath-rooms  and  water-closets  for  the  attendants,  and  _£"  is  a  store-room 
for  chemicals.  No  communication  whatever  exists  between  the  rooms 
in  which  the  infected  and  disinfected  articles  are  stored,  nor  between 
(tj  and  G2,  except  through  the  steam  chambers,  the  doors  of  which  are 
never  opened  at  both  ends  at  the  same  time.  The  work  is  directed 
by  telephone  from  the  office  K,  which  is  shut  off  completely  from 
iJand  J,  a  full  view  of  which  is  obtained  through  windows  hermeti- 
cally sealed. 

Steam  disinfectors  are  used  extensively  for  purposes  other  than  the 
■destruction  of  disease  germs  ;  they  are  most  useful  for  renovating  bed- 
ding and  in  the  treatment  of  clothing  infested  with  lice,  which  with 
their  eggs  are  killed  quickly  by  steam  at  any  pressure. 

Boiling  Water. — Articles  not  injuriously  affected  by  boiling  water* 
may  be  disinfected  most  conveniently  in  the  household  by  being  boiled 
for  a  half  hour.  This  suffices  to  kill  all  varieties  of  bacteria  and  the 
most  resistant  spores  of  pathogenic  bacteria ;  in  fact,  all  organisms  ex- 
cepting the  spores  of  a  number  of  non-pathogenic  bacteria  which  are 
not  destroyed  even  after  prolonged  boiling.  This  method  is  adapted 
particularly  to  bed-linen  and  body-linen  and,  in  short,  to  all  washable 
fabrics  except  woollens.  It  has  the  disadvantage  of  fixing  stains,  so 
that  they  become  permanent ;  therefore,  sheets,  night-dresses,  and  other 
articles  stained  with  blood  or  excreta,  should  have  a  preliminary  soaking 
in  cold  water,  so  that  the  spots  may  be  removed. 

Cold. — Although  cold  is  a  very  efficient  antiseptic,  but  not  com- 
monly classed  as  a  disinfectant,  it  appears  to  have  destructive  power 
over  certain  pathogenic  bacteria,  but  none  whatever  over  certain 
others,  even  when  extremely  low  temperatures  are  employed.  Dur- 
ing the  cholera  epidemic  in  Germany,  in  the  winter  of  1892—93, 
XJffelmann,^  experimenting  with  cholera  germs,  concluded  that  they 
have  considerable  power  to  withstand  cold  for  periods  varying  with 
the  temperature.  Renk  ^  placed  the  limit  of  endurance  in  ice  at  8 
days.  Inoculated  water,  containing  620,000  per  cc,  was  frozen  at 
—  9.6°  C.  and  kept  at  that  temperature  for  39  hours;  the  ice  was 
then  melted  and  tested,  and  the  results  were  negative.  Water  more 
richly  inoculated  and  kept  for  a  day  in  a  freezing-mixture  of  ice  and 
salt  yielded  negative  results.  Still  richer  water,  containing  countless 
bacteria,  was  frozen,  and  after  48  hours  yielded  24,400  per  cc,  and 
after  96  hours  gave  12  negative  results.  In  other  experiments  in 
which  freezing  was  interrupted,  no  organisms  were  found  after  6  and  7 
days.    But  AVuknow "'  kept  them  alive  more  than  a  month  at  — 32.5°  C. 

1  Eerlinor  klinisclie  WoohenHchrift,  1893,  No.  7. 

^  Fortschi'itte  tier  Modicin,  May  ]5,  1893.  '  Wratscli,  1893,  No.  8. 


520  DISINFECTANTS  AND  DISINFECTION. 

The  typhoid  organism,  as  is  well  known,  may  survive  the  action  of 
cold  for  a  long  time.  This  was  well  shown  in  the  experience  of  Ply- 
mouth, Pa.,  where,  in  1885,  a  most  devastating  epidemic  occurred  after 
the  thawing  out  of  an  accumulation  of  typhoid  excreta  situated  near  a 
brook  which  supplied  the  town  with  drinking-water.  (See  page  380.) 
Prudden  ^  has  shown  that  the  typhoid  bacillus  can  withstand  freezing 
temperatures  for  no  less  than  103  days,  but  that  alternate  freezing  and 
thawing  cannot  long  be  withstood. 

Non-sporulating  anthrax  bacilli  have  but  little  resistance  to  freezing 
temperatures,  and  are  killed  very  quickly,  but  the  spores  have  been  found 
by  Frankland,  Pictet,  and  others  to  be  not  affected  by  repeated  freezing^ 
and  thawing.  Meyer  ^  found  the  spores  to  be  unaffected  by  1 5  min- 
utes' exposure  to  the  temperature  of  liquid  air.  Kasanskey  ^  exposed 
16  culture  tubes  of  diphtheria  bacilli  to  the  winter's  cold,  so  that  for  4 
months  they  were  frozen  continuously,  the  temperature  at  times  fall- 
ing to  — 25°  C,  and  found  after  6  months  but  1  Avhich  contained 
living  bacilli.  Cultures  of  plague  bacilli  kept  at  — 24°  C.  yielded 
living  organisms  at  the  end  of  35  days,  but  none  after  6  mouths ;  but 
cultures  on  agar  exposed  to  lower  temperatures  were  active  at  the  end 
of  nearly  6  months. 

The  exceedingly  low  temperature  of  liquid  air,  — 312°  F.,  appears  to 
have  no  effect  ou  organisms  subjected  to  it  for  short  periods.  Ravenel  * 
immersed  silk  threads,  bearing  anthrax  spores,  B.  prodigiosus,  B.  ty- 
phosus, and  B.  diplitherke,  in  liquid  air  for  varying  periods,  and  then 
planted  them  in  bouillon.  Not  only  were  the  bacteria  not  killed,  but 
their  growth  was  in  no  way  inhibited,  multiplication  being  in  every  in- 
stance as  rapid  and  vigorous  as  with  the  controls.  The  anthrax  spores 
were  exposed  as  long  as  3  hours,  but  the  diphtheria  organism  no  longer 
than  30  minutes,  and  the  other  two  forms  not  more  than  1  hour. 

Still  more  conclusive  are  the  experiments  of  Macfadyen  and  Row- 
land,^ who  subjected  broth  emulsions  of  B.  typhosus,  B.  call  communis, 
B.  diphtherice,  B.  proteus  vulgaris,  B.  acidi  lactici,  Sp.  cholerce  Asiaticce, 
Sta'phylococeus  pyogenes  aureus,  B.  anthracis  (sporulating),  B.  phospho- 
rescens,  a  sarcina,  a  saccharomyces,  and  unsterilized  milk,  hermetically 
sealed  in  fine  quills,  to  the  refrigerating  influence  of  liquid  air  for  7 
days.  At  the  end  of  this  time,  the  quills  were  withdrawn  and  allowed 
to  thaw.  Culture  experiments  proved  that  the  vitality  of  the  various 
micro-organisms  was  in  no  way  impaired.  Every  species  grew  well, 
the  photogenic  bacteria  grew  and  emitted  light,  and  the  milk  became 
curdled. 

CHEMICAL  AGENTS. 

The  list  of  substances  falling  under  the  head  of  chemical  disinfect- 
ants is  very  long,  and  includes  a  wide  variety  of  organic  and  inorganic 
compounds,  some  of  which  are  gases,  some  liquids,  and  others  soluble 

1  Medical  Kecord,  March  26, 1887. 

»  Centralblatt  fiir  Bakteriologie,  XXVIIL,  p.  594. 

'  Ibidem,  XXV.,  p.  122.  *  Medical  News,  June  10,  1899. 

5  Lancet,  April  21,  1900. 


CHEMICAL  AGENTS.  521 

salts.  While  it  is  very  long — for  almost  any  chemical  substance  pos- 
sesses under  one  condition  or  another  a  certain  degree  of  bactericidal 
power — the  number  of  agents  which  may  be  regarded  as  trustworthy  in 
actual  general  practice  is  exceeding  small.  Many  substances  which 
have  a  high  reputation  for  efficiency  are  found  to  be  actually  worthless 
when  subjected  to  modern  methods  of  testing,  and  others  which  yield 
promising  results  in  the  laboratory  are  found  often  to  fail  when  used 
under  the  conditions  which  obtain  in  practice. 

The  undeserved  reputation  of  many  preparations  is  based  wholly 
upon  the  apparent  influence  which  they  have  exerted  in  limiting  the- 
spread  of  infectious  diseases,  and  it  has  not  been  impaired  by  unex- 
plainable  failure  to  accomplish  the  same  result  at  other  times.  An  out- 
break of  an  infectious  disease  occurs,  for  example,  in  a  boarding-school,, 
and  during  its  continuance  a  number  of  bottles  of  some  proprietary 
preparation  are  used  ;  no  further  cases  are  reported,  and  the  credit  is- 
given  to  the  disinfectant.  Six  months  later,  perhaps,  another  outbreak 
occurs,  and,  in  spite  of  the  use  of  the  same  agent,  it  spreads  and  the 
school  is  closed ;  this  result  is  not  charged  on  the  other  side  of  the 
account,  but  to  the  inscrutable  ways  of  Providence,  and  the  fame  of  the 
disinfectant  is  in  no  way  injured.  In  many  instances,  strength  and 
peculiarity  of  odor  are  the  only  qualities  necessary  for  the  building  up 
of  a  reputation  for  efficiency,  for  man  is  wont  to  attribute  potent  prop- 
erties to  unusual  things. 

Many  substances  have  undoubted  germicidal  power  over  certain 
forms  of  bacteria,  and  are  quite  inert  against  others  ;  some  will  kill 
every  known  form  under  some  conditions,  and  yet  may  wholly  fail  to- 
affect  bacteria  of  slight  resisting  power  protected  by  mucus  or  other 
matter,  or  may  even  be  rendered  inert  almost  immediately  by  chemical 
union  with  some  other  substance  accidentally  present. 

Chemical  disinfectants  act  in  various  ways  to  bring  about  the  de- 
struction of  bacteria.  Some  act  directly  upon  the  bacterial  protoplasm 
and  cause  its  coagulation  ;  some  bring  about  changes  in  reaction  favor- 
able to  life  and  growth  ;  some  destroy  nutritive  material  by  chemical 
change ;  some  take  up  all  the  available  oxygen,  thus  becoming  them- 
selves changed  in  character  while  depriving  the  bacteria  of  an  essential 
element ;  and  others  bring  in  such  an  excess  of  this  same  element 
that  the  bacteria  cannot  withstand  its  action.  Some  even  stimulate 
multiplication,  and  thus  act  only  indirectly  by  promoting  the  formation 
of  organic  compounds  which  exert  a  destructive  influence  upon  the 
organisms  by  which  they  have  been  produced.  The  disinfectant  power 
of  many  of  the  metallic  salts  depends  partly  upon  the  nature  of  the 
solvent. 

Different  agents  produce  their  best  results  in  different  degrees  of  con- 
centration ;  thus,  while  one  may  be  efficient  in  5  per  cent,  solution,, 
another  may  act  equally  well  or  better  in  0.10  per  cent,  or  even  weaker 
sohition.  Some  agents,  as,  for  instance,  alcohol,  arc  most  bactericidal 
at  some  one  point  of  concentration,  and  above  and  below  this  the  prop- 
erty progressively  diminishes.    In  applying  any  agent. whose  best  work- 


522  DISINFECTANTS  AND  DISINFECTION. 

ing  strength  is  known,  it  should  be  borne  in  mind  that  it  is  not  suf- 
ficient to  use  a  small  volume  of  solution  of  that  particular  strength,  but 
that  the  substance  itself  must  be  employed  in  such  an  amount  that  it 
shall  be  present  throughout  the  whole  mass  in  the  proportion  required. 
Thus,  an  agent  which  is  effective  in  2  per  cent,  solution  cannot  be  used 
in  that  strength  to  disinfect  an  equal  bulk  of  infective  material,  since 
the  mixture  would  then  contain  but  1  per  cent. 

Non-metallic  Elements  and  Their  Compounds. 

Oxygen. — The  disinfectant  property  of  pure  air  is  due  to  its 
oxygen,  which  attacks  organic  matter  under  favorable  conditions  and 
converts  it  in  great  part  to  carbon  dioxide  and  water.  Prolonged 
aeration  is  rightly  regarded  as  a  valuable  assistant  in  disinfection,  but 
it  should  not  be  overlooked  that  when  infected  objects  are  exposed  to 
moving  currents  of  outdoor  air,  they  are  subjected  also  to  the  powerful 
influence  of  the  chemical  rays  of  sunlight  and  to  the  possibility  of  desic- 
cation. Oxygen  acts  most  powerfully  in  the  nascent  state,  as  when 
liberated  from  compounds  whose  decomposition  results  in  the  escape  of 
the  gas  in  the  free  condition.  Among  these  compounds,  ozone,  the 
allotropic  form  of  oxygen,  containing  in  each  molecule  three  atoms 
instead  of  two,  and  hydrogen  peroxide,  may  be  mentioned  as  conspicu- 
ous examples  of  oxidizing  agents  which  part  very  readily  with  the 
hiosely  held  element. 

Ozone,  in  the  minute  amounts  in  which  it  exists  normally  in  air, 
can  hardly  be  regarded  as  an  important  influence  in  practical  disinfec- 
tion. Produced  artificially  by  means  of  the  silent  electric  discharge,  it 
is  found  to  be  possessed  of  marked  bactericidal  power,  and  has  been 
recommended  highly  for  special  work,  particularly  in  the  sterilization 
of  drinking-water.  The  researches  of  a  number  of  investigators  have 
demonstrated  that  dry  bacteria  are  not  much  affected  by  dry  ozone, 
but  that  in  a  moist  condition  they  are  quickly  destroyed  by  small 
amounts. 

Krukowitsch,  quoted  by  Kowalkowsky,^  experimenting,  in  1882, 
with  putrefactive  bacteria,  found  that  3  milligrams  of  ozone  per  cubic 
meter  of  air  killed  fresh  bacteria,  exposed  on  paper,  within  an  hour, 
and  8  milligrams  per  cubic  meter  sufficed  to  destroy  the  dried  organ- 
isms. Later  (1888),  Lukaschewitsch,  experimenting  with  B.  subtilis, 
B.  anthracis,  Sp.  cholerce  Asiaticce,  and  certain  putrefactive  bacteria, 
obtained  results  which  were  less  favorable,  but  in  agreement  in  so  far 
as  they  demonstrated  the  relatively  slower  action  exerted  on  dry  bacteria. 
Spores  of  B.  subtilis  and  B.  anthracis  in  a  dry  state  were  unaffected  by 
1.50  grams  of  ozone  per  cubic  meter,  and  the  comma  bacillus,  in  a 
moist  condition,  was  not  affected  until  after  15  hours'  exposure  to  the 
same  atmosphere. 

Ohlmiiller^  employed  a  much  greater  strength,  namely,  15  grams 

1  Zeitschrift  fiir  Hygiene,  IX.,  p.  89. 

^  Arbeiten  aus  dein  kaiserlichen  Gesundheitsamte,  VIIL,  1892,  p.  229. 


NON-METALLIC  ELEMENTS  AND   THEIR   COMPOUNDS.       523 

to  the  cubic  meter,  and  conducted  the  air  through  distilled  water,  in 
which  bacteria  were  suspended.  Water  containing  anthrax  spores  was 
sterilized  in  10  minutes  by  89.9  milligrams  of  ozone;  and  contain- 
ing millions  of  typhoid  and  cholera  germs  to  the  cubic  centimeter, 
in  2  minutes  by  less  than  20  milligrams.  River-water  and  sewage 
were  found  to  be  much  less  affected,  but  with  only  moderate  pol- 
lution it  appeared  probable  that  in  ozone  might  be  found  a  cheap  and 
efficient  means  of  purifying  drinking-water.  Later  on,  a  number  of 
processes  were  devised  for  this  purpose  and  carried  out  on  a  large  scale. 

In  the  hope  of  arriving  at  some  definite  conclusion  as  to  the  avail- 
ability of  ozone  as  a  room  disinfectant,  Ransome  and  Foulertou  ^  con- 
ducted a  series  of  experiments  in  which  large  quantities  were  used,  mixed 
with  air  or  with  pure  oxygen.  The  organisms  employed  as  tests  in- 
cluded B.  tuberculosis,  B.  mallei,  B.  diphtherice,  B.  anthracis  (sporing), 
B.  typhosus,  B.coli  communis, B.pyoGyaneus,B.pneumonice(Fned\ander), 
B.  prodigiosus.  Staph,  pyogenes  aureus,  Strep,  pyogenes,  Micr.  candicans, 
Saccharomyces  albicans,  Sarcina  ventriculi,  and  an  anaerobic,  sporing, 
butyric-acid-forming  bacillus.  The  results  demonstrated  that  dry  ozone 
has  no  appreciable  action  on  the  vitality  of  these  organisms ;  that  pro- 
longed exposure  does  not  diminish  the  pathogenic  virulence  of  B.  tuber- 
culosis in  sputum,  B.  mallei  or  B.  anthracis  ;  that  ozone  passed  through  a 
fluid  medium  containing  bacteria  has  germicidal  power  :  "  that  any  puri- 
fying action  which  ozone  may  have  in  the  economy  of  nature  is  due  to 
the  direct  chemical  oxidation  of  putrescible  matter  ;  and  that  it  does  not 
in  any  way  hinder  the  action  of  bacteria,  which  latter  are,  indeed,  in 
their  own  way,  working  toward  the  same  end  as  the  ozone  itself  in 
resolving  dead  organic  matter  to  simpler  non-putrescible  substances." 

Hydrogen  peroxide,  H^O^,  is  quite  stable  in  the  presence  of  some 
substances,  but  gives  up  its  loosely  combined  atom  of  oxygen  very 
readily  to  others.  It  is  a  powerful,  odorless  oxidizing  agent,  prepared 
by  the  action  of  dilute  sulphuric  acid  on  barium  peroxide.  It  is  de- 
structive of  bacteria,  but  has  no  action  on  the  enzymes  of  the  digestive 
juices,  and  in  dilute  form  is  neither  poisonous  nor  irritant  in  the  human 
system. 

According  to  Altehofer,^  in  the  proportion  of  1  part  in  1,000  of 
water  containing  the  organisms  of  cholera  and  typhoid  fever,  it  pro- 
duces sterility  within  24  hours.  In  1  per  cent,  solution,  according  to 
Traugott,-^  the  bacilli  of  diphtheria  and  typhoid  fever  are  killed  in  5 
minutes,  the  organisms  of  erysipelas  and  cholera  in  2  minutes.  Strepto- 
coccus pyogenes  in  1 0  minutes,  and  Staphylococcus  pyogenes  aureus  in 
from  1 5  to  30  minutes.  With  half  this  strength,  the  typhoid  organism 
and  Streptococcus  pyogenes  are  destroyed  with  equal  promptness,  the 
cholera  and  erysipelas  organisms  in  5  minutes,  the  bacillus  of  diph- 
theria in  15,  and  Staphylococcus  pyogenes  aureus  in  an  hour.  It  is 
believed  by  many  that  the  bactericidal  effect  of  sunlight  on  organisms 

>  Public  Health,  July,  1901,  p.  684. 

'^  Centmlbliitt  ffir  Jiiikteriolo^ie,  VrTL,  p.  129. 

"  ZeitHclirift  fur  llyf^iene  uiid  Infectioiiskraiikheiteii,  XIV.,  p.  427. 


524  niSINFECTA^'TS  AND   DISINFECTION. 

in  surface-waters  is  due  to  the  hydrogen  j^eroxide  produced  through  its 
influence. 

Chlorine,  both  in  the  free  gaseous  condition  and  in  solution  in  water, 
has  very  powerful  disinfectant  and  deodorant  properties.  It  decora- 
poses  the  oifensive  gaseous  products  of  putrefaction,  such  as  ammonia 
and  sulphuretted  hydrogen,  and  in  the  presence  of  moisture  unites  with 
hydrogen,  thus  liberating  oxygen  in  the  nascent  state,  which  is  enabled 
thereby  to  exert  its  power  against  organic  matter.  In  the  dry  state, 
its  disinfectant  action  on  dry  matter  is  but  slight  and  unreliable ; 
but  in  the  presence  of  a  moderate  degree  of  atmospheric  moisture,  its 
effect  on  organic  matter  is  considerable,  as  is  shown  by  its  bleach-^ 
ing  action  on  dyed  fabrics.  The  exhaustive  research  of  Fischer  and 
Proskauer  ^  demonstrated,  however,  that  chlorine  as  a  fumigating  agent 
is  untrustworthy,  and  that  its  application  is  attended  by  serious  disad- 
vantages. The  test-objects  employed  embraced  a  somewhat  wide  variety 
of  pathogenic  and  non-pathogenic  organisms,  and  were  exposed  under 
different  conditions  of  moisture  and  dryness  for  varying  periods  and 
to  different  percentages  of  the  gas.  The  results,  as  a  whole,  were 
highly  unsatisfactory  from  a  practical  standpoint,  on  account  of  the 
impossibility  of  properly  regulating  all  the  necessary  conditions,  the 
absence  of  penetrating  power,  the  destructive  action '  on  fabrics  and 
other  articles,  and  the  uncertainty  in  achieving  the  object  sought. 

"  Chloride  of  Lime,"  which  is  a  combination  of  calcium  chloride 
and  hypochlorite,  the  result  of  passing  chlorine  over  dry  slaked  lime, 
was  in  use  as  a  disinfectant  and  deodorant  for  a  long  time  before  the 
development  of  the  science  of  bacteriology.  In  1881,  in  the  course  of 
the  first  real  investigation  of  the  properties  of  what  were  commonly 
regarded  as  disinfectants,  Koch  obtained  very  unsatisfactory  results 
from  his  tests  with  this  agent,  which  thereupon  to  a  great  extent  was 
discarded.  In  1885,  Sternberg,  then  chairman  of  the  committee  of 
the  American  Public  Health  Association  to  which,  in  1884,  the  sub- 
ject of  disinfectants  had  been  referred,  took  very  different  ground 
regarding  this  and  other  hypochlorites,  and  asserted  their  efficiency  in 
no  uncertain  terms.  Since  then,  the  matter  has  been  the  subject  of 
many  investigations  by  competent  observers,  and  while  in  some  hands 
the  results  have  failed  to  be  uniformly  favorable,  the  work,  as  a  whole,, 
has  sustained  the  position  taken  by  Sternberg  as  a  result  of  his  own 
experunents. 

Woronzoff,  Winogradoff,  and  Kolesnikoff^  demonstrated  that 
anthrax  spores  were  killed  in  1  minute  by  a  5  per  cent,  solution, 
although  in  Koch's  experiments  they  had  been  found  still  active  at  the 
expiration  of  2  days.  Jaeger,^  in  1889,  concluded,  after  a  series  of 
tests  with  a  number  of  species  of  pathogenic  bacteria,  that  it  is  a  very 
efficient  disinfectant,  even  in  weak  solutions.     Nissen,^  in  1890,  after 

^  Mittlieilungen  aus  dem  kaiserlichen  Gesiindheitsamte,  II.,  p.  228. 
2  Centralblatt  fiir  Bakteriologie,  1887,  p.  641. 
^  Arbeiten  aus  dem  kaiserlichen  Gesundheitsamte,  V.,  p.  247. 
*Zeitschrift  fur  Hygiene,  VIII.,  p.  62. 


NON-METALLIO  ELEMENTS  AND   THEIR   COMPOUNDS.       525 

a  series  of  careful  experiments,  reported  that  the  organisms  of  cholera 
and  typhoid  fever  were  destroyed  in  5  minutes  when  the  material  in 
which  they  were  present  contained  0.12  per  cent,  of  the  agent,  and  in 
10  minutes  by  half  that  amount.  Anthrax  bacilli  were  killed  in  1 
minute  by  0.10  per  cent. ;  Staphylococcus  pyogenes  aureus  and  Strepto- 
coccus erysipelatis  in  5  minutes  by  0.12  and  0.15  per  cent.,  respectively, 
and  in  1  minute  by  0.20.  Anthrax  spores  of  low  resistance  were  de- 
stroyed in  15  minutes  by  5  per  cent,  and  in  70  minutes  by  1  per  cent. 
Very  resistant  spores,  capable  of  surviving  4  hours'  immersion  in  0.10 
per  cent,  corrosive  sublimate  and  10  minutes'  exposure  to  streaming 
steam,  were  killed  in  4.5  hours  by  5  per  cent. 

Klein,^  experimenting  with  sodium  hypochlorite  in  10  per  cent,  so- 
lution (1.0  per  cent,  chlorine)  on  the  colon  bacillus,  anthrax  spores, 
Staphylococcus  pyogeyies  aureus,  B.  enteritidis  sporogenes,  and  the  bacteria 
of  typhoid  fever,  cholera,  and  swine  fever,  found  that  all  were  killed  in 
20  minutes,  and  the  non-spore-bearers  in  10.  In  one-tenth  as  strong 
solution,  all  but  the  two  kinds  of  spores  were  destroyed  within  20 
minutes.  Duggan,^  working  according  to  Sternberg's  method,  reported, 
in  1885,  that  his  experiments  had  shown  "that  a  solution  containing 
0.25  per  cent,  of  chlorine  as  hypochlorite  is  an  effective  germicide,  even 
when  allowed  to  act  for  only  1  or  2  minutes,  while  0.06  j)er  cent,  will 
kill  spores  of  B.  anthracis  and  B.  subtilis  in  2  hours." 

The  composition  of  "chloride  of  lime,"  or,  more  properly,  chlor-inated 
lime,  and  its  mode  of  action,  are  matters  concerning  which  there  is  con- 
siderable disagreement.  The  substance  is  held  variously  to  be  :  (1)  a 
mixture  of  calcium  chloride  and  hypochlorite  ;  (2)  calcium  hy]30chlorite 
in  which  one  CIO  is  replaced  by  CI,  that 'is,  Ca(C10)Cl,  which,  in  con- 
tact with  water,  is  broken  up  into  calcium  chloride  and  hypochlorite ; 
(3)  a  compound  of  calcium  hypochlorite  and  oxychloride  with  4H2O, 
formed  according  to  the  equation 

4Ca02H2  +  2CI2  =  CaO^Cl^.  Ca302Cl24H20, 

which  is  split  up  in  water  into  calcium  chloride,  hypochlorite,  and 
hydroxide ;  and  (4)  a  compound  of  calcium  chloride  with  hydroxide,  of 
which  one  H  is  replaced  by  CI.  It  is  white  or  whitish  in  color,  and 
occurs  as  a  powder  or  as  friable  lumps ;  it  should  be  dry  or  nearly  so, 
and  should  have  no  more  than  a  faint  odor  of  chlorine,  which  element 
should  be  present  in  available  form  to  the  extent  of  not  less  than  35 
per  cent,  to  conform  to  the  requirements  of  the  U.  S.  P.  (British 
.standard  =  33  per  cent.,  German  standard  =  25  per  cent.). 

With  keeping,  under  various  conditions,  chlorinated  lime  may  undergo 
decomposition  in  a  number  of  ways.  A  pasty  condition  or  a  strong 
odor  of  chlorine  is  evidence  of  partial  decomposition.  It  is  only  par- 
tially soluble  in  water,  and  its  aqueous  preparations  are  made  best  by 
triturating  the  requisite  amount  with  water  to  the  consistency  of  cream, 

1  The  Lancet,  Nov.  26,  ]89f3,  p.  509. 

^  liepoi-t  of  the  Committee  on  Disinfeetants  of  the  American  Public  Health  Associ- 
ation:  Baltimore,  1885,  [).  12. 


526  DISINFECTANTS  AND  DISINFECTION. 

and  then  diluting  to  the  desired  vohime.  The  addition  of  acids  to  the 
solution  causes  evolution  of  chlorine,  but  the  carbon  dioxide  naturally- 
present  in  the  water  or  absorbed  from  the  air  decomposes  the  hypo- 
chlorite, yielding  calcium  carbonate  and  hypochlorous  acid,  the  latter 
of  which  breaks  up  into  active  oxygen  and  free  hydrochloric  acid. 

The  solution  known  as  the  "American  standard"  contains  6  ounces 
of  the  powder  to  the  gallon.  It  is  used  largely  in  the  disinfection  of 
discharges,  and  for  scrubbing  floors  and  other  woodwork.  A  weaker 
solution  is  employed  for  the  treatment  of  infected  bed-linen  and  wash- 
able clothing,  but  on  account  of  its  destructive  action,  these  articles 
should,  after  a  not  too  long  immersion,  be  washed  thoroughly  in  plenty 
of  fresh  water. 

Sodium  hypochlorite  solution,  otherwise  known  as  chlorinated 
soda,  Labarraque's  solution,  and  liquor  soda;  chloratse,  is  "an  aqueous 
solution  of  several  chlorine  compounds  of  sodium,  chiefly  NaClO  and 
NaCl,  and  containing  at  least  2.6  per  cent,  by  weight  of  available 
chlorine"  (U.  S.  P.).  It  is  used,  but  not  so  extensively,  for  the  same 
purposes  as  chlorinated  lime. 

Bromide  and  Iodine  have  powerful  disinfectant  properties,  but  for 
several  reasons  are  not  suited  to  the  purposes  of  practical  disinfection. 
In  some  respects,  bromine  is  superior  to  chlorine  as  a  germicide,  but 
it  is  disagreeable  and  dangerous  to  handle,  and  is  much  more  expensive. 
Iodine  is  less  efficient  than  chlorine,  and  offers,  neither  as  such  nor  as 
the  trichloride,  any  advantage  over  chlorine  and  the  hypochlorites,  but, 
on  the  contrary,  a  number  of  disadvantages  which  are  sufficient  to 
eliminate  it  from  the  list  of  practical  disinfectants. 

Sulphur  dioxide  easily  outranks  all  other  disinfectants  in  point  of 
length  of  service,  its  use  dating  back  to  very  ancient  times.  While  it 
has  undoubted  bactericidal  properties,  it  has  been  demonstrated  by 
Koch,  WolflPhiigel,  and  their  associates,  and  many  others,  to  be  wholly 
untrustworthy  for  -general  use,  and  although  still  very  extensively 
employed  by  public  sanitary  authorities,  is  rapidly  being  abandoned  in 
favor  of  more  efficient  and  reliable  agents.  It  is  purely  a  surface  dis- 
infectant under  conditions  most  favorable  to  its  action,  and  even  then 
is  effective  against  only  a  somewhat  limited  number  of  species  of  patho- 
genic bacteria.      It  is,  however,  very  efficient  against  mosquitoes. 

Sulphur  dioxide  is  a  colorless  irrespirable  gas,  produced  by  burn- 
ing roll  sulphur  or  "  flowers  "  in  an  iron  vessel,  placed  as  a  precaution 
against  fire  in  a  pan  of  water,  or  by  burning  sulphur  candles  or  carbon 
disulphide,  the  latter  in  a  lamp.  The  amount  of  sulphur  employed 
varies,  according  to  the  custom  of  the  operator,  from  1  to  6  pounds 
per  1,000  cubic  feet  of  air  space  ;  but  the  whole  amount  is  never  con- 
sumed, and,  indeed,  under  ordinary  circumstances,  combustion  ceases 
before  a  half  or  even  a  third  has  been  burned.  In  order  to  avoid  the 
necessity  of  burning  sulphur,  the  liquefied  gas,  contained  in  cylinders, 
is  employed  to  some  extent. 

In  the  absence  of  moisture,  the  action  of  sulphur  dioxide  on  even 
the  least  resistant  bacteria  is  practically  nil,  and  even  when  water  is 


LIME  AND  METALLIC  SALTS.  527 

evaporated  in  the  room  beforehand  or  at  the  same  time,  and  the  gas 
is  present  in  the  highest  percentage  possible,  the  exposed  organisms, 
whether  of  low  or  high  resistance,  are  likely  to  retain  their  vitality 
unimpaired.  It  is  true  that  some  experimenters  have  reported  great 
success  in  the  destruction  of  pathogenic  organisms  by  means  of  this 
agent,  but  the  adverse  reports  are  so  numerous  that  it  must  be  clear 
that  much  official  disinfection  by  means  of  it  is  worse  than  an 
empty  form  and,  by  reason  of  causing  a  false  sense  of  security,  a  posi- 
tive danger.  Even  were  it  an  efficient  disinfectant,  the  many  disad- 
vantages which  attend  its  use  would  suffice  to  make  it  undesirable  for 
general  purposes,  especially  in  view  of  the  fact  that  the  same  disad- 
vantages are  wholly  absent  in  other  processes.  In  the  presence  of 
moisture  and  air,  it  is  to  some  extent  oxidized  to  sulphuric  acid,  which 
corrodes  fabrics  and  other  objects ;  it  reduces  organic  matters  and 
destroys  organic  colors  ;  it  tarnishes  brass  and  silver  ware,  gilt  frames^ 
and  other  objects  ;  it  leaves  a  disagreeable  odor  which  persists  for  days 
and  even  weeks  after  thorough  aeration ;  bedding  and  other  articles 
become  impregnated  with  a  peculiar  highly  offensive  odor  which  renders 
their  use  unpleasant  and  even  impossible ;  and  it  has  such  little  power 
of  penetration  that  only  such  organisms  as  are  exposed  openly  are  likely 
to  be  affected. 

Where  sulphur  dioxide  is  the  official  disinfectant,  it  is  commonly 
enjoined  that  the  room  shall  be  cleansed  thoroughly  and  air  freely  ad- 
mitted for  some  days  after  fumigation.  The  necessity  of  this  supple- 
mentary process  is  in  itself  an  admission  of  the  inadequacy  of  the  main 
operation,  for  if  sulj)hur  is  an  efficient  disinfectant,  the  application  of 
soft  soap,  carbolic  acid,  hypochlorites,  and  other  agents  by  means  of 
the  scrubbing-brush  and  cloths,  the  removal  and  replacing  of  wall- 
papers, the  process  of  white-washing,  and  other  means  of  renovation 
recommended,  are  attacks  against  an  imaginary  evil.  Granted  that 
these  processes  are  necessary,  the  claims  of  sulphur  dioxide  as  a  prac- 
tical disinfectant  must  fall  to  the  ground ;  if  not  necessary,  they 
should  not  be  enjoined. 

Lime  and  Metallic  Salts. 

Lime,  quicklime,  or  calcium  oxide,  has  long  been  known  as  an 
agent  possessing  great  power  in  destroying  organic  matter,  and  has 
been  used  extensively  from  very  early  times  in  connection  with  dis^ 
posal  of  the  dead.  Treated  with  half  its  weight  of  water,  it  is  slaked 
to  a  dry  powder,  the  hydrate,  which,  mixed  with  sufficient  water, 
forms  the  well-known  "  white  wash  "  commonly  used  for  disinfecting, 
sweetening,  and  brightening  the  walls  of  cellars,  rooms,  barracks,, 
barns,  poultry-houses,  and  other  outbuildings.  Slaked  lime,  mixed 
with  four  volumes  of  water  to  the  consistency  of  cream,  forms  what 
is  commonly  known  as  "  milk  of  lime,"  which  is  used  extensively  in 
the  disinfection  of  excreta  and  privy  vaults. 

The  scientific  investigation  of  the  disinfectant  properties  of  lime  by 


628  DISINFECTANTS  AND  DISINFECTION. 

Liborius/  undertaken  at  the  instance  of  Koch,  demonstrated  its  value 
in  the  destruction  of  the  bacteria  of  typhoid  fever  and  cholera,  the 
former  of  which  were  found  to  be  destroyed  in  a  few  hours  by  lime- 
water  containing  0.0074  per  cent.,  and  the  latter  within  the  same  time 
Idv  0.0246  per  cent.  Cholera  bouillon  cultures,  containing  numerous 
coagula  of  albumin,  such  as  would  be  present  in  cholera  discharges, 
thus  offering  unfavorable  conditions  for  the  action  of  the  disinfectant, 
^^ere  completely  disinfected  within  the  course  of  a  few  hours  by  0.40 
per  cent,  of  pure  lime  or  by  2  per  cent,  of  ordinary  crude  lime.  He 
recommended  the  employment  of  the  pure  dry  powder  or  of  milk  of 
lime  containing  20  per  cent,  thereof. 

Favorable  results  were  obtained  also  by  Kitasato,^  who  found  that 
the  same  two  species  were  destroyed  by  about  0.10  per  cent,  in  from 
four  to  five  hours.  Pfuhl,^  carrying  the  experiments  somewhat  farther, 
recommended  the  use  of  milk  of  lime  of  20  per  cent,  strength,  freshly 
prepared  from  lime  of  good  quality,  for  the  disinfection  of  loose  dejec- 
tions, prescribing  that  it  should  be  added  in  sufficient  quantity,  with 
thorough  mixing,  until  the  whole  mass  is  strongly  alkaline  in  every 
part,  as  shown  by  testing  with  red  litmus-paper.  With  such  treatment, 
he  asserted  that  complete  sterilization  is  accomplished  within  an  hour. 
Extensive  researches  by  numerous  other  scientists,  although  diifering 
«omewhat  in  results  in  certain  unimportant  particulars,  have  confirmed 
the  conclusions  of  these  earlier  investigators  as  to  the  great  practical 
Talue  of  this  agent.  As  to  its  value  in  comparison  with  chlorinated 
lime,  there  is  disagreement,  some  authorities  favoring  the  one  and  some 
the  other,  but  practically  all  unite  in  the  opinion  that,  whichever  is  the 
more  efficient,  the  difference  is  slight. 

Of  great  j)ractical  importance  in  the  use  of  any  disinfectant  on  a 
large  scale  is  the  item  of  expense.  It  happens,  fortunately,  that  this 
valuable  aid  is  exceedingly  cheap,  and  that  its  use  with  a  liberal  hand 
in  excess  of  the  recommended  amount  may  be  urged  without  promoting 
lavish  expenditure  of  money.  In  the  disinfection  of  stools  it  is  com- 
monly advised  to  add  at  least  an  equal  volume  of  the  milk,  or  even 
twice  as  much,  and  to  allow  the  mixture  to  stand  for  two  hours  or 
longer  before  final  disposal.  In  camp  sanitation,  it  is  much  used  with 
excellent  results ;  but  for  their  attainment,  constant  watchful  super- 
vision is  necessary. 

It  should  be  borne  in  mind  that  air-slaked  lime  should  not  be 
employed  in  the  preparation  of  the  milk,  and  that  the  latter  on  stand- 
ing loses  its  homogeneous  character,  which  should  be  restored  by 
stirring  or  shaking  each  time  the  material  is  used.  The  milk  is 
most  poM'erful  when  freshly  prepared,  and  should  not  be  used  when 
older  than  a  few  days,  unless  most  carefully  protected  from  contact 
with  air. 

Ferrous  sulphate  and  other  salts  of  iron  have  long  been  used 
extensively  both  as  germicides  and  deodorants.      All  scientific  investi- 

^  Zeitschrift  fiir  Hygiene,  II.,  p.  15. 

==  Ibidem,  III.,  p.  404.  ^  Ibidem,  VI.,  p.  97. 


LTME  AND  METALLIC  SALTS.  529 

gations  of  the  disinfectant  properties  of  ferrous  sulphate  by  Koch, 
Sternberg,  and  others  have  demonstrated  the  utter  worthlessness  of  this 
agent.  Not  only  does  it  fail  as  a  germicide,  but,  as  has  been  pointed 
out  by  Foote,^  it  has  also  no  claim  to  be  considered  as  a  deodorant. 
Its  employment  in  this  capacity  not  infrequently  makes  a  bad  odor 
worse,  through  chemical  action  on  organic  compounds  produced  in  the 
process  of  putrefaction. 

Ferric  sulphate  has  been  shown  by  Riecke  ^  to  have  very  marked 
action  against  the  bacteria  of  typhoid  fever  and  cholera  in  acid  and 
alkaline  excreta,  when  added  in  an  equal  volume  of  5  per  cent,  solu- 
tion. The  disadvantages  attending  its  use,  however,  more  than  out- 
weigh any  considerations  which  may  be  urged  in  favor  of  its  employment 
in  place  of  other  more  efficient  and,  on  all  accounts,  less  objectionable 
agents. 

Ferric  chloride,  also,  has  some  claim  to  be  regarded  as  a  germicide, 
but  it  is  inferior  to  the  sulphate  and  is  open  to  the  same  objections. 

On  the  whole,  therefore,  the  iron  compounds  may  safely  be  passed 
by  in  the  practice  of  disinfection. 

Zinc  chloride,  like  ferrous  sulphate,  was,  until  subjected  to  the 
rigid  test  of  bacteriological  proof,  regarded  as  a  most  efficient  disin- 
fectant, and  to-day,  although  the  original  adverse  findings  of  Koch,  in 
1881,  have  been  confirmed  by  many  careful  experimenters,  it  is  still 
very  extensively  employed,  and  in  many  places  is  prescribed  officially 
by  the  local  health  authorities.  Under  some  conditions,  it  does  succeed 
occasionally  in  destroying  some  forms  of  bacterial  life,  but  its  place  in 
the  list  of  actual  and  supposed  disinfectants  is  well  down  toward  the 
very  bottom.  It  is,  however,  somewhat  efficient  as  a  deodorant.  The 
sulphate  and  other  salts  are  equally  inefficient  as  disinfectants. 

Aluminum  chloride  is  the  chief  soluble  constituent  of  a  number  of 
extremely  popular  proprietary  disinfectants,  prescribed  by  practising 
physicians  and  bought  with  and  without  advice  by  the  laity.  Like 
other  aluminum  compounds,  the  sulphate  and  the  alums,  for  example, 
it  is  powerfully  astringent,  even  in  dilute  form.  It  is  cheap,  has  no 
action  on  metallic  substances,  and  does  not  stain  nor  otherwise  injure 
fabrics.  Its  disinfectant  action  is  slight,  and  herein  it  agrees  farther 
with  other  aluminum  compounds.  A  number  of  proprietary  prepara- 
tions, in  which  it  is  present  either  as  principal  or  auxiliary  ingredient, 
examined  by  the  author  with  Dr.  R.  M.  Pearce,^  were  found  to  be 
inefficient.  The  test-objects  included  cultures  of  ^.  fm^Aracis  and  5. 
typhosus,  typhoid  dejecta,  diphtheritic  membranes,  and  tuberculous 
sputa.  Each  of  five  preparations,  in  the  strength  recommended,  was 
subjected  to  10  tests,  and  their  proportions  of  successful  disinfection 
varied  from  20  to  70  per  cent.  Anthrax  bacilli  were  destroyed  by 
one  ;  one  culture  of  B.  typhosus  was  killed  by  one,  another  by  all,  a 
third  by  two ;  one  typhoid  stool  was  unaffiscted  by  all,  a  second  was 

^  American  Journal  of  the  Medical  Sciences,  XCVIIL,  p.  329. 

'^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXIV.,  p.  303. 

'  Journal  of  the  Boston  Society  of  Medical  Sciences,  March,  1899. 


530  DISINFECTANTS  AND  DISINFECTION. 

sterilized  by  all,  and  a  third  by  three ;  one  specimen  of  diphtheritic 
membrane  was  sterilized  by  four,  and  another  by  only  one ;  tubercu- 
lous sputum  was  aifected  by  none. 

Fotassium  permanganate,  well  known  as  a  powerful  oxidizing 
agent,  is  much  used  in  surgical  practice  and  in  other  lines  of  special 
work.  In  the  process  of  sterilization  of  the  hands,  however,  it  is  in- 
capable, as  the  author  has  shown,^  of  producing  the  results  for  which 
it  is  employed.  In  contact  with  organic  matter  and  oxidizable  mineral 
substances,  it  parts  very  readily  with  its  available  oxygen,  and  it  is  to 
this  element  that  whatever  disinfectant  property  it  has,  is  due.  It 
cannot  be  used  in  the  treatment  of  excreta,  because  of  the  very  large 
amount  which  would  be  required  to  produce  complete  sterility  of  even 
a  single  ounce  of  fseces ;  nor  can  it  be  employed  in  the  treatment  of 
clothing,  because  of  the  permanent  stains  which  it  produces. 

Copper  sulphate  in  weak  solutions  destroys  sporeless  bacteria  in 
great  variety  within  a  short  time,  but  in  practical  work  its  use  is  rather 
limited.  Although  it  appears  to  be  of  considerable  value  in  the  destruc- 
tion of  certain  forms  of  algal  growth  in  public  water  supplies,  the 
assertions  made  concerning  its  germicidal  value  in  the  treatment  of 
infected  waters  have  not  as  yet  been  substantiated,  and  in  the  light  of 
a  number  of  recent  investigations  it  would  seem  probable  that  they 
must  fall  to  the  ground.  It  has  been  recommended  strongly  for  the 
sterilization  of  faeces,  but  its  cost  and  other  disadvantages,  not  to 
mention  its  inferiority  as  a  germicide  to  other  cheaper  and  more  avail- 
able substances,  make  it  improbable  that  its  employment  will  ever 
become  very  extensive. 

Mercuric  chloride  or  corrosive  sublimate  is,  beyond  question,  the 
most  powerful  of  all  the  metallic  salts  as  a  disinfectant,  but  at  the 
same  time  it  enjoys  a  reputation  for  practical  efficiency  that  is  not 
wholly  deserved.  A  number  of  the  earlier  experiments  which  gave  it 
its  standing  led  to  conclusions  which  could  not  be  justified  by  later 
work  conducted  on  lines  of  greater  accuracy  and  with  improved  technic ; 
but  while  Koch  and  others  saw  fit  to  modify  their  original  estimate  of 
its  general  efficiency,  it  would  appear  that  a  large  proportion  of  those 
who  have  occasion  to  employ  germicides  are  influenced  more  by  the 
original  than  by  the  later  investigations.  In  testing  its  disinfection 
properties  against  anthrax  spores  and  other  highly  resistant  organisms, 
widely  different  results  have  been  obtained  and  recorded  by  different 
observers,  but  these  are  explained  by  differences  in  nutrient  media, 
in  technic,  and  in  virulence ;  and  although  it  has  been  proved 
that  the  original  findings  were  far  too  favorable,  it  also  has  been 
proved  that  as  a  germicide  it  stands  far  above  all  other  metallic 
compounds.  But  it  should  be  understood  that,  under  conditions  which 
obtain  in  practice,  the  same  results  as  are  obtained  in  laboratory  experi- 
ments, made  with  broth  cultures  and  spores  dried  on  silk  threads,  are 
not  always  to  be  expected.     In  the  treatment  of  tuberculous  sputum, 

^  Annals  of  Surgeryj  October,  1904. 


LIME  AND  METALLIC  SALTS.  531 

for  example,  the  innermost  bacilli  are  protected  from  contact  with  the 
;disinfectant  by  the  coagulum  which  forms  on  the  surface  of  each  sepa- 
'  rate  mass.  Again,  in  the  treatment  of  other  organic  matter,  the  pos- 
sibility of  precipitation  as  albuminate  or  sulphide  or  other  insoluble 
compound  of  mercury  should  be  kept  in  mind. 

Precipitation  as  albuminate  may  be  prevented  by  the  addition  of 
about  5  parts  of  sulphuric,  hydrochloric,  or  tartaric  acid,  or  of  10  parts 
of  common  salt,  for  each  part  of  sublimate  in  1,000,  but  conversion  to 
sulphide  cannot  be  prevented,  if  the  conditions  necessary  for  its  forma- 
tion are  present.  In  the  disinfection  of  faeces,  for  which  purpose  cor- 
rosive sublimate  is  sometimes  used,  it  is  evident  that,  with  the  usual 
strength  of  solution  employed,  the  whole  of  the  salt  must  frequently 
be  precipitated  in  one  form  or  another  very  early  in  the  process.  In 
household  disinfection,  its  corrosive  action  on  plumbing  must  be  con- 
sidered as  a  serious  drawback. 

Its  chief  use  in  surgical  practice  is  as  a  sterilizing  agent  for  the  skin, 
ligatures,  etc.,  the  strength  used  being  commonly  1  part  in  1000  ;  but 
weaker  solutions,  even  1  in  10,000,  are  also  employed.  Unfortunately 
the  element  of  time  seems  not  to  be  generally  regarded  in  the  practice 
of  disinfection,  and  instantaneous  germicidal  action  appears  to  be 
assumed  as  the  result  of  contact  of  the  agent  with  pathogenic  bacteria. 
In  order  to  determine  the  length  of  time  required  for  solutions  of  dif- 
ferent strengths  to  destroy  some  of  the  commoner  pathogenic  organisms, 
the  author  ^  conducted,  with  Dr.  Harold  Walker,  a  series  of  experi- 
ments which  led  to  the  following  conclusions  : 

(1)  Diiferent  species  of  pathogenic  bacteria,  and  different  cultures 
of  the  same  species,  vary  very  greatly  in  their  resistance  to  the  action 
of  corrosive  sublimate.  (2)  With  some  species  resistance  is  diminished 
in  a  remarkable  degree  by  a  condition  of  dryness,  so  that  even  the 
1  :  10,000  solution  can  bring  about  sterility  in  a  very  short  time.  But 
some  species  are  not  materially  affected  in  this  respect  by  dryness. 
(3)  Corrosive  sublimate  in  as  weak  solution  as  1  :  5000  is  ineffective 
against  the  common  pathogenic  bacteria,  including  the  pus  organisms 
when  they  are  moist,  excepting  after  prolonged  contact.  Since  fifteen 
minutes'  contact  is  not  sufficient  for  the  destruction  of  B.  coli  communis, 
B.  pyoeyaneus,  and  Staph,  pyogenes  albus,  in  the  moist  state,  or  of  Staph, 
pyogenes  aureus  whether  moist  or  dry,  the  use  of  this  and  of  weaker 
preparations  in  surgical  work  and  for  irrigation  and  similar  purposes 
should  be  abandoned.  (4)  The  1  :  1000  solution  is  very  slow  in  its 
action  on  some  of  the  commonest  of  the  skin  bacteria,  and  since  under  the 
most  favorable  conditions  more  than  ten  minutes'  contact  may  be  nec- 
essary for  it  to  kill  Staphylococcus  pyogenes  albus,  it  should  not  be  relied 
upon  to  any  great  extent  to  ensure  sterility  of  the  hands  or  of  instru- 
ments. The  mere  dipping  of  the  hands  for  a  few  seconds  into  solutions 
of  this  strength  can  serve  no  useful  purpose,  but,  on  the  contrary,  can 
lead  to  mnch  harm  by  inducing  a  false  sense  of  security.  (5)  Corrosive 
sublimate  in  any  of  the  strengths  commonly  employed  is  a  much  over- 
*  Boston  Medical  and  Suigical  Journal,  April  23,  1903. 


532  DISINFECTANTS  AND  DISINFECTION. 

rated  disinfectant,  and,  under  the  best  of  conditions,  is  so  uncertain  in 
its  action  that  it  would  be  of  advantage  to  abandon  its  use  altogether  in 
surgery. 

Mercuric  cyanide,  much  praised  by  some,  has  been  proved  by  the 
author^  to  be  fe,r  inferior  to  the  chloride. 


Mineral  Acids. 

The  mineral  acids  possess,  in  different  degrees  of  dilution,  varying 
disinfectant  power  against  all  species  of  bacteria.  In  any  effective 
working  strength,  they  corrode  the  common  metals  ^nd  destroy  the 
tensile  strength  of  all  kinds  of  fabrics. 

The  bactericidal  effect  of  gastric  juice  on  the  bacteria  of  cholera,  dis- 
covered by  Koch,  was  ascribed  by  him  to  the  contained  hydrochloric 
acid  ;  and  experimenting  with  bouillon  cultures  of  this  organism,  Kita- 
sato^  showed  that  0.132  per  cent,  of  hydrochloric  or  0.049  of  sulphuric 
acid  produced  sterility  within  a  few  hours.  This  result,  so  far  as  it 
concerns  sulphuric  acid,  was  confirmed  by  Stutzer,^  who  found  that 
0.05  per  cent,  killed  in  15  minutes  the  organisms  suspended  in  dis- 
tilled water. 

The  experiments  of  Boer*  showed  that  the  bacillus  of  typhoid  fever 
in  bouillon  cultures  Avas  destroyed  in  2  hours  by  0.07  per  cent,  of  hy- 
drochloric acid,  and  in  the  same  time  by  0.12  per  cent,  of  sulphuric 
acid.  The  cholera  organism  was  killed  by  smaller  amounts,  0.02  per 
cent,  of  each,  within  the  same  time  ;  the  bacilli  of  anthrax  were  but 
slightly  more  resistant  than  the  cholera  germ  ;  and  those  of  diphtheria 
succumbed  to  the  same  amounts  as  Avere  fatal  to  those  of  typhoid 
fever.  Ivanoff  *  determined  the  amount  of  sulphuric  acid  necessary 
to  sterilize  sewage.  That  of  Potsdam,  three  times  as  foul  as  that 
of  Berlin  and  slightly  alkaline  in  reaction,  impregnated  with  cholera 
germs,  was  disinfected  by  0.08  per  cent,  in  15  minutes.  A  proprietary 
preparation,  containing  0.76  per  cent,  of  sulphuric  acid  and  nothing 
else,  tested  by  the  author,  sterilized  one  of  two  bouillon  cultures  of 
typhoid  bacilli  and  one  of  two  typhoid  dejecta  in  2  hom^s,  but  had 
no  effect  whatever  on  diphtheritic  membrane  and  tuberculous  sputum. 


Organic   Substances. 

Carbolic  acid,  phenol,  phenic  acid,  obtained  chiefly  from  coal,  is 
a  substance  of  varying  degrees  of  purity  and  disinfectant  power.  The 
highest  grade  is  practically  pure  phenol,  but  the  commoner  qualities 
contain  variable  amounts  of  cresols,  xylol,  and  other  higher  homo- 
logues,  all  of  which  have  marked  bactericidal  properties,  and  tar  oils 
which  have  none.     In  the  opinion  of  many  authorities,  the  crude  acid 

^  Boston  Medical  and  Surgical  Journal,  Januaiy  14,  1904. 

2  Zeitschrift  fiir  Hygiene,  III.,  1888,  p.  404. 

^  Ihidem,  XIV.,  1893,  p.  9.  *  Ibidem,  IX.,  1890,  p.  479, 

5  Ibidem,  XV.,  1893,  p.  86. 


ORGANIC  SUBSTANCES.  533 

is  superior  to  the  highest  grades  in  disinfecting  power  by  reason  of  the 
presence  of  the  cresols. 

Prior  to  Koch's  work  on  disinfectants  in  1881,  carbolic  acid  was 
beheved  generally  to  be  one  of  the  most  powerful  of  germicides,  a  belief 
which  was  due  doubtless,  in  part  at  least,  to  its  peculiar  and  power- 
ful odor.  Koch's  experiments  with  anthrax  spores  led  him  to  the 
conclusion  that,  even  in  5  per  cent,  solution,  it  was  an  inefficient  agent 
against  highly  resistant  organisms.  ,  Then  followed  a  number  of  in- 
vestigations by  others,  whose  conclusions  were  by  no  means  in  agree- 
ment. It  was  found  by  some  to  be  a  very  efficient  general  disinfectant, 
by  others  to  be  very  unreliable,  and  by  still  others  to  be  well  suited  to 
some  lines  of  work  and  not  to  others.  It  was  conceded  very  generally 
that  in  certain  respects  its  use  has  many  advantages  over  that  of  cor- 
rosive sublimate  and  other  metallic  salts  ;  that  it  is  not  destroyed  or 
precipitated  by  contact  with  albumin,  acids,  salts,  and  other  com- 
pounds ;  and  that,  even  in  weak  dilution,  it  destroys  many  of  the  com- 
mon pathogenic  organisms  very  quickly. 

Behring,  Sternberg,  and  others  found  it  effective  against  the  bacilli  of 
typhoid  fever  and  cholera  in  1  per  cent,  solution,  but  opposite  conclu- 
sions have  been  reported  as  to  its  action  against  the  former,  which  organ- 
ism is  said  to  flourish  in  mixed  cultures  in  the  presence  of  even  as  much 
as  5  per  cent.,  the  accompanying  species  being  destroyed.  According 
to  Vincent,^  the  colon  bacillus  is  killed  only  by  solutions  containing 
at  least  3  per  cent.  For  the  disinfection  of  tuberculous  sputum,  Schill 
and  Fischer  ^  found  it  to  be  reliable  in  5  per  cent,  solution  within  24 
hours.  An  experiment  by  the  author  and  Dr.  R.  M.  Pearce,^  in 
which  this  material  was  treated  with  17  different  preparations,  pro- 
prietary and  otherwise,  including  a  5  per  cent,  solution  of  carbolic 
acid,  was  successful  with  this  agent  and  4  others  after  a  2  hours' 
exposure.  With  typhoid  stools,  diphtheritic  membrane,  and  bouillon 
cultures  of  the  typhoid  organism,  disinfection  was  not  accomplished. 
Uffelmann  *  has  reported  that,  while  the  5  per  cent,  solution  did  not 
destroy  the  typhoid  organism  in  an  hour,  sterilization  was  complete 
after  24  hours'  exposure. 

Its  disinfectant  power  appears  to  be  increased  by  heat  and  by  the 
presence  of  mineral  acids  and  common  salt.  Thus,  Heider  ^  found 
that,  while  at  ordinary  room  temperature  a  5  per  cent,  solution  was 
ineifective  against  anthrax  spores  under  36  days,  at  55°  C  it  was  suc- 
cessful in  2  hours,  and  at  75°  C.  in  3  minutes.  The  influence  of  its 
association  with  common  salt,  which  alone  in  ordinary  amounts  has 
but  slight  bactericidal  power,  is  attested  by  Scheurlen,  Beckmann, 
Romer,  and  others. 

Scheurlen  ^  demonstrated  that,  while  1  per  cent,  solutions  had  no 
effect  against  pus  cocci  during  5  minutes'  exposure,  the  addition  of 

'  Annales  de  I'lnstitut  Pasteur,  IX.,  1805,  p.  23. 

'^  Mittheilungen  au.s  flcrii  kaiserlichen  Gesundheitsamte,  IT.,  1884,  p.  H5. 

•'  Loco  citato.  ■*  Deutsche  rnedicinische  Wochensclirift,  XVI.,  1890,  p.  37. 

*  Centralblatt  fiir  Bakten(.lo<,ne,  IX.,  1891,  p.  221. 

«  Archiv  fur  oxperimentale  Patiiologie,  etc.,  XXXVII.,  1896,  p.  74. 


534  DISINFECTANTS  AND  DISINFECTION. 

common  salt  in  considerable  amounts  brought  about  sterility  in  1 
minute,  and  that  the  same  agent  enhanced  its  action  materially  against 
anthrax  spores.  Beckmaun  ^  showed  that,  although  3  per  cent,  of  salt 
increased  the  general  disinfectant  power  of  a  1  per  cent,  solution  very 
considerably,  no  increase  in  its  power  against  anthrax  spores  was 
observable  until  24  per  cent,  had  been  added ;  but  in  this  amount,  salt 
itself  has  considerable  power,  and  it  would  seem  reasonable  to  attribute 
the  effect  of  the  mixture  very  largely,  if  not  wholly,  to  it.  Romer  - 
also  proved  the  same  thing  with  respect  to  the  action  of  a  stronger 
solution  (3  per  cent.),  which,  with  the  addition  of  8  per  cent,  of  salt, 
was  much  more  effective  against  the  same  organism. 

Similarly,  it  has  been  shown  by  Fraukel  and  Laplace  that  the  pres- 
ence of  small  amounts  of  the  mineral  acids  is  very  helpful,  but  it  is  to 
be  borne  in  mind  that  the  latter,  unassisted,  are  by  no  means  without  a 
very  considerable  degree  of  germicidal  poAver.  Both  authorities,  how- 
ever, have  proved  that  mixtures  of  carbolic  and  mineral  acids  are  more 
bactericidal  than  either  ingredient  in  the  proportions  used,  and  both, 
and  Nocht  as  well,  have  demonstrated  also  the  superiority  of  mixtures 
of  the  crude  acid  with  mineral  acids  over  combinations  of  the  pure 
phenol  with  mineral  acids  in  the  same  proportions.  According  to 
Epstein,^  carbolic  acid  in  alcoholic  solution  is  more  powerful  in  the 
same  amount  than  in  aqueous  solution,  which  tinding  is  endorsed  by 
Minervini.*  On  the  other  hand,  in  solution  in  oil,  according  to  Koch, 
it  loses  its  germicidal  property  completely. 

On  all  the  evidence  presented,  the  conclusion  must  be  drawn  that 
carbolic  acid,  while  eflPective  in  weak  and  saturated  aqueous  solution 
against  many  of  the  pathogenic  bacteria,  is  not  suited  to  the  purposes 
of  practical  general  disinfection.  When  used,  it  is  best  to  employ  the 
stronger  rather  than  the  dilute  solutions.  The  pure  acid  is  soluble  in 
about  11  parts  of  water,  but  the  commercially  pure  article  is  soluble  in 
about  20  parts,  giving  about  5  per  cent,  strength. 

The  so-called  carbolic  powders  are,  as  a  rule,  inert  mixtures  of  min- 
eral matter  and  waste  products  of  coal-tar  distillation.  Their  strong 
odor  appeals  to  the  imagination  and  promotes  their  sale. 

The  cresols,  meta-cresol,  ortho-cresol,  and  para-cresol,  which  occur 
as  impurities  of  carbolic  acid,  and,  according  to  many  authorities,  are 
more  powerful  as  germicides  and  less  poisonous  to  higher  organisms, 
are  constituents  of  a  large  number  of  preparations  which,  within 
recent  years,  have  come  into  extensive  use.  The  cresols  are  closely 
related  to  phenol,  from  which  they  differ  in  that  CH3  replaces  one  H 
in  the  benzol  ring,  and  according  to  the  position  of  CH3,  we  have 
meta-cresol,  ortho-cresol,  or  para-cresol.  The  latter  may  be  made 
synthetically  from  pure  para-toluidin.  Cresols  are  practically  insol- 
uble in  water,  but  solution  is  brought  about  by  soaps  and  by  cresol 
salts. 

1  Centralblatt  fiir  Bakteriologie,  1896,  Nos.  16  and  17. 

^  Miinchener  medicinische  Wochenschrift,  XLV.,  1898,  p.  298. 

*  Zeitsclirift  fiir  Hygiene  und  Infectionskrankheiten.  XXIV.,  1897,  p.'l. 

*  Ibidem,  XXIX.,  1898,  p.  117. 


ORGANIC  SUBSTANCES.  535 

Laplace  ^  was  the  first  to  draw  attention  to  the  fact  that  crude  car- 
bolic acid  and  strong  sulphuric  acid,  mixed  together,  form  a  compound 
soluble  in  water  and  of  high  disinfectant  power.  He  reported  that 
the  mixture  in  4  per  cent,  solution  destroyed  anthrax  spores  within  24 
hours,  while  pure  carbolic  acid  in  2  per  cent,  solution  had  no  effect 
whatever.  The  first  extensive  study  of  the  action  of  cresol  was  made 
by  Frankel,^  who  showed  that  the  mixture  of  sulphuric  acid  and 
crude  cresols  is  not  of  the  nature  of  a  new  compound,  but  that  each 
ingredient  exists  by  itself  and  exerts  its  own  action,  and  that  the  acid 
keeps  the  cresols  in  solution.  Hammer^  investigated  the  properties 
of  cresols  dissolved  in  sodium  meta-cresotinate ;  here,  also,  no  double 
compound  is  formed,  the  salt  acting  merely  as  a  solvent.  Sodium 
salicylate  acts  equally  well  as  a  solvent.  The  various  preparations 
containing  cresols  and  solvents  of  the  same  are  recommended  highly  as 
substitutes  for  phenol,  on  the  ground  of  higher  bactericidal  power, 
lower  toxicity,  and  of  being  less  irritating  in  surgical  work.  They 
may  be  diluted  at  will  with  water,  some  forming  milky  emulsions,  some 
clear  solutions. 

To  determine  the  toxic  properties  of  the  cresols,  Seybold  *  instituted 
a  series  of  experiments  with  guinea-pigs,  into  which  2  per  cent,  solutions 
of  the  individual  cresols  were  injected  subcutaneously.  The  most 
poisonous  was  found  to  be  para-cresol,  and  the  least  so  proved  to  be 
meta-cresol,  which  is  also  much  less  poisonous  than  phenol.  From  a 
study  of  the  comparative  disinfectant  action  of  the  several  cresols  and 
of  several  other  preparations,  including  tri-cresol  (prepared  synthetically 
from  toluene)  and  phenol,  he  concluded  that  of  the  three  isomers, 
meta-cresol  is  the  most  powerful,  and  that  the  cresols  are  all  superior 
to  phenol.  Tri-cresol,  which  is  40  per  cent,  meta-,  35  per  cent,  ortho-, 
and  25  per  cent,  para-cresol,  proved  to  have  double  the  bactericidal 
power  of  phenol  against  B.  pyocyaneus,  B.  prodigiosus,  and  Staphylo- 
GOGCus  pyogenes  aureus.  Another  preparation  of  cresol,  made  by  another 
manufacturer  and  examined  by  Schiirmayer,^  also  proved  to  be  far 
superior  to  phenol  and  to  a  number  of  the  more  commonly  known 
cresol  compounds.  A  proprietary  preparation  of  cresols,  examined  by 
the  author/  sterilized  in  5  per  cent,  dilution  in  2  hours,  cultures  of 
B.  typjhosus,  typhoid  dejecta,  diphtheritic  membrane,  and  tuberculous 
sputum. 

Among  the  more  commonly  used  cresol  preparations  may  be  men- 
tioned the  following : 

Creolin. — This  is  a  dark-brown,  thick,  alkaline  liquid,  which  con- 
tains about  10  per  cent,  of  cresols,  held  in  solution  by  soap,  and  a 
small  amount  of  phenol.  Mixed  with  water,  it  forms  a  turbid,  whitish 
emulsion.     According  to   Hiinerman,''  it  is  inferior  to  carbolic  acid 

^  Deutsche  medicinische  Wochenschrift,  1887,  No.  40. 

•''  Zeitschrift  fiir  ITy^iene,  VI.,  1889,  p.  521. 

»  Archiv  fiJr  Hygiene,  XI I.,  18<.»1,  p.  359  ;  XIV.,  1892,  p.  116. 

*  Zeitsclirift  fiir  Jlygieric  mid  iniectionskranklieiten,  XXIX.,  1898,  p,  377. 

5  Arcliiv  fiir  IIvf,nene,  XXV.,  1896,  p.  328.  «  Loco  citato. 

'  Centrcilblatt  I'Lir  Bakteriologie,  V.,  1889,  p.  650. 


536  DISINFECTANTS  AND  DISINFECTION 

against  anthrax  bacilli  and  pus  cocci,  but  Van  Ermengem  ^  found  it  very 
effective  in  5  per  cent,  solution  against  pus  cocti  and  the  germs  of  typhoid 
fever  and  cholera ;  and  Laser  ^  found  that  in  the  same  strength  it  disin- 
fects dejecta  completely.  The  results  obtained  by  various  experimenters 
are,  on  the  whole,  very  conflicting,  but  the  output  of  many  diiferent 
manufacturers  has  been  proved  to  vary  very  greatly  in  chemical  com- 
position and  bactericidal  power,  and  this  is  doubtless  the  cause. 

Lysol  is  a  brown  oily  liquid  containing  about  50  per  cent,  of  cresols 
with  neutral  potash  soap,  miscible  with  water  in  all  proportions,  form- 
ing a  soapy,  frothing  liquid,  and  with  alcohol  and  glycerin.  Gruber  ^ 
found  a  2  per  cent,  solution  more  effective  against  pus  cocci  than  a  3 
per  cent,  solution  of  phenol.  Buttersack's  *  experiments  led  to  the 
same  conclusion,  and  demonstrated  also  its  suitability  for  the  treatment 
of  sputum.  Vincent  ^  found  it  to  be  a  valuable  agent  for  the  disinfection 
of  fseces  and  vault  contents.  It  has  been  used  extensively  in  surgical 
practice  with  good  results,  but  instances  of  poisoning  through  absorption 
from  wounds,  sometimes  with  fatal  results,  are  fairly  numerous. 

Bacillol  is  a  product  of  the  distillation  of  tar,  and  contains  variable 
amounts  of  cresols  according  to  source,  but  should  contain  not  less  than 
50  per  cent.     It  is  very  cheap. 

Lysoform  is  a  cresol-formaldehyde  preparation,  soluble  in  water.  It 
has  great  deodorant  power,  but  is  rather  unsatisfactory  as  a  germicide. 
It  is  also  expensive. 

Saprol. — This  is  a  liquid  containing  20  per  cent,  of  mineral  oil  and 
80  per  cent,  of  crude  carbolic  acid.  It  is  lighter  than  water,  and  when 
thro-svn  into  it  diffuses  over  the  surface  in  a  thin  layer,  which  gradually 
yields  its  active  ingredients  to  the  strata  below,  which,  in  the  course 
of  a  day,  become  impregnated  to  the  extent  of  about  0.34  per  cent. 
In  this  strength,  according  to  Scheurlen,''  it  destroys  cholera  bacteria 
in  1  hour.  For  the  disinfection  of  privy  vaults,  Keiler^  determined 
that  it  must  be  added  to  the  extent  of  1  per  cent,  of  the  entire  contents. 
In  mixtures  containing  5  per  cent.,  the  same  observer  showed  that  the 
typhoid  fever  bacillus  is  destroyed  within  a  few  minutes.  Pfuhl^ 
found  it  to  be  much  superior  as  a  general  disinfectant  and  deodorant 
to  carbolic  acid,  but  not  suited  to  the  treatment  of  vault  contents. 
Laser,^  however,  found  that  1  per  cent,  will  disinfect  faces  and  urine  ; 
and  Scheurlen  ^^  reported  that  for  the  disinfection  of  vault  contents,  but 
two  other  agents  are  comparable  with  it,  namely,  milk  of  lime  and 
crude    carbolic  acid. 

Solveol  is  a  concentrated  aqueous  solution  of  cresols  with  sodium 
cresotinate,  containing  more  than  25  per  cent,  of  cresols.     It  is  highly 

1  Centralblatt  fiir  Bakteriologie,  VII.,  1890,  p.  75. 

2  Ibidem,  XII.,  1892,  p.  232.  _      ^  Ibidem,  XI.,  1892,  p.  117. 

*  Arbeiten  aus  dem  kaiserlichen  Gesundheitsamte,  VIIL,  1892,  p.  369. 

*  Annales  de  I'lnstitnt  Pasteur,  IX.,  1895,  p.  26. 
6  Archiv  fiir  Hygiene,  XVIII.,  1893,  p.  35. 

'  Ibidem,  XVlll.,  1893,  p.  57. 

*  Zeitschrift  fiir  Hvgiene  und  Infectionskrankheiten,  XV.,  1893,  p.  192. 
9  Centralblatt  fiir  Bakteriologie,  XII.,  1892,  p.  234. 

^»  Archiv  fiir  Hygiene,  XIX.,  1893,  p.  347. 


ORGANIC  SUBSTANCES.  537 

recommended  for  use  in  surgical  practice,  being  unirritating  and  much 
less  toxic  than  carbolic  acid.  According  to  Hammer/  it  is  more 
powerful  in  2  per  cent,  solution  than  creolin,  lysol,  and  carbolic  acid 
in  2.5  per  cent,  strength.  Hammerl  ^  also  found  it  superior  to  carbolic 
acid  and  the  other  cresol  preparations. 

Solutol  is  a  solution  of  about  60  j)er  cent,  of  cresols  in  sodium  cresol. 
According  to  Hueppe,^  it  is  far  superior  to  creolin,  lysol,  solveol,  and 
phenol,  in  which  conclusion  he  agrees  with  Buttersack.*  Hammer^ 
also  and  others  have  found  it  to  be  well  suited  to  the  purposes  of 
general  disinfection. 

Alcohol. — Ordinary  alcohol  is  employed  extensively  as  a  preserva- 
tive of  organic  material  in  great  variety,  and  hence  has  come  to  be  re- 
garded as  a  powerful  disinfectant  as  well  as  antiseptic.  Koch's  ex- 
periments showed  that  although  the  growth  of  anthrax  bacilli  was 
inhibited  by  1  per  cent.,  and  wholly  stopped  by  8  per  cent.,  the  spores 
were  unaffected  by  nearly  4  months'  exposure  to  absolute  alcohol,  equal 
parts  of  the  same  and  water,  and  mixtures  of  1  part  of  alcohol  and  2 
parts  of  water.  Sternberg  and  others  have  shown  that  against  some 
forms  of  bacteria  it  is  inefficient  as  a  germicide  in  any  degree  of  con- 
centration, and  that  in  different  strengths  it  affects  other  forms  to  dif- 
ferent extents.  Epstein's  ^  experiments  led  him  to  the  conclusion  that 
absolute  alcohol  is  devoid  of  germicidal  properties,  and  that,  diluted 
with  water  to  50  per  cent,  strength,  it  exerts  more  action  than  at  any 
other  strength.  Considerably  stronger  or  weaker  solutions  show  much 
diminished  power. 

Frank's ''  best  results  were  obtained  with  40  per  cent,  alcohol,  which 
destroyed  anthrax  spores  in  5  minutes.  He  found  the  vapor  of  50  to 
80  per  cent,  alcohol  to  be  more  or  less  productive  of  results,  but  that 
of  90  to  99  per  cent,  and  of  mixtures  below  40  per  cent,  to  be  quite 
ineffective.  W.  von  Brunn  ^  came  to  practically  the  same  conclusions, 
as  did  also  Ahlfeld,^  whose  belief  it  is  that  the  water  in  the  mixture 
causes  the  envelope  of  the  bacteria  to  swell  and  permits  the  entrance  of 
the  alcohol  into  the  interior. 

Minervini  ^"  found  that,  at  ordinary  temperatures,  alcohol  and  its 
aqueous  dilutions  are  powerless  against  spore-bearers,  even  with  long 
exposure,  and  that,  against  the  sporeless  bacteria,  the  action  is  variable 
according  to  the  amount  of  water  present.  The  most  powerful  action 
was  exerted  by  50  to  70  per  cent,  alcohol.  Heated  under  pressure  in 
an  autoclave,  the  power  increases  directly  with  the  percentage  of  water. 
Many  germicides  which  are  effective  in  aqueous  solution,  appear  to 
lose  more  or  less  of  their  power  in  alcohol.     Minervini  found  3  per 

>  Archiv  fur  Hygiene,  XII.,  1891,  p.  359.  ^  ibidem,  XXL,  1894,  p.  198. 

•''  Berliner  ItliniKche  Wochenschrift,  1893,  No.  21. 

*  Arbeiten  ans  dem  kaiserlichen  Gesundheitsamte,  VIII.,  1892,  p.  369. 
*"  Loeo  citato. 

**  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXIV.,  1897,  p.  1. 
^  Miinchen(;r  niedicinische  Wochenschrift,  1901,  No.  4,  p.  134. 
»  Ibidem,  1901,  No.  7,  p.  2f)5. 

*  Ilygieni.sclie  JiiindH(;liau,  1901,  p.  111. 

'"  Zeitschrift  fiir  Hygiene  und  InfectionHkranklieiten,  XXIX.,  1898,  p.  117. 


538  DISINFECTANTS  AND  DISINFECTION. 

cent,  of  carbolic  acid  in  strong  alcohol  to  act  with  undiminished  energy, 
but  observed  that  corrosive  sublimate,  nitrate  of  silver,  and  other 
agents  were  more  powerful  as  the  percentage  of  alcohol  in  the  solution 
diminished.  According  to  Epstein,  not  only  carbolic  acid,  but  also 
corrosive  sublimate,  lysol,  and  thymol  are  more  powerful  in  50  per  cent, 
alcohol  than  in  water,  but  other  agents  are  weaker. 

Leuti^  has  reported  that  while  0.4  per  cent,  of  corrosive  sublimate 
in  absolute  alcohol  had  no  efiPect  on  anthrax  spores  in  48  hours,  0.1 
per  cent,  in  98  per  cent,  alcohol  destroyed  them  in  half  the  time.  Sim- 
ilar results  were  obtained  with  10  per  cent,  of  carbolic  acid  ;  in  abso- 
lute alcohol,  it  was  powerless,  but  in  30  per  cent,  alcohol,  it  killed  them 
in  48  hours. 

Essential  Oils. — The  volatile  oils  have  long  been  known  to  possess 
a  certain  degree  of  antiseptic  power,  but  bacteriological  experimenta- 
tion has  failed  to  demonstrate  that  they  are  very  active  as  germicides. 
Those  highest  in  favor  are  the  oils  of  peppermint,  eucalyptus,  and 
thyme,  which  contain,  respectively,  menthol,  euccdyptol,  and  thymol. 
The  latter  was  in  somewhat  extensive  use  in  surgical  practice  prior  to 
1870.  It  is  only  slightly  soluble  in  alcohol,  ether,  chloroform,  and 
fixed  and  volatile  oils.  By  many  it  has  been  regarded  as  superior  to 
phenol.  Spencer  Wells  much  preferred  it  in  his  extensive  experience 
in  ovariotomy.  According  to  Behring,^  however,  it  is  only  about  a 
fourth  as  powerful,  and  Sauter^  ranks  it  even  below  salicylic  acid. 
Eiioalyptol  is  practically  insoluble  in  water,  but  soluble  in  alcohol  and 
other  solvents.  Concerning  this  agent,  too,  there  is  much  diversity  of 
opinion,  some  regarding  it  as  vastly  superior  to  phenol,  others  as  much 
inferior.  Lister  praised  it  higlily.  Behring  found  it  to  be  about  equal 
to  thymol.  3Ienthol  is  sparingly  soluble  in  water,  but  freely  in  alcohol 
and  other  solvents.  It  has  been  highly  praised  as  a  surgical  antiseptic, 
and  as  freely  criticised.  Omeltschenko  *  ranks  the  oil  of  peppermint 
above  that  of  eucalyptus,  but  below  that  of  thyme.  All  three  are 
placed  by  him  below  the  oils  of  cinnamon  and  cloves. 

Aside  from  the  conflicting  evidence  as  to  the  power  of  the  various 
volatile  oils,  their  cost  alone  would  be  sufficient  to  restrict  their  gen- 
eral use  as  disinfectants.  They  are  employed  considerably  in  various 
combinations  in  mouth  washes  and  in  a  number  of  decidedly  expensive 
proprietary  disinfectants,  one  at  least  of  which,  tested  by  the  author, 
has  been  found  to  be  eflicient  in  the  sterilization  of  tuberculous  sputum, 
one  of  the  few  uses  for  which  its  manufacturers  make  no  claims. 

Soaps. — It  is  well  known  that  ordinary  soaps,  both  hard  and  soft, 
are  possessed  of  considerable  bactericidal  power,  investigated  first  by 
Koch,  who  proved  that  potash  soap  in  the  proportion  of  1  to  5,000 
had  a  distinct  inhibitory  effect  on  the  growth  of  anthrax  bacilli,  and  in 
five  times   that  strength  prevented   it  altogether.       This   action   was 

1  Annali  dell'istituto  d'igiene  sperimentale  della  reale  Univei-sita  di  Roma,  III., 
1893,  p.  515. 

2  Zeitschrift  fiir  Hygiene,  IX.,  1890,  p.  395. 

^  Centralblatt  fiir  gesammte  Therapie,  VI.,  p.  376. 
*  Centralblatt  fur  Bakteriologie,  IX.,  1891,  p.  813. 


ORGANIC  SUBSTANCES.  539 

admitted  by  Kiiisl/  who,  however,  asserted  that  against  other  kinds  of 
bacteria,  B.  typhosus  for  example,  it  was  inert.  In  1890,  Behring,^ 
after  experimenting  with  40  different  kinds  of  soap,  proved  that  their 
disinfectant  power  was  considerable,  and  concluded  that  it  was  depen- 
dent upon  their  alkalinity.  Koch,  howev^er,  had  demonstrated  that,  with 
equal  degrees  of  alkalinity,  soft  soap  was  8  times  as  powerful  as  potash 
alone ;  and  Serafini  ^  has  pointed  out  that  the  free  alkali  present,  even 
in  concentrated  soap  solutions,  is  so  small  in  amount  that  it  can  exert 
no  disinfectant  action  whatever,  and  that  neither  the  alkali  nor  the 
fatty  acid,  but  the  combination  of  the  two,  is  the  effective  agent. 

I^ijland,*  experimenting  with  a  potash  soap  containing  47.2  per  cent, 
of  water  and  a  hard  soap  containing  14.5  per  cent.,  found  that  the 
former  in  0.24  per  cent,  solution  killed  cholera  bacteria  in  10  minutes, 
and  the  latter  in  the  same  strength  was  not  wholly  effective  in  1 5,  but 
in  0.30  per  cent,  solution  destroyed  them  within  1  minute.  The 
cholera  organism  was  used  by  Jolles  ^  in  testing  five  soaps,  all  of  which 
proved  to  be  inefficient.  By  10  per  cent,  solutions,  the  bacteria  were 
destroyed  within  1  minute  ;  by  4  per  cent.,  in  10  minutes  ;  by  2  per 
cent.,  and  in  three  instances  by  1  per  cent.,  in  30  minutes. 

In  a  later  series  of  tests  with  typhoid  fever  bacilli,  Jolles  ^  tried  an 
almost  neutral  soap,  containing  but  0.041  per  cent,  of  free  alkali,  and 
with  1  per  cent.,  sterilized  a  bouillon  culture  within  12  hours,  with  3 
per  cent,  within  2  hours,  and  with  6  per  cent,  in  15  minutes.  He 
showed  that  the  action  was  much  influenced  by  temperature.  The 
above  results  were  brought  about  at  temperatures  between  4°  and  8° 
C,  but  at  18°  C,  the  time  which  elapsed  before  complete  sterilization 
was  accomplished  M^as  about  double.  This  result  is  not  in  accordance 
with  the  general  rule  that  disinfectants  are  more  active  with  increased 
temperature.  He  obtained  practically  the  same  results  with  other 
varieties  of  bacteria,  and  reported  that,  because  of  its  action  on  the 
most  common  pathogenic  forms,  soap  is  especially  valuable  and  adapt- 
able for  precisely  the  kind  of  work  in  which  it  is  the  most  natural 
agent ;  that  is,  in  washing  dirty  and  infected  clothing. 

Serafini,''  however,  is  of  the  opinion  that,  in  the  ordinary  washing  of 
clothes,  soaps  exert  but  little  disinfection,  because  of  the  many  influ- 
ences, hardness  of  the  water,  for  example,  which  cause  a  diminution 
of  their  power.  He  recommends  the  avoidance  of  soft  soaps,  on 
account  of  the  presence  of  all  of  the  impurities  of  the  fats  and  alkali 
from  which  they  are  made,  and  advises  one  to  distrust  the  ordinary 
colored  soaps,  which  are  likely  to  contain  rosin.  If  soap  is  the  sole 
reliance,  he  recommends  using  it  in  strong  solution  at  30°  to  40°  C. 
(86°  to  104°  F.),  and   immersing  therein  for  a  number  of  hours  the 

'  rnaii^niral  thesis,  Munich,  1885. 

''  Zeitschrift  fiir  Hygiene,  IX.,  1890,  p.  395. 

•'  Archiv  fiir  Hygiene,  XXXIIL,  1899,  p.  369. 

^  lhi(l<-m,  XVIII.,  1893,  p.  3.35. 

'•"  Zeitschrift  fiir  Hygiene  iind  Infectionskrankheiten,  XV.,  1893,  p.  460. 

«  Ibidem,  XIX.,  1895,  p.  130. 

'  Loco  citato. 


540  DISINFECTANTS  AND  DISINFECTION. 

articles  to  be  treated.  Even  with  long  soaking,  Beyer  ^  reports  unvary- 
ing failure  of  soap  against  pus  cocci  and  the  bacilli  of  cholera  and 
typhoid  fever  on  clothing  in  hospital  practice. 

Reithoffer,"  experimenting  with  common  soft  soap  containing  traces 
of  free  alkali  and  2.55  per  cent,  of  potassium  carbonate,  a  white 
almond-oil  soap  perfumed  with  nitrobenzol  and  containing  0.062  per 
cent,  of  free  alkali,  and  a  patented  potash  soap  containing  0.031  per 
cent,  of  free  alkali,  found  that  all  three,  even  in  1  per  cent,  solution, 
were  highly  efficient  against  cholera  germs  within  very  few  minutes, 
and,  therefore,  recommends  soap  as  a  practical  disinfectant  for  clothing, 
furniture,  etc.,  during  epidemics  of  that  disease.  For  washing  body- 
and  bed-linen,  furniture,  wood-work,  floors,  etc.,  he  recommends  a  4  to 
5  per  cent,  soap  solution  as  probably  efficient  under  all  conditions  after 
from  5  to  10  minutes'  contact,  but  suggests  care  in  avoiding  the  com- 
mon commercial  soft  soaps,  which  are  frequently  of  poor  quality. 
Experimenting  with  B.  typhosus  and  B.  coll,  he  proved  that  here  again 
the  soaps  possessed  a  high  degree  of  power,  though  much  larger 
amounts  were  necessary  than  in  the  case  of  B.  cholerce.  He  demon- 
strated that  a  10  per  cent,  solution  was  necessary  for  the  destruction 
of  the  typhoid  gemis  within  1  minute,  and  that  a  5  per  cent,  solution 
required  from  3  to  10  minutes  according  to  the  kind  of  soap,  the  soft 
soap  being  slowest  in  action,  as  was  true  also  against  the  cholera  germs. 
Against  the  colon  bacillus,  the  action  was  still  slower :  5  per  cent,  of 
the  almond  soap  required  15  minutes,  and  the  same  strength  of 
potash  soap  failed  to  accomplish  complete  sterilization  in  20  minutes. 
The  superiority  of  the  almond  soap  suggested  the  possibility  that  its 
increased  power  might  be  due  to  the  nitrobenzol  with  which  it  was 
perfumed,  and  experiment  showed  this  to  be  true.  Against  pus  cocci, 
all  three  agents  failed  completely  ;  Staphylococcus  pyogene^s  aiweus  was 
unaffected  by  20  per  cent,  solutions  at  the  expiration  of  more  than  an 
hour.  For  the  disinfection  of  the  hands,  5  per  cent,  solutions  were 
found  to  be  almost  immediately  effective  against  cholera  germs,  but 
longer  and  more  thorough  washing  is  recommended  in  typhoid  infec- 
tion. 

According  to  Mikulicz,^  tincture  of  green  soap,  the  German  officinal 
Spiritus  saporiatus,  containing  10.2  parts  of  potash  soap,  0.8  of  olive 
oil,  1  of  glycerin,  43  of  alcohol,  and  45  of  water,  is  admirable  in  undi- 
luted form  for  sterilizing  the  hands  in  surgical  work.  They  should  be 
scrubbed  for  5  minutes  with  the  preparation  in  its  full  strength.  In 
his  experiments.  Staphylococcus  pyogenes  aureus  was  killed  in  a  half 
minute  and  S.  p.  albus  in  a  minute. 

From  all  the  evidence,  conflicting  though  it  be  in  certain  respects,  it 
must  be  evident  that  in  soap  we  have  an  agent  wjiich,  with  all  its  limi- 
tations, is  entitled  to  very  serious  consideration,  at  least  as  an  auxiliary 
in  complete  disinfection. 

^  Fortschritte  der  Medicin,  1897,  No.  1. 

*  Archiv  fur  Hygiene,  XXVII.,  1896,  p.  350. 

*  Deutsche  medicinische  Wochenschrift,  June  15,  1899. 


ORGANIC  SUBSTANCES.  541 

Medicated  Soaps. — In  order  to  increase  the  disinfectant  properties  of 
ordinary  soaps,  various  agents,  including  mercury  compounds,  carbolic 
acid,  and  the  cresol  preparations,  are  incorporated  in  them.  Com- 
pared with  ordinary  soaps,  these  preparations  appear  to  be  of  doubtful 
utility,  although  in  the  hands  of  some  experimenters  they  have  yielded 
good  results.  From  an  extensive  investigation  of  these  soaps,  Symes  ^ 
concluded  that,  for  all  practical  purposes,  most  of  them  possess  no 
added  value,  but  that  the  mercury  soaps  are  useful  in  disinfection 
of  the  hands.  A  1  per  cent,  solution  of  the  biniodide  soap  killed  pus 
cocci  in  1  minute,  while  the  other  soaps  failed  to  do  so  in  3  hours. 
Nijland  ^  found  that  the  addition  of  disinfectants  to  soaps  increases 
their  action  in  some  cases  and  diminishes  it  in  others,  the  latter  especi- 
ally when  the  added  substance  combines  with  the  ordinary  constituents. 
According  to  his  experiments,  the  most  powerful  of  all  is  the  corrosive 
sublimate  soap,  which,  however,  has  less  power  than  the  corresponding 
amount  of  sublimate  alone.  In  0.003  per  cent,  solution  it  killed 
cholera  bacilli  in  water  within  10  minutes.  RideaP  asserts  that  the 
double  iodide  of  potassium  and  mercury  has  stronger  germicidal 
powers  than  corrosive  sublimate,  and  is  easily  incorporated  iu  the  soap 
stock.  He  recommends  the  admixture  of  1  to  3  parts  each  of  mer- 
curic and  potassic  iodide  in  100  of  soap.  "  Potassio-mercuric  iodide 
has  the  advantage  of  being  compatible  with  strong  alkalies.  .  .  . 
Moreover,  it  does  not  precipitate  albumin,  and  is  not  easily  reduced." 
McClintock  ^  tried  to  make  an  antiseptic  soap  in  which  the  mercury  salt 
should  exist  unchanged  and  active,  and  found  the  double  iodide  to  be 
the  most  available  agent  in  the  proportion  of  0.5  to  2.0  per  cent.  A 
solution  containing  1  per  cent,  of  the  soap  Avas  found  to  be  fatal  to  pus 
cocci  and  cholera,  diphtheria,  and  typhoid  fever  bacilli  in  1  minute.  The 
soap  attacked  neither  nickel,  silver,  aluminum,  nor  steel  instruments, 
nor  lead-pipes,  and  did  not  coagulate  albumin. 

Concerning  carbolic  acid  and  cresol  soaps,  the  weight  of  evidence  is 
clearly  in  support  of  the  assertion  that  they  are  in  no  way  superior  to 
common  soaps.  Many  contain  no  more  than  sufficient  to  make  them 
powerful  in  odor,  which  is  not  sufficient  to  confer  any  marked  bacteri- 
cidal power.  Nocht  ^  calls  attention  to  the  solvent  property  of  soap  on 
carbolic  acid,  showing  that  at  60°  C.  a  3  per  cent,  solution  of  soap 
will  dissolve  6  per  cent.,  and  double  that  strength  will  dissolve  12  per 
cent,  of  carbolic  acid.  He  found  that  a  cold  solution  of  soap  containing 
1.5  per  cent,  of  carbolic  acid  was  fatal  to  pus  cocci  and  non-sporing 
bacteria  in  half  an  hour,  but  recommends  the  employment  of  3  per 
cent,  solution  of  a  5  per  cent,  soap  for  the  treatment  of  clothing, 
leather  articles,  and  other  objects.  Reithoffiar  ^  found  that  carbolic  acid 
is  weakened  by  the  presence  of  soap,  and  that  a  soft  soap  containing  40 
per  cent,  of  lysol  was  no  more  effective  against  pus  cocci,  B.  coli  and 

'  Bristol  Medico-Chirurgical  Journal,  Sept.,  1899. 

^  Loco  citato. 

•'  Disinfection  and  Disinfectants,  London,  1898,  p.  485. 

♦  Medical  News,  April  17,  1897,  p.  485. 

*  Zeitschrift  fur  Hygiene,  VII.,  1889,  p.  521.  «  Loco  citato. 


542  DISINFECT  A  ^'TS  AND  DISINFECTION. 

B.  typhosus,  than  ordinary  soaps,  and  was  much  weaker  than  a  solu- 
tion of  lysol  alone  in  the  same  lysol  strength.  Tonzig  ^  found  that 
various  creolin  soaps  were  ineffective,  like  other  soaps  containing  cor- 
rosive sublimate  and  other  disinfectants,  because  new  compounds  are 
formed  with  the  ordinary  constituents  of  the  soap,  and  the  natural 
disinfectant  properties  of  the  same  are  thereby  diminished. 

In  the  disinfection  of  hands  by  means  of  medicated  soaps,  it  should 
be  borne  in  mind  that  the  added  disinfectant  is  commonly  present  in  in- 
sufficient amounts,  and  that,  as  used,  the  soaps  form  a  very  weak  solu- 
tion, which,  in  the  time  ordinarily  given,  can  have  but  little,  if  any, 
effect. 

Formaldehyde. — Formaldehyde,  otherwise  known  as  methyl  alde- 
hyde and  oxymethylen,  the  simplest  known  compound  of  carbon,  hydro- 
gen, and  oxygen,  was  discovered  by  Professor  A.  W.  Hoffmann  in 
1867,  but  its  germicidal  properties  were  not  recognized  until  1886,  and 
were  not  put  to  practical  use  until  1891.  It  is  a  gaseous  product  of 
oxidation  of  wood  alcohol,  made  most  simply  by  passing;  a  current  of 
the  alcohol  vapor  over  platinum  sponge  previously  heated  ;  as  the  vapor 
comes  in  contact  with  the  incandescent  platinum,  it  is  oxidized  to  alde- 
hyde and  water  (CH3OH  +  O  =  CH^O  +  H.O).  The  continuous 
current  maintains  the  incandescence.  On  a  large  scale,  it  is  produced 
by  treating  the  alcohol  in  copper  tubes  containing  incandescent  coke. 

Formaldehyde  is  soluble  in  water  up  to  40  per  cent.,  and  gives  a 
neutral  solution,  but  the  commercial  preparations  are  usually  slightly 
acid  in  reaction  from  traces  of  formic  acid.  Its  solution  cannot  be 
stronger  than  40  per  cent.,  and  attempts  to  concentrate  it  or  to  condense 
the  vapor  cause  it  to  polymerize  to  a  white  indistinctly  crystalline  solid, 
trioxymethyien  or  paraformaldehyde  (C3Hg03),  which  is  almost  insolu- 
ble in  water,  melts  at  171°  C,  when  ignited,  burns  with  a  blue  flame, 
but  when  gently  heated  in  an  open  dish,  is  converted  again  to  the  gas- 
eous formaldehyde.  When  the  solution  is  heated  in  a  closed  vessel 
under  pressure,  polymerization  is  prevented  by  the  presence  of  borax 
or  of  neutral  salts,  as  chloride  of  calcium. 

Formaldehyde  vapor  is  exceedingly  pungent  and  very  irritating  to 
the  eyes  and  nose.  It  has  a  strong  affinity  for  many  organic  sub- 
stances, and  combines  with  nearly  all  foul-smelling  products  of  decom- 
position, forming  odorless  compounds,  and  thus  acting  as  a  deodorant. 
It  transforms  gelatin  in  solution  to  a  tough  transparent  substance  in- 
soluble in  boiling  water,  causes  blood  serum  to  lose  its  coagulability  by 
heat,  combines  with  the  protoplasm  of  bacteria,  and  converts  egg  albu- 
min into  a  substance  insoluble  in  water  and  indigestible.  With  am- 
monia, it  forms  an  inert  compound,  hexamethylentetramin,  which  has 
the  odor  of  neither  substance  (4NH3  +  6CH2O  =  (CH2)6N4  +  6HP). 
It  has  no  action  on  copper,  brass,  zinc,  nickel,  silver,  iron,  steel,  or 
other  metallic  substances,  causes  no  diminution  in  the  tensile  strength 
of  fabrics,  and  has  no  bleaching  or  other  effect  on  colors,  excepting  to 
intensify  the  effect  of  certain  of  the  coal-tar  dyes  (fuchsin,  saflfraniu, 
^  Gazetta  degli  ospedali  e  delle  cliniche,  1900,  No.  6. 


ORGANIC  SUBSTANCES.  543 

and  perhaps  others).  It  may,  however,  fix  blood,  pus,  and  fsecal  stains 
on  clothing.  It  has  no  injurious  action  on  clothing  and  other  woven 
fabrics,  furs,  articles  of  rubber,  leather,  and  paper,  photographs,  paint- 
ings, woodwork,  and  furniture. 

The  antiseptic  properties  of  formaldehyde  were  noted  first  in  1886 
by  Loew  and  Fischer,^  but  its  value  as  a  practical  disinfectant  was 
made  known  first  by  Trillat  ^  in  a  communication  to  the  French  Acad- 
emy of  Science  in  1892,  and  since  that  time  it  has  been  the  subject 
of  very  extensive  investigation,  which  has  demonstrated  conclusively 
that  formaldehyde  is  by  far  the  most  powerful  and  practical  chemical 
disinfectant  known.  In  general,  it  is  used  in  the  form  of  gas  gener- 
ated in  different  ways  from  methyl  alcohol  or  from  the  aqueous  40  per 
cent,  solution,  commonly  known  by  the  commercial  name  Formalin,  or 
from  the  solid  polymer  trioxymethylen,  otherwise  known  as  paraformal- 
dehyde and  by  the  trade  name  Paraform.  In  some  processes  of  disin- 
fection and  deodorization,  it  is  applied  directly  in  the  form  of  aqueous 
solution. 

Methods  of  Use,  and  Apparatus. — At  first,  the  gas  was  generated 
directly  from  methyl  alcohol,  by  means  of  lamps  specially  constructed 
for  the  purpose.  The  first  of  these  was  devised  by  Trillat,  who  was 
followed  by  Gambler,  Barthel,  Dieudonn6,  Krell,  ToUens,  and  others, 
who  presented  various  modifications  and  improvements. 

In  1896,  Professor  Robinson,  of  Bowdoin  College,  exhibited  at  the 
annual  meeting  of  the  American  Public  Health  Association  a  lamp 
devised  by  him,  which,  it  is  generally  agreed,  is  the  best  yet  invented. 
It  consists  of  a  disk  of  moderately  thick  asbestos,  closely  perforated 
with  small  holes  and  platinized  with  a  strong  solution  of  platinic 
chloride,  and  a  cylindrical  dish  upon  which  it  is  superimposed.  In  use, 
the  dish  is  filled  partly  with  methyl  alcohol,  and  the  disk,  at  first 
remov^ed,  is  wetted  with  alcohol,  which  is  then  ignited.  As  soon  as  the 
alcohol  is  consumed,  the  disk  is  replaced,  when  it  is  at  a  sufficiently  high 
temperature  to  convert  the  fumes  from  the  methyl  alcohol  beneath  to 
formaldehyde,  and  as  long  as  the  process  continues,  is  maintained  at 
the  proper  degree  of  heat.  But  this,  in  common  with  all  other  lamps 
of  the  kind,  is  open  to  several  objections,  among  which  may  be  men- 
tioned the  small  yield  of  formaldehyde,  which  necessitates  the  employ- 
ment of  a  large  number  of  generators ;  the  fact  that  a  large,  if  not  the 
greater,  part  of  the  alcohol  is  converted  to  carbon  monoxide  and  dioxide, 
and  the  danger  of  fire. 

Trillat,  recognizing  the  defects  of  his  own  and  other  lamps,  and  being 
convinced  of  the  futility  of  attempting  to  disengage  the  gas  by  evap- 
orating the  aqueous  solution  from  open  vessels,  whereby  polymerization 
is  caused,  attempted  to  devise  an  apparatus  in  which  the  aqueous  solu- 
tion could  be  employed  without  the  occurrence  of  this  undesirable 
phenomenon.  The  outcome  of  his  study  was  the  autoclave  which  bears 
his  name. 

'  Journal  fur  praktisclic  Clieniie,  XXXIIL,  p.  221. 
•^  (Jomj.U's  reiHiiis,  CXIV.,  p.  1278. 


5^4 


DISINFECTANTS  AND  DISINFECTION. 


Trillat's  autoclave,  shown  in  Fig.  92,  consists  of  a  cylindrical  silver- 
lined  pot  of  heavy  copper,  of  about  a  gallon  capacity,  with  a  cover  rest- 
ing on  a  rubber  gasket  and  secured  by  means  of  turn-buckles.  The 
cover  carries  a  pressure  gauge,  a  thermometer,  and  an  outlet  controlled 
by  a  valve  and  terminating  in  a  narrow  brass  tube.  The  pot  is  sup- 
ported on  a  tripod,  and  beneath  it  is  a  Swedish  lamp,  the  flame  of 
which  is  fed  by  vapors  from  kerosene  oil  forced  out  by  compressed  air. 
In  the  pot  is  placed  not  more  than  three-fourths  nor  less  than  one- 
fourth  of  its  capacity  of  a  mixture  of  the  40  per  cent,  solution  of 
formaldehyde  and  chloride  of  calcium,  the  latter  for  the  purpose  of 
preventing  polymerization  under  pressure.  This  mixture,  which  con- 
tains 150  grams  of  the  chloride  to  the  liter,  is  known  as  FormochloroL 


Fig.  92. 


Fig.  93. 


Trillat's  autoclave. 


Sanitary  Construction  Company's 
regenerator. 


The  formaldehyde  solution  used  should  be  practically  free  from  methyl 
alcohol,  which,  while  of  no  practical  interest  under  ordinary  circum- 
stances, is  an  objectionable  impurity  when  the  solution  is  heated  under 
pressure,  since  then  it  unites  with  a  corresponding  amount  of  formal- 
dehyde to  form  inert  methylal.  The  cover  is  firmly  fixed  by  the  turn- 
buckles,  and  then  the  lamp  is  put  in  operation.  When  the  gauge  shows 
a  pressure  of  three  atmospheres,  the  outlet  tube  is  introduced  into  the 
keyhole  of  the  door  of  the  room  to  be  disinfected,  and  the  valve  is  opened 
gradually  so  as  to  release  the  vapor.     The  disengagement  of  the  gas  is 


ORGANIC  SUBSTANCES. 


645 


continued  until  a  sufficient  amount  of  the  liquid,  based  upon  the  amount 
of  air  space  treated,  is  consumed.  According  to  Trillat,  in  the  case  of 
a  room  of  ordinary  size,  say  18  feet  square  and  10  from  floor  to  ceiling, 
the  operation  should  require  about  an  hour.  The  objections  urged 
against  this  form  of  apparatus  are  its  cost,  the  want  of  uniformity  in 
the  amount  of  gas  delivered  within  a  given  time,  and  the  danger  of 
explosion  from  the  possibility  of  the  non-working  of  the  valve,  or  from 
obstruction  by  one  cause  or  another  of  the  outlet  tube. 

A   number   of  other  apparatuses  for  the  same  purpose  have  been 
devised,  and  to  several  of  them  these  objections  do  not  apply.     One  of 


Fig.  94. 


Lentz's  regenerator. 

these  is  the  regenerator  made  by  the  Sanitary  Construction  Companjp 
and  used  extensively  by  public  authorities.  (See  Fig.  93.)  It  consists 
of  a  copper  reservoir,  holding  about  3  quarts,  from  the  bottom  of  which 
leads  a  quarter-inch  copper  tul)e,  which  forms  a  coil  2  inches  below, 
and  then  turns  upward  and  extends  above  the  top  of  the  apparatus, 
where  it  is  fitted  with  a  rubber  tube  carrying  a  fine  copper  nozzle, 
through  which  the  gas  is  delivered.  Beneath  the  coil  is  a  Swedish 
lamp  similar  to  that  used  with  the  Trillat  autoclave.    The  formaldehyde 


546 


DISINFECTANTS  AND  DISINFECTION. 


Fig.  95. 


solution  is  admitted  to  the  heated  coil  through  a  valve,  and  is  trans- 
formed to  vapor,  which  escapes  through  the  nozzle.  Neither  pressure 
nor  the  presence  of  calcium  chloride  is  necessary,  and  the  rapidity  of 
action  and  amount  of  solution  used  can  be  determined  by  observing 
the  height  of  the  liquid  in  the  glass  gauge  on  the  side  of  the  reservoir. 
The  apparatus  is  very  much  cheaper  than  the  Trillat  and  similar  auto- 
claves. 

Another  regenerator  which  meets  with   favor  is  that  of  Lentz  (see 
Fig.  94),  in  which  the  formaldehyde  solution  is  heated  in  a  retort  by 

means  of  a  Swedish  lamp,  the  gas 
emerging  through  the  metallic  deliv- 
ery tube  connected  by  rubber  tubing 
with  the  nozzle,  which  is  inserted 
through  a  keyhole. 

In  order  to  avoid  the  use  of  the 
liquid  preparation,  and  to  employ  in 
its  place  the  solid  polymer  trioxyme- 
thylen,  or  paraform,  the  Schering 
lamp  was  devised,  and  in  1897  was 
brought  into  notice  by  Aronson,^ 
after  he  had  made  a  series  of  tests 
which  yielded  good  results.  This 
very  simple  and  inexpensive  appa- 
ratus, shown  in  Fig.  95,  consists  es- 
sentially of  a  metallic  shell,  not 
unlike  an  open  piece  of  stove-pipe, 
-  supjDorted  on  legs,  and  carrying  in  its 
i=-  upper  part  a  basket  made  of  sheet- 
'-  iron  and  wire  gauze,  and  an  alcohol 
lamp  carrying  6  or  more  wicks.  For 
convenience,  the  paraform  is  supplied 
in  pastilles  weighing  a  gram  each, 
and  these  are  placed  in  the  basket  to 
the  number  of  2  for  every  35  cubic  feet  of  air  space  to  be  disinfected. 
The  lamp  is  supplied  with  alcohol  to  the  extent  of  2  cc.  for  each  pas- 
tille. The  wicks  should  project  not  more  than  about  a  twelfth  of  an 
inch,  which  is  sufficient  to  give  a  flame  which  will  heat  the  basket  and 
its  contents  sufficiently  to  cause  volatilization  of  the  agent,  with  abso- 
lutely no  danger  of  its  taking  fire  and  thus  yielding  no  formaldehyde 
gas.  By  the  time  the  alcohol  is  consumed,  the  pastilles  will  have  been 
volatilized  completely  or  nearly  so.  If  the  space  to  be  treated  be  of 
such  size  that  the  requisite  number  of  pastilles  cannot  be  placed  in  the 
basket,  more  than  one  apparatus  should  be  used.  This  process  has  the 
advantage  of  simplicity  and  economy  of  time,  for  when  the  apparatus 
is  placed  in  position  with  its  lamp  burning,  it  requires  no  further  atten- 
tion on  the  part  of  the  operator,  who  then,  with  other  lamps,  is  enabled 
to  start  the  jjrocess  elsewhere,  and  thus  accomplish  much  more  than 
^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXV.,  1897,  p.  186. 


Schering  paraform  lamp. 


ORGANIC  SUBSTANCES.  547 

another  who,  operating  an  autoclave,  or  similar  apparatus,  is  obliged  to 
give  it  constant  attention  as  long  as  the  gas  is  being  generated. 

Still  another  apparatus  is  that  used  in  what  is  known  as  the  "  Bres- 
lau  method,"  in  which  the  gas  is  disengaged  in  company  with  an 
abundance  of  steam,  by  boiling  dilute  formaldehyde  solution.     The 

Fig.  96. 


Breslau  regenerator  and  lamp. 


apparatus  shown  in  Figs.  96  and  97,  taken  from  the  description  of 
the  method  by  von  Brunn,^  consists  of  a  copper  boiler  about  14  inches 
in  diameter  and  3  in  depth  at  the  periphery,  with  an  immovable  cover 
slightly  domed,  in  the  center  of  which  is  an  outlet  tube,  to  which  a 
stout  rubber  tube  can  be  attached.     The  cover  is  provided  also  with 


Fig.  97. 


Vertical  section  of  Breslau  regenerator.    (Lamp  in  position.) 

two  handles  and  an  orifice  closed  by  a  screw  cap.  A  jflange  around 
the  upper  border  of  the  boiler  keeps  the  latter  in  place  when  it  is  put 
on  its  support,  which  is  a  cylinder  of  enamelled  sheet  iron  about  14 
inches  in  height,  provided  in  its  lower  half  with  slits  for  the  free  en- 
trance of  air,  and  on  its  inner  side  with  thn^c  su])ports  for  an  alcohol 
'  Zeit.sf:lirift  fiir  Ilyfificnc  nnd  Tnfectionskranklieiten  XXX.,  p.  201. 


548  DISINFECTANTS  AND  DISINFECTION 

lamp.  The  lamp  is  an  open  dish,  through  the  bottom  of  which,  in  two 
concentric  rings,  20  tubes  project  upward  as  high  as  the  sides  of  the 
vessel.  With  this  apparatus,  3.5  liters  (nearly  4  quarts)  of  fluid  can 
be  brought  to  boil  in  10  minutes,  and  nearly  the  whole  can  be  evapo- 
rated in  an  hour.  The  amount  of  alcohol  placed  in  the  lamp  should 
be  about  one- fourth  of  the  volume  of  the  solution  in  the  boiler,  and 
this  will  be  consumed  before  the  boiler  is  empty.  Like  the  Sobering 
lamp,  the  apparatus  may  be  left  in  the  room  or  it  may  be  used  outside 
with,  a  delivery  tube  passing  through  the  keyhole.  In  order  to  achieve 
the  best  results,  a  dilution  of  1  part  of  the  40  per  cent,  solution  of 
formaldehyde  with  4  of  water  is  recommended.  With  this  dilution, 
one  avoids  the  polymerization  observed  Avhen  the  undiluted  solution  is 
heated,  which  is  due  to  the  fact  that  the  water  is  driven  oiF  faster  than 
the  formaldehyde. 

A  somewhat  similar  apparatus  has  been  devised  for  the  generation 
of  steam  in  connection  with  the  use  of  the  Schering  lamp.  It  consists 
essentially  of  a  circular  copper  boiler,  surrounding  the  Schering  lamp 
and  heated  by  a  circular  open  alcohol  lamp  which  is  really  a  sort  of 
gutter  into  which  a  measured  amount  of  alcohol  is  poured. 

In  1897,  Rosenberg*  described  and  attempted  to  introduce  a  simple 
form  of  lamp  for  the  vaporization  of  formaldehyde  from  holziu,  a  dilute 
methyl  alcohol  containing  35  per  cent,  of  formaldehyde  and  5  of 
menthol,  the  latter  being  added  in  order  to  prevent  the  formation  of 
methylal  and  to  overcome  any  tendency  to  explode.  The  method  has 
been  tried  by  a  number  of  experimenters,  but  the  results  have  not  led 
to  its  extensive  employment. 

A  number  of  inventors  have  devised  methods  for  spraying  the  40 
per  cent,  solution  of  formaldehyde  itself,  among  them  Lingner,  Praus- 
nitz,  Fliigge,  and  Czaplewski.  The  latter"  disengages  the  gas  by  means 
of  a  jet  of  steam  acting  in  a  concentrated  solution  of  formaldehyde,  and 
presents  figures  showing  the  process  to  be  the  cheapest  of  all. 

In  1898,  Schlossmann  advocated  the  use  of  a  mixture  of  formalin 
and  glycerin,  which,  by  means  of  a  steam  jet  from  an  apparatus  of 
special  construction,  can  be  disseminated  in  the  air  in  the  form  of  a  fine 
mist,  which,  being  heavier  than  air,  is  supposed  to  settle  and  carry  down 
all  the  bacteria  mechanically.  The  mixture  contains  10  per  cent,  of 
glycerin,  and  is  called  glycoformal ;  the  glycerin  is  supposed  to  prevent 
polymerization  as  well  as  to  act  mechanically.  According  to  Schneider,* 
the  addition  of  glycerin  is  wholly  unnecessary  and  disadvantageous, 
since  this  substance  is  deposited  all  about  in  fine  droplets  and  makes 
cleaning  more  difficult.  It  is  said  also  by  van  Ermengen  ^  that,  in  ad- 
dition to  making  objects  slimy  and  wet,  it  often  attacks  the  polish  on 
furniture.      Kaup,^  Czaplewski,^  and  others  agree  that  the  addition  of 

^  Zeitschrift  fiir  Hygiene  iind  Infectionskrankheiten,  XXIV.,  1897,  p.  488. 
^  MiJnchener  niedicinische  AVochenschrift,  1898,  No.  41. 

*  Berliner  klinische  Wochenschrift,  June  20,  1898. 

*  Archiv  fur  Hygiene,  XXXVI.,  1899,  p.  127. 

^  Bulletin  du  Service  de  sante  et  de  I'hygiene  publique  de  Belgique,  1899,  p.  28. 

*  Wiener  medicinische  Wochenschrift.  1899,  Nos.  42^4. 
''  Miinchener  medicinische  Wochenschrift,  1898,  p.  1306. 


ORGANIC  SUBSTANCES.  549 

glycerin  is  unnecessary.  The  process  is  also  too  expensive,  and  has 
the  additional  disadvantage  of  leaving  an  odor  which  is  very  lasting. 

Another  method  of  generating  the  gas  which  does  away  with  special 
apparatus  and  also  the  need  of  a  flame  is  that  of  Evans  and  Russell/ 
which  depends  upon  the  fact  that  when  formalin  and  potassium  per- 
manganate are  brought  together,  a  violent  reaction  occurs,  with  the 
evolution  of  much  heat  and  rapid  liberation  of  the  gas,  and  also 
vaporization  of  the  water.  Numerous  experiments  demonstrated  that, 
for  the  attainment  of  the  best  results,  6.5  ounces  of  the  permanganate 
in  the  form  of  powder  or  very  small  crystals  should  be  employed  with 
each  pint  of  formalin.  In  any  given  case,  the  necessary  amount  of 
each  having  been  determined,  the  permanganate  is  placed  in  a  suitable 
vessel  and  the  formalin  is  poured  upon  it.  The  evolution  of  the  gas 
being  very  rapid,  it  is  necessary  for  the  operator  to  leave  the  room  as 
quickly  as  possible.  On  account  of  the  frothing  which  occurs  in  con- 
sequence of  the  violence  of  the  reaction  very  tall  vessels  are  required. 
Experience  has  shown  that  these  are  best  made  of  tin  and  with  flaring 
tops.  It  is  recommended  that  they  have  a  diameter  of  10  inches  at 
the  bottom  and  a  height  of  17  inches,  the  sides  having  a  perpendicular 
height  of  8  inches  and  then  flaring  at  an  angle  of  about  50  degrees. 

Quantitative  determinations  proved  that  the  yield  of  gas  averages 
81  per  cent,  of  the  amount  present  in  the  solution,  and  that  about 
four-fifths  of  this  are  set  free  within  5  minutes,  the  remainder  being 
given  off  in  rapidly  diminishing  amount  during  the  next  12  hours. 
A  very  large  number  of  bacteriological  tests  demonstrated  that  the 
method  is  entitled  to  be  ranked  as  highly  efficient. 

Dieudonne^  advocates  the  evaporation  of  diluted  formalin  with  the 
aid  of  heated  bricks,  the  liquid  being  poured  over  them,  or  of  red-hot 
steel  bolts,  weighing  about  7  pounds,  held  in  a  sheet-iron  pocket  in  the 
vessel  in  which  the  liquid  is  contained.  A  perforated  cover  is  employed 
to  minimize  the  amount  of  loss  of  liquid  by  spurting. 

Another  simple  method  of  generating  the  gas  and  steam  at  the  same 
time  is  that  of  Schering,^  in  which  pastilles  of  paraform  and  unslaked 
lime  are  employed.  These  are  wet  with  warm  water,  and  the  heat 
which  is  produced  in  the  process  of  slaking  the  lime  is  sufficiently 
intense  to  cause  the  volatilization  of  formaldehyde  from  the  paraform 
and  the  formation  of  steam  at  the  same  time.  One  may  use  also 
unslaked  lime  and  diluted  formalin,  dropping  the  former  into  the  latter. 

Germicidal  Properties. — The  first  to  note  the  antiseptic  effect  of 
formaldehyde  were  Loew  and  Fischer  in  1886,  but  although  Loew  con- 
tinued his  observations  for  some  months,  and  Buchner  and  Segall  made 
a  study  of  its  antiseptic  action  in  1889,  Trillat,  in  1892,  was  the  first 
to  draw  attention  to  the  importance  of  the  agent.  Almost  at  the 
same    time  came  a  publication  by  Aronson.'*     Trillat    reported   that 

1  Thirteenth  Report  of  the  State  Board  of  Health  of  Maine,  1904,  p.  234. 

'■TJie  ilrztliehe  Praxis,  I'.HJ],  No.  2. 

MlyKienisclK;  Rundschau,  1!)00,  p.  708. 

*  ]ierliner  kliniscfie  Woclienschrift,  1892,  No.  30. 


550  DISINFECTANTS  AND  DISINFECTION. 

bouillon,  infected  with  B.  anthracis,  was  sterilized  by  1  part  of  formal- 
dehyde in  50,000,  and  that  for  the  prevention  of  decomposition  of 
meat  juice,  the  agent  acted  as  powerfully  as  corrosive  sublimate  in  half 
the  amount.  Aronson  reported  that  growth  of  B.  typliosis,  B.  anthra- 
cis, and  pus  cocci  in  bouillon  was  prevented  absolutely  by  1  part  in 
20,000,  and  very  much  inhibited  by  1  in  40,000.  Then  followed 
other  experimenters,  and  within  six  years,  formaldehyde  had  been  the 
subject  of  more  extensive  investigation  than  has  ever  been  devoted  to 
any  other  germicide. 

With  the  autoclave,  Roux  and  Trillat  ^  reported  that  a  number  of 
pathogenic  bacteria,  including  anthrax  spores,  were  killed  ;  B.  suhtUis 
and  B.  mesentericus  survived.  Bosc,^  at  the  same  time,  reported  suc- 
cessful sterilization  of  a  large  number  of  varieties  under  different  con- 
ditions in  a  large  air  space  (more  than  25,000  cubic  feet),  using  3  liters 
of  formalin.  Staphylococci  in  the  pocket  of  a  pair  of  trousers  were  de- 
stroyed, but  others  more  protected  escaped,  although  the  colon  bacillus 
between  the  two  sides  of  a  folded  mattress,  apparently  still  more  pro- 
tected, was  killed.  Of  a  large  variety  of  sjaecies,  including  anthrax 
spores,  B.  jjyocyaneus,  and  B.  diphtheria;,  the  only  exposed  organisms 
that  escaped  were  B.  subtilis  and  B.  mesentericus.  The  dust  and  walls 
were  quite  sterile. 

PfuhP  found  that  all  exposed  organisms  were  destroyed  by  the 
Trillat  method,  but  that  dried  Staphylococcus  pyogenes  aureus,  anthrax 
spores,  and  B.  typhosus  under  a  nurse's  apron,  and  others  under  a 
military  overcoat,  were  not  affected  ;  diphtheria  bacilli  dried  on  threads 
and  a  fresh  diphtheria  agar  culture  under  a  woollen  blanket  were  de- 
stroyed. Fresh  typhoid  agar  cultures  under  a  blanket  were  not  killed  ; 
staphylococcus  agar  cultures  were  inhibited.  Striiver,^  with  a  Munke 
autoclave  much  like  Trillat's,  vaporized  800  cc.  of  formochloral  in  a 
room  of  about  1,250  cubic  feet  capacity,  and  after  12  hours,  found 
that  all  organisms  which  had  been  exposed  w^ere  dead,  but  that  anthrax 
spores  and  B.  typhosus  in  a  tight  closet  and  anthrax  spores  in  the  folds 
of  upholstery  of  a  chair  were  not  affected. 

With  holzin,  Rosenberg,^  using  about  4  cc.  to  the  cubic  foot  of  air 
space,  sterilized  all  his  test  objects  within  3  hours.  These  included 
anthrax  bacilli  and  spores,  streptococci,  and  the  bacteria  of  diphtheria, 
cholera,  and  typhoid  fever,  all  on  silk  threads  wrapped  in  blotting- 
paper,  placed  in  pockets  and  sleeves  and  under  the  collar  of  a  coat, 
Striiver,^  with  the  same  agent  in  a  like  amount,  was  not  so  successful. 
He  exposed,  for  24  hours,  anthrax  spores  on  threads  and  the  tyj^hoid 
fever  bacillus  on  pieces  of  linen  ;  neither  the  spores  nor  the  other 
organism  protected  by  several  layers  of  cotton  cloth  were  destroyed. 
In  another  experiment,  using  much  less  holzin,  the  spores  not  protected 
by  several  layers  of  cloth  were  destroyed. 

1  Annales  de  I'lnstitiit  Pasteur,  1892,  p.  283. 

''  Ibidem,  1896,  p.  298. 

^  Zeitschrift  fur  Hygiene  und  Infectionskrankheiten,  XXIV.,  1897,  p.  289. 

*  Ibidem,  XXVII.,  1897,  p.  357. 

^  Loco  citato.  ^  Ibidem. 


ORGANIC  SUBSTANCES.  551 

The  first  experiments  with  paraform  pastilles  were  those  of 
Aronson/  who  volatilized  2  pastilles  to  every  35  cubic  feet,  and  at  the 
end  of  24  hours  found  that  his  test-objects,  which  included  anthrax 
spores,  staphylococci,  streptococci,  B.  pyocyaneus,  and  the  germs  of 
tuberculosis,  diphtheria,  and  typhoid  fever,  on  gauze,  threads,  and 
other  material  were  destroyed.  He  repeated  the  test  with  but  half  the 
amount  of  paraform,  and  again  found  everything  sterile  excepting  the 
anthrax  spores,  some  of  which  were  still  active.  Gehrke,^  using  2 
pastilles  to  each  35  cubic  feet,  and  with  practically  the  same  test-(.)bjects 
as  Aronson  had  used,  found,  after  24  hours,  that  all  that  had  been 
exposed  were  dead,  excepting  the  anthrax  spores.  Fairbanks  ^  with 
like  amounts,  reported  similar  results;  all  exposed  organisms  and 
some  which  had  been  lightly  protected  between  pieces  of  cloth, 
and,  in  certain  instances,  others  more  completely  protected  by  cloth 
and  placed  between  bulky  articles,  were  destroyed.  In  one  series 
of  tests,  among  the  protected  objects,  only  the  typhoid  and  diphtheria 
organisms  were  killed,  but,  as  usual,  all  the  exposed  germs  were 
destroyed. 

In  a  series  of  experiments  by  the  author  at  the  Pathological  Labora- 
tory of  the  Boston  City  Hospital  in  1897,*  as  a  preliminary  test,  only 
a  fourth  of  the  recommended  number  of  pastiles  were  volatilized  in  a 
small  room,  in  which  were  placed  test  objects,  only  one  of  which  (a 
smear  of  Diplococcus  intracellularis  meningitidis)  was  sterile  after  18 
hours'  exposure.  With  half  the  recommended  number,  the  results  were 
better,  but  not  satisfactory.  The  test-objects  introduced  were  paper 
smears  of  anthrax  spores.  Staphylococcus  pyogenes  aureus,  B.  typhosus, 
and  a  very  resistant  non-pathogenic  spore-bearing  bacillus.  After  21 
hours'  exposure,  these  were  found  to  be  sterile  without  exception,  but 
dust  from  several  places  in  the  room  gave  growths,  although  from  others 
the  results  were  negative.  A  surgical  dressing,  lying  in  a  pail,  yielded 
abundant  growth  before  the  experiment,  but  later  was  found  to  be  quite 
sterile.  Two  Petri  plates,  exposed  for  20  minutes  after  the  room  was 
aired,  showed  7  and  4  colonies,  respectively. 

In  the  next  experiment,  the  full  recommended  number  of  pastilles 
was  employed.  The  test-objects  were  smears  of  the  same  organisms 
as  before,  but  they  were  more  numerous  and  were  differently  disposed. 
Some  were  enclosed  in  cotton  bags  heavily  sized,  some  in  similar  bags 
which  had  had  the  sizing  removed  by  boiling ;  some  were  placed  in 
Erlenmeyer  flasks,  two  of  which  were  introduced  well  into  the  middle 
of  a  hair  mattress.  In  addition,  a  number  of  moist  dressings  and  wet 
l^loody  dressings  enclosed  in  cotton  bags  were  employed.  After  20 
hours'  exposure,  cultures  were  made,  which  showed  the  following  results  : 
The  smears  in  boiled  and  unboiled  bags  and  the  slightly  moist  dress- 
ings, also  enclosed  in  bags,  were  sterile  without  exception.     The  wet 

'  Zeitschrift  fur  Hygiene  unci  Tnfectionskrankheiten,  XXV.,  1897,  p.  168. 
2  Deutsche  medieiniscbe  WocheriHchrift,  Ay)ril  14,  1898,  p.  242. 
'■'•  Centi-alblatt  fiir  BakterioloKie,  cte.,  XXIII.,  Ahtli.  I.,  Nos.  1,  3,  and  16. 
*  American  Journal  of  the  Medical  Sciences,  .Jan.,  1898. 


552  DISmFECTANTS  AND   DISINFECTION. 

bloody  dressings  gave  abundant  growths.  The  flasks  in  the  mattress 
agreed  in  results ;  the  typhoid  and  staphylococcus  smears  in  each  were 
sterile,  but  those  of  anthrax  spores  and  of  the  non-pathogenic  spore- 
bearer  were  not  affected.  The  same  was  found  to  be  the  case  with  the 
smears  in  a  flask  lightly  plugged  with  cotton  and  standing  in  an  open 
closet.  All  four  smears  in  another  open  flask  placed  in  a  closed  closet 
were  unaffected.  Dust  cultures  from  various  parts  of  the  room  were 
negative  in  almost  every  case.  Before  the  lamps  were  lighted,  3  Petri 
plates  were  exposed  for  25  minutes,  and  yielded,  respectively,  86,  124, 
and  53  colonies,  about  half  of  which  in  each  case  were  of  Staphyloeoccus 
pyogenes  albus  with  a  few  of  aureus,  and,  in  one,  of  citreus.  Three 
more  plates  were  exposed  for  the  same  length  of  time  after  the  room 
was  aired,  and  the  result  was  practically  negative.  Two  colonies  of 
mould  developed  on  one,  and  nothing  whatever  on  the  other  two.  A 
repetition  of  the  experiment  a  week  later  with  the  same  number  of  pas- 
tilles, but  with  only  the  original  test-objects,  gave  the  same  negative 
results.  Preliminary  dust  cultures  showed  abundant  growths  ;  after 
20  hours'  exposure,  all  but  one  dust  culture,  and  that  from  a  closed 
closet,  gave  negative  results. 

Power  of  Penetration. — Certain  of  the  earlier,  and  an  occasional  one 
of  the  more  recent,  experimenters  have  claimed  for  formaldehyde  a  much 
greater  penetrating  power  than  can  be  explained  by  any  law  of  physics 
or  chemistry  ;  but  it  is  now  very  generally  agreed  that  while  this  agent 
is  beyond  doubt  the  most  powerful  and  practical  disinfectant  we  pos- 
sess for  large  air  spaces  and  general  work,  it  is,  in  the  gaseous  form, 
merely  a  surface  disinfectant  which  sometimes  does  and  oftener  does  not 
penetrate. 

In  addition  to  the  works  already  quoted,  the  following  may  be  cited. 
Abba  and  Rondelli'  reported  that,  in  the  interior  of  a  heap  of  clothing 
and  on '  objects  covered  with  clothes,  no  sterilization  was  effected. 
Doty  ^  says  that  a  careful  analysis  of  reported  results  shows  that  it  can- 
not be  depended  upon  when  deep  penetration  is  required,  but  for  super- 
ficial disinfection  of  furniture,  clothing,  and  fabrics  which  may  be 
freely  spread  out  and  exposed,  it  is  of  undoubted  value.  It  can  also 
be  relied  upon  to  penetrate  letters  and  other  thin  packages  placed  in  an 
air-tight  chamber.  To  this  last  statement  are  opposed  the  results 
obtained  by  Dr.  E.  K.  Sprague,  U.  S.  M.-H.  S.,^  who,  attempting  to 
sterilize  cultures  in  sealed  envelopes  with  the  Kinyoun-Francis  disin- 
fecting apparatus,  failed  every  time.  Experimenting  with  ordinary 
objects  in  a  vacuum  chamber  heated  to  90°  C,  with  a  vacuum  of 
15—20  inches,  and  with  much  more  formalin  than  can  be  used  under 
ordinary  circumstances — 360  cc.  vaporized  in  58  cubic  feet — he  finds 
that  he  cannot  recommend  it  "  even  when  combined  with  a  high  degree 
of  heat,  as  a  disinfectant  upon  which  reliance  can  always  be  placed  for 

^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXVII.,  1898,  p.  49. 
2  New  York  Medical  Journal,  Oct.  16,  1897,  p.  517. 

^  Report  on  Formaldeliyd  Disinfection  in  a  Vacuum  Chamber,  Treasury  Depart- 
ment, Washington,  Government  Printing  Office,  1899. 


ORGANIC  SUBSTANCES.  553 

the  treatment  of  articles  requiring  much  penetration,  especially  when 
the  exposure  is  limited  to  a  half  hour." 

Wilson's  ^  experience  led  him  to  report  adversely  on  its  penetrative 
power.  Organisms  protected  by  the  folds  of  a  blanket  were  not 
killed.  Pfuhl  ^  warns  us  against  expecting  more  than  it  can  per- 
form, and  says  that  it  will  always  be  only  a  surface  disinfectant, 
not  to  be  relied  upon  to  influence  matters  only  slightly  covered  or  in 
dust  which  lies  in  measurable  thickness  in  cracks  of  floors  and  walls. 
He  demands  a  less  severe  test  of  a  disinfectant  than  the  ability  to  de- 
stroy anthrax  spores,  and  asserts  that  when  formaldehyde  in  the  air 
will  kill  Staphylococcus  jjyogenes  aureus  dried  on  silk  threads,  other 
pathogenic  organisms  which  enter  into  house  disinfection,  the  strepto- 
cocci and  the  bacteria  of  cholera,  diphtheria,  tuberculosis,  and  typhoid 
fever,  will  be  destroyed. 

It  is  important  to  bear  in  mind  the  lack  of  penetrating  power  of 
formaldehyde  gas,  since  a  disregard  of  this  fact  will  cause  much  sup- 
posed disinfection  to  be  a  positive  danger,  because  of  over-confidence 
in  the  results  actually  achieved.  Therefore,  in  practice,  all  obstacles 
to  thorough  dissemination  must  be  removed  as  far  as  is  possible. 

Conditions  Favoring  Action. — Concerning  the  influence  of  moisture 
on  the  efficiency  of  formaldehyde  gas,  there  is  a  decided  diiference 
of  opinion.  Abba  and  Rondelli  ^  believe  that  dryness  aids  the  proc- 
ess. Symanski  ^  reports  that  it  acts  best  in  dry  air  with  high  tem- 
peratures. Robinson^  regards  dampness  as  a  disadvantage.  Trillat 
also  believes  that  the  presence  of  moisture  makes  the  results  uncertain. 
On  the  other  hand,  Strehl  ®  is  of  the  opinion  that  moisture  enhances 
its  action  ;  Novy  maintains  the  same  view ;  and  Hammerl  and  Ker- 
mauner,''  commenting  on  the  use  of  paraform  pastilles,  assert  that 
the  process  is  effective,  if  sufficient  moisture  is  supplied,  and  recom- 
mend vaporizing  four  times  the  amount  of  water  necessary  to  saturate 
the  air  at  the  existing  temperature. 

The  results  obtained  by  the  author  in  the  experiments  above  men- 
tioned, and  in  other  tests  with  cultures  and  decolorized  fuchsin  solution 
in  tubes  and  flasks  stopped  with  absorbent  cotton,  led  him  to  the  con- 
clusion that  penetration  is  influenced  largely  by  moisture ;  "  through 
dry  pervious  substances,  as  cotton  cloth,  absorbent  cotton,  hair,  etc.,  it 
appears  to  penetrate  more  or  less  easily,  but  not  always  in  sufficient 
amount  to  exert  germicidal  action.  ...  In  the  presence  of  moisture 
the  penetrating  power  is  practically  mV."  ^  With  this  statement, 
Rideal  ^  does  not  agree.  He  says  :  "  Inasmuch  as  the  vapor  is  so  sol- 
ul)le  in  water,  one  would  expect  that  materials  previously  moistened 

'  Brooklyn  Medical  .Journal,  Nov.,  1897,  p.  741. 

2  Zeitschrift  fur  Hygiene  und  Infectionskrankheiten,  XXIV.,  1897,  p.  289. 

^  Ivoco  citato. 

*  Ibidem,  XXVITT.,  1898,  p.  219. 

"  Ninth  Kcport  of  the  State  Board  of  Health  of  Maine,  1896,  p.  180. 

«  ("entralhlatt  fiir  Bakteriologie,  etc.,  XXIX.,  1896,  p.  785. 

'  Miinclietier  medicinische  Woclienschrift,  Nov.  22  and  29,  1898. 

*  Loco  citato. 

®  Disinfection  and  Disiiifcclaiils,  'h\  Ivlilion,  London,  189H,  p.  333. 


554  DISINFECTANTS  AND  DISINFECTION. 

would  absorb  more  of  the  gas  than  dry  fabrics,  and  therefore  show 
greater  efficiency,  as  I  have  found  in  my  experiments."  But  when 
the  gas  is  absorbed  by  moisture,  it  can  no  longer  act  as  a  gas,  but  as 
a  solution  which  has  influence  m  situ,  and  may  give  oif  fumes  to  the 
parts  in  its  immediate  vicinity.  Rubuer  and  Peerenboom  ^  say  that 
the  dry  gas  has  no  influence  on  dry  objects,  but  if  the  objects  are  too 
wet,  the  concentration  of  the  formaldehyde  solution,  formed  by  absorp- 
tion, is  too  weak  to  be  effective. 

The  advocates  of  the  Breslau  method,  von  Brunn,  Fliigge,  and 
others,  regard  the  concomitant  liberation  of  steam  as  a  most  essential 
part  of  the  process,  on  the  ground  that,  as  the  moisture  condenses  on 
the  walls  and  contents  of  the  room,  the  gas  is  absorbed  and  then  acts 
directly  on  the  object  in  the  form  of  solution. 

It  is  agreed  very  generally  that  a  high  temperature  is  most  con- 
ducive to  good  results.  Abba  and  Rondelli,  Trillat,  Symauski,  and 
others  whose  works  have  been  quoted,  and  IvanoflP,"  are  of  this  mind. 
Brough,^  whose  experience  in  public  disinfection  is  large,  reports  that 
low  temperatures  are  decidedly  detrimental. 

Toxicity. — Formaldehyde  is  commonly  regarded  as  non-poisonous 
for  higher  organisms  under  ordinary  conditions,  and  most  experiment- 
ers who  have  confined  animals  in  spaces  undergoing  disinfection  have 
reported  no  permanently  injurious  effects.  Aronson,^  in  1892,  noted 
the  effects  of  the  gas  on  guinea-pigs  confined  for  an  hour  in  an  atmos- 
phere strongly  impregnated  with  it ;  they  showed  great  discomfort  and 
uneasiness,  but  on  removal  soon  recovered  completely.  He  reported 
some  results  of  experiments  by  Zuntz,  who  determined  the  fatal  subcu- 
taneous dose  for  rabbits  to  be  0.240  gram  per  kilogram  of  body-M-eight. 
In  Aronson's  later  experiments,^  guinea-pigs  and  rabbits,  left  overnight 
in  rooms  containing  an  amount  sufficient  for  practical  disinfection,  were 
found  to  be  alive,  and  on  being  killed  showed  no  evidence  even  of 
serious  irritation  of  the  bronchial  mucosa. 

Pottevin  *'  found  that  a  2  per  cent,  solution  in  subcutaneous  doses 
of  0.250  gram  per  kilogram  was  fatal  to  guinea-pigs  in  a  few  days, 
and  that  inhalation  of  the  vapors  was  likewise  fatal  in  2  or  3  days. 
Trillat  says  that  it  is  toxic  only  when  inhaled  many  hours,  but  gives 
no  definite  number.  De  Schweinitz  exposed  a  calf  for  5  hours  ;  it 
showed  no  particular  distress  and  soon  recovered  completely  in  fresh 
air.  Kobert  exposed  guinea-pigs  for  36  hours  without  results. 
Fairbanks  exposed  mice  and  rabbits ;  Pfuhl,  white  mice ;  Doty, 
guinea-pigs,  mice,  fowls,  and  insects,  and  no  deaths  occurred.  Doty's 
time  of  exposure  was  from  3  to  15  hours;  he  noted  occasional  evi- 
dence of  inflammation  of  the  respiratory  tract,  but  nothing  more. 

Opposed  to  these  negative  findings  are  positive  results  observed  by 

^  Hygienische  Rundschau,  1899,  p.  265. 

2  Centralblatt  fur  Bakteriologie,  XXII.,  1897,  p._50. 

^  Transactions  of  the  Massachusetts  Medical  Society,  1898. 

^  Berliner  klinische  Wochenschrift,  1892,  No.  30. 

^  Zeitschrift  fiir  Hygiene  und  Infectionskrankheiten,  XXV.,  1897,  p.  168. 

^  Annales  de  I'lnstitut  Pasteur,  Nov.  25,  1894. 


ORGANIC  SUBSTANCES.  555 

Brough  and  the  author.  Brough  ^  has  repeatedly  found  that  cats  and 
dogs,  accidentally  overlooked  in  rooms  undergoing  disinfection,  have 
been  unable  to  survive  even  until  the  door  was  0})ened.  He  notes  that 
flies  are  always  killed,  and  bedbugs  also,  when  not  protected. 

In  an  experiment  conducted  by  the  author^  in  a  room  of  7,660 
cubic  feet  capacity,  in  which  650  cc.  of  formalin  were  vaporized,  two 
rabbits  were  left  over  night  in  a  wire  cage.  Soon  after  the  gas  began 
to  be  generated,  l)oth  animals  showed  evidence  of  great  discomfort, 
but  at  the  end  of  1 5  hours,  when  the  room  was  opened,  neither  appeared 
to  be  much  aifected.  But  it  should  be  noted  that  the  amount  of  for- 
malin used  was  not  large  for  the  air  space — no  more  had  been  vaporized 
because  of  the  inefficient  working  of  the  generator.  On  the  following 
day,  2,150  cc.  of  formalin  were  used,  and  in  the  morning  one  rabbit 
was  dead  and  the  other  alive,  but  breathing  through  the  mouth  with 
great  difficulty ;  he  improved  noticeably  within  2  hours,  but  died  36 
hours  later.  Both  animals  were  subjected  to  thorough  examination  in 
the  Pathological  Laboratory  of  the  Boston  City  Hospital,  from  the 
records  of  which  the  following  description,  which  evidences  the  very 
extensive  poisonous  action  of  the  gas,  is  taken  : 

"No.  1.  Section  of  the  tongue  shows  nothing  abnormal.  Section  of 
mucous  membrane  of  the  mouth  shows  desquamation  of  the  surface 
epithelium  with  hemorrhage  and  infiltration,  with  lymphoid  cells  in  the 
tissue  beneath.  Section  of  oesophagus  is  normal.  There  is  no  pneu- 
monia. The  liver  shows  marked  injection,  with  granular  and  fatty 
degeneration  of  cells  around  the  central  veins  of  lobules.  The  lym- 
phatic gland  shows  some  dilatation  of  the  lymph  sinuses  with  hemor- 
rhage.    In  the  kidney  there  is  slight  degeneration  of  the  epithelium. 

"jS^o.  2.  In  the  liver  there  is  considerable  dilatation  of  hepatic 
veins,  with  some  degeneration  of  liver  cells  in  the  centre  of  the  lobules. 
The  kidney  is  congested.  The  epithelium  of  the  convoluted  tubules  is 
somewhat  svv'ollen  aiid  granular,  and  there  is  a  small  amount  of  coagu- 
lated albumin  in  the  capsular  space  of  the  glomeruli.  In  many  of  the 
convoluted  tubules  there  is  more  or  less  granular  and  circular  reticulum, 
and,  in  places,  desquamation  of  the  cells.  The  spleen  shows  a  slight 
amount  of  hemorrhage  in  the  pulp.  Pancreas  shows  no  change.  One 
of  the  lymphatic  glands  shows  a  marked  degree  of  oedema,  with  for- 
'  mation  of  fibrin  in  the  lymph  sinuses.  In  the  lung  there  is  intense 
bronchitis  with  consolidation  extending  into  the  surrounding  lung 
tissue.  This  is  more  marked  in  the  very  smallest'  bronchi.  In 
one  place,  in  the  centre  of  a  focus,  there  are  numbers  of  short  bacilli. 
The  exudation  of  the  alveoli  is  almost  entirely  purulent,  with  some 
large  cells  mixed  with  pus.  In  another  place  in  the  tissue  there  were 
numliers  of  large  bacilli.  There  is  only  a  slight  amount  of  fibrin  in 
the  exudation.  In  another  portion  of  the  lung  there  were  very  much 
larg(!r  foci  which  were  filkid  with  organisms.  All  the  blood  vessels  of 
the  lung  are  grwitly  injected. 

"  It   is  difficult   to  explain   the  absence  of  bacteria  in   the   cultures 
'  Loco  citato.  ^  Ibidem. 


556  DISINFECTANTS  AND   DISINFECTION. 

made  from  the  lung  in  the  second  case.  The  general  character  of  the 
lesions  in  both  cases  shows  the  action  of  a  soluble  chemical  poison  on 
the  tissues.  The  changes  are  much  more  marked  in  the  second  case 
than  in  the  first,  but  in  both  they  are  of  the  same  general  character." 

In  another  experiment  in  which  the  volume  of  formalin  vaporized 
was  not  sufficient  to  destroy  more  than  a  small  proportion  of  the  test- 
objects,  a  number  of  roaches  in  a  glass  dish  covered  with  wire  gauze 
were  killed ;  and  in  others  conducted  in  a  glass  cabinet  in  which  small 
volumes  of  formalin  were  vaporized,  flies  were  very  quickly  killed. 

Against  mosquitoes,  Rosenau  ^  finds  formaldehyde  to  be  far  inferior 
in  all  respects  to  sulphur  dioxide. 

Amount  Necessary  for  Room  Disinfection. — The  amount  of  formal- 
dehyde necessary  to  disinfect  any  given  air  space  depends  very  much 
upon  the  thoroughness  with  which  the  escape  of  the  gas  is  prevented 
during:  the  time  given  for  action.  Under  ordinary  conditions  and  with 
the  observance  of  all  reasonable  precautions,  it  is  generally  agreed  that 
for  each  1,000  cubic  feet,  a  pint  of  formalin,  or  about  60  pastilles  of 
paraform,  ought  to  suffice.  Striiver^  would  use  45  pastilles  per  1,000 
cubic  feet  against  sporeless  bacteria,  but  in  practical  disinfection  one 
cannot  always  discriminate.  Fliigge^  advises  that,  in  small  rooms 
containing  the  usual  amount  of  furniture,  the  number  of  pastilles  be 
increased  from  2  to  2.5  per  cubic  meter,  or  to  72  per  1,000  cubic 
feet. 

With  the  Breslau  method,  it  is  claimed  that  less  than  half  a  pint  of 
formalin  (190  cc.)  Avill  suffice  for  1,000  cubic  feet  with  7  hours'  ex- 
posure. Novy  *  also  is  of  the  opinion  that  in  the  presence  of  sufficient 
moisture,  even  less  will  be  found  adequate;  namely,  150.  Provided 
the  gas  is  prevented  from  escaping,  there  can  be  no  doubt  that  the 
smaller  amounts  are  effective  within  much  less  time  than  that  usually 
given  in  practical  Avork.  In  a  series  of  experiments  in  a  practically 
air-tight  glass  cabinet,  using  as  test-objects  smears  of  anthrax  spores, 
Staphylococcus  pyogenes  aureus,  a  highly  resistent  non-pathogenic  spore- 
bearer,  and  the  bacilli  of  diphtheria  and  typhoid  fever,  the  author  found 
everything  sterile  after  two  and  a  half  hours'  exposure  to  an  atmosphere 
containing  the  equivalent  of  110  cc.  formalin  in  1,000  cubic  feet. 
Using  it  to  the  extent  of  about  a  pint  to  the  1,000  cubic  feet,  the  same 
result  was  attained  in  less  than  a  half  hour. 

Disadvantages. — The  principal  disadvantage  observed  in  disinfection 
by  formaldehyde,  aside  from  its  cost,  which  is  considerable,  is  the  odor, 
which  is  sometimes  very  persistent,  especially  when  much  moisture 
is  present,  and  which,  except  under  very  unusual  conditions,  is  plainly 
l^erceptible  outside  the  room  in  which  the  gas  is  disengaged.  Usually, 
however,  this  is  a  transient  trouble,  and  is  met  by  thorough  aeration. 
If  deemed  advisable  on  the  score  of  saving  time,  and  when  the  gas  has 

^  Bulletin  No.  6,  of  the  Hygienic  Laboratory,  Washington,  September,  1901. 
'•*  Loco  citato. 

•^  Zeitschrift  fiir  Hvgiene  nnd  Infectionskrankheiten,  XXIX.,  1898,  p.  276. 
*  Medical  News,  1898,  p.  64L 


PRACTICAL  DISINFECTION.  557 

been  absorbed  by  the  condensed  moisture  on  the  walls  and  furniture,  it 
may  be  neutralized  by  means  of  ammonia  water,  which  may  be  exposed 
in  the  room  in  shallow  dishes  or  vaporized  from  a  flask  or  other  appa- 
ratus and  conducted  into  the  room  by  means  of  an  outlet  tube  through 
the  keyhole  of  the  door.  Fliigge  recommends  the  latter  method,  and 
advises  the  use  of  about  120  cc.  of  the  25  per  cent,  solution  to  each 
100  cc.  of  formalin,  and  320  cc.  to  each  100  pastilles  of  paraform  used. 
Articles  of  clothing,  stuffed  furniture,  and  the  like  must  otherwise  re- 
Cjuire  sometimes  several  days  of  airing. 

Technic  of  Room  Disinfection. — See  under  Practical  Disinfection, 
page  561. 

Other  Applications  of  Formaldehyde. — Besides  its  use  in  the  gaseous 
state  for  house  disinfection,  formaldehyde  in  the  form  of  its  aqueous 
solution  is  well  adapted  to  the  sterilization  of  urine,  fseces,  sputum,  and 
other  waste  products,  furniture,  wood-work,  toilet  articles,  and  other 
objects,  and  it  is  also  valuable  as  a  deodorant.  In  the  disinfection  of 
urine,  the  addition  of  one-twentieth  of  its  volume  of  formalin  will  be 
found  to  produce  sterility  within  an  hour.  Tuberculous  sputum  and 
diphtheritic  membranes,  covered  by  a  sufficient  volume  of  a  mixture  of 
about  two  and  a  half  tablespoonfuls  of  formalin  in  a  quart  of  water, 
are  sterilized  within  2  hours.  Liquid  stools  plus  and  equal  volume  of 
the  same  mixture  are  disinfected  completely  within  the  same  period. 
Walter^  states  that,  with  2.5  per  cent,  formalin  (1  per  cent,  formalde- 
hyde), fseces  are  deodorized  in  1  minute,  and  that,  treated  with  10  per 
cent,  solution,  they  are  sterilized  in  10  minutes.  He  states  also  that  a 
3  per  cent,  solution  applied  to  the  hands  destroys  all  adherent  organ- 
isms very  quickly,  especially  if  mixed  with  alcohol,  but  this  can  hardly 
be  true. 

A  mixture  of  1  part  of  formalin  and  20  of  water  is  very| 
efficient  as  a  wash  for  furniture,  wood-work,  and  other  objects,  for  i 
spraying  carpets  and  woollen  clothing,  etc.,  and  for  soaking  bed-linen  I 
and  other  washable  fabrics.  A  tablespoonful  to  a  quart  of  water  will 
remove  all  odor  from  the  hands  after  autopsies,  and  will  deodorize  other  i 
parts  of  the  body  to  which  it  may  be  applied. 

Prevention  of  Dissemination  of  Infections  Material;  Practical 

Disinfection. 

Even  with  the  best  disinfectants  available,  and  with  the  exercise  of 
the  greatest  care  in  their  application,  practical  disinfection  is  by  no 
means  always  effective  in  preventing  the  transmission  of  infective  ma- 
terial to  new  fertile  ground.  Hence  it  is  advisable  and  necessary  to 
keep  the  infected  area  as  small  as  possible  and  to  prevent  the  accumu- 
lation of  infective  material  by  destroying  it  continuously  and  as  quickly 
as  possible  after  it  is  thrown  off  by  the  body.  With  the  exercise  of 
due  care,  the  waste  products  which  act  as  vehicles  for  the  infective 
ngeiits  of  our  common  and  occasional  scourges  may  be  so  effectively 
dealt  with  from  hour  to  hour  and  from  day  to  day  as  to  make  the  after- 

'  Zeitschrif't  I'iJr  \\yi(\(:\w  iind  Inrcctionskninklieiten,  XXI.,  IS',)!),  p.  421. 


558  DISINFECTANTS  AND  DISINFECTION. 

treatmeut  of  the  room  and  its  contents  somewhat  of  a  mere  form,  car- 
ried out  as  a  matter  of  routine  practice,  or  in  order  to  make  assurance 
doubly  sure. 

According  to  the  nature  of  the  disease,  these  agents  reside  in  dis- 
charges from  the  mouth,  nose,  and  throat  (diphtheria  and  pertussis), 
in  sputum  (puhiionary  tuberculosis,  influenza,  and  pneumonia),  in  dis- 
charges from  the  bowels  (typhoid  fever,  cholera,  dysentery,  and  tuber- 
culosis), in  the  urine  (typhoid  fever),  and  in  matters  thrown  off  by  the 
skin  (acute  exanthemata).  Therefore,  the  course  to  be  pursued  during 
the  continuance  of  a  sickness  or  convalescence  varies  according  to  the 
nature  of  the  disease. 

The  limitation  of  the  infected  area  and  of  the  amount  of  material 
which  may  require  disinfection  on  the  termination  of  the  disease  should 
be  a  matter  for  immediate  action  on  the  discover}'  of  the  existence  of 
the  disease.  The  patient,  especially  in  the  case  of  the  acute  exanthe- 
mata, should  be  placed  in  a  room  which,  if  possible,  may  be  isolated 
from  the  rest  of  the  house,  and  from  which  all  unnecessary  furniture, 
especially  of  the  upholstered  kind,  hangings,  carpets,  and  rugs  have 
been  removed.  Disinfectants  for  the  prompt  treatment  of  infective 
matter  should  be  kept  near  at  hand,  together  with  a  sufficient  number 
of  appropriate  vessels  and  utensils. 

In  order  to  prevent  or  restrict  the  carriage  of  living  organisms  from 
the  room,  ingress  should  be  denied  to  all  whose  presence  is  unneces- 
sary ;  the  wearing  of  other  than  cotton  and  linen  dresses,  that  is, 
smooth-surfaced  and  washable,  by  the  attendants  should  be  interdicted ; 
no  food  remainder  should  be  taken  away  to  be  consumed  by  others ;  no 
used  bed-linen  or  body-lineu  removed  until  after  immersion  in  disin- 
fectant solutions,  and  no  discharges  finally  disposed  of  until  after 
appropriate  treatment.  If  it  be  necessary  to  use  the  broom,  the  dust 
should  be  kept  down  by  the  use  of  wet  sawdust  or  tea  leaves,  which, 
with  the  gathered  dirt  and  dust,  should  be  treated  with  disinfectant 
and  burned. 

Under  no  circumstances  should  the  process  known  as  "  dusting," 
which  is  merely  the  scattering  of  dust  through  the  air  from  surfaces 
where  it  was  at  rest  and  upon  which  and  elsewhere  it  will  again  be 
deposited,  be  allowed,  but  such  surfaces  should  be  wiped  with  cloths 
moistened  with  or  wrung  out  in  disinfectant  solution  and  afterward 
soaked  and  boiled.  According  to  season,  the  windows  should  be  pro- 
vided with  wire  screens  to  keep  out  flies,  which  not  only  are  an  annoy- 
ance, but,  through  their  habit  of  visiting  all  manner  of  excreta  and 
other  filth,  act  as  carriers  of  infection. 

Disinfection  of  Faeces.  —  The  discharges  from  the  bowels  in 
typhoid  fever,  dysentery,  cholera,  and  intestinal  tuberculosis,  should 
be  received  in  vessels  containing  an  amount  of  disinfectant  solu- 
tion equal  to,  or,  better,  larger  than,  the  probable  volume  of  the 
discharges.  Whatever  the  agent  used,  it  should  be  brought  into  imme- 
diate contact  with  the  entire  mass  of  the  discharge  by  thorough  mixing, 
and  the  whole  should  stand  under  cover  for  about  an  hour  before  final 


PRACTICAL  BISrN'FECTION.  55^ 

disposition.  Milk  of  lime,  although  efficient,  leaves  a  bulky  residue 
which  cannot  be  conveniently  disposed  of  through  the  usual  channels. 
Chlorinated  lime  is  also  efficient,  but  is  disagreeable  in  odor.  Cor- 
rosive sublimate  is  unsuitable  for  reasons  elsewhere  stated.  Phenol, 
in  5  per  cent,  solution,  with  or  without  the  addition  of  mineral  acids  or 
common  salt,  and  the  various  cresol  disinfectants,  may  be  employed, 
but  their  odor  is  not  always  tolerable  to  the  patient.  Dilute  formalin 
presents  no  objections,  and  is  very  efficient  and  rapid  in  action. 

Urine. — In  typhoid  fever  and  tuberculosis  of  the  urinary  tract,  the 
urine  should  be  sterilized  by  the  addition  of  an  equal  volume  of  a  5 
per  cent,  solution  of  chlorinated  lime,  carbolic  acid,  or  one  of  the  cresol 
compounds,  but  better  by  the  addition  of  about  a  twentieth  of  its 
volume  of  formalin. 

Sputum. — In  pneumonia  and  pulmonary  tuberculosis,  the  sputum 
should  be  received  in  spit-cups  partly  filled  with  disinfectant  solution, 
and  kept  covered  when  not  in  actual  use.  It  may  be  treated  with  5 
per  cent,  carbolic  acid,  or  about  5  per  cent,  of  any  of  the  cresol  com- 
pounds, or  with  4  per  cent,  of  formalin.  Milk  of  lime  and  chlorinated 
lime  are  also  efficient.  Corrosive  sublimate  is  very  uncertain.  By 
reason  of  its  consistency  and  adhesive  properties,  sputum  is  one  of  the 
most  difficult  materials  to  sterilize.  It  is  especially  dangerous,  as  it 
may  contain  large  numbers  of  entangled  bacteria,  which,  on  drying, 
may  be  disseminated  by  air  currents. 

Discharges  from  Mouth,  etc. — In  diphtheria  and  pertussis,  all 
discharges  from  the  mouth  and  throat  should  be  received  on  pieces 
of  rag,  which  should  be  burned.  The  diphtheria  organism  retains 
its  vitality  a  long  time  in  the  dry  state,  and  so  may  exist  in  the 
air  of  the  room,  if  particles  of  false  membrane  which  happen  to  be 
thrown  out  in  coughing  or  sneezing  are  allowed  to  dry  on  walls,  fur- 
niture, and  elsew^here. 

Eating  Utensils,  etc. — All  eating  utensils  used  by  patients  with 
pneumonia,  diphtheria,  pertussis,  the  exanthemata,  and  tuberculosis 
should  be  well  scalded.  All  napkins  should  be  treated  in  the  same 
manner  as  infected  bed-linen.  All  remains  of  meals  should  be  de- 
stroyed. 

Bed-lin6n  and  Clothing. — In  any  case  of  sickness  in  which  isola- 
tion is  advisable  or  in  which  the  morbific  agent  is  known  to  exist  in 
the  bowel  discharges,  all  used  body-linen,  bed-linen,  towels,  napkins, 
wash-cloths,  handkerchiefs,  etc.,  even  if  not  obviously  soiled,  should 
be  immersed  for  an  hour  in  disinfectant  solutions,  and  then  conveyed 
under  cover  to  the  laundry  or  other  suitable  place,  and  boiled  for  an 
hour.  Should  the  organism  survive  the  first  treatment,  which  event 
with  proper  care  is  unlikely,  it  will  perish  in  the  second.  Should  there 
be  no  ftccal  or  other  stains,  the  boiling  may  be  carried  out  without  the 
preliminary  soaking ;  but  in  no  case  should  the  articles  in  a  dry  state 
])e  removed  from  tlie  room  except  under  cover  or  wrapped  in  a  sheet 
wetted  with  an  efficient  disinfectant. 

In   scarlet  fevfr,  for  exani])l(',  tlie  morbific  agent,  whatever  it  may 


560  DISINFECTANTS  AND  DISINFECTION. 

be,  is  exceedingly  tenacious  of  life,  and  resides  in  the  fine  particles  of 
epidermis  which  are  continually  cast  oif  by  the  skin,  and  it  is  easily 
conceivable  that  an  armful  of  linen  from  a  case  of  this  disease  might 
shed,  in  its  journey  to  the  laundry,  a  number  of  dust  particles  capable 
of  much  mischief.  Neither  lime  nor  chlorinated  lime  may  be  used  on 
clothing,  on  account  of  probable  injury.  Corrosive  sublimate  1  :  1,000, 
phenols  and  cresols  in  5  per  cent,  solution,  and  formalin  in  4  or  5  per 
cent,  solution,  may  be  advised.  Colored  goods  are  sometimes  affected 
by  some  of  the  cresol  compounds,  but  to  no  greater  extent  than  may 
be  caused  by  ordinary  laundry  soap. 

Hands. — In  the  nursing  of  cases  of  infectious  disease,  the  soiling 
and  infection  of  the  hands  are  frequently  unavoidable.  After  every 
use  of  the  bed-pan,  every  wiping  away  of  discharges,  every  handling 
of  the  patient's  body,  and,  in  short,  after  every  act  by  which  the 
hands  may  become  infected,  they  should  be  washed  immediately  and 
thoroughly,  although  not  necessarily  with  that  thoroughness  which  is  so 
essential  in  surgical  practice.  Ordinary  soap-and-water  treatment 
should  be  supplemented  by  the  application  of  some  more  powerful 
disinfectant.  Carbolic  acid  and  the  cresols  may  serve,  but  they  leave 
a  disagreeable  smell,  and  have  sometimes  an  unpleasant  effect  on  the 
skin.  Formaldehyde  in  3  per  cent,  solution  is  efficient,  but  when 
applied  frequently,  causes  a  hardening  of  the  epidermis  which  is  far 
from  agreeable.  Corrosive  sublimate  1  :  1000  is  not  so  efficient,  and 
its  use  is  often  followed  by  dermatitis.  Schenk  and  Zaufal  ^  recommend 
the  use  of  sand  soap  followed  by  immersion  in  corrosive  sublimate 
1  :  1000,  as  hot  as  the  hands  can  bear. 

Air. — All  attempts  to  disinfect  the  air  of  the  sick-room  in  the 
presence  of  the  patient  are  futile,  for  the  presence  of  sufficient  of  any 
chemical  disinfectant  to  have  any  effect  on  the  bacteria  present  would 
cause  the  air  to  be  irrespirable.  It  is  a  common  practice  to  place 
about  the  room  dishes  containing  carbolic  acid,  permanganate  solution, 
chlorinated  lime,  iodine,  and  other  agents,  and  to  suspend  sheets  wrung 
out  in  all  kinds  of  active  and  inert  solutions,  in  the  vain  hope  that 
thereby  the  air  is  made  better  for  the  patient  and  incapable  of  trans- 
ferring infection  to  others.  Whether  the  agent  used  is  a  true  disin- 
fectant in  any  strength  whatever,  and  whether  the  sheet  is  continuously 
or  only  intermittently  wet,  do  not  appear  to  enter  in  any  way  into  the 
question  of  efficiency.  Ordinarily,  anything  sold  in  the  shops  at  a 
high  price  and  under  a  label  alleging  not  infrequently  the  impossible, 
will  be  accepted  without  question.  But  it  may  safely  be  asserted  that 
no  disinfectant  known  can  be  of  the  slightest  service  when  used  in  this 
way,  and  if  this  is  true  of  the  disinfectant,  it  must  be  of  the  sheet. 

Much  can  be  done  to  remove  the  well-known  disagreeable  sick-room 
smell,  due  to  the  excreta  and  to  matters  eliminated  by  the  lungs  and 
skin,  but  all  hope  of  producing  sterility  of  the  air  should  be  aban- 
doned. If  pathogenic  organisms  are  present  in  the  air,  a  much  easier 
and  more  reasonable  method  of  dealing  with  them  is  that  of  thorough 
^  Miinchener  medicinische  Wochenschrift,  Apiil  10,  1900. 


PRACTICAL   DISINFECTION.  561 

aeration,  and  this  is  one  of  the  most  important  parts  of  treatment  in 
general.  The  germicidal  properties  of  sunlight  should  also  not  be 
overlooked  when  it  is  possible  to  make  use  of  this  important  aid.  If 
good  ventilation  is  not  sufficient  to  keep  the  air  sweet,  the  old-fashioned 
pastilles,  containing  benzoin,  may  be  employed  as  occasion  demands, 
or  one  or  two  paraform  pastilles  may  be  volatilized  slowly  in  a  small 
lamp  for  the  purpose.  In  very  small  amounts  in  the  air,  the  gas  is  in 
no  way  disagreeable  or  irritating,  and  acts  very  powerfully  as  a  de- 
odorant, not  by  supplanting  the  smell,  but  by  destroying  it  by  chemical 
union. 

Room  Disinfection. — Not  until  the  termination  of  the  disease  or  the 
removal  of  the  patient  should  the  disinfection  of  the  sick-room  and  its 
contents  be  attempted.  This  is  not  such  an  easy  matter  as  is  com- 
monly believed,  and  much  supposed  disinfection  is,  by  reason  of  a 
lack  of  thoroughness,  no  better  than  none  at  all,  or,  indeed,  worse,  be- 
cause of  undeserved  confidence  and  unfounded  sense  of  safety.  Even 
with  the  utmost  cai'c,  one  can  hardly  expect  absolute  perfection  of  re- 
sults, although  in  ideal  disinfection  every  micro-organism  present  should 
be  destroyed.  Fliigge,^  who  has  devoted  much  time  and  study  to  the 
question  of  house  disinfection,  avers  that  with  any  process  by  which 
90  per  cent,  of  the  pathogenic  bacteria  present  are  destroyed,  one  should 
be  content,  and  that  no  process  practicable  will  kill  all  of  them. 

The  processes  employed  up  to  within  very  recent  years  are  notori- 
ously inadequate,  and  the  far  superior  processes  in  use  to-day  may  yet 
be  made  more  perfect.  House  disinfection  is  often  most  insufficient, 
even  when  what  has  been  done  has  been  carried  out  with  every  care 
and  under  most  favorable  conditions,  since  it  is  the  usual  practice  to 
disinfect  only  the  particular  room  which  the  patient  has  occupied  dur- 
ing his  sickness,  without  regard  to  the  fact  that  all  the  connecting 
rooms,  hallways,  and  distant  parts  of  the  house  may  have  become 
infected. 

The  open  doorway  opposes  no  unseen  obstacle  to  the  passage  of 
minute  dried  particles  of  false  membrane  or  epidermal  scales  floating 
in  the  air,  nor  are  these  attracted  to  and  retained  by  the  interposed 
sheet  like  particles  of  iron  by  a  magnet.  Even  when  the  door  is  closed, 
there  are  air  currents,  now  one  way,  now  the  other,  under  it  and  above 
the  threshold.  Infective  material  may  be  carried  in  one  way  and 
another  by  members  of  the  family,  visitors,  attendants,  and  even  by 
the  patient  himself,  to  various  parts  of  the  house,  and  the  room  in 
which  he  has  lain  ill  may,  by  reason  of  proper  attention,  be  the  least  in- 
fected one  in  the  house,  but  yet  in  ordinary  practice  it  is  the  only  one 
treat(;d.  Probably  oftener  than  not,  much  more  than  one  room,  and  in 
not  a  small  ])ro])ortion  of  cases,  the  whole  house,  should  receive  atten- 
tion. 

The  existing  methods  of  room  disinfection  comprise  mechanic;  1 
treatment,  direct  a]iplica.tion  of  <lisinfectant  solutions  as  spray  or 
washes,  liberation  of  gaseous  ag(!iits,  and  combinations  of  all  three. 
'  Zeitschrift  fiir  Hygiene  und  InfectioMskrankheiten,  XXIX.,  1898,  p.  276. 


562  DISINFECTANTS  AND  DISINFECTION. 

The  bread  process,  devised  by  Esmarch/  consists  in  rubbing  the  walls 
with  pieces  of  bread,  to  which  bacteria  adhere  with  great  tenacity. 
This  is  not  applicable  to  rough  walls,  and  when  thoroughly  and  prop- 
erly done,  involves  such  an  amount  of  labor  and  material  as  to  be  ex- 
ceedingly expensive.  The  bread  pieces,  together  with  all  crumbs 
Avhich  break  off  and  fall  to  the  floor,  are  carefully  removed  and  de- 
stroyed by  fire.  For  the  rest  of  the  room  and  its  contents,  other  proc- 
esses are  necessary,  including  scrubbing  with  soft  soap  and  water, 
wiping  ^7ith  disinfectants,  and  transportation  of  certain  articles  of 
clothing,  furniture,  bedding,  etc.,  to  the  public  disinfecting  station  to 
be  treated  by  steam. 

The  method  of  treating  walls,  floors,  furniture,  and  clothing  by 
spraying  with  solutions  of  mercuric  chloride  and  other  agents  com- 
mends itself  in  some  quarters  and  not  in  others.  According  to  Rideal, 
35,000  houses  in  Paris  were  disinfected  by  means  of  sublimate  spray, 
1  :  1000,  in  1893,  and  a  still  larger  number  in  1894  with  satisfactory 
results  and  with  no  bad  effects  from  the  poison.  It  appears,  however, 
according  to  later  evidence,^  that  a  number  of  the  employes  of  the  dis- 
infecting squad  have  shown  symptoms  of  mercurial  poisoning,  and 
Rideal  mentions  cases  of  salivation  in  India  attributed  to  corrosive 
sublimate  wash  for  floors.  The  spraying  process,  whether  satisfactory 
or  not,  and  whether  dangerous  to  health  or  not,  is  not  quick,  and  requires 
other  treatment  which  consumes  time  and  adds  to  the  expense. 

The  ideal  disinfectant  would  be  a  gas  with  no  destructive  or  harm- 
ful action  on  anything  but  micro-organisms,  capable  of  penetrat- 
ing materials  by  which  they  are  hidden,  and  acting  with  great  quick- 
ness. Such  an  agent,  it  is  safe  to  say,  will  never  be  discovered,  for, 
even  though  the  other  requirements  may  be  met,  it  is  improbable  that 
the  physical  law  governing  diffusion  will  ever  be  modified  by  any  gas 
as  yet  undiscovered.  Gaseous  disinfection  must  ever  be  superficial  or 
nearly  so,  and  should  be  assisted  by  other  methods  to  bring  about  the 
best  results.  Gaseous  disinfectants' which  exert  any  injurious  influence 
on  the  objects  treated  cannot  be  tolerated,  and  it  happens  that  this 
class,  which  includes  chlorine  and  sulphur  dioxide,  has  been  found 
wanting  in  efficiency. 

Formaldehyde  gas  approaches  more  nearly  the  requirements  of  the 
ideal  disinfectant  than  any  thus  far  tried,  and  is  rapidly  supplanting  all 
others.  In  its  application,  no  matter  how  it  is  generated,  whether  from 
formalin  or  paraform,  it  is  essential  that  every  obstacle  possible  shall 
be  interposed  against  its .  escape  from  the  space  under  treatment,  and 
that  all  objects  withm  that  space  shall  be  so  disposed  as  to  present  as 
much  of  their  surface  as  possible  to  its  action  ;  and  even  then,  absolute 
perfection  of  results  cannot  be  attained.  Fliigge  ^  relates  that  twice  he 
prepared  a  small  room,  containing  but  little  furniture,  by  placing  patho- 
genic organisms  on  marked  locations,  and  had  the  local  disinfecting 
squad  perform  their  office  under  careful  supervision,  and  in  both  in- 

'  Zeitschrift  fiir  Hvgiene,  II.,  1887,  p.  491. 

2  Journal  of  State  Medicine,  IV.,  1896,  p.  146.  ^  Loco  citato. 


PRACTICAL  DISINFECTION.  563 

stances  found  that  a  fair  percentage  of  the  bacteria  escaped  destruction. 
He  suggests,  with  good  reason,  that,  in  routine  practice,  the  results  must 
ordinarily  be  far  less  favorable. 

For  the  attainment  of  the  best  results,  the  various  articles  of  furni- 
ture should  be  moved  away  from  the  walls,  all  articles  of  clothing, 
blankets,  and  other  textiles  should  be  suspended  freely  on  lines  or 
clothes-horses,  the  pockets  of  clothing  turned  inside  out,  and  all  cracks 
and  other  outlets  carefully  stopped  with  wet  cotton,  putty,  adhesive 
paper,  or  other  suitable  material. 

Particular  attention  should  be  paid  to  the  complete  closure  of  all 
inlet  and  outlet  registers ,  those  in  the  walls  should  be  pasted  over 
with  stout  paper,  and  those  in  the  floor  should  be  so  treated  or  covered 
with  thick  cloth  wrung  out  in  sublimate  solution  or  diluted  formalin. 
Loosely  fitting  window-sashes  may  be  made  tight  by  means  of  wooden 
wedges,  and  the  cracks  around  them  properly  stuifed.  If  there  is  a 
stove  in  the  room,  its  doors  and  openings  for  drafts  should  be  securely 
sealed.  Open  fireplaces  and  Franklin  stoves  require  complete  closure 
of  their  flue-outlets.  The  doors  of  all  closets  and  cupboards  and  the 
drawers  of  all  bureaus  and  cabinets  should  be  left  open.  All  soiled 
places  on  the  walls,  floor,  and  furniture,  possibly  due  to  infective 
material,  should  be  wetted  with  formalin  or  sublimate  solution. 

When  the  room  has  been  properly  prepared,  the  generation  of  the 
gas  may  be  begun.  If  paraform  lamps  or  the  Breslau  apparatuses  are 
employed,  the  operator  leaves  the  room  and  stops  the  crack  under  the 
door  with  wet  cotton  and  closes  the  keyhole  with  a  gummed  label  or 
with  putty.  If  an  autoclave  or  other  similar  apparatus  is  employed, 
the  stopping  of  the  keyhole  of  the  door  is  necessarily  deferred  until 
the  generation  of  the  gas  is  completed.  The  room  is  then  left  unopened 
over  night  or,  if  the  process  is  begun  in  the  morning,  through  the  day. 
On  the  expiration  of  the  required  time,  ammonia  in  the  necessary 
amount  is  vaporized  through  the  keyhole,  or  the  room  is  entered  at 
once,  the  windows  thrown  open,  and  free  aeration  established.  In  the 
latter  case,  the  operator's  eyes  should  be  protected  by  closely  fitting 
goggles,  and  he  should  hold  his  breath,  if  possible,  until  his  object  is 
accomplished.  If  ammonia  is  employed  to  neutralize  the  gas,  the 
room  will  be  sooner  inhabitable  than  otherwise,  especially  if  steam  has 
been  generated  simultaneously  with  the  gas,  as  advocated  by  Fliigge, 
for  aeration  may  require  many  hours,  and,  in  some  cases,  days,  to  rid 
the  room  of  the  odor.  This  is  a  matter  of  extreme  importance  with 
people  of  small  means  living  in  limited  spaces,  who  cannot  afford  even 
the  temporary  inconvenience  and  expense  of  finding  outside  accommo- 
dations. 

Mattresses  which  have  been  polluted  by  soakage  of  urine  and 
excreta,  thick  clothing,  and  other  articles  which  do  not  lend  themselves 
to  su])erficial  gaseous  disinfection,  require  treatment  by  steam  in  the 
special  apparatuses  described  on  a  preceding  page.  Straw,  corn-husk, 
and  "excelsior"  mattresses  should  be  differently  treated.  Their  con- 
tents should  be  rem<jvc(l  and  burned,  and  the  ticking  soaked  in  disin- 


564  DISINFECTANTS  AND  DISINFECTION. 

fectauts  and  boiled.  Stuffed  furniture  covered  with  woven  fabrics 
should  be  taken  out  of  doors  and  be  well  beaten  and  left  exposed  to  the 
air  and  direct  sunlight.  If  upholstered  in  leather,  it  should  be  well 
wiped  in  all  the  crevices  with  cloths  wrung  out  in  sublimate  solution  or 
diluted  formalin. 

Heavy  clothing  and  other  fabrics  sometimes  are  sent  to  be  treated  by 
the  benzene  process/in  the  belief  that,  by  this  means,  not  only  are 
grease  spots  removed,  but  that  sterilization  is  effected.  Riipp,^  how- 
ever, has  pointed  out  that,  in  the  ordinary  benzene  process,  pus  cocci 
and  the  bacilli  of  typhoid  fever,  anthrax,  diphtheria,  and  tuberculosis 
are  not  destroyed. 

Disinfection  of  Books. — Books  are  extremely  difficult  to  sterilize 
with  certainty,  on  account  of  the  protection  that  is  given  to  bacteria  by 
the  juxtaposed  pages.  Unbound  books  may  be  subjected  to  treatment 
by  steam,  but  this  process  is  not  suited  to  bound  volumes,  because  of 
its  effect  on  the  glue.  For  bound  books,  the  only  available  disinfectant 
is  formaldehyde,  but  even  this  agent  is  not  efficient,  unless  the  leaves  are 
so  disposed  that  the  gas  can  have  access  to  every  page.  Books  of  value 
will  require  very  thorough  and  repeated  treatment ;  but  those  of  small 
value,  known  to  have  been  probably  or  possibly  infected,  are  best 
destroyed  by  fire.  If  formaldehyde  treatment  is  deemed  advisable, 
they  should  be  placed  on  edge,  with  the  leaves  opened  as  much  and  as 
freely  as  possible,  and  subjected  repeatedly  to  the  action  of  the  gas  in 
a  tight  closet  or  box. 

Disinfection  of  Water-closets.  —  Water-closet  bowls  may  be 
treated  with  dilute  formalin  or  5  per  cent,  solution  of  the  cresol 
preparations.  The  wood-work  around  and  near  them  may  be  washed 
with  the  same  agents.  Sublimate  solution  should  not  be  used  in 
plumbing  fixtures,  on  account  of  its  action  on  lead. 

^  Correspondenzblatt  fiir  Schweizerische  Aerzte,  1897,  No.  19. 


CHAPTER    IX. 
MILITARY  HYGIENE. 

Since  the  most  important  factor  in  the  efficiency  of  an  army  is  its 
health,  it  follows  that  everything  which  may  influence  this  in  any  way 
for  the  better  or  worse  should  be  looked  after  with  the  utmost  care. 
The  men  who  compose  an  army  are  drawn  from  civil  life,  in  which  each 
individual  has.  to  a  grc^ater  or  lesser  extent,  independent  control  of  his 
time,  choice  of  occupation,  selection  of  food  and  dwelling-place,  and 
general  sanitary  care.  After  enlistment,  soldiers  lose  most  of  this  inde- 
pendence ;  thev  are  housed,  clothed,  fed,  and  exercised  under  regulations 
which  it  is  beyond  their  power  to  amend ;  they  are  moved  from  one 
point  to  another,  differing  perhaps  very  widely  in  climatic  and  other 
conditions,  under  orders  which  they  may  not  presume  to  question  ;  their 
hours  for  sleep,  meals,  work,  and  recreation  are  fixed  for  them  without 
consultation  with  them,  and  without  regard  to  individual  or  communal 
preference. 

Since  the  government  necessarily  deprives  the  soldier  of  his  indepen- 
dence of  action,  it  is  bound  by  every  principle  of  fairness  to  him  to  look 
after  his  health  and  comfort,  to  promote  contentment,  and  to  ward  off 
ennui  by  all  reasonable  and  proper  means.  Thus,  the  care  of  troops  is 
a  double  obligation  ;  the  men  have  every  right  to  expect  it,  and  the 
efficiency  of  the  army  is  dependent  upon  it.  But  no  matter  how  care- 
ful the  sanitary  administration,  it  is  a  matter  of  common  knowledge 
that  in  all  wars,  excepting  the  Franco-Prussian,  and  in  that  only  with 
regard  to  the  Germans,  the  mortality  from  disease  has  been  far  in  ex- 
cess of  that  from  casualties,  and  in  all  armies,  more  discharges  are  due 
to  sickness  than  to  injuries. 

The  responsibility  for  the  care  of  troops  and  health  of  camps  is 
placed  upon  the  medical  officers,  who  have  no  power  to  com- 
mand and  are  ham])ered  by  being  subordinate  to  laymen  having 
often  no  adequate  appreciation  of  matters  purely  medical.  They 
have  only  advisory  functions,  and  must  be  most  careful  in  recom- 
mending changes  to  the  very  conservative  military  mind,  which  finds 
in  long  continuance  of  a  condition  the  strongest  argument  for  its 
longer  retention,  and  is  prone  to  look  upon  recommendations  for 
sweejnng  changes  as  evidence  of  whimsical  disposition  and  deficient 
training  in  sanitary  science.  Nevertheless,  the  medical  officer  has 
a  very  heavy  responsibility  placed  upon  him,  and  must  advise  his 
lay  superiors  and  explain  the  irn])ortance  of  the  principles  underlying 
sanitary  practice.  He  must  make  proper  recommendations  for  the 
protection  of  health  of  the  troops  in  war  and  in  peace,  in  camps  and  in 
garrison. 

f.65 


566  MILITARY  HYGIENE. 

Since  tlie  efficiency  of  a  military  body  is  so  largely  dependent 
upon  the  health  of  the  units  of  which  it  is  composed,  the  result 
of  a  campaign  may  be  largely  influenced  by  the  adoption  or 
rejection  by  the  commanding  officer  of  the  recommendations  of 
his  medical  adviser.  Unfortunately,  if,  by  reason  of  physical  un- 
fitness of  the  troops,  a  movement  fails  or  an  epidemic  of  disease 
occurs,  the  public  at  once  places  the  blame  upon  the  medical  depart- 
ment, and  especially  upon  the  head  thereof,  the  Surgeon-General,  and 
demands  a  reorganization,  a  sifting  out  of  incompetent  material,  and 
especially,  a  change  in  the  head,  quite  regardless  of  the  possible  fact 
that  the  choice  of  an  unsanitary  camping  place  may  have  been  made 
against  the  judgment  and  advice  of  the  medical  branch,  that  the  com- 
missary department  may  have  been  largely  to  blame,  or  that  other 
influences  quite  beyond  the  control  of  the  medical  corps  may  have  been 
at  fault. 

The  medical  officer,  both  at  home  and  in  most  countries  abroad,  has 
much  with  which  to  contend.  The  corps  is,  as  a  rule,  not  sufficiently 
large  for  the  body  for  which  it  is  to  care,  but  is  expected  to  perform 
an  amount  of  work  and  assume  a  responsibility  which  would  fairly  tax 
the  capacity  of  one  of  double  size.  In  an  emergency  requiring  large 
additional  levies  and  consequent  employment  of  civilian  physicians 
untrained  in  military  life,  the  responsibility  becomes  proportionately 
greater. 

The  recent  experiences  of  this  country  and  of  England,  Avhen  the 
outbreak  of  war  necessitated  the  assembling  and  transportation  of 
large  armies,  serve  very  well  as  illustrations.  With  us,  on  the  break- 
ing out  of  war  with  Spain,  a  standing  army  of  25,000  was  suddenly 
increased  by  enlargement  of  the  regular  service  and  enrollment  of  vol- 
unteers to  ten  times  that  size,  but  the  small  body  of  trained  military 
surgeons,  too  small  before,  could  hardly  have  been  expected  to  be  equal 
to  the  demands  of  the  new  army,  even  with  the  assistance  of  the 
physicians  from  civil  life,  who,  although  doubtless  highly  efficient  in " 
civil  practice,  were  for  the  most  part  inexperienced  in  camp  hygiene. 
The  difficulties  of  sanitary  administration  were  very  largely  increased 
by  the  recklessness  and  ignorance  of  the  volunteers  in  personal  hygiene 
and  general  sanitation.  The  results  were  what  might  be  expected,  and 
are  too  well  known  to  need  further  mention.  The  blame  for  all  the 
disastrous  experience  was  placed  at  once  upon  the  medical  department, 
which  had  but  little  to  say  in  the  choice  of  camps,  and  nothing  what- 
ever to  do  with  the  inadequate  means  of  transportation  and  other  factors 
in  the  production  of  a  large  mortality  from  disease.  The  experience 
of  the  English  in  the  war  in  South  Africa  was  essentially  the  same,  and 
was  due  to  the  same  causes. 

In  the  large  standing  armies  on  the  Continent,  a  different  order  of 
things  obtains.  The  officers  of  the  line  are  more  inclined  to  defer  to 
the  opinions  and  advice  of  the  medical  staff  in  matters  requiring  expert 
sanitary  knowledge,  and  the  authorities  demonstrate  a  much  higher 
appreciation  of  the  value  of  an   adequate  medical   service.      As  an 


THE  RECRUIT.  567 

illustration  of  the  difference  in  the  ordering  of  such  matters  in  Ger- 
many and  England,  the  following  is  cited  : 

The  British  first  infantry  division  and  first  cavalry  brigade,  with 
two  batteries  of  field  artillery,  a  company  of  engineers,  telegraph 
corps,  railway  company,  ammunition  corps,  and  hospital  corps,  ordered 
to  South  Africa  in  the  autumn  of  1899,  and  the  German  expeditionary 
corps,  consisting  of  two  brigades  of  infantry,  three  squadrons  of  cav- 
alry, four  batteries  of  light  artillery,  a  batallion  of  pioneers,  with  a 
telegraph  corps,  railway  company,  sanitary  company,  ammunition 
corps,  and  hospital  corps,  organized  in  the  summer  of  1900  for  service 
in  China,  were  about  equal  in  number  of  men.  For  the  care  of  these 
troops,  the  English  authorities  detailed  49  regular  medical  officers  and 
13  civilian  surgeons,  a  total  of  62  ;  the  Germans  detailed  91  regular 
army  surgeons,  or  nearly  50  per  cent.  more.  The  English  hospital 
ship  had  3  surgeons  ;  the  German  had  10.  The  English  sent  4  field 
hospitals  with  1 6  surgeons  ;  the  Germans  sent  an  equal  number  with 
24.  The  English  general  hospital  had  18  surgeons,  of  whom  11  were 
civilians ;  the  German  had  19,  all  of  whom  were  regulars. 

The  superior  medical  equipment  of  the  Germans  is  not  dictated  by 
extravagance,  but  by  a  greater  appreciation  of  the  necessity  of  furnish- 
ing adequate  medical  service. 

In  a  standing  army  such  as  is  maintained  in  this  country,  it  would 
be  far  better  to  err  on  the  side  of  extravagance  than  of  undue  economy 
in  the  size  of  the  medical  corps.  There  should  be  systematic  instruc- 
tion in  general  hygiene,  which  should  not  be  limited  to  the  medical 
officers  alone,  for  the  line  officers  also  should  be  required  to  acquaint 
themselves  with  the  principles  of  the  science,  and  especially  with  the 
sanitation  of  camps.  Then,  when  the  medical  officers  point  out  meth- 
ods of  conserving  the  Jiealth  of  troops,  those  in  actual  command  would 
be  in  a  better  position  to  apply  their  authority  with  a  larger  apprecia- 
tion of  the  advice  given. 

Military  hygiene  has  to  deal  with  the  selection  and  examination  of 
men  offering  themselves  as  recruits,  their  habitations,  clothing,  exercise, 
food,  diseases,  and  medical  care ;  with  camp  sanitation,  including 
water  supply  and  sewerage,  disposal  of  waste,  and  general  police ;  and, 
in  general,  with  all  matters  having  any  bearing  on  the  health  and, 
impliedly,  the  efficiency  of  troops. 

THE  RECRUIT. 

Not  every  adult  man  accustomed  to  hard  work  can  be  transformed 
into  a  good  soldier,  for  there  are  many  points  of  disqualification  for 
military  service,  and  an  unsound  man  can  never  be  depended  upon 
when  his  services  are  needed.  The  ideal  recruit  is  one  who,  in  the 
first  place,  is  well  built  and  of  superior  muscular  force,  capable  of 
resisting  influences  tending  to  depress  the  nervous  and  physical  powers. 
According  to  the  great  Na])oleon,  "The  first  (piality  of  a  soldier  is  the 
power  to  endure  fatigue  and  privation  ;  courage  is  only  second."     This 


668  MILITARY  HYGIENE. 

primary  qualification  is  very  commonly  thought  to  be  an  attribute 
more  of  the  country-bred  than  of  the  city-bred  lad. 

Dr.  Woodhull/^  Lt. -Colonel,  Med.  Dep't  U.  S.  A.,  however,  says  on 
this  point :  "  In  raising  new  troops,  when  it  is  possible  to  select,  for 
sharp  and  immediate  active  service  take  town-bred  men.  If  a  year  or 
two  can  be  added  in  which  to  train  them,  take  country-bred  men. 
Open-air  military  life  is  physical  promotion  to  city  men  accustomed  to 
irregular  hours,  unwholesome  meals,  and  poorly  ventilated  rooms.  To 
country  lads  the  irregular  and  sometimes  scanty  meals,  broken  rest, 
necessity  for  prompt  and  exact  action,  and  above  all  the  certainty  of 
acquiring  such  diseases  as  measles,  whooping-cough,  and  mumps,  which 
town  boys  always  have  in  childhood,  are  very  exhausting.  After  a 
year's  training,  country  youths  are  more  valuable." 

Under  the  regulation  of  the  United  States  Army,^  any  male  citizen 
or  person  who  has  legally  declared  his  intention  to  become  a  citizen,  if 
above  the  age  of  21  and  under  the  age  of  35  years,  able-bodied,  free 
from  disease,  of  good  character  and  temperate  habits,  may  be  enlisted  ; 
but  in  regard  to  age  or  citizenship,  the  rule  does  not  apply  to  soldiers 
who  have  already  served  honestly  and  faithfully  a  previous  enlistment. 
Boys  between  the  ages  of  16  and  18  may  be  enlisted  as  musicians  or 
to  learn  music,  with  the  written  consent  of  father  or  guardian  and 
approval  of  the  Adjutant-General. 

Enlisted  men  of  good  character  and  faithful  service,  who,  at  the  ex- 
piration of  their  terms,  are  undergoing  treatment  for  injuries  incurred 
or  disease  contracted  in  the  line  of  duty,  may  reenlist,  and  if  the  dis- 
ability prove  to  be  permanent,  they  will  be  subsequently  discharged. 
An  enlisted  man,  not  under  treatment,  but  with  infirmities  contracted 
in  the  line  of  duty  not  such  as  to  prevent  his  performing  the  duties  of 
a  soldier,  may  be  reenlisted  by  authority  of  the  War  Department,  on 
application  made  through  the  surgeon  and  proper  military  channel, 
since  it  is  recognized  that  what  he  may  lack  in  some  minor  particulars 
in  soundness  may  be  counterbalanced  by  experience  and  habits  of  dis- 
cipline. 

Those  whose  enlistment  is  prohibited  include  former  soldiers  having 
bad  record,  deserters,  drunkards,  insane  persons,  minors  below  16 
years  of  age  (musicians),  persons  who  have  been  convicted  of  felony 
or  who  have  been  imprisoned  under  sentence  of  a  court ;  and  for  first 
enlistments  in  time  of  peace,  non-citizens,  except  those  who-  have 
legally  declared  their  intentions  to  become  citizens,  those  who  cannot 
speak,  read,  and  write  English,  and  those  over  35  years  of  age. 

Age. — Recruiting  officers  are  directed  by  the  regulations  to  be  very 
particular  to  ascertain  the  true  age  of  the  recruit,  boys  below  18  not 
being  accepted  in  time  of  peace,  excepting  as  musicians  or  to  learn 
music,  and  then  only  with  the  consent  of  guardians  and  approval  of 
the  Adjutant-General.  The  minimum  age  for  all  arms  of  the  service 
is  18  years;  the  maximum  for  the  cavalry  is  30,  and  for  other  arms 

^  Notes  on  Military  Hygiene  for  Officers  of  the  Line,  New  York,  1898,  p.  18. 
^  Eegulations  for  the  Army  of  the  United  States,  Washington,  1899,  p.  Il3. 


THE  RECRUIT.  569 

35  ;  but  for  reenlistments  there  is  no  limit  of  age.  Men  of  all  ages 
between  18  and  45  are  accepted  in  the  volunteer  service.  In  the 
British  service,  ihe,  limits  of  age  are  18  and  25  years,  except  for  the 
medical  staff  corps  and  engineers,  for  which  the  maximum  is,  respec- 
tively, 28  and  30. 

It  is  almost  the  universal  opinion  that  recruits  ought  not  to  be  ac- 
cepted below  20,  or,  better,  22.  At  18  years,  the  recruit  is  immature ; 
the  bones  are  not  fully  formed,  nor  have  they  reached  their  final  hard- 
ness ;  the  epiphyses  have  not  become  incorporated  with  the  shafts  of 
the  long  bones ;  the  joints  are  not  fully  developed  ;  the  muscles  are 
soft  and  not  wholly  developed ;  the  chest  has  by  no  means  attained  its 
full  capacity ;  and  the  organs  of  the  body,  in  general,  are  immature. 
So  it  happens  that,  at  this  age,  it  is  useless  to  expect  them  to  be  in 
good  condition  after  long-continued  exertion  or  to  undergo  privations 
which  are  as  nothing  to  the  man  of  mature  years  and  strength.  At 
this  period  of  life,  he  is  still  in  the  growing  stage  and  needs  all  the 
energy  of  his  body  to  bring  the  organism  to  completion,  and  the  in- 
fluences which  mature  soldiers  contend  against  with  varying  degrees  of 
success,  namely,  vicissitudes  of  weather,  long  marches,  hard  work  in 
trenches,  possible  overcrowding  in  barracks  and  camps,  poor  ventila- 
tion, and  poor  and  insufficient  food,  send  him  very  quickly  to  the 
hospital. 

It  is  beyond  reason  to  expect  the  same  work  and  endurance  of  a 
youth  of  18  to  20  as  of  a  fully  mature  man.  During  the  Civil  War, 
most  of  the  boys  who  enlisted  under  18,  and  many  of  those  above  that 
age  and  under  20,  had  to  be  discharged  within  the  first  few  months. 

It  has  been  demonstrated  repeatedly  that  the  least  efficient  armies 
are  those  containing  the  greatest  proportion  of  men  below  the  age  of 
22.  The  first  Napoleon  objected  to  boys,  saying  on  one  occasion,  "  I 
demand  a  levy  of  300,000  men.  But  I  must  have  grown  men ;  boys 
serve  only  to  fill  the  hospitals  and  encumber  the  roadsides.^'  A  re- 
markable example  of  the  importance  of  maturity  in  soldiers  is  related 
by  Tardieu.^  In  the  campaign  of  1805,  in  which  the  army  marched 
400  leagues  to  reach  Austerlitz,  hardly  any  sick  or  stragglers  were  left 
on  the  way.  In  this  array  the  youngest  were  22  years  of  age  and  had 
had  two  years'  training.  In  the  campaign  of  1809,  on  the  other  hand, 
the  army,  which  had  but  a  short  distance  to  march  on  its  way  to 
Vienna,  filled  all  the  hospitals  on  the  way  with  its  sick.  More  than 
half  the  soldiers  of  this  army  were  under  20  years  of  age  and  inex- 
])erienced.  In  the  celebrated  march  of  Lord  Roberts  from  Kabul  to 
Kandahar,  the  young  soldiers  gave  out  from  day  to  day  and  fell  behind, 
Avhile  the  old  campaigners  appeared  to  gain  in  vigor  with  each  day's 
march. 

Not  only  are  young  recruits  less  able  to  undergo  the  usual  work  and 
the  hardships  than  seasoned  men,  but  they  are  much  more  susceptible 
to  disease.     Aitken  ^  relates  that,  during  the  Crimean  War,  when  the 

'  Dictionnairt;  (V\\y<s\<iw,  III.,  p.  '1. 

^  On  the  Groutli  of  the  Ilcmiii  mid  ^'omif,'  Soldier,  2d  J'^lition,  Luiidon,  1S87,  p.  58. 


570  MILITARY  HYGIENE. 

Commander-in-Chief,  Lord  Raglan,  was  informed  that  2,000  recruits 
were  ready  to  be  sent  to  him,  he  replied:  "Those  last  sent  were  so 
young  and  unformed  that  they  fell  victims  to  disease  and  were  swept 
away  like  flies."  He  preferred  to  wait  rather  than  have  such  young 
lads  sent  to  him  as  soldiers.  Other  commanders  in  the  Crimea  testi- 
fied that  young  recruits  were  of  very  inferior  value. 

The  greater  susceptibility  of  young  soldiers  to  typhoid  fever  was 
demonstrated  by  Dr.  Farr,  the  British  Registrar-General,  and  by  Dr. 
Balfour,  who  showed  that,  in  1883,  the  army  in  India  contained  41 
per  cent,  of  soldiers  under  25  years  of  age,  and  that  among  this  con- 
tingent the  death-rate  from  this  disease  was  4.34  per  thousand,  while 
that  of  the  men  of  25  to  29  years  was  but  1.50  per  thousand.  In 
newly-arrived  regiments,  nearly  half  of  the  total  death-rate  was  from 
this  disease.  Aitken  gives  a  number  of  instances  of  the  influence  of 
youth  and  short  residence  on  the  prevalence  of  this  fever.  At  one 
station,  for  example,  out  of  44  cases,  35  occurred  in  one  regiment  com- 
posed principally  of  young  soldiers,  and  33  among  men  of  less  than 
one  year's  residence  in  India. 

In  1883,  in  India,  36.55  per  cent,  of  those  invalided  home  were 
under  25  years  of  age,  and  in  1884,  38.70,  the  principal  diseases  neces- 
sitating invaliding  being  anaemia,  debility,  phthisis,  hepatitis,  and  dis- 
eases of  the  heart  and  arteries.  Throughout  the  Peninsular  AVar,  from 
1805  to  1814,  it  was  observed  that  the  "  corps  which  arrived  for  service 
were  always  ineffective  and  sickly  in  proportion  as  they  were  made  up 
of  men  who  had  recently  joined  the  ranks,"  and  it  was  calculated  that 
300  men  having  five  years'  experience  were  worth  more  than  1,000 
newly-arrived,  including  the  usual  proportion  of  young  recruits. 

Surgeon-General  Sternberg,  of  the  U.  S.  Army,  in  his  annual  report 
for  1885,  shows  that  the  greater  proportion  of  sickness  occurred  among 
soldiers  under  31  years  of  age,  and  that  up  to  the  age  of  25,  the  rate 
was  so  much  above  the  average  for  the  whole  army,  that  he  questions 
whether  their  services  had  been  a  fair  return  for  the  cost  of  their  main- 
tenance. In  1899,  the  British  Medical  Association  passed  a  resolution 
requesting  the  Council  to  communicate  to  the  War  Office  the  opinion 
of  the  Section  of  Medicine,  that  no  soldier  ought  to  serve  in  the  tropics 
earlier  than  22  years  of  age. 

In  favor  of  the  young  recruit,  Woodhull  says  that  young  men  are 
more  easily  trained  and  moulded  than  older  men,  especially  for  the 
cavalry,  and  when  well  led,  fight  as  well,  as  far  as  mere  courage  goes. 
But  as  we  cannot  keep  young  soldiers  several  years  in  training,  and  as 
large  bodies  of  troops  can  only  be  raised  for  sudden  war,  men  not 
absolutely  mature  must  be  rejected.  Lord  Wolseley  prefers  young  men, 
and  says  :  ^  "  Give  me  young  men  :  they  do  what  they  are  bid,  and  they 
go  where  they  are  told  ;  they  become  more  amenable  to  discipline,  and 
though  when  you  catch  them  first  they  may  have  some  difficulty  in 
carrying  their  knapsacks,  once  they  get  beyond  that  they  are  in  a  fit 
condition  to  take  the  field." 

^  Quoted  by  Aitken.     Loco  citato. 


THE  RECRUIT.  571 

If  young  men  are  enlisted,  the  work  should  be  suited  to  their 
strength,  and  it  should  be  kept  in  mind  that  they  are  still  in  the  grow- 
ing and  developing  stage,  and  should  have  no  greater  amount  of 
physical  exercise  than  is  suited  to  their  condition.  In  other  words, 
their  work  should  be  proportioned  to  their  growth,  and  in  two  years 
they  will,  perhaps,  have  developed  into  valuable  soldiers.  Taken 
between  the  ages  of  18  and  20,  and  drilled  and  trained  with  due  regard 
to  his  immaturity  and  limit  of  endurance,  the  recruit  often  shows  great 
progress  in  general  development  within  the  first  half-year,  particularly 
if,  before  enlistment,  he  was  poorly  fed,  clothed,  and  housed,  and 
engaged  in  an  indoor  occupation.  His  work  should  be  moderate  in 
the  beginning  and  only  gradually  increased,  since  changes  for  the  better 
in  the  human  body  cannot  be  brought  about  suddenly  like  those  for  the 
worse,  induced  by  attempting  to  do  too  much  at  the  outset.  Since  his 
lungs,  heart,  and  blood-vessels  are  not  yet  fully  developed,  he  can 
neither  go  through  the  manual  nor  cover  ground  like  the  seasoned 
soldier.  The  heart  is  called  upon  by  the  new  and  unaccustomed 
exercise  to  contract  at  a  greater  rate  than  had  been  its  habit,  and  he 
soon  becomes  "  winded."  When  this  stage  is  reached,  and  he  begins 
to  feel  or  show  distress,  he  should  be  allowed  and  encouraged  to  rest 
until  the  throbbing  of  the  heart  and  the  swelling  of  the  blood-vessels 
subside  and  permit  his  lungs  to  resume  easy  breathing ;  otherwise,  he 
is  more  than  likely  to  break  doAvn  sooner  or  later.  With  properly 
regulated  exercise  and  good  food,  he  ought  soon  to  show  gain  and  not 
loss  in  weight.  Should  progressive  loss  be  observed,  it  is  a  question 
whether  he  is  likely  to  become  an  efficient  soldier,  and  he  should  forth- 
with be  referred  for  medical  examination.  Under  the  regulations  of 
the  British  army,  all  recruits  are  kept  under  medical  observation 
during  the  first  three  months  of  service,  during  which  time,  in  addition 
to  the  ordinary  drill,  they  have  an  hour  of  gymnastic  exercise  daily, 
under  the  supervision  of  a  medical  man  ;  and  if,  during  this  period,  a 
man  shows  unfavorable  indications,  he  is  examined  by  a  medical  board. 
Should  this  body  conclude  that  he  will  not  ultimately  develop  into  an 
efficient  soldier,  he  is  at  once  discharged  on  that  ground. 

Height. — In  this  country,  the  minimum  height  for  all  branches  of 
the  service  is  5  feet  4  inches,  "  although  recruiting  officers  are  allowed 
to  exercise  their  discretion  as  to  the  enlistment  of  desirable  recruits 
(such  as  band  musicians,  school  teachers,  tailors,  etc.),  who  may  fall 
not  more  than  one-fourth  of  an  inch  below  the  minimum  standard  of 
height."  The  maximum  for  the  cavalry  alone  is  5  feet  10  inches,  and 
for  all  other  branches,  according  to  weight.  The  minimum  height  is 
subject  to  change,  if  necessary ;  but  it  has  been  demonstrated  that  5 
feet  2  inches  is  about  the  lowest  limit  for  efficiency,  men  below  that 
heiglit  having  proved,  as  a  class,  to  have  comparatively  little  staying 
power,  and  to  break  down  for  want  of  strength.  In  the  British  army, 
the  minimum  for  the  infantry  is  the  same  as  with  us  ;  the  limits  for  the 
cavalry  an;  •")  feet  0  in(;hes  to  5  feet  11  inches;  for  the  household 
cavalry,  5  feet  11  inches  to  0  ftict  1  inch.      In  the  French  army,  the 


572  MILITARY  HYGIENE. 

minimum  for  Cuirassiers  is  5  feet  7  inches ;  for  the  infantry  5  feet  1 
inch. 

Military  organizations  composed  exchisively  of  very  tall  men  of 
imposing  appearance,  are  intended  for  display,  and  not  for  the  usual 
work  of  the  soldier,  and,  indeed,  have  often  proved  to  be  lacking  in 
the  essentials  of  good  soldiers,  unless  they  are  unusually  well-propor- 
tioned. The  superiority  of  additional  height  is  commonly  found  to  lie 
in  the  leg  and  neck,  and  when  6  feet  3  inches  is  exceeded,  the  in- 
dividual, as  a  rule,  is  not  proportionately  developed  in  the  chest  and 
muscular  system.  Such  men  are  said  to  be  more  prone  to  diseases  in 
general,  and  more  especially  to  pulmonary  complaints,  than  men  of 
medium  height,  and  they  become  fatigued  more  early  on  the  march  and 
under  all  circumstances  where  endurance  is  of  the  first  necessity. 
Their  muscles  are  longer,  possess  less  fasciculi,  and  work  longer  levers 
than  those  of  the  short  men.  They  also  offer  a  better  target  for  the 
enemy.  On  the  other  hand,  very  short  men  are  quite  as  objectionable 
as  their  over-tall  comrades.  During  the  Civil  AVar,  the  smallest  men 
enlisted  broke  down,  as  a  rule,  after  but  a  few  weeks'  service  in  the 
field.  There  are,  of  course,  exceptionally  short  men  who  are  unusually 
muscular,  but,  as  a  class,  they  are  wanting  in  strength. 

Weight. — In  this  country,  there  is  no  minimum  weight  for  the 
cavalry,  ''  in  which  enlistments  may  be  made  without  regard  to  a  min- 
imum, provided  the  chest  measurement  and  chest  mobility  are  satis- 
factory." The  maximum  for  this  branch  is  165.  In  all  other  branches, 
the  minimum  and  maximum  are  respectively  128  and  190,  but  a 
recruit,  exceptionally  good  in  all  other  respects,  may  be  accepted  in  any 
branch  at  120. 

Examination  of  the  Recruit. — The  first  step  in  the  examination  of 
a  recruit  is  thorough  washing  with  soap  and  water.  "  It  is  not  believed 
to  be  good  policy  to  enlist  men  who,  though  able-bodied  and  intelligent, 
appear  at  recruiting  stations  in  ragged  or  filthy  dress,  as  the  chances 
are  such  men  are  tramps  and  vagabonds  and  will  not  make  good 
soldiers.  Men  who,  though  attired  in  clean  and  respectable  clothing, 
are  found  to  be  filthy  in  their  persons,  should  be  promptly  rejected  for 
like  reason."^  He  is  then  presented  to  the  examining  officer  without 
clothing,  in  a  well-lighted  room  large  enough  for  exercise  in  walking, 
running,  and  jumping.  Here,  he  is  subjected  to  a  searching  physical 
examination,  and  each  deviation  from  the  normal  standard  is  noted. 
In  addition,  his  family  and  personal  history  are  obtained  of  the  appli- 
cant, whose  replies  to  the  prescribed  questions  are  recorded  with  such 
other  information  as  bears  on  his  fitness  for  the  duties  of  a  soldier. 
This  inquiry  is  made  before  the  physical  examination  is  begun. 

The  examination  is  very  thorough,  and  includes  the  mental  condition, 
the  senses,  the  principal  organs  of  the  body,  the  general  formation,  the 
chest  capacity,  the  condition  of  the  teeth,  skin,  joints,  and  feet,  and  the 
presence  or  absence  of  hernia,  varicocele,  and  other  disqualifications. 

The  leading  characteristics  of  a  good  constitution,  as  enumerated  by 
1  Manual  for  the  Medical  Department,  Washington,  1898,  p.  65. 


THE  RECRUIT. 


573 


Dr.  C.  S.  Tripler,  U.  S.  A.,  are  as  follows:  "  A  tolerably  just  propor- 
tion between  the  different  parts  of  tJie  trunk  and  members,  a  well- 
shaped  head,  thick  hair,  a  countenance  expressive  of  health,  with  a 
lively  eye,  skin  not  too  white,  lips  red,  teeth  white  and  in  good  condi- 
tion, voice  strong,  skin  firm,  chest  well  formed,  belly  lank,  parts  of 
generation  well  developed,  limbs  muscular,  feet  arched  and  of  moderate 
length,  hands  large.  The  gait  should  be  sprightly  and  springy,  speech 
prompt  and  clear,  and  manner  cheerful.  All  lank,  slight,  puny  men, 
with  contracted  figures,  whose  development  is,  as  it  were,  arrested, 
should  be  set  aside.  The  reverse  of  the  characteristics  of  a  good  con- 
stitution will  indicate  infirm  health  or  a  weakly  habit  of  body  :  loose, 
flabby,  white  skin ;  long,  cylindrical  neck ;  long,  flat  feet ;  very  fair 
complexion  ;  fine  hair  ;  wan,  sallow  countenance." 

On  being  accepted,  the  recruit  must  be  vaccinated  immediately,  unless 
there  is  unmistakable  evidence  of  successful  vaccination  within  a  rea- 
sonable period. 

Chest  Capacity. — The  determination  of  chest  capacity  is  of  great 
value  and  importance,  since  it  furnishes  an  index  of  the  vigor  of  the 
candidate.  The  factors  employed  are  the  chest  measurements  and 
extent  of  mobility.  The  chest  girth  is  measured  by  means  of  a  tape- 
measure  passed  round  on  a  line  including  the  lower  portions  of  the 
scapulae  and  on  a  level  with  or  just  below  the  nipples.  It  is  taken  at 
forced  inspiration  and  forced  expiration,  and  the  difference  in  the  two 
measurements  represents  the  chest  mobility,  which  is  one  of  the  best 
indications  of  capacity  for  endurance,  and  is  of  much  greater  value  than 
the  actual  maximum  and  minimum  circumferences,  since  a  very  large 
chest  may  have  less  mobility  than  one  considerably  smaller.  For  men 
under  5  feet  7  inches,  the  mobility  should  be  not  less  than  2  inches ; 
between  that  height  and  6  feet,  not  less  than  2.5  inches ;  6  feet  and 
above,  not  less  than  3  inches. 

Chest  girth,  weight,  and  height  are  very  closely  correlated  in  the 
growth  and  development  of  a  healthy  man,  and  these  proportions 
should  be  carefully  observed.  The  following  table  of  physical  propor- 
tions is  taken  from  the  Manual  for  the  Medical  Department : 


Height. 

Weight. 

Chest  measurement. 

Feet. 

Inches. 

Pounds. 

At  expiration. 
Inches. 

Mobility. 
Inches. 

Hi 

64 

128 

32 

2 

Hi 

65 

130 

32 

2 

Hi 

66 

132 

32^ 

2 

H,. 

67 

134 

33 

2 

5A 

68 

141 

33i 

2^ 

5A 

69 

148 

33i 

2i 

Srf 

70 

155 

34 

2^ 

5xi 

71 

162 

34| 

n 

6 

72 

169 

34f 

3 

6A 

73 

176 

35i 

3 

"It  is  not  necessary  that  the  applicant  should  conform  exactly  to  the 
figures  indicated  above,  a  variation  of  a  few  pounds  from  either  side  of 


574  MILITARY  HYGIENE. 

the  standard  in  the  minimum  and  maximum  weights  and  of  a  fraction 
of  an  inch  in  chest  measurement  being  permissible  if  the  applicant  is 
otherwise  in  good  health  and  desirable  as  a  recruit.  The  table  is  given 
to  show  what  is  regarded  as  a  fair  proportion,  but  the  weight  must  be 
at  least  125  pounds,  except  for  cavalry,  or  when  less  is  especially- 
authorized  by  the  Adjutant-General." 

It  will  be  observed  that  up  to  5  feet  7  inches,  the  normal  weight  is 
taken  to  be  2  pounds  to  the  inch,  and  for  each  inch  above  that 
height,  7  pounds  are  added,  and  that  the  chest  girth  at  expiration  is, 
for  all  heights  above  the  minimum,  just  below  half  the  height. 

Grounds  for  Rejection. — The  most  frequent  single  cause  for  rejection  is 
defective  development;  during  1898,  more  than  a  fourth  of  the  rejec- 
tions of  candidates  for  the  regular  army  were  made  on  this  ground. 
Second  in  order  was  defective  vision  ;  third,  diseases  of  the  circulation. 
Such  is  the  order  Avhich  commonly  obtains  also  in  the  British  army. 
Other  causes,  in  order,  were  diseases  of  the  genito-urinary  organs, 
diseases  of  the  digestive  apparatus,  bad  character,  general  uniitness, 
deafness,  and  illiteracy.  Men  of  defective  development,  if  admitted, 
are  noted  for  the  time  which  they  spend  in  the  hospital  and  in  the 
guard-house.  During  the  early  part  of  the  Civil  War,  thousands  of 
physically  inefficient  men  were  allowed  to  enter  the  army,  only  to  be 
discharged  after  a  few  weeks'  service,  most  of  which  was  passed  in  the 
hospitals.  Another  element  which  it  is  most  important  to  exclude  is 
the  habitually  intemperate.  As  Dr.  Tripler  has  said,  "First  in  a 
mutiny  and  last  in  a  battle,  the  intemperate  soldier  is  at  once  an 
example  of  insubordination  and  a  nuisance  to  his  comrades." 

Inasmuch  as  the  ability  to  march  is  one  of  the  prime  qualifications 
of  a  soldier,  particular  attention  is  paid  to  the  condition  of  the  legs, 
ankles,  and  feet.  The  existence  of  enlarged  veins  of  the  ankle  or 
thigh  or  back  of  the  knee  is  sufficient  cause  for  rejection.  Large  or 
recent  bunions,  and  corns  on  the  sole,  flatfoot,  and  "  hammer-toe  "  are 
disqualifications.  Foetid  perspiration  of  the  feet  is  an  intolerable 
nuisance  to  others  in  close  association,  and  is  sufficient  ground  for 
exclusion. 

The  loss  of  many  teeth  or  a  condition  of  general  decay  indicates,  as 
a  rule,  a  lack  of  stamina.  Moreover,  the  soldier  in  the  field  needs  good 
teeth  to  chew  his  hard  biscuit  and  not  always  tender  meat.  An  insuffi- 
cient number  of  opposed  molars  to  insure  proper  mastication  is  suf- 
ficient ground  for  rejection.  In  1898,  in  England,  of  66,501  recruits 
for  regular  service,  1,767,  or  nearly  1  in  38,  were  rejected  on  account 
of  bad  teeth  alone  ;  but  this  figure  gives  no  indication  of  the  proportion 
of  candidates  who  might  have  been  rejected  on  that  ground,  since  many 
were  summarily  rejected  on  other  grounds  without  examination  of  the 
teeth. 

Defective  hearing,  that  is,  inability  to  distinguish  ordinary  conversa- 
tion with  either  ear  at  50  feet,  is  a  disqualification,  smce  orders  may  be 
either  not  heard  at  all  or  misunderstood. 


THE  HYGIENE  OF  THE  SOLDIER.  575 

THE  HYGIENE  OF  THE  SOLDIER. 

Personal  cleanliness  is  of  great  importance  in  the  maintenance  of 
health  and  efficiency,  and  should  be  the  subject  of  much  attention  on 
the  part  of  inspecting  officers.  General  bathing  can  hardly  be  expected 
in  a  large  camp  in  the  winter  months,  or  at  any  time  when  water 
is  scarce ;  but  whatever  the  season,  a  small  amount  of  water,  a  quart 
or  so,  applied  with  a  wash-rag  or  sponge,  and  with  soap,  should  be 
sufficient  for  a  decent  degree  of  cleanliness.  In  the  warmer  months, 
where  water  is  plenty,  full  baths  and  swimming  should  be  encouraged. 
During  prolonged  campaigns  with  limited  opportunities  for  keeping  the 
person  and  clothing  clean,  many  men  are  disabled  by  chafing  and  ul- 
cerations, following  irritation  of  the  skin  by  perspiration,  dust  and  dirt, 
and  contact  with  unwashed,  hardened  underclothes.  Body  lice  always 
make  their  appearance,  and  add  much  to  the  discomfort,  which  is  only 
temporarily  relieved,  but  eventually  augmented,  by  scratching  with  the 
nails.  Infested,  dirty  men  convey  the  evil  by  contiguity  to  their  cleaner 
associates,  who  then  suffer  not  only  in  body  but  in  mind,  filled  with 
disgust  and  loathing,  and  longing  to  return  to  civil  life. 

Contentment  and  cheerfulness  are  very  essential  to  the  well-being 
of  an  army  ;  discontent  and  ennui  undermine  health  and  discipline  and, 
consequently,  efficiency.  In  the  continental  armies,  ennui,  leading  to 
homesickness,  is  believed  to  be  a  prime  cause  of  the  large  number  of 
suicides  and  cases  of  insanity.  This  is  more  marked  with  the  infantry, 
which  branch  requires  less  time  devoted  to  work.  In  all  armies,  it 
is  recognized  as  leading  to  excessive  use  of  tobacco  and  liquor,  and  to 
all  manner  of  bad  habits.  On  the  march  and  in  time  of  general  ac- 
tivity, the  mind  is  stimulated  and  needs  no  special  diversion ;  but  after 
a  camp  has  been  permanently  established,  and  the  men  have  settled  down 
to  the  routine  of  camp  life,  they  begin  to  fret,  and  soon  seek  solace 
in  tobacco,  alcohol,  and  gambling,  and  not  infrequently  in  perversions 
of  the  generative  function.  Gambling  is  not  only  an  unhealthy  excite- 
ment, but  engenders  serious  quarrels,  bitterness  and  disappointment, 
and  is  commonly  carried  on  in  crowded  quarters  and  foul  air. 

The  ability  to  keep  troops  in  camps  contented  is  regarded  as  one  of 
the  strongest  evidences  of  capacity  for  command  and  administration. 
To  keep  men  occupied  is  not  sufficient ;  the  occupation  should  not  be 
wholly  routine  drilling  and  marching,  but  interesting  and  pleasant  work 
of  other  kinds,  and  entertainments  largely  of  an  amusing  nature.  Extra 
drills,  known  to  the  men  to  be  unnecessary,  and  carried  out  only  to  keep 
them  busy,  do  not  relieve  the  situation,  but  add  to  the  difficulty.  The 
establishment  of  reading-rooms  and  opportunities  for  following  mechan- 
ical trades  are  of  much  service.  All  men  of  experience  testify  to  the 
great  value  of  athletic  sports,  competitive  target  shooting,  gardening 
for  ])]easure  and  profit,  vocal  and  instrumental  concerts,  vaudeville  and 
minstrel  shows,  theatricals,  and,  in  fiict,  anything  which  will  offer  a 
change  from  the  hum-drum  of  life.  Very  little  things  suffice  to  break 
the  monotony  of  life  in  camps,  just  as  in  the  country  and  at  summer 


576  MILITARY  HYGIENE. 

hotels,  where  the  arrival  of  the  train  or  stage,  or  the  passing  of  a 
strange  carriage,  is  an  event  calling  forth  the  deepest  interest,  and  a 
new  arrival  a  genuine  excitement. 

Clothing  of  the  Soldier. 

Since  the  primary  object  of  clothing  is  the  conserving  of  body  heat 
in  cold  weather  and  protection  from  the  direct  heat  of  the  sun,  it  is 
essential  that  that  worn  in  any  one  kind  of  climate  should  be  adapted 
to  the  necessities  of  that  particular  climate.  It  is  obvious  that  the 
same  uniform  cannot  be  used  in  the  Northwest  and  in  the  West  Indies 
and  the  Philippine  Islands,  where  the  blue  uniform,  ordinarily  used  in 
our  army,  has  been  universally  condemned  on  account  of  its  weight. 
Therefore,  the  material  should  vary  according  to  the  nature  and  place 
of  service.  In  choosing  material  for  uniforms,  the  chief  points  to  be 
borne  in  mind  are  the  properties  of  heat  conduction  and  heat  absorp- 
tion, permeability,  and  durability. 

Wool  is  a  poor  conductor,  and  is  not  easily  penetrated  by  cold 
winds  ;  therefore,  it  is  very  suitable  for  cold  climates,  but  is  likely 
to  be  oppressive  in  the  tropics.  It  absorbs  water  freely,  being  very 
hygroscopic,  and  thus  it  absorbs  the  perspiration  and  prevents  it 
from  evaporating  directly  from  the  surface  of  the  skin  and  causing 
thereby  loss  of  heat.  The  chief  disadvantage  of  wool  is  the  diffi- 
culty with  which  it  is  properly  washed.  When  improperly  washed, 
the  fiber  shrinks  rapidly,  and  the  fabric  becomes  smaller  and  much  less 
soft  and  absorbent.  During  washing,  woollen  materials  should  never 
be  rubbed  or  wrung.  They  should  be  placed  in  water  containing  a 
proper  amount  of  soap  in  solution,  and  moved  about  freely,  well  i-insed 
in  water  containing  no  soap,  and  hung  up  to  dry  without  wringing. 
The  soap  used  should  be  of  good  quality,  as  free  as  possible  from 
excess  of  alkali,  which  injures  the  woollen  by  acting  upon  the  natural 
fat  of  the  wool,  which  is  largely  cholesterin. 

Cotton  and  Linen. — Both  these  articles  are  good  heat  conductors, 
but  are  non-absorbent  of  moisture.  Both  soak  up  moisture  from  the 
skin,  and  evaporation  of  this  requires  so  much  heat  as  sometimes  to 
cause  chilling  of  the  body.  Both  are  durable,  and  neither,  particularly 
cotton,  need  be  very  expensive.  For  underclothing,  both  are  much 
inferior  to  wool,  which,  being  a  poor  heat  conductor  and  a  good  absorb- 
ent of  moisture,  prevents  rapid  cooling  of  the  body  when  it  is  in  a  con- 
dition of  active  perspiration  after  physical  exercise.  It  is  far  more 
permeable,  also,  to  air,  which  it  holds  in  the  spaces  between  the  fibers, 
and  which  adds  to  its  property  of  non-conduction. 

Light  woollen  underclothing,  therefore,  is  preferable  to  either  cotton 
or  linen.  A  very  good  material  is  what  is  commonly  known  as  merino, 
a  mixture  of  woollen  and  cotton,  in  which  the  cotton  constitutes  about 
a  third.  This  combines,  in  a  way,  the  advantages  of  both  materials, 
and  is  a  much  more  washable  fabric  than  pure  woollen. 

Shoddy  is  a  very  inferior  material,  made  of  the  fiber  of  old,  used 


CLOTH  IN  O    OF  THE  SOLDIER.  577 

woollen  goods,  mixed  with  fresh  wool,  with  which  it  is  woven.  The 
manufacturers  do  not  introduce  any  more  fresh  wool  than  is  absolutely 
necessary. 

Color. — ^^The  color  of  clothing  has  an  important  bearing,  both  phys- 
iologically and  from  a  military  point  of  view.  Color  influences  the 
absorption  of  heat  more  than  the  nature  of  the  material  itself.  AVhite 
materials  absorb  least  and  black  the  most  heat.  The  difference  in  ab- 
sorptive power  of  diiferent  colors  is  shown  in  a  marked  degree  by  the 
fact  that  white  cotton  over  a  black  surface  will  reduce  the  temperature 
in  the  sun  more  than  10  degrees  F.  Gray  stands  next  to  white,  and 
blue  next  to  black. 

From  a  military  point  of  view,  color  is  important,  since  different 
colors  vary  in  their  conspicuousness,  and,  therefore,  strategically,  the 
one  which  stands  forth  the  least  in  the  landscape  is  the  best.  The 
most  conspicuous  color  is  red,  next  white,  then  black  and  other  dark 
shades,  light  blue  and  light  brown  and  gray ;  but,  naturally,  much  de- 
pends on  the  background  :  thus,  green  would  be  inconspicuous  against 
grass  and  other  green  vegetation,  but  would  show  very  distinctly 
against  bare  soil,  whereas  the  light  brown  of  the  ordinary  khaki  is 
the  least  conspicuous  in  the  latter  position.  Color  also  influences  the 
absorption  of  odors  by  materials  in  practically  the  same  order  in  which 
it  influences  the  absorption  of  heat ;  that  is,  black  and  the  dark  shades 
are  most  absorbent,  and  white  the  least. 

Military  dress  coats  are  usually  closely  fitting,  warm  and  oppres- 
sive, and  interfere  with  proper  expansion  of  the  chest,  through  tight- 
ness. In  active  service  in  the  field,  they  are  not  worn.  Undress  coats 
are  usually  loose,  and  are  far  more  comfortable  and  adapted  to  muscu- 
lar effort.  The  khaki  suits,  worn  by  our  troops  in  the  tropics,  are  stiff 
and  heavy  at  first,  but  become  softer  and  more  pliable  with  repeated 
washing.     They  are  sufficiently  loose  for  all  purposes  of  comfort. 

Trousers  are  made  sufficiently  roomy  in  the  seat,  and  reasonably 
tight  about  the  waist,  with  an  inner  belt,  as  no  suspenders  are  worn. 
The  bottoms  are  cut  narrow  rather  than  with  a  "  spring." 

Gaiters  and  leggings  are  used  for  protecting  the  ankles  and  legs 
from  dust  and  mud.  They  are  made  of  brown  cotton  duck  with  lacings, 
and  commonly  are  not  well-fitting.  When  lined,  as  they  sometimes 
are,  with  thin  leather,  they  are  likely  to  be  uncomfortably  hot.  The 
puttee  is  made  of  a  soft  kind  of  cloth,  in  a  strip  4  inches  wide  and 
6  or  7  feet  long.  To  one  end,  about  2  feet  of  strong  tape  are 
fastened.  In  applying  the  puttee,  it  is  rolled  up  with  the  tape  in  the 
center  of  the  roll.  Two  turns  are  wound  over  the  top  part  of  the 
ankle-boot  and  it  is  then  wound  spirally  up  the  leg  to  a  point  below 
the  knee,  and  the  tape  at  the  end  is  then  continued  spirally  over  the 
whole  and  fastened  at  the  end.  It  is  found  to  be  more  comfortable 
and  more  pliable  than  leggings,  and  does  not  blister  the  heels,  which 
leggings  sometimes  do. 

Head  Covering. — The  head  covering  is  a  very  important  article  in 
the  dress  of  a  soldier.  It  should  protect  against  cold,  heat,  rain,  and 
:'.7 


578  MILITARY  HYGIENE. 

the  burning  sun.  It  should  be  light,  durable,  and  comfortable,  not  too 
closely  fitting  nor  pressing  unduly  anywhere.  Leather  helmets,  worn 
in  some  armies  abroad,  and  felt  helmets  formerly  used  in  ours,  are  hot, 
heavy,  and  oppressive.  The  ordinary  white  helmet  is  conspicuous,  but 
comfortable  in  the  sun.  The  ordinary  forage  cap  is  flexible  and  ser- 
viceable, but  is  not  sufficiently  ventilated  for  hot-weather  use.  The 
campaign  hat  of  drab  felt  with  broad  bi'im  and  high  crown  has  been 
found  to  fill  most  of  the  requirements  in  the  field.  In  Cuba  and  in 
our  new  possessions,  it  was  found  at  first  to  be  too  heavy,  but  experi- 
ence, especiaMy  during  the  rainy  season,  has  shown  that  it  has  advan- 
tages not  possessed  by  any  other  form  of  head  covering. 

In  foreign  armies,  unnecessarily  heavy  helmets  and  other  head  cov- 
erings are  used  largely  for  purposes  of  display,  but  to  a  certain  extent 
also  as  a  protection  against  mechanical  injury.  In  the  matter  of  dis- 
play, there  can  be  no  question  that  many  of  them  fulfil  their  object 
admirably  ;  but  as  a  means  of  defence,  helmets  of  heavy  leather  and 
metal,  weighing  from  three  to  four  pounds  and  more,  would  hardly  seem 
to  secure  such  an  amount  of  protection, as  to  compensate  for  the  great 
discomfort  and  the  waste  of  energy  which  their  use  entails.  In  hot 
climates,  helmets  of  bamboo,  provided  with  puggeries,  are  very  largely 
used,  being  light  and  affording  good  protection  from  the  sun. 

Stockings. — Concerning  stockings,  a  great  divergence  of  opinion 
exists.  Woollen  stockings  frequently  cause  the  feet  to  perspire,  even 
in  cold  weather  ;  but  they  are  much  warmer,  and  hence  more  conducive 
to  comfort  than  cotton  at  that  time.  Cotton  is  naturally  more  com- 
fortable in  summer,  and,  to  many  people,  also  in  winter.  In  our  army, 
both  kinds  are  issued.  Many  regard  thick  woollen  stockings  as  the 
best  for  walking,  in  all  climates,  and  as  a  protection  against  foot-sore- 
ness ;  yet  it  is  probable  that  many  cases  of  sore  feet  are  brought  about 
by  the  excessive  perspiration  induced  by  them.  Perhaps  a  happy 
mean  is  a  thin  woollen  stocking  or  one  of  fine  merino.  It  is  impor- 
tant that  the  stocking  should  fit  the  foot  properly,  for  an  ill-fitting 
stocking,  particularly  one  too  long  in  the  foot  or  too  broad,  gives  rise 
to  folds  which  cause  excoriations  and  blisters. 

Boots. — The  value  of  well-fitting  comfortable  boots,  permitting 
unobstructed  action  of  the  muscles  and  joints  and  free  circulation 
of  blood  when  walking  for  pleasure  and  exercise,  is  too  well  known 
to  need  extensive  discussion.  To  the  soldier,  the  importance  of  good 
boots  is  still  greater,  since,  as  has  been  said,  an  efficient  army  is  one 
that  can  march  well ;  and  soldiers  cannot  march  with  crippled  feet. 
INIoreover,  it  happens  frequently  in  time  of  war,  that  in  an  emergency 
which  makes  a  man  dependent  upon  his  walking  power  for  his  own 
life  and  liberty  or  for  the  proper  carrying  out  of  his  order,  a  good  boot 
is  his  best  friend. 

The  sole  should  be  thick  and  generously  broad,  so  as  to  project  all 
round  beyond  the  upper,  but  should  not  be  too  heavy.  The  heel 
should  be  broad,  low,  and  flat.  The  boot  should  be  square  at  the  toe 
or  slightly  rounded  on  the  outer  side  in  accordance  with  the  natural 


CLOTHING   OF  THE  SOLDIEA  579 

outline  of  the  foot,  so  as  to  allow  the  toes  full  play  in  walking.  When 
placed  side  by  side,  the  inner  margins  of  each  should  nearly  touch 
throughout  the  whole  length  from  the  end  of  the  toe  to  the  ball  of  the 
foot.  The  inside  should  nowhere  have  rough  inner  seams  or  projec- 
tions, which  may  cause  chafing  and  blistering.  If  treated  to  a  liberal 
amount  of  oil  or  grease  at  frequent  intervals,  the  leather  will  be  made 
more  supple  and  at  the  same  time  more  impervious  to  water.  A  prep- 
aration, recommended  by  the  late  Professor  Parkes,  consists  of  a  mixt- 
ure of  a  half  pound  of  shoemaker's  dubbing  in  a  half  pint  each  of 
linseed  oil  and  of  a  solution  of  India-rubber.  Solution  is  effected  by 
gentle  heat,  which  should  not  be  applied  by  naked  flame,  since  the 
India-rubber  solution,  containing  naphtha  or  ether,  is  exceedingly 
inflammable.  This  preparation  is  well  rubbed  into  the  leather  and 
renewed  at  intervals  of  three  months.  This  is  said  to  be  the  best 
water-proofing  material  for  leather. 

Cavalry  boots  with  long  legs  are  not  suited  to  walking,  as  they  are 
likely  to  produce  chafing.  On  account  of  the  disadvantages  attending 
their  use  on  dismounted  duty,  they  have,  since  1902,  been  given  up  in 
all  branches  of  the  United  States  army. 

Underclothing. — Undershirts  should  be  of  woollen  or,  better,  of 
merino,  since  pure  woollen  is  unbearable  by  many  and  because  of 
the  rapid  deterioration  which  follows  improper  washing.  The  woollen 
undershirts  issued  at  first  to  the  troops  in  Cuba  and  the  Philippines 
were  complained  of  as  causing  much  irritation  of  the  skin  from  prickly 
heat.  In  the  tropics,  a  light  weight  woollen  undershirt  is  of  the  high- 
est importance  in  the  prevention  of  body  chilling  from  evaporation  of 
perspiration.  Half  cotton  and  half  woollen  or  two-thirds  cotton  and 
one-third  woollen  are  highly  recommended  as  advantageous  combina- 
tions. 

The  ordinary  shirt  of  the  soldier  is  made  of  flannel,  with  a  collar 
and  breast  pockets.  It  is  made  fairly  full  and  is  very  comfortable. 
Woodhull  recommends  the  carrying  of  an  extra  shirt  for  wearing  next 
the  body,  the  two  being  worn  alternately.  "  At  the  close  of  the  day's 
work  the  worn  shirt  should  be  taken  off,  dried,  stretched,  well-beaten, 
and  hung  in  the  wind  and  sun.  This  should  be  done  even  when  there 
is  no  change."  Drawers,  stockings,  and  trousers  should  be  treated  in 
the  same  manner.  Drawers  are  necessary  for  cleanliness  and  warmth. 
They  are  made  of  the  same  material  as  undershirts.  In  many  of  the 
foreign  armies,  drawers  are  not  issued,  and  men  who  desire  them  are 
obliged  to  furnish  them  at  their  own  expense. 

Abdominal  Bands. — Abdominal  protectors,  either  in  the  form  of 
the  well-known  abdominal  band  or  of  small  flannel  aprons  to  be  worn 
next  the  skin  over  the  bowels,  are  regarded  as  very  essential  in  pre- 
venting bowel  trou])les,  which  so  commonly  appear  after  abrupt  changes 
in  tcin])erature ;  protectors  are  especially  valuable  in  the  tropics,  where 
diarrhrjeal  diseases  should  be  prevented  as  much  as  possible,  on  account 
of  their  possible  serious  and  fatal  results.  The  abdominal  band,  com- 
monly called  also  "  cholera  belt,"  encircles  the  whole  of  the  lower  part 


580  MILITARY  HYGIENE. 

of  the  body.  The  flannel  apron  protects  only  the  anterior  part,  and  is 
fastened  with  a  tape  around  the  waist. 

The  "  kummerbund "  is  much  preferred  by  many.  This  is  a  com- 
mon article  of  dress  among  the  natives  of  hot  Eastern  countries.  It 
is  a  broad  fold  of  cloth,  wound  tightly  five  or  six  times  about  the 
waist,  for  the  protection  of  the  lower  part  of  the  spine  from  the  sun's 
rays,  and  to  act  as  a  support  to  the  back  and  loins.  It  is  made  of 
silk  or  cotton,  or  a  mixture  of  the  two,  in  lengths  of  ten  to  fifteen 
feet  and  about  twelve  to  eighteen  inches  in  width.  To  put  it  on, 
one  needs  the  assistance  of  a  companion.  It  is  folded  once  length- 
wise, so  that  its  breadth  is  reduced  a  half  and  its  thickness  doubled, 
and  then,  while  stretched  taut,  one  end  is  placed  in  position  and  held 
there,  and  the  person  turns  the  body  round  rapidly  until  the  full 
length  is  wound  off,  when  the  end  is  carefully  fastened,  so  that  it  may 
not  work  loose. 

These  protectives  of  the  abdomen  prevent  the  evaporation  of  per- 
spiration and  chilling  of  the  abdomen ;  without  them,  diarrhoea  is 
likely  to  be  induced  by  slight  causes. 

Water-proof  blankets  of  rubber  or  other  material  are  very  im- 
portant as  a  protection  against  rain  or  soil  moisture.  When  obliged 
to  lie  on  damp  ground,  they  are  a  great  protection.  In  the  tropics, 
at  certain  seasons,  the  rainfall  is  exceedingly  heavy  and  makes  the 
use  of  some  form  of  water-proof  overcoat  necessary  ;  but  since  these 
are  very  hot,  it  is  important  to  obtain  them  of  as  light  a  material  as 
possible  without  sacrificing  lightness  to  durability.  India-rubber 
itself  cannot  be  worn  habitually  or  for  a  long  time,  because  of  its 
causing  great  discomfort  through  retention  of  heat  and  perspiration. 
It  is  of  much  more  value  in  the  form  of  a  blanket  to  spread  on  the 
ground  than  as  an  article  of  clothing.  Cloth  may  be  made  water- 
proof by  alternate  dipping  into  solutions  of  aluminum  sulpliate  and 
soap,  or  by  thorough  soaking  in  raw  linseed  oil  and  exposing  to  the 
sun  until  thoroughly  dry. 

Other  articles  issued  during  very  cold  weather  for  extra  warmth 
include  hoods,  gloves,  overshoes,  and  overcoats.  The  overcoats  are 
uulined. 

The  Soldier's  Exercise  and  Work. 

Marching. — Since  the  most  efficient  army  is  that  which  has  the 
greatest  capacity  to  endure  hardship,  it  follows  that  such  an  army  can 
do  the  longest  and  best  marching.  While  the  civilian  may  regard 
daily  walks  of  ten,  fifteen,  twenty,  and  more  miles  as  no  great  strain 
on  the  system,  the  first-mentioned  figure  is  accounted  good  average 
travelling  for  soldiers  on  a  long  march,  and  the  second  for  short 
movements  ;  but  either  of  these  figures  may  represent  exceedingly 
good  work  by  the  best  of  men  in  some  climates  and  seasons  and  over 
some  roads,  or  by  raw  recruits  in  their  first  marches  over  the  best  of 
roads.     This  is  not  for  a  moment  to  be  looked  upon  as  evidence  of 


THE  SOLDIER'S  EXERCISE  AND    WORK.  581 

the  civilian's  superiority  over  the  soldier  as  a  walker,  for  the  two  per- 
form the  exercise  under  very  different  conditions. 

The  civilian,  in  the  first  place,  walks  alone  or  with  a  companion 
or  two,  at  his  own  gait  and  according  to  his  own  will.  He  may  vary 
his  step  and  may  rest  at  his  pleasure  ;  he  carries  no  greater  burden  than 
a  walking  stick,  and  may  suit  himself  in  the  matter  of  dress  and  in  the 
manner  of  wearing  it.  The  soldier,  on  the  contrary,  is  one  of  a  large 
body  proceeding  somewhat  stiffly  at  a  pace  set  by  one  in  command 
and  not  alterable  at  will.  He  carries  his  arms,  accoutrements,  and  all 
his  belongings,  and,  perhaps,  his  rations  for  a  number  of  days,  and  is 
hampered  by  straps  and  clothing  which  interfere  with  free  circulation. 
He  rests  when  ordered,  may  be  halted,  without  resting,  with  annoying 
frequency,  and  may  "  march  at  ease  "  only  when,  in  the  judgment  of 
the  commanding  officers,  this  is  practicable.  At  one  time,  he  is  moving 
with  exasperating  slowness  on  account  of  obstacles  ahead,  and  again,  is 
hurrying  to  catch  up  with  those  gone  before.  Moreover,  his  marching 
ground  is  chosen  for  him,  and  his  miles  are  either  through  dust  or 
mud,  for  a  soil  so  damp  as  to  give  ofP  no  dust  is  speedily  converted  to 
mud  by  the  impress  of  many  feet.  Therefore  it  is,  that  the  soldier's  10 
miles  represents  much  more  physical  exertion  than  the  civilian's  20, 
and  his  15  miles  much  more,  all  things  considered,  than  50  per  cent, 
increase  over  his  10.  Forced  marches  of  25  miles  and  longer  are 
very  exhausting,  and  cannot  be  kept  up  for  more  than  a  very  short 
time. 

One  of  the  most  notable  instances  of  long  distance  marching  in  a  few 
hours  in  recent  times  is  that  of  the  City  of  London  Imperial  Volun- 
teers who,  in  South  Africa,  in  August,  1900,  covered  30  miles  in  10 
hours  hoping,  according  to  a  despatch  of  Lord  Roberts,  to  prevent 
General  DeWet  from  crossing  the  Krugersdorp-Potchefstroom  railway. 
The  celebrated  march  of  Lord  Roberts  from  Kabul  to  Kandahar,  in 
1880,  over  very  rough  country,  was  performed  in  23  days.  The  long- 
est day's  marches  were  20  and  21  miles,  and  the  average  distance  cov- 
ered was  nearly  17  miles. 

Among  the  best  known  long  marches  are  several  by  United  States 
troops,  who  hold  the  record  for  long  distance  continuous  marching. 
In  1859,  for  example,  a  regiment  of  infantry  marched  from  Fort 
Leavenworth,  Kansas,  to  a  point  in  California,  a  distance  of  1,800 
miles  in  190  days,  28  of  which  were  given  up  to  resting,  so  that  in 
162  days  of  actual  marching,  an  average  distance  of  a  little  more  than 
11  miles  was  traversed.  In  1860,  a  portion  of  another  regiment  went 
from  Camp  Floyd,  Utah,  to  Fort  Buchanan,  New  Mexico,  a  distance 
of  1,000  miles  in  140  days. 

In  the  Franco-Prussian  War  of  1870,  a  company  of  French  chas- 
seurs marched,  in  very  inclement  weather,  over  an  exceedingly  difficult 
road,  for  41  hours,  with  one  rest  of  an  hour,  another  of  two  and  a  half 
hours,  and  halts  of  8  minutes  in  each  of  the  marching  hours.  The 
exact  distance  marched  is  not  known,  1)iit  the  instance  is  cited  as  one 
of  exceptional  endurance  and  hardship. 


582  MILITARY  HYGIENE. 

In  oivr  army,  ordinary  and  quick  marching  call  respectively  for  90 
and  120  steps  of  30  inches  each  per  minute,  or  slightly  over  2.5  and 
3.4  miles  per  honr.  Double  time,  which  is  quickly  exhausting,  calls 
for  180  steps  of  35  inches  each  per  minute,  the  equivalent  of  nearly  6 
miles  per  hour ;  it  can  be  sustained  for  not  longer  than  2  miles  by 
more  than  average  good  troops.  With  the  weight  carried,  30  inches 
per  step  is  quite  sufficient.  In  the  French  army,  2.5  miles  per  hour 
are  considered  good  average  marching,  beginning  with  120  steps  per 
minute,  increasing  gradually  to  125  and  135,  and  returning  during 
the  second  half  hour  to  the  original  rate.  The  English  quick-step  is 
the  same  as  ours  ;  the  "  double  quick  "  is  less  than  ours  in  length  and 
frequency — 33  inches,  175  to  the  minute.  The  German  step  is  between 
31  and  32  inches,  and  114  to  the  minute;  the  Austrian  and  Italian, 
29  inches,  120  to  the  minute;  the  Russian,  28  inches,  120  to  the 
minute.  From  the  above,  it  will  be  observed  that  in  none  of  the 
great  armies  of  the  world  is  the  marching  rate  equal  to  that  of  the 
active  civilian  when  out  for  an  exercise  walk. 

Every  soldier  is  obliged  to  carry,  besides  his  arms  and  accoutre- 
ments, certain  necessary  articles,  the  aggregate  Aveight  of  which  is 
variable,  but  always  considerable.  In  the  carrying  of  this  weight, 
great  care  is  necessary  feo  to  dispose  it  that  it  shall  not  be  over-burden- 
some or  detract  from  his  efficiency.  In  all  services,  the  reduction  to  a 
minimum  of  the  weight  to  be  carried  is  a  matter  of  great  importance, 
but  the  disposition  of  the  weight  is,  perhaps,  of  greater  importance,  for 
considerable  harm, may  be  induced  by  interference  with  respiration  and 
circulation  by  pressure  from  the  necessary  straps  across  the  chest  and 
under  the  arm-pits.  Under  flivorable  circumstances,  his  impedimenta, 
with  the  exception  of  arms  and  canteen,  may  be  transported  for  him, 
the  result  being  not  only  greater  covering  of  ground  with  less  strain, 
but  great  conservation  of  efficiency.  In  adjusting  weight,  care  should 
be  taken  to  avoid  compression  of  the  chest  as  much  as  possible  and  to 
equalize  the  distribution  so  as  to  avoid  fatiguing  any  one  set  of  mus- 
cles unduly. 

The  German  infantry  soldier  is  more  heavily  equipped  than  the  Brit- 
ish or  American,  the  total  load  exceeding  70  pounds,  of  which  his 
clothing,  exclusive  of  the  heavy  polished  leather  hemlet,  accounts  for 
nearly  24  pounds,  and  his  arms  and  equipments,  filled  water-bottle, 
and  entrenching  tools  nearly  43  pounds,  the  remainder  being  rations 
and  sundries.  His  kit  is  carried  in  a  leather  knapsack,  around  which 
his  rolled  overcoat  is  fastened,  and  to  the  back  of  which  his  camp  ket- 
tle is  strapped.  The  Russian  soldier  also  carries  more  than  70  pounds  ; 
the  Italian,  about  the  same ;  the  French,  between  65  and  70,  and  the 
Austrian,  about  60  pounds. 

The  blanket  bag,  which  was  substituted  for  the  knapsack  in  our  army 
in  1882  and  abandoned  after  twenty  years'  use,  is  more  oppressive 
than  the  blanket  roll ;  but  the  blanket  roll  is  also  oppressive,  since, 
being  carried  across  the  body  from  one  shoulder,  with  the  ends  tied 
together,  it  impedes  the  movements  of  the  chest.     Morever,  its  use 


THE  SOLDIER'S  EXERCISE  AND    WORK.  583 

involves  a  certain  degree  of  inconvenience,  since  when  the  blanket 
itself  is  in  use,  the  articles  contained  must  he  cared  for  in  some  other 
way.  Other  devices  to  take  the  place  of  blanket  rolls  and  knapsacks 
are  in  use,  and  meet  with  different  degrees  of  approval.  The  one  most 
highly  commended  neither  impedes  respiration  or  circulation,  nor  in- 
volves contact  with  the  back  and  consequent  shutting  out  access  of  air. 
The  weight  is  supported  chiefly  by  the  hips. 

With  new  levies,  the  first  marches  should  not  exceed  a  very  few 
miles,  the  distance  being  increased  gradually  day  by  day,  until  they 
become  well  seasoned,  with  occasional  days,  not  including  Sundays,  set 
apart  for  rest  and  recreation.  When  thoroughly  seasoned,  there  is  less 
friction,  and  with  greater  experience,  comes  increased  efficiency.  It 
takes  but  a  short  time  for  new  soldiers  to  learn  not  to  attempt  to  carry 
unnecessary  articles,  which,  at  first,  they  are  invariably  prone  to  look 
upon  as  essential  to  comfort  and  pleasure. 

Cavalry  and  infantry  should  march  separately  if  possible,  and  in  as 
open  order  as  practicable,  in  order  to  avoid  crowd-poisoning,  which  is 
a  consequence  not  alone  of  indoor  overcrowding,  but  also  of  close 
aggregation  of  men  in  the  open  air. 

If  possible,  marching  by  night  and  in  the  hottest  part  of  the  day 
should  be  avoided,  for  in  hot  weather  the  men  are  easily  exhausted  by 
exercise  in  the  blazing  sun,  and  since  they  can  get  no  sleep  during  the 
day,  they  need  the  night  hours  for  their  proper  rest.  The  early  morn- 
ing hours  are  the  best  for  marching,  as  for  other  forms  of  work,  the 
men  being  then  at  their  best ;  but  unless  absolutely  necessary,  their 
sleep  should  not  be  broken  before  the  usual  time,  since  what  is  thereby 
gained  in  distance  is  more  than  lost  through  the  interruption  of  neces- 
sary sleep.  Before  starting,  a  light  breakfast,  including  hot  coffee, 
should  be  taken. 

During  the  first  hour,  the  pace  should  be  fairly  slow,  and  when 
two  miles  have  been  covered,  there  should  be  a  halt  of  at  least  a 
quarter  of  an  hour,  during  which  the  men  should  attend  to  calls  of 
nature  and  throw  off"  their  loads  and  rest  at  full  length.  When  the 
march  is  resumed,  the  distance  to  be  covered  may  be  lengthened  by  a 
half  mile,  and  when  this  distance  has  been  traversed,  there  should  be 
another  halt  of  about  the  same  length  as  the  first.  After  this,  the  rate 
may  be  increased  to  three  miles  per  hour  with  a  halt  of  ten  minutes  in 
each  hour,  and  this  rate  is  sufficiently  fast,  except  for  forced  marches. 
The  halt  in  the  middle  of  the  day  for  dinner  should  be  of  several  hours' 
duration,  so  that  the  men  may  have  a  good  rest,  avoid  heavy  work 
directly  after  a  hearty  meal,  and  look  after  the  condition  of  their 
feet.  As  it  is  unsafe  to  eat  heartily  or  drink  copiously  while  greatly 
fatigiHid  or  overheated,  a  reasonable  interval  should  be  allowed  before 
dinner. 

Halts  due  to  accidental  circumstances  are  very  trying  to  patience 
and  strength,  and  when  their  probable  duration  can  be  determined,  this 
shf)uld  be  communicated  down  the  column,  in  order  that,  if  the  inter- 
v;d    is   to   }>c   of  sufficiently  long  duration,   the   men   may   have   the 


584  MILITARY  HYGIENE. 

advantage  of  resting,  rather  than  stand  with  their  arras,  losing  patience 
and  temper.  Since,  also,  irregular  rate  of  moveraent  is  fatiguing  and 
annoying,  minor  obstacles,  such  as  mud  and  water,  should  not  be 
allowed  to  interfere  with  regular  progress.  Music  of  all  kinds  is  very 
invigorating  to  marching  men ;  band  music,  fife  and  drum,  the  drum 
alone,  and  singing.  In  the  continental  armies,  singing  is  much 
encouraged,  as  it  keeps  up  the  spirits  and  gives  a  rhythm  and  swing  to 
the  march. 

If  the  weather  is  hot,  men  should  be  allowed  to  promote  evapora- 
tion of  perspiration  by  opening  their  coats  or  blouses ;  otherwise,  water 
is  lost  from  the  body  without  performing  its  function  of  reducing  the 
body-heat.  To  avoid  excessive  thirst,  a  full  drink  of  water  should 
be  taken  before  starting.  The  canteens  should  be  filled  with  water 
or  cold  tea  for  use  during  the  day ;  but  free  drinking  on  the  march 
is  not  to  be  advised,  since  it  tends  to  beget  constant  thirst.  The 
mouth  should  be  kept  closed  as  much  as  possible  during  the  march, 
and  the  sensation  of  thirst  can  be  controlled  t)y  holding  a  smooth 
pebble  in  the  mouth  or  chewing  a  green  leaf.  Simple  occasional 
moistening  of  the  mouth  is  better  than  free  and  frequent  drinking. 

In  case  of  exhaustion  by  excessive  loss  of  fluid  by  perspiration,  drink- 
ing on  the  march  is  necessary  ;  but  under  the  usual  conditions,  the  can- 
teen should  be  used  only  at  meals  and  near  or  at  the  end  of  the  day's 
march.  Another  reason  for  abstaining  as  much  as  possible  from  drink- 
ing is  the  uncertainty  of  supply,  for  no  dependence  can  be  placed  on 
the  probability  of  refilling  the  canteen  during  the  day's  march.  Hence, 
each  man  should  conserve  his  supply  as  though  he  were  certain  that  no 
more  is  to  be  had  before  the  day's  destination  is  reached.  The  amount 
carried  may  be  kept  fairly  cool  by  wrapping  the  canteen  in  a  wet  cloth, 
the  evaporation  from  which  causes  perceptible  lowering  of  temperature. 
A  little  vinegar  or  lime  juice,  if  obtainable,  added  to  the  water,  gives 
it  a  relish  and  helps  to  allay  thirst. 

"  In  many  parts  of  the  West,  water  is  so  scarce  that  judicious 
management  is  required  to  forward  troops  over  the  route.  Some 
camping-stations  having  only  enough  for  one  or  two  companies,  the 
command,  if  larger,  must  pass  in  detachments.  Or  it  may  happen  that 
the  distance  between  the  nearest  water-supplied  sites  is  too  great  to  be 
marched  without  rest,  in  which  case  a  dry  camp  must  be  formed  at 
some  intervening  point.  The  passage  of  the  Gila  Bend  Desert,  35  or 
40  miles  from  water  to  water,  is  usually  effected  by  making  a  night 
march  of  25  miles,  when  the  troops  go  into  camp  to  rest  for  a  few 
hours  before  resuming  their  journey,  and  to  have  coffee  issued  from  a 
water-supply  carried  in  the  wagons."  (Smart.^)  On  arriving  at  a 
camping-place,  the  water  supply  should  be  immediately  guarded  to 
prevent  pollution  and  trampling  of  the  margin.  If  the  supply  is 
small,  the  guard  should  be  doubly  efficient.  If  the  supply  presented 
is  a  small  and  shallow  stream,  it  may  be  well  to  make  small  reser- 
voirs by  means  of  temporary  dams,  one  for  drinking-water  for  the 
1  Buck's  Hygiene  and  Public  Health,  New  York,  1879,  Vol.  II.,  p.  119. 


THE  SOLDIER'S  EXERCISE  AND    WORK.  585 

men,  another  below  for  the  horses,  and  another  for  bathing  and  laundry- 
purposes. 

Straggling  should  be  prevented  as  much  as  possible,  since  it  is  a 
very  serious  evil  to  the  morale  and  efficiency  of  the  body  as  a  whole. 
If  straggling  becomes  considerable,  the  column  should  be  halted 
until  the  stragglers  can  overtake  it,  else  they  will  get  no  rest,  since 
the  hourly  intervals  for  rest  must  be  utilized  by  them  in  coming  up, 
and  the  column  is,  perhaps,  already  in  motion  again.  Those  claiming 
to  be  sick  or  unable  to  march  should  be  examined  by  the  medical 
officers,  who  will  separate  the  really  unfit  from  the  malingerers  ;  the 
former  are  given  careful  transportation  ;  the  latter,  disposed  of  accord- 
ing to  their  deserts. 

At  the  end  of  a  day's  marching,  the  men  should  be  dismissed  as  soon 
as  possible,  and  they  should  be  careful  to  guard  against  becoming  chilled 
through  reckless  removal  of  clothing,  and  should  again  look  after  the 
condition  of  their  feet  and  persons. 

On  long  marches,  an  occasional  day  should  be  taken  for  complete  rest 
and  recuperation,  otherwise  an  inevitable  diminution  in  efficiency  will 
be  occasioned.  Woodhull  cites  an  interesting  instance  of  overmarching 
in  the  Franco-Prussian  War.  The  German  Garde-Corps,  consisting  of 
30,000  infantry,  left  the  Rhine  on  August  3d,  lost  less  than  9,000  in 
action,  and  on  September  2d,  the  day  after  Sedan,  numbered  13,000  for 
duty.  On  September  19th,  they  reached  Paris  with  but  9,000  men, 
more  than  11,000  having  been  broken  down  by  exertion,  little  actual 
sickness  having  occurred. 

Care  of  the  Feet  on  the  March. — If  good  marchers  make  the  best 
soldiers,  it  follows  that  the  possession  of  the  best  soldiers  is  largely 
dependent  upon  the  condition  of  the  feet,  and,  therefore,  it  is  incumbent 
on  the  line  officers  and  medical  corps  to  see  that  the  individual  men 
are  properly  instructed  in  their  care,  and  that  they  are  faithful  in  per- 
formance. The  footsore  man,  so  far  as  efficiency  is  concerned,  is  a  sick 
man  and  becomes  the  equivalent  of  baggage.  He  cannot  march,  and 
suffers  pain  when  at  rest.  Nearly  all  new  men  not  accustomed  to 
marching  are  likely  to  suffer  from  excoriations  across  the  toes,  on  the 
insteps  and  malleoli,  and  on  the  back  and  sides  of  the  heels.  This  is 
due  to  friction,  and,  if  attended  to  at  once,  may  be  prevented  from 
becoming  serious. 

The  application  of  strips  of  adhesive  plaster  of  generous  size  to  the 
affected  parts  will  afford  the  same  protection  as  is  given  by  a  leather 
glove  to  the  hand  engaged  in  any  frictional  work.  Blisters  should  not 
be  opened,  except  by  a  minute  puncture  at  the  edge ;  after  the  fluid  has 
oozed  away,  the  spot  should  be  protected  with  adhesive  plaster.  The 
extensive  opening  of  a  blister  permits  access  of  air  to  the  sore  area 
beneath,  and  the  stimulation  therefrom  is  very  active  and  painful. 
Men  should  be  instructed  to  trim  their  toenails  square  across  and  not 
too  close. 

Jiefore  marching  is  begun,  all  men  with  any  soreness  of  the  feet 
should  rfj)ort  themselves  and  be  examined,  and  at  the  end  of  the  day, 


586  MILITARY  HYGIENE. 

if  not  before,  they  should  be  regularly  inepected.  Meu  unused  to 
marching  will  often  find  greasing  or  soaping  the  feet  and  stockings  an 
excellent  prophylactic  against  soreness.  A  neutral  grease  like  mutton- 
tallow  is  preferable  to  soap,  since  sometimes  it  happens  that  the  latter 
assists  the  perspiration  in  macerating  the  cuticle.  If  the  boots  are 
made  supple  with  grease,  they  tend  less  to  cause  soreness,  and,  in  addi- 
tion, are  rendered  waterproof.  An  excellent  plan  for  officers  and  others 
who  can  aflPord  them,  is  to  wear  silk  stockings  under  the  ordinary  socks, 
esj)ecially  when  the  feet  are  naturally  tender.  The  feet  may  be  tough- 
ened by  being  soaked  in  warm  strong  solutions  of  alum  or  common 
salt.  Zinc  ointment,  containing  5  per  cent,  of  tannin,  is  also  very 
useful.  Salicylated  talc  (talc  87,  starch  10,  salicylic  acid  3  parts  by 
weight)  is  used  in  the  German  army  both  on  the  march  and  in  garrison. 
It  is  sifted  from  a  dredging-box  into  the  shoes  and  over  the  feet. 

If  the  soreness  is  due  to  the  stockings  and  not  to  the  shoe,  it  is 
often  advantageous  to  change  them  from  one  foot  to  the  other,  or  to  put 
them  on  inside  out.  Some  of  the  continental  armies  use  bandages  in 
place  of  stockings,  and  some  use  neither,  substituting  therefor  a  liberal 
coating  of  grease.  Soreness  is  due  often  to  neglected  bunions,  corns, 
both  hard  and  soft,  and  infleshed  nails.  These  troubles  need  special 
treatment.  In  the  British  army,  the  authorities  have  caused  a  number 
of  the  non-commissioned  officers  to  be  instructed  in  chiropody,  and  the 
success  of  the  experiment  has  made  it  probabk^  that  a  permanent  corps 
of  trained  chiropodists  will  be  established  for  the  infantry. 

During  the  long  halt  at  midday,  each  man  should  remove  his  shoes 
and  stockings,  and,  if  water  is  to  be  had  in  abundance,  he  should 
remove  the  acrid  perspiration  and  dirt  from  his  feet  by  thorough  wash- 
ing, paving  particular  attention  to  the  surfaces  between  the  toes,  where 
excoriations  and  soft  corns  are  prone  to  appear.  Dusting-powder  or 
zinc  ointment  on  absorbent  cotton  may  be  applied,  if  advisable,  between 
the  toes.  The  feet  should  be  made  quite  dry  before  the  stockings  are 
again  drawn  on.  If  water  cannot  be  obtained  in  sufficient  amount, 
wiping  with  a  cby  or  moist  cloth  wnll  be  found  to  add  materially  to 
comfort,  and  is  much  to  be  preferred  to  long  soaking,  which,  by  soft- 
ening the  cuticle,  assists  the  formation  of  blisters.  At  the  end  of  the 
day,  the  feet  should  be  Avashed  and  the  stockings  changed ;  those 
removed  should  be  washed  as  soon  as  practicable  and  dried  during  the 
night. 

Care  of  Other  Parts. — Not  uncommonly,  soldiers,  especially  raw 
recruits,  are  much  inconvenienced  and  annoyed  by  chafing  at  various 
points,  particularly  on  the  inside  of  the  thighs  and  between  the  nates. 
This  is  promoted  by  perspiration  and  restrained  by  dusting-powder, 
zinc  ointment,  vaseline,  and  cleanliness.  Woodhull  advises  against 
washing  the  face  and  neck  in  the  morning  while  on  the  march,  because 
the  removal  of  the  natural  secretion  makes  the  skin  more  susceptible 
to  the  influence  of  heat  and  dust.  He  recommends  washing  the  eyes 
and  mouth,  and  merely  wiping  the  face  and  neck  with  a  damp  cloth. 
At  night;  the  face,  neck,  and  whole  body  should  be  washed,  if  possible  ; 


THE  SOLDIER'S  FOOD;   "RATIONS."  587 

but,  foremost  of  all,  the  head,  armpits,  feet,  and  genitals  and  adjacent 
parts. 

Care  should  be  taken  that  the  bowels  are  not  neglected  while  on  the 
march,  any  more  than  while  in  garrison.  If  purgatives  are  required, 
those  given  should  be  mild  in  character,  and  not  such  as  may  require 
repeated  operations  at  short  intervals. 

The  Soldier's  Food  ;  "  Rations." 

The  word  "  ration  "  is  understood  commonly  to  mean  the  amount  of 
food  issued  to  each  soldier  for  a  single  meal.  This,  however,  is  far 
from  being  the  truth.  Under  the  regulations,  "  a  ration  is  the  allow- 
ance for  sustenance  of  one  person  for  one  day,  and  consists  of  the  meat, 
the  bread,  the  vegetables,  the  coffee  and  sugar,  the  seasoning,  and  the 
soap  and  candle  components."  Enlisted  men  and  hospital  matrons, 
and,  when  the  circumstances  of  their  service  make  it  necessary,  civil- 
ians employed  by  the  army,  each  draw  one  ration  each  day.  The 
ration  is  not  necessarily  the  diet,  since  parts  of  it  may  be  exchanged 
for  other  things  or  for  the  cash  equivalent  with  which  to  buy  them. 
It  is  fixed  by  law,  and  can  be  changed  only  by  legislative  enactment. 

The  different  articles  composing  the  ration  for  troops  in  garrison  or 
in  permanent  camps,  excepting  in  Alaska,  and  their  amounts,  are  as 
follows : 

Articles.  Quantities. 

Meat  Components.  Ounces. 

Fresh  beef 20 

or  Fresh  mutton  when  the  cost  does  not  exceed  that  of  beef  ...  20 

or  Bacon .  12 

or  Canned  meat,  when  fresh  meat  is  not  available 16 

or  Dried  fish 14 

or  Pickled  fish 18 

or  Canned  fish 16 

Bread  Components. 

Flour 18 

or  Soft  bread 18 

or  Hard  bread 16 

or  Corn  meal 20 

Vegetable  Components. 

Beans .    2f 

or  Peas 2f 

or  Rice If  ">• 

nr  Hominy If 

Potatoes 16 

or  Potatoes  12^  and  Onions  3^ 16 

or  Potatoes  12|  and  canned  tomatoes  3^      16 

or  Potatoes  11|  and  other  fresh  (not  canned)  vegetables  when  ob- 
tainable 4f,  or  desiccated  vegetables  (when  fresh  vegetables 
cannot  be  furnished)  2f. 

Fruit  Components. 

Dried  or  evaporated  prunes,  apples  or  peaches  If  (when  practi- 
cable, 30  per  cent,  of  the  issue  to  be  prunes). 


588  MILITARY  HYGIENE. 

Articles.  Quantities. 

Coffee  and  Sugar  Components.  Ounces. 

Coffee,  green If 

or  roasted l/^- 

or  Tea,  green  or  black -jj 

Sugar ^ 

Seasoning  Components. 

Vinegar  (gills) _ ^^ 

or  Vinegar  ^\  gill  and  Cucumber  pickles  /y  gill 

Salt    .    .    .  ". if 

Pepper,  black -^-^ 

The  ration  issued  to  troops  in  the  field  in  active  campaign  is  the  same 
in  amount,  but  is  somewhat  less  elastic.  Thus,  the  various  forms  of 
fish  are  eliminated,  as  also  are  peas  and  hominy,  and  when  potatoes  are  not 
procurable  locally  the  desiccated  form  is  served.  The  fruit  component 
consists  of  canned  jam  (1|-  ounces). 

What  is  known  as  the  "  travel  ration "  is  issued  in  place  of  the 
ordinary  ration  "  when  troops  travel  otherwise  than  by  marching,  or 
when  for  short  periods  they  are  separated  from  cooking  facilities  and 
do  not  carry  cooked  rations."  It  consists  of  the  following  articles  and 
is  issued  in  the  amounts  stated,  per  hundred  rations : 

Articles.  Pounds  per  100  rations. 

Soft  bread         112.5 

or  Hard  bread      100 

Canned  corned  beef  or  corned-beef  hash 75 

Baked  beans 25 

Canned  tomatoes 50 

Coflee,  roasted,  pounds 8 

Sugar 15 

On    arrival  at   their   destination,  the   ordinary  ration    is   resumed. 

AVhen  travelling  unaccompained  by  an  officer,  each  man  may  be  al- 
lowed a  cash  sum  per  day  for  the  purchase  of  liquid  cofi'ee  in  place  of 
the  coffee  and  sugar  portion  of  the  travel  ration. 

The  "emergency  ration"  consists  of  three  IJ-ounce  cakes  made  of 
equal  parts  of  pure  chocolate  and  pure  sugar ;  three  4-ounce  cakes 
made  of  a  compound  of  1  part  of  flour  made  from  dried  lean  meat  and 
2  parts  of  parched  ground  wheat,  with  seasoning  of  salt ;  |  ounce  of 
fine  salt  and  1  gram  of  black  pepper.  Each  complete  ration  is  contained 
in  a  separate  tin  box,  which  may  be  opened  only  by  direct  orders  from 
an  officer  or  in  case  of  extremity.  Of  this,  as  many  days'  rations  are 
issued  at  once  as  may  seem  necessary.  Abroad,  the  well-known  pea 
sausage,  consisting  of  pea  flour  and  fat  pork,  is  much  used  in  the 
emergency  ration.  This,  mixed  with  hot  water,  makes  a  very  good 
soup,  but  soon  proves  to  be  cloying.  Meat  biscuits  and  dried  meats 
also  are  much  used. 

It  will  be  observed  that  the  ordinary  ration  is  fairly  flexible  as  it 
stands,  but  it  may  be  made  more  so  by  exchanging  articles  not  wanted. 
It  is  established  by  law,  but  is  not  necessarily  the  daily  dietary.     Thus, 


THE  SOLDIER'S  FOOD;   "RATIONS."  589 

the  various  articles  (excepting  the  fresh  vegetables,  bread,  and  baking- 
powder)  not  needed  for  consumption  may  be  purchased  by  the  com- 
missary as  savings  at  the  invoice  prices.  "  Savings  and  sales  of  fresh 
beef  (except  of  that  issued  for  the  sick  in  hospital,  the  detachment  of 
the  hospital  corps,  and  the  hospital  matron  serving  therein)  are  pro- 
hibited,"^ but  the  fresh  meat  allowance  may  be  reduced  in  amount  and 
its  money  value  drawn  in  other  things.  For  each  ration  of  flour 
turned  in,  the  company  is  entitled  to  one  ration  of  bread  or  the  price 
of  one  flour  ration. 

In  many  permanent  camps,  gardens  may  be  cultivated  and  a  supply 
of  fresh  vegetables  thus  obtained  both  for  immediate  and  future  use. 
Commutation  for  these  is  allowed  at  the  prices  of  potatoes  and  onions 
in  the  vicinity  or  in  the  market  from  which  supplies  are  derived,  in 
the  proportion  of  80  per  cent,  of  potatoes  and  20  per  cent,  of  onions. 
The  amounts  of  money  from  all  sources  form  the  company  fund,  which 
is  disbursed  by  the  company  commander  solely  for  the  benefit  of  his 
own  men. 

Fruits  and  vegetables  are  very  essential  in  the  dietary,  on  account 
of  their  antiscorbutic  properties.  The  most  valuable  of  the  anti- 
scorbutics is  held  commonly  to  be  lime  juice ;  the  juice  from  the 
fresh  limes  is  superior  to  the  bottled  article.  Lemons  are  of  about 
the  same  value  as  limes.  Among  vegetables,  potatoes,  onions,  and 
cabbage  take  high  rank.  The  legumes  are  devoid  of  antiscorbutic 
properties.  According  to  Woodhull,  the  best  antiscorbutic  is  the 
agave.  "  To  prepare  it,  cut  off  the  leaves  close  to  the  root,  cook 
them  well  in  hot  ashes,  express  the  juice,  and  drink,  raw  or  sweet- 
ened, 1-4  wineglassfuls  three  times  a  day.  The  white  interior  of  the 
leaves  may  be  eaten."  The  dried  vegetables  and  fruit  are  less  valu- 
able than  the  fresh,  and  should  be  allowed  to  supersede  the  latter  only 
when  these  cannot  be  obtained,  but  they  are  far  superior  to  com- 
pressed vegetables,  which,  in  the  process  of  compression,  lose  much 
of  their  salts  and  a  portion  of  their  proteids.  Dried  vegetables  should 
be  soaked  well  in  water  before  use,  else  they  may  cause  digestive 
disturbance  and  diarrhoea. 

Alcohol  in  the  Ration. — The  question  of  the  advisability  of  in- 
cluding a  spirit  allowance  in  the  ration  has  been  the  subject  of  much 
careful  consideration  in  all  countries,  and  has  been  answered  with 
practical  unanimity  in  the  negative.  But  there  are  times  when  a  single 
issue  of  spirits,  or  repeated  issues  according  to  circumstances,  may  be 
useful  and  even  necessary.  Thus,  on  a  forced  march,  when  exhaustion 
is  great,  a  stimulant  may  be  of  very  great  necessity,  although  it  is  said 
that  hot  tea,  if  time  admits  of  its  preparation,  may  be  equally  or  still 
more  serviceable.  When  given  at  all,  spirits  should  be  taken  well 
diluted,  and  never  in  concentrated  form. 

During  the  Civil  War,  a  daily  issue  of  a  gill  of  whiskey  to  each 
officer  and  man  of  the  Army  of  the  Potomac  was  ordered,  half  k)  be 
given  out  in  the  morning  and  half  in  the  evening.  This  was  brought 
'  Army  Kegulatif)n.s,  p.  180. 


590  MILITARY  HYGIENE. 

about  by  the  fact  that  for  several  weeks  the  men  had  been  subjected  to 
unusual  hardships  and  extra  duty,  and  were  breaking  down  under  the 
strain.  The  issue,  which  was  to  continue  "until  further  orders,"  was 
greeted  with  enthusiastic  appreciation  of  the  farsightedness  of  the 
authorities  responsible  for  it.  "Until  further  orders  "  proved  to  be 
exactly  one  month,  and  hot  coffee  was  substituted  for  the  whiskey,  the 
issue  of  which  was  ordered  to  be  "  immediately  discontinued.''  During 
the  month,  the  general  condition  of  health  of  the  troops  was  not  only 
in  no  way  improved,  but  became  markedly  worse,  while  drunkenness, 
with  its  attendant  evils,  became  much  more  common. 

Concerning  the  use  of  beer  and  light  wines,  a  very  different  opinion 
is  held  by  many  of  those  best  qualified  to  judge  by  results  observed. 
In  several  of  the  great  armies  of  Europe,  an  allowance  of  light  wine 
is  customary,  and  it  seems  reasonable  to  suppose  that  where  the  im- 
portance of  a  large  standing  army  is  so  great,  alcohol  in  this  form 
would  not  be  issued,  were  it  not  upon  the  belief,  based  on  long  experi- 
ence, that,  directly  or  indirectly,  it  is  a  benefit,  and  not  an  evil.  A 
little  light  wine  at  the  close  of  a  day  of  hard  work,  but  not  before  or 
during  its  performance,  appears  to  be  recuperative  and  restful,  either  in 
the  usual  strength  or  diluted  Avith  water.  In  this  country,  the  so-called 
canteen  system  is  believed  to  have  been  productive  of  a  distinct  gain 
for  temperance  among  the  soldiers ;  and  by  temperance  is  not  meant 
total  abstinence. 

The  canteen  is  a  place  at  a  military  post  where  small  wares,  little 
luxuries,  tobacco,  and  the  lighter  alcoholic  drinks  may  be  purchased 
under  close  supervision,  so  that  abuses  cannot  occur.  There  is  no 
inducement  held  out  for  the  men  to  buy  drink,  and  what  is  sold  must 
be  consumed  on  the  premises.  What  small  profit  is  derived  goes  to 
the  post  exchange,  which,  besides  the  canteen,  comprises  a  general 
store,  a  lunch  counter,  recreation  rooms  supplied  with  reading  matter, 
and  a  gymnasium. 

It  is  believed  that  the  canteen  system,  before  its  abolishment,  had 
worked  out  the  solution  of  much  of  the  problem  concerning  drunken- 
ness in  our  army.  The  soldier  accustomed  in  civil  life  to  the  use  of 
beer  was  enabled  to  obtain  it  in  a  decent  way  and  only  to  a  reasonable 
extent,  and  hence  had  no  temptation  to  seek  alcohol  in,  perhaps, 
stronger  forms  elsewhere  and  not  under  supervision.  He  was  more 
likely  to  remain  habitually  sober,  instead  of  being  occasionally  help- 
lessly drunk  and  commonly  in  difficulties.  It  is  said  that  the  order  of 
things  that  obtained  on  pay  day  under  the  old  system  had  been  very 
largely  abolished.  Then,  pay  day  was  a  source  of  satisfaction  to  nobody 
but  the  saloon-keepers,  who  sold  bad  liquor  at  high  rates ;  men  were 
absent  days  at  a  time  without  leave ;  courts-martial  were  busy,  and 
there  was  much  guard-house  service.  Those  Avho  have  studied  the 
matter,  regard  the  canteen  as  the  friend  of  decency  and  discipline,  and 
the  enemy  of  every  saloon  near  a  garrison.  Naturally,  the  saloon- 
keepers and  that  class  of  reformers  who  believe  in  the  possibility  of 
bringing  about  radical  changes  in  human  nature  by  legislation,  became 


THE  SOLDIER'S  FOOD;   "  EATIONS."  591 

violently  opposed  to  the  continuance  of  the  system ;  and,  indeed,  the 
latter  were  so  successful  in  their  agitation  against  it  that,  in  spite  of 
the  practical  unanimity  of  the  officers  of  the  army  of  all  grades  in  its 
favor,  it  was  abolished  by  Act  of  Congress  in  January,  1901. 

Preparation  of  Food. — The  art  of  cooking  is  a  very  valuable  ac- 
complishment of  a  soldier,  especially  when  on  active  service.  In  camps, 
cooking  is  done  by  persons  enlisted  for  that  purpose,  one  cook  being 
allowed  by  law^  for  each  company,  troop,  or  battery.  On  application, 
he  must  first  pass  the  regular  examination  of  a  recruit,  and  then  one 
in  which  he  must  demonstrate  his  knowledge  of  methods  and  skill  in 
caring  for,  preparing,  and  serving  food.  Kitchens  are  placed  under 
the  immediate  charge  of  non-commissioned  officers,  who  are  held  re- 
sponsible for  their  condition  and  for  the  proper  use  of  rations.  Only 
those  employed  or  those  on  duty  are  allowed  to  visit  or  remain  in  the 
kitchens. .  The  general  supervision  of  the  cooking  and  messing  devolves 
upon  the  company  commanders,  who  are  charged  to  exercise  personal 
care  and  judgment  to  prevent  waste  and  nuisance,  and  to  see  "  that 
suitable  men  in  sufficient  numbers  are  fully  instructed  in  managing  and 
cooking  the  ration  of  the  field,"  since  when  the  conveniences  for  cook- 
ing on  a  large  scale  are  not  at  hand,  it  becomes  necessary  for  men  to 
divide  into  small  squads  and  prepare  their  own  meals. 

The  baking  of  bread  is  carried  on  in  post  bakeries,  under  the  charge 
of  enlisted  men  detailed  as  chief  and  assistant  bakers.  Baking  by 
companies  at  posts  is  expressly  prohibited,  but  is  the  rule  in  temporary 
camps  and  with  marching  columns,  portable  ovens  of  various  kinds 
and  barrel  ovens  being  employed.  The  barrel  oven  is  best  made  with 
a  barrel  with  iron  hoops,  which  is  placed  on  its  side,  covered  com- 
pletely with  clay  or  stiff  mud,  except  at  its  open  end,  and  then  with  a 
thick  layer  of  dry  earth,  leaving,  however,  a  small  (3 -inch)  opening  at 
the  top  of  the  inner  end  to  serve  as  a  flue.  A  fire  is  made  in  the 
barrel  and  kept  up  until  all  the  wood  is  burned,  leaving  an  oven  of 
clay,  for  which  the  hoops  act  as  a  support. 

In  the  field,  on  account  of  transportation,  it  is  necessary  that  cooking 
appliances  should  be  as  simple  and  economical  of  space  as  possible. 
The  greater  the  amount  of  baggage,  the  greater  the  number  of  wagons 
necessary  ;  the  greater  the  number  of  wagons,  the  greater  the  number 
of  animals  and  the  greater  the  amount  of  necessary  forage. 

Is  the  U.  S.  Ration  Adequate  in  Amount  and  Composition  ? — 
This  question  has  agitated  the  minds  of  many  during  recent  times,  and, 
more  particularly,  since  the  outbreak  of  the  war  with  Spain,  and  the 
ration  has  been  denounced,  whether  justly  or  unjustly,  in  respect  to  both 
quantity  and  quality.  For  a  better  understanding  of  the  subject,  a 
comparison  of  the  official  ration  with  those  of  other  countries  in  which 
warfare  is  a  larger  industry  than  with  us  may  not  be  amiss. 

The  British  soldier  receives,  on  home  service,  12  ounces  of  meat 
and  1  pound  of  bread,  and  obtains  what  he  can  of  vegetables  and 
groceries  from  a  per  diem  allowance  of  7  cents,  which  is  deducted  from 
his  pay.     What  he  needs  in  addition,  he  Iniys  at  the  canteen  (at  cost) 


592  MILITARY  HYGIENE. 

or  elsewhere.  In  the  field,  he  receives  1  pound  of  fresh,  salted,  or 
preserved  meat,  or,  when  the  supply  of  cattle  is  abundant,  1,25  pounds 
of  fresh  meat;  1.25  pounds  of  fresh  bread,  or  1  pound  of  buscuit,  or 
1  pound  of  flour  or  meal ;  ^  ounce  of  coffee  and  i  ounce  of  tea,  or  a 
double  allowance  of  either,  or  ^  ounce  of  chocolate  or  cocoa ;  2  ounces 
of  sugar,  I  ounce  of  salt,  ^L-  ounce  of  pepper ;  1  ounce  of  compressed 
vegetables,  or  ^  pound  of  potatoes  or  other  fresh  vegetables,  or  2 
ounces  of  split  peas,  or  ^  pound  of  onions,  or  2  ounces  of  rice ;  -^ 
gill  of  lime  juice  with  \  ounce  of  sugar  when  fresh  vegetables  are  not 
issued  or  when  the  medical  officer  thinks  necessary ;  ^  gill  of  spirits, 
when  considered  necessary,  besides  tobacco,  light,  and  fuel.  This  ra- 
tion is  subject  to  change  for  better  or  worse,  according  to  circumstances. 
The  French  soldier  receives  10.6  ounces  of  meat,  26.4  ounces  of 
munition  bread  and  8.8  ounces  of  white  bread  for  soup,  or  19.4  ounces 
of  hard  bread ;  3.5  ounces  each  of  dried  vegetables,  chiefly  beans,  and 
fresh  vegetables,  with  salt  and  pepper.  Much  of  this  comes  out  of  his  pay. 
The  German  soldier  receives  in  time  of  peace,  according  as  he  is 
in  garrison  or  in  camp  and  field  manoeuvres,  5.30-17.65  ounces  of 
meat,  or  4.40-6.00  ounces  of  bacon ;  26.50-35.30  ounces  of  bread, 
3.18-6.00  ounces  of  rice,  or  4.25-6.00  of  groats,  or  8.10-12  of  peas 
or  beans,  or  53.00—71.00  of  potatoes  ;  and  in  camp  or  field  manoeuvres, 
a  liter  of  beer,  or  a  half  liter  of  wine,  or  a  tenth  liter  of  spirits,  and 
1.75  ounces  of  butter.  In  time  of  war,  he  receives  13.25  ounces  of 
fresh  or  salted  meat,  or  8.80  ounces  of  smoked  meat  or  sausage,  26.50 
ounces  of  bread,  4.40  ounces  of  rice  or  groats,  or  8.80  of  peas,  beans, 
or  flour,  or  53.00  ounces  of  potatoes,  0.90  ounce  of  roasted  or  1  ounce 
of  raw  coffee,  and  0.90  ounce  of  salt. 

The  Russian  soldier,  in  time  of  peace,  receives  7.25  ounces  of  meat, 
43.35  of  rye  bread  or  28.9  of  biscuit,  32.65  of  flour,  and  4.80  of 
groats.  In  time  of  war,  he  receives,  according  to  whether  he  is  on  the 
smaller  or  larger  war  ration,  14.45—21.65  ounces  of  meat,  36.15  of 
rye  bread,  4.80  of  groats,  and  1.35—2.70  of  suet  or  butter.  He  is 
allowed  also  money  for  1.50  ounces  extra  of  meat,  and  an  additional 
cent  and  a  half  for  vegetables  and  other  articles. 

The  Austrian  soldier  receives  in  peace  6.70  ounces  of  meat,  30.90 
of  bread  or  17.65  of  hard  bread;  6.60  of  flour,  or  2.50  of  peas  or 
beans,  or  4.95  of  groats,  or  5.30  of  millet,  or  4.00  of  barley,  or  3.70 
of  rice,  or  19.75  of  potatoes;  5.55  of  sauer  kraut,  and  0.60  of  suet. 
In  time  of  war,  9.90  ounces  of  meat  or  6.00  of  salted  meat  or  bacon  ; 
25.20  of  flour,  3.50  of  hard  bread,  5.30  of  peas,  or  4,94  of  groats,  or 
5.55  of  sauer  kraut,  or  8.80  of  potatoes  ;  and  1.05  of  suet,  with  coffee, 
and  beer,  wine  or  spirits,  and  4  cents  for  extra  vegetables. 

The  Spanish  soldier  receives  24  ounces  of  bread,  and  is  required  to 
spend  7  cents  out  of  his  daily  pay  of  9  cents  for  the  rest  of  his  sub- 
sistence. In  time  of  war,  his  pay  is  increased  from  2.5  to  5  cents  per  day. 
The  Italian  soldier  receives  7.05-10.60  ounces  of  meat,  0.50  of 
bacon,  32.40  of  bread,  5.30  of  rice,  0.70  of  sugar,  0.50  of  coffee,  0.50 
of  salt,  and  a  quarter  liter  of  wine. 


THE  SOLDIER'S  FOOD;   "RATIONS."  593 

Comparison  of  these  figures  with  those  of  our  own  ration,  demon- 
strates at  once  that  ours  is  in  all  respects  the  most  liberal  ration  in  the 
world.  In  only  one  instance  is  there  a  conspicuous  superiority  in  the 
amount  of  an  important  constituent ;  namely,  the  very  generous  allow- 
ance of  potatoes  in  the  German  ration.  Not  only  is  the  U.  S.  ration 
the  most  abundant,  but  it  admits  of  greater  variety  than  any  other. 
But  even  at  that,  it  is  held  by  many  to  be  insufficient  in  amount  for 
the  proper  performance  of  the  work  a  soldier  may  be  called  upon  to 
perform.  Experts  in  the  making  of  dietaries  have  proposed  increasing 
the  flour  and  soft  bread  allowance  by  about  a  fourth,  and  adding  about 
5  ounces  of  flour  to  the  alternative  allowance  of  hard  bread  and  20 
per  cent,  to  the  alternative  allowance  of  corn  meal,  with  a  reduction 
of  40  per  cent,  in  the  allowance  of  potatoes,  and  the  alternative  of 
money  value  in  milk  or  cheese  in  place  of  the  allowance  of  peas  or  beans. 

In  the  consideration  of  the  question  of  quality  and  variety,  it  should 
be  borne  in  mind  that,  while  it  is  necessary  to  have  a  standard  of  food 
value  fixed  by  law,  it  is  not  necessary  to  consume  precisely  the  articles 
named.  Nor  is  it  possible  to  fix  a  money  value  to  the  ration,  and  give 
out  the  cash  equivalent  in  place  of  actual  food,  for  the  soldier  is  not 
always  near  a  market,  and,  moreover,  if  he  were,  it  is  most  evident 
that  the  same  amount  of  money  in  different  places  would  yield  very 
different  amounts  of  nutriment,  since  in  one,  the  food  supply  is  abun- 
dant and  cheap,  and,  in  another,  scanty  and  expensive.  What  the  soldier 
eats,  depends  upon  circumstances,  and  largely  upon  the  discretion  of 
company  commanders  guided  by  the  advice  of  the  medical  officers,  but, 
as  said  before,  the  actual  food  value  is  fixed  by  Congress,  and  is  based 
on  the  experience  and  study  of  many  years. 

Is  the  United  States  Ration  Suited  to  the  Tropics  ? — The  ques- 
tion of  the  suitability  of  our  ration  to  the  tropics  is  one  which  has 
assumed  great  importance  since  the  necessity  arose  for  maintaining  large 
armies  in  our  new  possessions,  and  its  discussion  has  been  marked  by 
a  much  more  temperate  tone,  and  has,  therefore,  yielded  better  results. 
The  beginning  of  the  discussion  may  be  said  to  have  arisen  from  the 
fact  that  it  became  generally  understood  that  bacon  was  a  necessary 
constituent  of  the  daily  food,  both  in  camp  and  in  active  operations,  in- 
stead of  an  alternative,  as  may  be  gathered  from  the  w^ording  of  the 
statute — fresh  beef,  or  fresh  mutton,  etc.,  07^  pork,  or  bacon,  or  salt 
beef,  or  dried  fish,  or  pickled  fish,  or  fresh  fish.  Bacon  has  its  advan- 
tages at  certain  times,  but  is  not  eagerly  sought  after  by  those  not  in 
good  health,  nor  is  it  acceptable  in  very  hot  climates  as  a  regular  diet 
any  more  than  any  other  fatty  food.  Fats  are  much  needed  in  cold 
climates  for  the  production  of  heat ;  in  hot  climates,  the  necessity  for 
their  use  is  but  slight  in  comparison.  But  when  fresh  meat  cannot  be 
obtained  either  on  the  hoof  or  from  cold  storage,  and  when  the  appe- 
tite is  chjyf;d  by  canned  meats  (and  this  is  soon  brought  about),  bacon 
is  acce})tab]e  as  an  occasional  substitute. 

To  those  at  a  distance  and  unacquainted  with  local  conditions,  the 
ideal  supj)ly  of  fresh  meat  is  cattle  on  the  hoof.     But  the  cattle  of  the 


594  MILITARY  HYGIENE. 

tropics  are  not  the  same  as  those  which  we  know,  nor  are  they  always 
to  be  had  in  even  small  numbers.  Sending  live  cattle  from  home,  to 
be  driven  along  on  the  march  to  be  killed  as  needed,  is  not  always 
practicable,  for  even  if  landed  in  good  condition,  they  cannot  be  kept 
on  the  march,  and,  unless  the  country  traversed  is  good  grazing  land, 
they  lose  weight  and  die  oiF  rapidly.  Canned  meats  are  much  inferior 
to  fresh  meats,  and  cannot  long  be  eaten  with  relish.  The  canned  so- 
called  roast  beef  is  commonly  the  residue  of  meat  after  the  extractives 
have  been  boiled  out  of  it  for  the  manufacture  of  meat  extract,  and  it 
is,  therefore,  lacking  in  flavor,  although  not  materially  diminished  in 
nutritive  properties.  It  is  often  as  tasteless  and  almost  as  difficult  to 
chew  as  towelling,  and  is  far  from  inviting  in  appearance,  especially 
when  the  cans  are  opened  at  ordinary  hot  summer  temperature. 

According  to  many  experienced  minds,  the  consumption  of  meat  in 
any  form  should  be  much  limited  in  the  tropics.  Roquemaure  ^  advises 
the  European  in  the  tropics  to  take  nothing  into  his  stomach,  except 
articles  easily  digested ;  mutton,  beef,  and  pork  only  in  moderation, 
and  not  too  thoroughly  cooked,  and  not  regularly  or  too  often  ;  birds, 
eggs,  and  fish  are  more  to  be  commended ;  especially  to  be  relied  upon 
are  rice,  dried  vegetables,  fresh  vegetables,  starchy  foods,  and  ripe  fruits 
in  good  condition.  Kohlbriigge^  places  above  all  other  influences  in 
the  deterioration  of  Europeans  in  the  tropics  the  too  extensive  use  of 
animal  fats,  which,  he  claims,  are  responsible  for  much  of  the  diarrhoeal 
troubles  of  the  tropics.  He  recommends  the  vegetable  oils  for  supply- 
ing what  fats  are  needed  by  the  body. 

The  observations  of  Dr.  L.  L.  Seaman,^  in  Porto  Rico,  lead,  in  part, 
to  the  same  conclusion.  He  relates  that,  within  a  week  after  landing 
in  the  summer  of  1898,  in  spite  of  the  strictest  sanitary  precautions 
and  personal  hygiene,  the  entire  force  with  which  he  was  connected 
suffered  from  some  form  of  intestinal  catarrh  from  one  cause  and 
another,  and  that  medication  was  ot  no  avail,  since  the  diet  of  bacon, 
salted  beef,  canned  beans  and  pork,  and  hardtack  proved  to  be  a  con- 
tinual irritant,  by  which  the  troubles  were  aggravated  and  the  power 
of  resistance  much  reduced.  Under  such  conditions,  malaria  and 
typhoid  fever  gained  a  foothold  in  the  system  with  much  ease ;  first 
came  the  malarial  fevers  of  the  various  types,  and,  in  the  early  part  of 
September,  on  the  introduction  of  the  germs  from  Tampa  and  Chicka- 
mauga,  typhoid  fever  broke  out,  and,  spread  by  flies,  continued  with 
varying  severity  until  embarkation  for  home  in  November.  The  value 
of  a  milk-diet  was  emphatically  demonstrated. 

Koerfer's*  recommendation  to  Europeans,  to  leave  their  pork  fat, 
meats,  and  alcohol  at  home  with  their  heating  stoves  and  furs,  when 
they  go  to  reside  in  the  tropics,  is  quoted  in  confirmation. 

While  the  use  of  green  vegetables   is  universally  recommended  in 

'  TTygidne  alimentaire  aux  pays  chands,  Bordeaux,  1895. 

^  Die  Acclimatisation  der  Europaer  in  den  Tropen :  Deutsche  medicinische  Wochen- 
SGhrift,  1898,  Nos.  27  and  28. 

8  New  York  Medical  Journal,  March  18  and  25,  1899. 
*  Deutsche  medicinische  Wochenschrift,  July,  1898. 


THE  SOLDIER'S  FOOD;   "RATIONS." 


595 


the  tropics,  it  is  not  always  ea.sy,  and,  in  fact,  it  is  often  extremely  diffi- 
cult or  impossible,  to  obtain  them,  since  the  natives  of  the  tropics  are 
commonly  content  to  live  on  rice,  dried  beans,  and  fruit,  with  an  occa- 
sional taste  of  fish  or  meat.  Canned  vegetables,  while  grateful  to  the 
system,  are  not  wholly  to  be  recommended,  on  account  of  transporta- 
tion. A  can  of  string  beans,  for  example,  contains  a  maximum  of 
water  and  a  minimum  of  nutriment,  and  for  its  real  service  in  the 
dietary  may  be  said  to  be  hardly  worth  its  cost  of  carriage.  Dried 
vegetables  and  fruits  are  more  economical,  but  should  be  well  soaked 
before  use. 

The  Court  of  Inquiry,  appointed  to  investigate  the  food  supply  of 
the  army  during  the  war  with  Spain,  reported  among  other  conclusions 
the  following  :  "  As  to  the  effects  of  the  food  supply,  having  regard  to 
sufficiency  and  quality,  it  seems  to  be  clearly  established  that  the  army 
ration  as  supplied,  without  modification,  to  the  troops  serving  in  the 
West  Indies  was  by  no  means  w^ell  adapted  for  use  in  a  tropical  climate. 
If  this  be  true,  the  unfitness  of  the  ration  should  have  manifested 
itself  by  its  failure  to  keep  the  troops,  who  subsisted  upon  it,  in  the 
best  possible  condition  for  service  in  hot  climates.  This,  in  the  opinion 
of  the  court,  is  fully  established  in  evidence."  Seaman  advocates  a 
reduction  in  the  meat  components,  the  use  of  salted  meats  not  oftener 
than  twice  per  week,  and  an  increase  in  the  allowance  of  vegetable  and 
farinaceous  foods  and  dried  fruits. 

Dr.  Edward  L.  Munson,  U.  S.  A.,^  has  studied  the  subject  of  trop- 
ical diet  from  the  standpoints  of  physiological  science,  availability,  and 
practicability,  and  concludes  that  the  articles  of  the  ration  are  correct 
as  they  stand,  being  admirably  selected  and  of  good  variety,  but  need 
some  rearrangement  in  their  respective  amounts.  He  proposes  certain 
modifications,  and  offers  four  dietaries,  the  average  of  which  is  not 
widely  variant  from  a  proposed  nutritive  standard  for  soldiers  in  the 
tropics,  as  follows  :  Protein,  100  grammes  ;  carbohydrates,  650  ;  fats, 
65.  (Nitrogen,  16  ;  total  carbon,  392  ;  fuel  value,  3,491  calories.) 
Dietary  I.  contains  the  greatest  amount  of  food  material  which  may  be 
drawn  by  the  soldier  : 


TEOPICAL  DIETAEY  I. 

.Articles. 

Quantity, 
ounces. 

Fats, 
grams. 

Carbohy- 
drates, 
grams. 

Protein, 
grams. 

Nitrogen, 
grams. 

Fuel 

value, 

calories. 

Fresh  beef     

P'lour 

Beans     

Potatoes 

Dried  fruit 

SiJg.'ir 

10 
18 

2.4 
16 

3 

3.5 

44.75 
5.60 
1.22 
o!45 
1.53 

380.46 
40.18 
81.70 
33.80 
94.25 

41.68 

55.08 

15.16 

9.50 

1.77 

6.67 
7.90 
2.42 
1.52 
0.27 

590 
1,850 
240 
380 
220 
397 

Total 

52.9 

53.55 

630.39 

123.19 

18.78 

3,677 

Total  carbon,  395.14  grams ;  nitrogen  to  carbon,  1  :  19.6. 


'  The  Ideal  Ration  for  an  Army  in  the  Tropics.     (Prize  e.ssay.)     Boston  Medical  and 
Hiirgical  Joumal,  May  3,  10,  17,  and  24,  1900. 


596 


MILITARY  HYGIENE. 


Dietary  II.  is  especially  applicable  to  field  service ;  in  this,  the  fatty 
constituents  attain  their  maximum  and  the  potential  energy  is  high  : 


TROPICAL  DIETARY  11. 


Articles. 


Quantity, 
ounces. 


Fats, 
grams. 


Carbohy- 
drates, 
grams. 


Protein, 
grams. 


Nitrogen, 
grams. 


Fuel 
value, 
calories 


Bacon     .    . 
Hard  bread 
Beans     .    . 
Dried  fruit 
Sugar     .    . 


6 
18 
2.4 
3 
3.5 


105.06 
6.63 
1.22 
1.53 


371.81 
40.18 
50.70 
94.25 


15.64 

73.12 

15.16 

1.77 


2.49 

11.74 

2.42 

0.27 


1,042 

1,926 

240 

220 

397 


Total 


32.9 


114.44 


556.94 


105.69 


16.92 


3,825 


Total  carbon,  328.76  grams ;  nitrogen  to  carbon,  1 :  23. 


Dietary  III.  is  proposed  for  garrison  duty 


TROPICAL  DIETARY  III. 


Articles. 

Quantity, 
ounces. 

Fats, 
grams. 

Carbohy- 
drates, 
grams. 

Protein, 
grams. 

Nitrogen, 
grams. 

Fuel 

value, 

calories. 

Fresh  beef 

Soft  bread 

Potatoes  and  onions    .    . 

Dried  fruit 

Sugar     

10 
20 
16 

3 

3.5 

44.75 

6.80 
0.72 
1.53 

299.20 
73.09 
50.70 
94.25 

41.68 

53.83 

8.60 

1.77 

6.67 
8.61 
1.40 
0.27 

590 
1,506 
340 
220 
397 

Total 

52.5 

53.80 

517.24 

105.88 

16.95 

3,053 

Total  carbon,  328.76  grams ;  nitrogen  to  carbon,  1 :  18. 


Dietary  IV.  is  a  combination  of  the  several  articles  of  the  ration  most 
closely  approaching  in  character  the  food  materials  used  by  the  natives 
of  the  tropics,  proportioned  according  to  the  proposed  standard  : 


TROPICAL  DIETARY  IV. 


Articles. 

Quantity, 
ounces. 

Fats, 
grams. 

Carbohy- 
drates, 
grams. 

Protein, 
grams. 

Nitrogen, 
grams. 

Fuel 
value, 
calories. 

Fresh  fish  (cod),  whole  . 

Soft  bread 

Rice 

Potatoes  and  tomatoes     . 

Dried  fruit 

Sugar     

14 
20 

4 
16 

3 

3.5 

0.79 
6.80 
0.45 
0.54 
1.53 

299.20 
88.87 
65.80 
50.70 
94.25 

•  31.73 

53.83 

8.75 

8.17 

1.77 

5.07 
8.61 
1.40 
1.36 
0.27 

120 
1,506 
407 
297 
220 
341 

TotaP 

64.5 

10.11 

598.82 

104.25 

16.71 

2,947 

Total  carbon,  327.50  grams ;  nitrogen  to  carbon,  1 :  19.6. 


^  It  will  be  noticed  that  the  first  and  sixth  columns  do  not  add  up  according  to_  the 
totals  expressed.  The  latter,  however,  being  used  in  the  table  below,  are  retained 
unchanged. 


POSTS  AND  CAMPS. 


597 


The  following  table  shows  the  mean   nutrient  composition  of  the 
four  dietaries,  and  admits  of  ready  comparison  of  one  with  another  : 


Dietary.  wua.iuLy,  rats,  ^  ■  rrotein,        iMurogen,      ^J"^^ 

calories. 


No.  I. 
No.  II. 
No.  III. 
No.  IV. 
Average 


Quantity, 

Fats, 

Carhohy- 

Protein, 

Nitrogen, 

ounces. 

giams. 

grams. 

grams. 

grams. 

52.9 

53.55 

630.39 

123.19 

18.78 

32.9 

114.44 

556.94 

105.69 

16.92 

52.5 

53.80 

517.24 

105.88 

16.95 

64.5 

10.11 

598.82 

104.25 

16.71 

50.7 

57.97 

575.85 

109.75 

17.34 

3,677 
3,825 
3,053 
2,947 
3,375 


Total  carbon,  350  grams ;  nitrogen  to  carbon,  1  :  20. 


Posts  and  Camps. 

Posts  are  permanent  camps  or  those  of  position,  and  camps,  in  the 
usual  sense,  are  temporary  or  incidental.  At  posts,  the  troops  are 
housed  in  barracks,  while  at  temporary  camps  they  occupy  tents  and 
huts.  The  same  sanitary  considerations  apply  equally  well  to  both,  but 
choice  of  location  of  temporary  camps  in  time  of  war  is  determined 
commonly  by  immediate  and  strategical  considerations.  Both  should 
be  laid  out  in  such  a  manner  as  to  insure  proper  air  supply,  cleanliness, 
and  general  salubrity,  and  should  be  as  compact  as  is  consistent  with 
the  princi])les  of  hygiene,  for  a  compact  camp  is  more  easily  cared  for 
and  defended,  while  one  unnecessarily  extended  involves  increased  labor, 
slower  delivery  of  orders  and  supplies,  and  greater  difficulties  in  sani- 
tary policing.  With  the  tactical  and  strategical  requirements  and  gen- 
eral plan,  which  is  a  matter  of  regulation,  the  hygienist  has  nothing  to 
do,  and  his  interest  lies  only  in  the  distances  between  different  bodies 
of  men,  the  size  of  company  areas,  the  cubic  space  per  man,  the  proper 
location  of  sinks,  latrines,  and  urinals,  the  measures  adopted  for  surface 
drainage,  disposal  of  sewage,  garbage  and  stable  manui-e,  the  water- 
supply,  and  other  matters  having  a  bearing  on  the  health  ojf  the  troops. 

The  general  plan  of  a  camp  is  shown  in  Fig.  98,  taken  from  the  In- 
fantry Drill  Regulation,  and  amended  in  the  matter  of  distances  and 
intervals  by  Dr.  P.  C.  Harris,  U.  S.  A.,^  since  no  distances  and  inter- 
vals are  given  in  the  regulation,  for  they  must  vary  according  to  the 
nature  of  the  ground  and  the  strength  of  the  command.  The  plan  is 
made  "  on  a  basis  of  3  men  to  a  common  tent  or  10  to  a  conical  wall 
tent ;  the  maximum  allowance  of  tentage  is  6  men  to  a  common  tent 
and  20  to  a  conical  wall." 

Sites. — One  of  the  most  important  matters  connected  with  military 
hygiene  is  the  selection  of  a  proper  site  for  camps.  Everything  bear- 
ing on  the  health  of  those  who  are  to  occupy  the  camp  should  be  con- 
sidered important,  and  every  effort  should  be  made  to  insure,  so  far  as 
it  is  possible,  that  there  is  no  point  of  least  resistance  in  the  barriers 
against  disease.     If  an  unhealthy  site  is  chosen,  no  amount  of  care  can 

'Camps  of  In.struction,  Jicprint,  Buffalo,  Dec.  14,  1898. 


698 


MILITARY  HYGIENE. 


ward  off,  though  it  may  check  the  extent  of,  evil  consequences.  In 
active  warfare,  choice  of  sites  is  not  always  a  wide  one,  and  convenience 
and  necessity  play  a  greater  part  than  sanitary  consideration.  When 
practicable,  they  should  be  placed  on  high,  well-drained  ground. 


Fig.  98. 


SHospital  Tent. 


-f 

I 


QfficerB  Bath  and  Sink  Tentt. 


.*« 


L.. 


^'- 


(fffieem  Kitchen. 


Field  and  Staff  Hajoi 


!  BH  and  Batt 


Non-ComSiaff  Band 
and  Brum  Corps  Tent*. 


!)• 


Battalion  Offlcen  Tenta, 


T  Company  Offlcen  Tenta. 

•-fe'-o^--s*'-o^^'ta^^*'i>^K^*-!'i'-<i^+^i^t^iWif-*i^^ll^*'<>^ 

•  ^    t      I        II         I       ■         ■      •  ■       -         ■      '        '       ' 

i^\  I      I  _,  I       I I 


yjm 


\M 


iittkl    rUB 


ytti  ma 


m 


Company  Tents. 


•...fit  ###♦#♦•#♦ 


—ls'-o^-i^-saV-4 — s«V-t- — asv-i — se^—i-r-3e'q--i---3e'-o^—lt — seV—i- — 3s'»-'--i-  — sd^--i---se^o^4---so-o---kKfi 


-^ 


Caajpany  KJicbeus. 

^    ^     ^ 
•       •        • 


*    * 


Company  Bath  and  Sink  Tent*. 
•       •       *        • 


Soale  e4t»ct-l  ioota 


Explanation. 

^  Bxnmlnff  Water 

HWB  Concrete  Foandatlou. 


Plan  of  camp  (reduced  so  that  scale  of  64  feet  to  the  inch  no  longer  applies). 

Proximity  to  water  is  always  necessary,  and  this  may  involve  ex- 
posure to  malarial  infection  ;  but,  other  things  being  equal,  the  driest 
site  should  be  selected.  Where  the  choice  is  restricted,  advantage 
should  be  taken,  in  cold  weather,  of  any  available  protection  from 
winds,  and,  in  hot  climates,  from  the  burning  sun.  The  general  slope 
of  the  ground  should  be  considered,  so  that  surface  drainage  may  be 
best  provided  for. 


POSTS  AND   CAMPS.  599 

The  soil  should  be  dry  and  porous ;  clay  and  other  soils  of  low 
permeability  to  air  and  moisture,  but  with  high  retentive  power  for  the 
latter,  should,  if  possible,  be  avoided.  If  the  ground- water  level  is  high, 
it  should  be  lowered  by  tile  draining  or  ditching,  in  case  the  camp  is  to 
be  one  of  permanence.  A  clay  soil  or  a  soil  underlaid  at  a  short  dis- 
tance by  a  clay  soil  is  regarded  commonly  as  the  worst  possible  site  for 
a  camp,  since  it  is  retentive  of  water  and  is  cold,  and  causes  the  atmos- 
phere immediately  above  to  be  damp.  Old  river  bottoms,  deep  allu- 
vium, and  marshy  ground  should  be  avoided.  Grass  land  may  com- 
monly be  accepted  as  good  campiiag  ground,  but  ground  covered  with 
rank  vegetation,  as  in  the  tropics,  is  not  acceptable,  because  such  is 
generally  rich  in  decaying  organic  matter,  and  the  presence  of  rank 
vegetation  is  in  itself  evidence  either  of  a  very  humid  atmosphere  or 
of  an  undesirable  degree  of  soil  moisture.  Lands  subject  to  periodical 
flooding,  especially  by  salt  water,  should  be  avoided  as  unhealthy. 

Above  all,  it  should  be  a  rule  to  avoid  old  camp  grounds,  for  these 
usually  are  left  in  a  filthy  condition  by  the  previous  occupants,  and  the 
soil  is  always  contaminated  extensively  and,  perhaps,  infected.  If  an 
old  camp  site  is  particularly  desirable  on  account  of  the  accessibility 
of  wood,  water,  and  grass  (the  three  essentials  demanded  by  the  line 
officer),  a  position  to  windward  and  as  near  as  is  consistent  with  hy- 
gienic considerations  may  be  selected. 

Dryness  of  the  site  and  vicinity  is  of  prime  importance  in  its  bear- 
ing on  the  health  of  troops,  but  too  great  dryness  with  much  dust  is 
hurtful  to  the  eyes.  A  position  on  the  side  of  a  hill  is  warmer  than 
one  at  the  top  and  drier  than  one  at  the  bottom,  and  is  favorably  situ- 
ated as  regards  that  most  essential  provision  in  camp  sanitation, 
drainage. 

Barracks. — Barracks  are  permanent  structures  for  the  lodgment  of 
soldiers,  and  are  built  commonly  of  one  or  two  stories,  but  not  more. 
Each  building  of  a  group  should  be  completely  independent  of  the 
others  and  placed  with  reference  to  prevailing  winds  and  exposure  to 
the  sun.  It  is  essential  that  the  site  be  dry ;  the  foundation  walls 
solidly  laid ;  the  walls,  of  whatever  material  constructed,  dry  and  pro- 
tected against  capillary  moisture ;  the  floors,  of  hard  wood,  tightly  laid  ; 
and  the  ventilation  efficient.  Barrack  rooms,  which  are  the  soldiers' 
living  rooms  as  well  as  sleeping  quarters,  are  generally  made  long  and 
narrow,  and  each  occupant  has  floor  space  and  air  space  according  to 
the  regulations  obtaining  in  the  country  which  he  serves.  In  this 
country,  600  cubic  feet  of  air  space  per  man  are  reckoned  adequate, 
and  this,  in  a  room  12  feet  from  floor  to  ceiling,  gives  a  floor  space  of 
50  square  feet.  Cavalry  and  artillerymen  are  given  somewhat  more, 
on  account  of  the  odors  which  cling  to  them  from  contact  with  horses. 
A  less  amount  is  allowed  when  troops  are  quartered  in  ordinary  dwell- 
ings. At  Southern  posts,  800  cubic  feet  of  air  space  and  70  square 
feet  of  floor  space  are  allowed.  In  England,  the  allowances  are  the 
same  as  with  us  for  infantrymen  in  th(!  North  ;  in  India,  they  are  from 
1500  cubic  feet  and  75  square  feet  to  double  those  limits.     In  France, 


600  MILITARY  HYGIENE. 

the  cubic  space  allowed  is  420  cubic  feet  for  infantry  and  500  for 
cavalry.     In  Germany,  it  is  500  cubic  feet. 

The  wash-rooms,  urinals,  and  latrines  should  be  placed  with  due 
regard  to  convenience  and  to  general  hygienic  considerations. 

Ventilation  should  be  planned  with  a  view  to  the  greatest  possible 
reduction  of  the  natural  impurities  due  to  occupancy,  but  with  the  pres- 
ent cubic  space  allowance,  w^hatever  the  system  employed,  ideal  results 
cannot  be  attained.  Barrack  life  is  necessarily  one  of  overcrowding, 
but  the  conditions  which  now  obtain  are  far  superior  to  those  which 
formerly  prevailed.  The  evils  of  overcrowding  of  soldiers  were  first 
brought  to  light  by  an  investigation  of  the  health  of  British  soldiers 
in  1858.  It  was  shown  that,  whereas  the  mortality  rate  of  the  popu- 
lation of  England  and  Wales  of  the  same  age  as  the  army  was  9.2  for 
town  and  country  and  7.7  for  country  alone,  and  12.4  for  the  most 
unhealthy  town  (Manchester),  that  of  the  diiferent  arms  of  the  service 
ranged  from  11  for  the  household  cavalry  to  20.4  for  the  footguards. 
According  to  age  periods,  the  mortality  was  distributed  as  follows  : 

Ages  20  to  25.  {«J'1'«-;  ;■;;::::;.;■  ;■;;■" 
Ages2o,„30.{CJ5>i-...^       •..•■........  ^9| 

Ages 30 .0 35. {Cj^ij;-;: :::;;;  ::;:::::::;»:^ 

Ages  35  to  40. 1  «["'»"'' ;j-« 

°  (.  boldiers 19.3 

Since  the  soldiers  were  picked  men,  all  applicants  with  any  evidence 
of  Aveakness  or  tendency  to  disease  being  rejected,  these  data  indicated 
a  serious  condition  of  affairs.  Comparison  was  made  with  the  rates 
obtaining  among  the  class  of  agricultural  laborers,  their  work,  like  that 
of  the  soldiers,  being  mainly  out  of  doors.  It  would  be  expected  that 
the  latter,  being  well  clothed,  housed,  and  fed,  and  given  free  medical 
care,  would  present  the  better  showing,  but  such  proved  not  to  be  the 
case,  for  the  mortality  of  the  laborer  being  expressed  as  1,  that  of  the 
household  cavalry  was  1.8,  dragoons  2.2,  infantry  of  the  line  2.9,  and 
footguards  3.3.  Comparison  with  men  in  other  occupations  showed 
that  the  soldiers  presented  the  most  unfavorable  statistics. 

Inquiry  as  to  the  cause  revealed  that,  whereas  among  civilians  at  the 
soldiers'  ages  the  deaths  from  diseases  of  the  lungs  were  6.3  per  1000, 
they  were  7.3,  10.2,  and  13.8  respectively  for  the  cavalry,  infantry  of 
the  line,  and  guards ;  and,  furthermore,  that  of  the  entire  number  of 
deaths  from  all  causes  in  the  army,  the  proportion  due  to  lung  diseases 
amounted  to  53.9,  57.3,  and  67.7  per  cent,  respectively  in  the  arms 
above  mentioned.  Finally,  by  exclusion,  the  cause  of  this  great  mor- 
tality was  attributed  to  overcrowding  and  lack  of  ventilation.  Com- 
parison of  the  mortality  of  the  array  at  home  with  that  of  the  troops 
quartered  before  Sebastopol  in  1856  was  much  in  favor  of  the  latter. 
The  rates,  reckoned  per  annum,  were  as  follows  :  Before  Sebastopol, 
including  death  by  violence  and  accident,  12.5  ;  at  home,  17.9  (infan- 
try), and  20.4  (guards). 


POSTS  AND  CAMPS.  601 

Increase  in  space  allowance  was  soon  followed  by  a  marked  decrease 
in  phthisis  mortality. 

Tents. — In  the  United  States  Army,  four  kinds  of  tents  are  used: 
1.  The  conical,  or  modified  Sibley,  tent.  This  is  16  feet  5  inches  in 
diameter  at  the  base ;  wall,  3  feet  high ;  apex,  10  feet  from  the  floor ; 
the  area  of  the  floor  equals  212  square  feet ;  the  air  space,  1450  cubic 
feet;  allowance,  20  infantry  or  17  cavalry.  The  original  Sibley  tent 
had  a  diameter  of  18  feet  at  the  base  and  was  13  feet  high.  The  apex 
was  cut  off,  thus  giving  place  to  a  circular  aperture  which,  being  left 
open  in  fair  weather,  promoted  ventilation.  In  foul  weather,  it  was 
covered.  The  allowance  was  the  same.  2.  Common  tent,  "  I "  or 
modified  "  A."  Wall,  2  feet  high ;  base,  8  feet  4  inches  by  6  feet  10 
inches ;  ridge,  6  feet  10  inches  from  the  ground  ;  floor  space,  57  square 
feet ;  air  space,  250  cubic  feet ;  allowance,  4  mounted  or  6  infantry. 
3.  Wall  tent.  Wall,  3  feet  9  inches  ;  floor,  9  square  feet ;  ridge,  8 
feet  6  inches  above  the  ground;  floor  space,  81  square  feet;  air  space, 
500  cubic  feet ;  covered  by  fly  or  false  roof.  4.  Shelter  tent.  These 
are  issued  to  troops  in  the  field,  and  are  not  regarded  as  tent  allowance, 
but  are  provided  in  order  that  men  and  officers  in  bivouac  while  on 
active  campaign  or  on  the  march  with  deficient  means  of  transportation 
may  be  sheltered.  One  forms  a  shelter  for  2  men,  each  of  whom 
carries  his  half,  w^hich  weighs  about  2|  pounds.  The  pieces  are 
joined  together  by  buttons  and  put  over  a  ridge  pole,  which  is  sup- 
ported by  uprights  about  4  feet  high.  The  corners  are  fastened  to 
pegs  driven  into  the  ground,  and  the  uprights  are  steadied  by  guy 
lines.  Hospital  tents  are  wall  tents  of  a  larger  size ;  they  may  be 
closed  or  open  at  the  ends,  and  several  may  be  joined  together  so  as  to 
make  a  continuous  whole.  They  are  14X15  with  a  4J-foot  wall; 
ridge,  12  feet  from  the  ground. 

The  English  army  uses  the  circular,  or  bell,  tent.  Diameter  at  base, 
12  feet  6  inches;  walls,  1  foot;  apex,  10  feet;  floor  space,  123  square 
feet;  air  space,  492  cubic  feet;  allowance,  12  to  16  men,  and  in  war 
18  to  20.  Formerly,  the  ventilation  was  practically  nil,  but  now  it 
has  been  somewhat  improved.  The  French  army  uses  a  similar  tent, 
ventilated  at  the  top.  The  air  space  is  1059  cubic  feet ;  allowance, 
16  men.  The  Germans  use  a  conical  tent  like  the  English  bell  tent. 
Diameter,  under  15  feet;  apex,  12  feet  from  the  ground;  floor  space, 
180  square  feet;  air  space,  1050  cubic  feet;  allowance,  15  men. 
They  use  also  small  bivouac  tents  designed  to  shelter  2  or  more  men. 
The  diflferent  parts  are  distributed  among  and  carried  by  the  men  who 
are  to  use  them. 

It  will  be  observed  that,  of  the  four  armies  mentioned,  ours  is  the 
most  liberal  in  point  of  air  space,  the  minimum  allowance  in  the  larger 
tents  being  72^  cubic  feet,  against  a  maximum  of  41  in  the  English 
service,  66  in  the  French,  and  70  in  the  German  service. 

The  material  of  which  tents  are  made  is  cotton  duck,  which  has 
proved  to  be  muf;h  better  for  shedding  water  than  linen.  Compara- 
tively  little  ventilation   occurs  through  this  material  under  the  best 


602  ■  MILITARY  HYGIENE. 

of  circumstances,  and  none  at  all  when  it  is  wet  by  rain,  for  then  it  is 
impervious  to  air.  Ventilation  of  tents  is  always  defective,  and  com- 
monly the  atmosphere  becomes  exceedingly  foul.  Since  there  is  so 
little  ventilation,  it  is  necessary  that  the  sides  should  be  kept  raised 
during  the  day,  in  order  that  thorough  airing,  and,  if  possible,  sunning, 
may  occur ;  and  at  night,  when  practicable,  the  sides  to  leeward  should 
be  open,  and  the  others,  too,  if  advisable. 

Dr.  Edward  L.  Munson,  U.  S.  A.,^  has  suggested  improvements  in 
the  regular  tentage,  and  especially  in  the  hospital  tents,  for  service  in 
our  tropical  possessions,  since  the  several  forms  in  use,  although 
well  adapted  to  our  climatic  conditions,  are  intensely  hot  and  close  in 
the  high  temperatures  and  humid  atmosphere  that  there  obtain.  He 
proposes  enlarging  the  tent  fly  of  the  hospital  tent  2  feet  in  length 
and  4  in  width,  and  that  it  be  raised  upon  a  light  false  ridge,  4 
feet  longer  than  the  true  ridge  and  projecting  2  feet  to  the  front  and 
rear.  Further,  he  proposes  that  the  canvas  forming  the  top  of  the 
tent  be  cut  out  for  a  space  2  feet  wide  on  each  side  of  the  ridge  and 
running  the  entire  length  of  the  tent,  except  1  foot,  front  and  rear, 
the  canvas  thus  removed  being  replaced  by  heavy  rope  netting  with  a 
2-inch  mesh.  In  order  better  to  reflect  the  heat  rays,  the  fly  should 
be  made  of  white  canvas,  the  tent  itself  being  of  dark  canvas,  with  a 
view  to  subduing  the  light  in  the  interior.  An  experimental  tent, 
made  under  orders  of  the  Surgeon-General,  was  pitched  within  a  few 
feet  of  a  regular  hospital  tent  and  a  regular  conical  wall  tent,  for  pur- 
poses of  comparison.  Thermometric  observations  showed  an  average 
diiference  of  7  degrees  in  favor  of  the  improved  tent,  which  was  never 
less  than  4.5  degrees  cooler,  twice  was  8.5  degrees,  and  once  10.5 
degrees  cooler  than  the  regular  hospital  tent.  Compared  with  the 
conical  wall  tent,  the  temperature  ranged  9.5  to  18.5  degrees  lower 
in  the  improved  tent,  which  difference  "  means  in  the  tropics  all  the 
difference  between  comfort  and  distress  for  the  well  and  such  relief 
from  great  and  depressing  heat  as  would  do  much  to  bring  about  recov- 
ery in  the  sick."  The  experimental  tent  demonstrates  that  no  tent 
should  be  issuedfor  use  in  the  tropics  without  the  protection  afforded 
by  a  fly.  The  U.  S.  A.  Board  of  Equipment  promptly  adopted  the 
improved  hospital  tent. 

Dr.  Myles  Standish,  M.  Y.  M.,^  first  called  attention  to  the  intense 
white  glare  to  which  the  occupant  of  the  hospital  tent  is  subjected  from 
the  covering  above  his  head,  and  which  must  be  a  source  of  actual 
injury  to  eyes  already  in  a  pathological  condition.  Reasoning  from 
general  laws,  he  recommends  a  pale  blue  or  an  olive  green  as  the  safest 
color. 

In  India,  the  British  use  a  tent  with  a  double  fly,  having  an  air 
space  of  2373  cubic  feet  and  accommodating  16  healthy  or  8  sick  men, 

^  Tentage  for  Tropical  Service,  Boston  Medical  and  Surgical  Journal,  Nov.  16,  1899, 
p.  487. 

■^  Color  the  Canvas  of  Hospital  Tents.  Reprint,  Transactions  of  the  Association  of 
Military  Surgeons  of  the  United  States,  1896. 


POSTS  AND   CAMPS.  603 

which  gives  a  far  greater  allowance  of  space  than  in  the  service  else- 
where. For  field  service,  tents  of  686  cubic  feet  capacity,  accommo- 
dating 16  British  or  20  native  soldiers,  and  smaller  ones  of  392 
cubic  feet  capacity,  accommodating  8  British  or  10  native  soldiers, 
are  in  use. 

Tents  are  arranged  best  in  short  single  lines,  the  individual  tents 
being  distant  from  each  other  at  least  once  and  a  half  the  tent's  diam- 
eter ;  the  intervals  are  not  fixed  by  regulation.  If  possible,  the  tent 
should  face  the  east,  so  that  when  the  day  is  advanced,  the  southern 
wall  may  be  lifted  so  as  to  admit  the  sun's  rays  to  the  whole  of  the 
interior.  Each  tent  should  be  ditched  as  soon  as  it  is  placed  in 
position. 

The  tent  ditch  should  be  6  inches  wide  and  4  deep,  and  should  con- 
nect with  the  company  ditches,  and  these  in  turn  with  each  other, 
forming  a  complete  system  of  surface  drainage.  All  surface  drainage 
from  higher  ground  should  be  prevented  by  being  intercepted  and 
turned  aside. 

The  floor  of  the  tent  should  never  be  lowered  by  excavating,  for 
men  should  sleep  above  the  level  of  the  ground,  and  never  below  it. 
If  the  soil  is  not  quite  clean  and  firm,  it  should  be  dug  out  to  the 
depth  of  about  a  foot  and  replaced  by  clean  gravel  or  sand,  if  such  is 
obtainable,  and  then  covered  with  boards.  Elevated  platforms  are 
eminently  desirable,  and  tents  not  so  provided  should  be  moved  every 
week  to  the  open  spaces  between,  so  that  the  sun  may  exert  its  purify- 
ing influence  and,  together  with  fresh  air,  may  put  the  vacated  sites 
again  in  a  condition  for  occupancy.  The  floors  of  the  tents  should, 
when  possible,  be  covered  with  loose  boards,  if  these  are  obtainable; 
and  occasionally  the  surface  of  the  soil  should  be  scraped  and  replaced 
with  clean  gravel  or  sand.  In  malarial  and  yellow  fever  districts, 
nettings  to  exclude  mosquitoes,  especially  at  night,  and  individual 
netting  on  light  frame-work  for  the  protection  of  the  head,  the  other 
parts  of  the  body  being  protected  by  clothing,  will  be  found  to  have 
great  influence  in  checking  infection. 

Huts. — During  cold  weather,  woOden  huts  are  much  better  adapted 
for  occupation  than  tents,  and  have  come  into  extensive  use  in  the 
German,  French,  and  English  armies,  both  in  war  and  in  time  of 
peace.  The  use  of  log  cabins  is  advocated  by  Colonel  Charles  Smart, 
M.D.,  U.  S.  A.,  to  house  4  men  apiece.  The  inside  dimensions  given 
are  13X7  feet ;  walls,  6  feet ;  ridge,  10  feet  from  the  floor ;  the  door 
to  open  in  the  middle  of  one  side ;  the  chimney  opposite  the  door  out- 
side the  wall ;  the  roof  consists  of  canvas  14X12  feet,  with  a  larger 
fly.  This  is  regarded  as  the  best  size  and  allowance,  but  the  present 
tactics  require  squads  of  8,  for  whom,  according  to  Woodhull,  "there 
should  be  two  huts  8X11  feet  end  to  end,  6  feet  apart,  with  one  con- 
tinuous roof  and  door  in  the  adjacent  ends,  but  not  midway.  The 
chimney  should  be  in  the  middle  of  one  long  end.  Two  platforms 
each  6^  X  4|-  feet,  one  h^ngthwise  and  one  across  the  end,  would  ac- 
commodate 2  men,  sleeping  with  their  heads  adjacent.     The  covered 


604  MILITARY  HYGIENE. 

porch  between  the  huts  would  be  6  X  9  feet  in  the  clear,  the  sleeping 
platform  be  open  beneath,  and  under  no  pretence  should  two-storied 
bunks  be  allowed."  On  damp  sites,  the  walls  should  be  raised  a  foot 
from  the  surface ;  but  on  dry  soil,  they  may  be  built  directly  on  the 
ground  level,  the  soil  well  pounded  down,  covered  with  sand  and 
gravel,  and  concreted. 

The  floor  of  the  huts  raised  from  the  ground  is  made  best  of  split  or 
dressed  logs.  The  canvas  roof  and  fly  are  attached  in  such  a  way  that 
they  may  readily  be  removed  when  it  is  desired  to  admit  the  sun  to 
the  interior.  Portable  huts  may  be  furnished,  having  frames  of  wood 
or  iron.  The  German  huts  are  made  with  wooden  or  iron  frames 
covered  with  felt  and  hned  with  canvas.  They  are  easily  ventilated 
and  warmed.  The  French  huts  are  made  circular  in  shape  ;  the  walls 
are  of  boards  with  glass  windows.  They  are  easily  ventilated  and 
heated.  The  huts  should  be  at  least  10  feet  apart  at  the  ends,  and 
the  interspaces  should  be  carefully  protected  from  pollution. 

Water  Supply. — It  goes  without  saying,  that  one  of  the  first  consid- 
erations in  the  establishment  of  a  permanent  camp  is  an  adequate  sup- 
ply of  potable  water,  which  subject  is  presented  elsewhere.  It  is  cus- 
tomary to  allow  at  least  5  gallons  per  capita  per  diem  for  all  purposes, 
and  as  much  more  as  is  practicable.  Water-closets  and  baths  require, 
naturally,  a  very  generous  allowance.  Hospitals  require  much  more 
per  capita  than  barracks.  For  horses,  from  5  to  10  gallons  per  diem 
are  required.  In  general,  it  may  be  said  that  the  more  generous  the 
supply,  the  greater  the  general  cleanliness  and  efficiency. 

In  temporary  camps,  the  supply,  both  as  to  quality  and  quantity,  is 
determined  by  natural  conditions,  and  must  be  taken  as  it  is  found. 
If  purification  of  that  intended  for  drinking  appears  to  be  necessary, 
the  methods  mentioned  in  the  consideration  of  the  subject  of  water 
supplies  may  be  adopted  according  to  availability.  The  simplest  are 
boiling  and  the  application  of  alum,  with  subsequent  filtration,  if  possi- 
ble, through  sand  held  in  suitable  receptacles  such  as  half  barrels  with 
perforations  through  their  bottoms.  The  so-called  "  mechanical  fil- 
ters," so  much  used  in  the  purification  of  public  water  supplies,  are 
more  efficient  and  convenient.  Experience  has  shown  that,  no  mat- 
ter how  urgent  the  necessity  for  care  in  the  avoidance  of  pollution  of 
water,  it  is  always  difficult  to  prevent  some  of  the  men  from  reckless- 
ness in  drinking.  The  operation  of  purification  should  be  in  the  im- 
mediate charge  of  a  non-commissioned  officer,  properly  instructed  and 
with  a  suitable  detail. 

Sewerage. — The  introduction  of  an  abundant  water  supply  in  a 
camp  is,  of  course,  followed  by  more  or  less  lavish  use  of  water  for 
all  general  purposes,  and  this  necessitates  a  system  of  sewerage  for 
carrying  off"  liquid  waste  and  human  excreta.  Camp  sewers  should 
be  constructed  in  a  proper  manner  of  bricks  or  drain-pipe,  and  never 
of  wood.  The  method  of  final  disposal  of  the  sewage  at  the  outfall 
will  depend  upon  individual  circumstances.  All  permanent  camps 
should  be  properly  sewered. 


POSTS  AND   CAMPS.  605 

In  case  of  outbreaks  of  typhoid  fever,  cholera,  or  other  diseases 
of  the  same  general  class,  the  excreta  should  be  disinfected  before 
being  otherwise  disposed  of.  In  army  practice,  chloride  of  lime 
4  per  cent,  and  carbolic  acid  5  per  cent,  are  commonly  used,  with 
weaker  solution  of  carbolic  acid  and  corrosive  sublimate  1  :  1000  for 
washing  floors  and  articles  of  furniture  or  for  soaking  soiled  clothes. 
Milk  of  lime  is  highly  to  be  recommended  for  excreta,  as  is  also  for- 
maldehyde solution,  if  it  can  be  obtained.  The  Manual  for  the  Med- 
ical Department  says  on  this  point :  "■  Sulphate  of  iron  and  other  cheap 
antiseptics  and  deodorants  may  be  used  when  necessary.  But  the 
necessity  for  their  use  is  a  reproach  upon  the  sanitary  police  of  a 
post,  and  should  only  be  required  under  exceptional  circumstances, 
The  alvine  discharges  of  healthy  persons  do  not  require  disinfection, 
and  when  properly  disposed  of,  do  not  require  treatment  with  any 
chemical  agent  whatever.  If  water-closets  or  earth-closets  are  offen- 
sive, this  is  due  to  faulty  construction,  to  insufficient  supply  of  water 
or  dry  earth,  or  to  neglect  of  ordinary  cleanliness.  The  attempt  to 
remedy  such  defects  by  the  systematic  use  of  antiseptics  is  expensive 
and  unsatisfactory  in  its  results.  The  same  is  true  of  foul  drains,  bad 
smelling  urinals,  accumulations  of  garbage,  etc.  The  proper  remedy 
for  such  conditions  is  cleanliness  and  strict  sanitary  police." 

When  there  is  reason  to  believe  that  infectious  diseases  are  present 
in  camps,  the  latrines  and  cesspools  should  be  disinfected  with  milk 
of  lime  to  the  extent  of  one-twentieth  of  their  contents,  to  which  should 
be  added  every  day  an  amount  equal  to  at  least  a  tenth  of  the  daily 
addition  of  excrement.  Hospital  sewage  is  dangerous  enough  to 
warrant  treatment  on  the  spot  with  disinfectants. 

In  the  absence  of  a  regular  system  of  sewerage,  Sternberg  recom- 
mended cylindrical  galvanized  iron  vessels  18  inches  in  depth  and 
diameter,  with  a  trough  around  the  upper  end  3  inches  deep,  filled 
with  disinfectant.  Into  this,  the  cover  fits,  and  thus  serves  as  a  valve 
and  prevents  the  'escape  of  foul  odors  and  the  entrance  of  flies.  A 
second  cover  with  a  hole  serves  as  a  seat.  The  receptacle  is  to  be 
partly  filled  with  carbolic  solution  or  the  contents  are  to  be  treated 
with  caustic  lime,  or  ashes,  or  dry  earth.  These  vessels  should  be 
removed  at  regular  times,  and  clean  ones  should  be  substituted  while 
they  are  removed,  emptied,  and  cleaned. 

Sinks  and  Latrines. — A  sink,  in  military  parlance,  is  a  cesspool  or 
privy  vault  in  a  temporary  camp ;  usually,  a  trench  from  twelve  to 
fifteen  feet  in  length,  about  two  feet  in  width  and  eight  in  depth,  with 
the  earth,  which  has  been  thrown  up,  piled  along  one  side.  The  requi- 
site number  should  be  dug  before  a  camp  is  occupied  or  as  quickly 
thereafter  as  possible.  They  should  be  placed  to  leeward,  or  in  such 
position  that  the  prevailing  winds  shall  not  convey  the  odor  therefrom 
over  the  company  areas,  and  they  should  never  be  placed  near  existing 
wells.  They  should  not  be  placed  any  farther  away  from  the  men's 
quarters  than  is  absolutely  necessary.  For  convenience  of  use,  a  strong 
pole  is  laid  horizontally  on  upright  forks  at  the  proper  height  and  on 


606  MILITARY  HYGIENE. 

the  side  opposite  the  excavated  earth.  The  latter,  kept  as  dry  as 
possible,  is  thrown  back  each  day  over  the  deposited  excreta,  often 
with  caustic  lime,  chlorinated  lime,  or  ashes. 

Behring  ^  recommends,  in  case  of  necessity,  from  5  to  7.5  liters  of 
milk  of  lime  for  each  250  men ;  Pfuhl  ^  advises  400  cc.  per  man. 
The  addition  of  chlorinated  lime  possesses  a  double  advantage,  since  it 
not  only  acts  as  a  disinfectant,  but  also  serves  to  drive  way  flies,  which 
otherwise  collect  and  may  become  active  agents  in  the  spread  of  infec- 
tious disease. 

Small  sinks  for  each  company  are  regarded  as  much  better  on  several 
accounts  than  one  or  more  large  ones  for  each  regiment.  They  afford 
greater  privacy  when  enclosed  with  brushwood,  and  are  generally  better 
looked  after,  since  the  responsibility  for  their  care  is  more  definitely 
fixed.  When  filled  to  within  two  feet  of  the  surface,  the  remaining 
earth  should  be  thrown  in  and  rounded  over,  the  site  marked,  and,  at 
the  same  time,  new  trenches  prepared.  On  breaking  camp,  all  sinks, 
however  little  used,  should  be  filled  up  and  marked. 

When  the  probable  stay  is  to  be  more  than  of  a  few  days'  duration, 
the  horizontal  poles  are  commonly  replaced  by  box  seats,  open  at  the 
back.  In  winter,  the  trenches  should  be  completely  covered  by  box 
seats  with  covers  ;  hinging  of  the  top  or  rear  side  will  be  necessary  for 
the  proper  throwing  in  of  the  excavated  earth. 

The  word  latrine  is  commonly  used  as  synonymous  with  sink.  It  is 
properly  defined  as  "  a  privy  or  water-closet,  especially  in  trough  form 
accommodating  several  at  the  same  time."  ^  A  further  description  of 
a  latrine  is  elsewhere  given  (see  page  612).  Latrines  are  more  com- 
monly installed  in  barracks  or  permanent  camps.  They  require  fre- 
quent flushing,  if  connected  with  a  system  of  sewerage,  and  frequent 
emptying  and  cleansing,  if  not  so  connected.  The  seats  and  floors 
should  be  kept  thoroughly  clean  by  periodical  washing ;  tAvice  daily  is 
strongly  recommended. 

Urinals  apart  from  sinks  and  latrines  are  installed  in  both  perma- 
nent and  temporary  camps,  and  in  both  it  is  essential  that  they  be  of 
easy  access,  and  their  use  compelled  on  account  of  the  nuisance  arising 
from  indiscriminate  voiding  of  urine  on  the  ground  and  of  the  possi- 
bility of  the  dissemination  of  typhoid  fever  by  the  urine  of  ambula- 
tory cases  of  that  disease  and  of  convalescents  therefrom.  In  inclement 
weather  and  at  night,  all  parts  of  a  camp,  and  especially  the  company 
areas,  are  liable  to  urinary  contamination,  which  should  be  prevented 
as  far  as  possible  by  stringent  rules  and  constant  vigilance. 

Inspections. — Under  the  Army  Regulations,  an  annual  inspection  of 
the  buildings  at  every  post  is  made  by  the  commanding  officer  and 
quartermaster  on  the  first  day  of  March,  and  immediately  afterward 
a  report  is  submitted  giving  a  description  and  showing  the  condition 
and  capacity  of  each  building,  and  the  character  and  extent  of  any 
additions,  alterations,  and  repairs.     Sanitary  inspections  are  more  fre- 

^  Zeitschrift  fiir  Hygiene,  IX.,  p.  395. 

'^  Ibidem,  IV.,  p.  97.  ^  Standard  Dictionary. 


POSTS  AND  GAMPS.  607 

quent  and  more  searching  in  character.  The  surgeon  is  required  to  ex- 
amine, at  least  once  a  month,  and  to  note,  in  the  medical  history  of  the 
post,  the  sanitary  condition  of  all  public  buildings,  the  drainage,  sew- 
erage, amount  and  quality  of  water  supply,  clothing  and  the  habits  of 
the  men,  and  character  and  cooking  of  the  food,  and  immediately  after 
such  examination  to  report  thereon  in  writing  to  the  commanding 
officer,  with  such  recommendations  as  he  may  deem  proper.  Super- 
ficial inspection  is  not  enough,  for  everything  may  look  clean  exter- 
nally and  yet  the  general  condition  may  be  bad. 

The  condition  of  the  air  is  of  much  more  importance  during  the 
sleeping  hours  than  during  the  day  ;  therefore,  ventilation  should  be 
investigated  at  night.  Walls  and  floors  should  be  carefully  examined, 
especially  if  they  are  made  of  porous  material.  Walls  found  to  be 
contaminated  with  organic  filth  should  be  scraped  and  then  thoroughly 
whitewashed.  The  floors,  whether  of  barracks,  tents,  or  huts,  should 
be  scrupulously  clean  and  dry  ;  the  bedding  should  be  free  from  damp- 
ness ;  the  spare  clothing  and  the  men  themselves  and  their  clothing  in 
use  should  be  clean.  The  site  and  immediate  surroundings  of  every 
permanent  or  temporary  structure  should  be  examined  with  particular 
reference  to  the  drainage  and  general  condition  of  the  soil. 

Sanitary  Police. — Exceedingly  strict  sanitary  policing  is  necessary  to 
keep  a  camp  in  a  healthy  condition.  The  responsibility  for  condition 
rests  with  the  commanding  officer,  but  is  shared  in  by  the  company 
officers,  who  must  look  after  their  quarters  and  men.  Under  the  title 
of  "  officer  of  the  day,"  company  commanders  serve  in  turn,  each  for  a 
day,  in  charge  of  general  sanitation,  and  each  is  responsible  to  his  com- 
manding officer  for  the  order  and  cleanliness  of  the  camp  on  the  day 
of  his  service. 

It  has  been  demonstrated  repeatedly  that  untrained  or  inex})erienced 
soldiers  cannot  be  depended  upon  for  thorough  cleaning  or  keeping 
things  clean,  for  they  do  not  know  how  to  take  care  of  themselves, 
because  at  home  they  are  looked  after  by  others  ;  and  unless  sanitary 
police  be  very  strict,  a  clean  and  everyway  good  natural  site  may 
quickly  be  contaminated  and  made  unhealthy.  Until  discipline  is  well 
established,  the  enforcement  of  proper  sanitary  regulations  is  extremely 
difficult,  for  while  they  may  be  most  carefully  formulated,  the  neces- 
sary orders  are  difficult  of  enforcement.  Even  with  the  utmost  care 
and  vigilance,  contamination  of  the  site  is  only  a  question  of  time,  but 
the  more  efficient  the  system,  the  longer  is  that  time  deferred.  A  camp 
in  which  no  attention  is  paid  to  cleanliness  of  the  company  streets  and 
to  habits  of  personal  cleanliness  is  sure  to  be  an  unhealthy  one,  and 
men  who  will  permit  such  conditions  to  obtain  are  commonly  bad 
soidiers  in  every  sense  of  the  word,  with  no  esprit  de  corps,  slovenly  in 
all  their  habits,  conspicuously  attentive  to  sick  call,  and  with  no  respect 
for  themselves  or  their  sujx'riors. 

In  such  a  camp,  the  development  of  epidemics  of  infectious  diseases, 
particularly  typhoid  fever,  is  only  a  question  of  time,  since  it  needs 
only  the  ijitroductiou  of  the  specific  germ  and  favorable  opportunities 


608  MILITARY  HYGIENE. 

for  its  dissemination.  Since  this  disease  is  endemic  in  all  parts  of  the 
country,  it  is  not  strange  that  among  large  numbers  of  men  brought  in 
from  different  quarters  there  should  be  one  or  more  carriers  of  the 
infection.  In  any  camp  of  whatever  degree  of  efficiency  in  sanitary 
police,  unless  such  cases  are  recognized  at  once  and  their  excreta  com- 
pletely disinfected  or  otherwise  disposed  of,  so  that  no  danger  shall  be 
possible  therefrom,  the  site  is  likely  to  become  polluted  and  the  bacilli 
to  be  distributed  through  the  usual  agencies. 

One  of  the  first  essentials  of  maintaining  cleanliness  in  camp  is  good 
surface  drainage.  If  the  soil  is  damp,  the  site  soon  becomes  an  expanse 
of  mud,  owing  to  the  constant  impress  of  hundreds  of  feet.  Mud  assists 
in  the  conservation  of  refuse  and  filth  which  it  envelops  and  masks, 
and  hence  arises  the  necessity  for  efficient  and  thorough  ditching,  and 
for  filling  up  depressions  likely  to  retain  surface  water.  The  usual 
pathways  and  sidewalks  should  be  made  as  dry  as  possible  by  the  appli- 
cation of  gravel,  and  by  such  other  methods  as  are  applicable  to  each 
individual  case. 

All  refuse  of  whatsoever  kind  should  be  prevented  from  accumulating 
within  the  lines  ;  eveiything  should  be  promptly  removed  and  disposed 
of,  if  possible,  by  burning.  Kitchen  refuse  should  be  deposited  in 
covered  receptacles,  which  should  be  carried  away  twice  daily.  On  no 
account  should  it  be  left  exposed  on  the  ground  or  elsewhere,  since  not 
only  does  it  speedily  develop  the  well-known  nauseous  odor  of  swill, 
and  thus  become  a  nuisance,  but  it  is  an  attraction  for  flies,  which,  by 
their  investigation  of  all  sorts  of  filth,  including  the  faecal  discharges  in 
the  sinks,  and  then  of  the  soldiers'  food  both  in  the  kitchen  and  at  mess, 
have  agam  and  again  proved  themselves  to  be  largely  responsible  for 
the  spread  of  epidemic  diseases,  as  will  be  explained  more  in  detail  on  a 
later  page. 

The  final  disposition  of  kitchen  refuse  is  often  a  problem  fraught 
with  serious  difficulties,  When  possible,  it  should  be  burned  in  one  of 
the  numerous  forms  of  incinerators  devised  for  the  purpose ;  but  on  no 
account  should  it  be  spread  out  in  the  vicinity  of  the  apparatus  to  dry. 
If  it  be  advisable  to  bury  any  part  of  it,  at  whatever  distance 
below  the  surface  it  is  deposited,  it  should  be  well  covered  with  clean 
earth.  The  deeper  it  is  buried,  the  longer  will  it  resist  complete 
decomposition. 

Stable  manure  should  be  removed  every  day  and  deposited  at  a  suffi- 
cient distance  and  in  such  a  location  as  to  insure  that  it  shall  not  be  a 
nuisance  or  a  source  of  danger  to  the  water  supply.  Incombustible 
harmless  refuse  should  be  removed  out  of  sight,  and  not  be  allowed  to 
accumulate,  for  anything  promoting  untidiness  of  appearance  mvites 
additional  untidiness  by  its  example. 

Considering  the  many  details  of  camp  police  and  the  necessity  for 
co5peration  on  the  part  of  every  man,  it  is  not  strange  that,  in  our 
war  with  Spain,  the  hasty  gathering  together  of  large  bodies  of  un- 
disciplined troops  from  all  parts  of  the  country  into  large  improvised 
camps,  largely  mider  the  control  of  inexperienced  officers  both  of  the 


POSTS  AND   CAMPS.  609 

line  and  medical  service,  was  followed  very  quickly  by  the  outbreak  of 
epidemic  diseases,  which  carried  otf  large  numl^ers  of  men  who,  to  a 
certain  degree,  were  victims  of  their  own  carelessness.  It  is  related, 
for  example,  that  a  certain  regiment  of  volunteers,  encamping  nearly 
side  by  side  with  one  of  regulars,  was  invaded  to  an  extraordinary 
degree  by  typhoid  fever,  while  the  regulars  were  practically  free  from 
disease.  One  of  the  medical  officers  informed  the  author  that  most  of 
these  men  were  so  dirty,  lazy,  ignorant,  intemperate,  and  immoral,  that 
nothing  short  of  an  extensive  epidemic  among  them  could  have  been 
expected,  and  was  expected  from  the  start.  They  saw  some  active 
service,  and  were  conspicuous  for  general  inefficiency  and  lack  of  disci- 
pline. Their  ranks  were  reduced  very  largely  by  disease,  and  the 
casualties  were  practically  nothing.  The  survivors  returned  to  civil 
life  and  were  welcomed  as  heroes ;  those  who  perished  in  consequence 
of  their  own  and  their  comrades'  revolting  habits  of  life  are  enrolled 
with  those  who  sacrificed  their  lives  in  defence  of  their  country's 
honor. 

The  necessity  of  constant  supervision  and  of  enforcement  of  disci- 
pline has  been  well  set  forth  by  John  S.  Wise,^  who  says  :  "  To  appre- 
ciate fully  the  truth  that  men  are  but  children  of  a  larger  growth,  one 
must  have  commanded  soldiers.  Without  constant  guidance  and 
government  and  punishment,  they  become  careless  about  clothes,  food, 
ammunition,  cleanliness,  and  even  personal  safety.  They  will  at  once 
eat  or  throw  away  the  rations  furnished  for  several  days,  never  con- 
sidering the  morrow.  They  will  cast  aside  or  give  away  their  clothing 
because  today  is  warm,  never  calculating  that  tomorrow  they  may  be 
suffering  for  the  lack  of  it.  They  will  open  their  cartridge  boxes  and 
dump  their  cartridges  on  the  roadside  to  lighten  their  load,  although  a 
few  hours  later  their  lives  may  depend  upon  having  a  full  supply. 
When  they  draw  their  pay,  their  first  object  is  to  find  some  way  to  get 
rid  of  it  as  quickly  as  possible.  An  officer,  to  be  really  efficient,  must 
add  to  the  qualities  of  courage  and  firmness,  those  of  nurse,  monitor, 
and  purveyor  for  grown-up  children,  in  whom  the  bumps  of  improvi- 
dence and  destructiveness  are  abnormally  developed." 

A  striking  and  interesting  object-lesson  in  camp  sanitation  is  given 
by  Colonel  Charles  R.  Greenleaf,  M.  D.,  Medical  Inspector,  U.  S.  A.^ 
Two  camps  located  very  near  together,  nearly  equal  in  the  number  of 
men  contained  (about  12,000),  and  with  the  same  conditions  of  climate, 
soil,  water  supply,  and  food,  showed  very  different  records  of  morbid- 
ity and  mortality.  In  one,  "  the  men  were  scourged  with  sickness  and 
death,  and  large  numbers  of  them  were  permanently  invalided  ;  local 
epidemics  became  general,  and  soon  the  entire  camp  was  so  thoroughly 
infected  that  it  was  of  necessity  abandoned."  In  the  other,  "but  little 
sickness  (the  percentage  never  exceeding  five  and  a  half  of  the  aggro- 
gate  strength),  few  deaths,  and  a   few  cases  permanently  invalided  ; 

'  The  Eiyl  of  an  Era,  Boston,  1900,  p.  347. 

^  An  Object  Lesson  in  Military  Sanitation,  Boston  Medical  and  Surgical  Journal, 
Nov.  16,  1S09,  p.  485. 


610  MILITARY  HYGIENE. 

local  epidemics  of  contagious  disease,  due  to  importation/'  were  quickly 
controlled,  and  never  extended  beyond  the  respective  commands  which 
brought  them,  nor  did  a  single  case  of  infectious  disease  originate  in  the 
camp. 

The  difiPerence  in  the  health  conditions  of  the  two  camps  was  due  to 
the  fact  that  in  one,  "  the  advice  of  sanitarians  was  seldom  asked,  and 
when  asked  was  not  followed,  and  nearly  every  law  of  health  was 
either  ignored  or  violated,"  while  in  the  other,  "the  advice  of  sani- 
tarians was  freely  sought,  accepted,  and  carried  out,  no  pains  being 
spared  to  secure,  as  far  as  possible,  compliance  with  the  laws  of  health." 
The  benefits  of  sanitation  were  recognized  by  both  officers  and  men, 
and  the  advice  of  its  teachers  was  carried  out  by  all  to  the  fullest 
extent. 

The  following  sanitary  regulations,  published  for  the  governing  of 
certain  model  camps  established  in  the  Presidio  Reservation,  one  for 
five  regiments  of  volunteers  returning  from  the  Philippine  Islands, 
one  for  four  regiments  of  out-going  volunteers,  or  about  5200  men, 
and  one  for  about  2000  recruits  for  the  regular  regiments  already  in 
tlie  Philippines,  are  communicated  by  Dr.  Greenleaf.  ("  In  planning 
these  camps  the  primary  objects  were  to  remove  the  kitchens  as  far  as 
possible  from  the  latrines,  to  provide  a  safe  method  for  the  disposal 
of  excreta,  garbage,  etc.,  to  secure  means  for  the  personal  cleanliness 
of  the  men,  to  heat  their  quarters,  and  to  supply  them  with  an  abun- 
dance of  good  food  and  water.") 

"The  commanding  officer  of  the  troops  occupying  the  camps  will 
detail  from  his  command  two  sanitary  inspectors ;  one  from  the  line, 
preferably  a  major  of  the  regiment,  and  the  other  a  regimental  medical 
officer,  whose  daily  duty  it  shall  be  to  jointly  inspect  the  regiment,  in- 
quiring into  the  general  police  of  the  company  quarters  and  streets,  the 
kitchens,  the  food,  its  preparation,  quality  and  method  of  serving,  the 
latrines,  urinals  and  sewers,  and  making  to  the  regimental  commander 
a  brief  report  of  any  unsanitary  conditions  they  may  discover,  this 
report  to  be  forwarded  the  same  day  to  the  medical  inspector  of  the 
army  at  department  headquarters. 

"  One  medical  officer  and  one  hospital  steward  from  each  regiment 
will  be  required  to  be  present  for  duty  with  the  regiment  at  all  times 
of  the  day  and  night. 

"  A  daily  sick  call  will  be  held,  and  slight  cases  of  illness  treated  in 
quarters  or  in  the  regimental  hospitals  provided  for  that  purpose,  but 
all  men  who  are  likely  to  remain  sick  more  than  three  days  will  be 
promptly  sent  to  the  General  Hospital  at  the  Presidio  of  San  Fran- 
cisco. 

"  If  any  case  of  infectious  disease  occurs,  the  fact  will  be  promptly 
reported  to  the  camp  surgeon,  who  is  authorized  to  make  proper  dispo- 
sition for  its  isolation  and  care. 

"  An  ambulance  fully  equipped  with  a  team  will  be  assigned  to  the 
camp  by  the  commanding  officer  of  the  Presidio.  This  ambulance  will 
report  daily  to  the  camp  surgeon  at  sick  call,  remaining  in  the  camp 


POSTS  AND  CAMPS.  611 

during  the  day,  subject  to  his  orders.  Under  no  circumstances  will 
this  ambulance  be  used  for  any  other  purpose  than  the  transportation 
of  the  sick,  or  medical  supplies.  The  commanding  officer  of  the 
Presidio  will  also  cause  another  ambulance  to  be  sent  to  the  camp  for 
service  at  night  time.  This  ambulance  will  remain  on  duty  from  re- 
treat to  reveille  for  night  emergency  service.  When  the  night  ambu- 
lance reports  for  duty,  the  day  ambulance  will  be  relieved  and  returned 
to  the  post." 

"  Company  commanders  will  caution  their  men  against  exposure  to 
the  fogs  and  high  winds  that  prevail  here,  especially  in  the  early 
morning  and  evening,  at  which  time  overcoats  will  be  worn.  Riding 
on  the  '  dummy '  of  the  street  cars,  especially  at  night,  is  particularly 
hazardous  to  men  recently  returned  from  service  in  the  tropics.  Guard 
duty  and  other  military  functions  required  at  these  hours  Avill  be  held 
in  overcoats,  and  at  breakfast  and  supper  the  stoves  in  the  dining-rooms 
will  be  provided  with  fires.  The  sale,  by  civilians,  of  food  or  drink 
within  the  limits  of  the  camp  will  be  forbidden. 

"  At  retreat,  urine  tubs,  two  to  each  company,  will  be  placed  in  each 
company  street,  and  men  desiring  to  urinate  at  any  time  during  the 
night  will  be  required  to  use  them.  The  tubs  will  be  removed  from 
the  company  street  at  reveille  to  a  place  convenient  for  the  scavengers, 
who  will  remove,  clean  and  place  lime  in  them  for  use  the  next 
night. 

"The  quartermaster's  department  will  be  required  to  provide  an 
ample  force  of  scavengers  to  clean  the  latrines  and  urinal  troughs  at 
least  once  daily,  and  to  refill  the  troughs  with  milk  of  lime ;  they  will 
also  remove  all  kitchen  garbage,  and  either  cremate  it  or  dispose  of  it 
in  such  place  as  the  quartermaster  shall  direct.  Particular  care  will  be 
enjoined  on  company  cooks  to  keep  grease  traps  clean,  and  to  deposit 
all  solid  garbage  in  cans  prepared  for  that  purpose  in  time  for  its  re- 
moval by  the  scavengers. 

"  The  quartermaster's  department  will  furnish  to  each  regiment  an 
ample  supply  of  necessary  policing  implements,  to  enable  the  men  to 
thoroughly  and  effectively  police  the  camp  daily." 

These  regulations.  Dr.  Greenleaf  reports,  were  promptly  carried  out 
by  officers  and  men,  and,  in  spite  of  the  fact  that  nearly  every  body  of 
men  brought  some  form  of  infectious  disease,  including  typhoid  fever, 
tropical  dysentery,  diphtheria,  smallpox,  measles,  and  mumps,  not  a 
single  case  of  any  infectious  disease  originated  in  the  camps,  all  of  the 
imported  cases  being  promptly  segregated  from  the  command,  all  in- 
fected material  disinfected  or  destroyed,  and  all  men  who  had  been 
exjiosed  isolated  and  quarantined. 

In  all  these  camps,  the  latrines  and  bath-houses  were  placed  on  the 
flanks  and  rear;  the  kitcliens  and  mess  halls,  in  the  central  lines.  In 
tlie  rear  of  each  mess  hall,  a  zinc-lined  wash  trough,  supplied  with  a 
dozen  bib  cocks,  was  placed  to  be  used  as  a  lavatory  ;  near  the  door  of 
each  kitchen  was  a  grease  trap  connected  with  the  sewer,  and  galva- 
nized cans  for  garbage  and  ashes  were  placed  on  the  porch.     Large 


612  MILITARY  HYGIENE. 

caldrons  for  heating  water  for  lanndry  and  other  purposes  were  set  up 
in  convenient  places.  Two  galvanized  wash-tubs  were  furnished  to 
each  company,  and  "night  soil  tubs  were  placed  in  every  company 
street  at  '  tattoo '  for  the  use  of  the  men  during  the  night,  a  sentinel 
being  posted  in  the  street  to  see  that  the  orders  regarding  their  Ui-c 
were  carried  out."  The  construction  of  latrines  and  disposal  of  excreta 
were  carried  out  according  to  the  recommendations  of  a  board  of 
medical  officers,  consisting  of  Major  Reed,  U.  S.  A.,  and  Majors  Vaughan 
and  Shakespeare,  U.  S.  V.,  as  follows  : 

"A  trough  made  of  No.  22  galvanized  iron,  fourteen  feet  long, 
twenty-two  inches  wide  at  the  top,  parabolic  in  cross  section,  and  with 
a  maximum  depth  of  eighteen  inches,  if  set  in  a  light  wooden  frame- 
work, which  serves  as  a  protective  crate  in  transportation,  gives  sup- 
port to  the  trough  while  in  position,  and  serves  for  the  attachment  of 
a  lid  in  two  sections,  furnished  with  seven  seat  holes.  These  holes  are 
shaped  so  as  to  render  soiling  of  the  seat  difficult,  and  a  slanting  board 
one  foot  wide,  permanently  fixed  at  a  proper  angle  above  the  seat,  pre- 
vents the  men  from  getting  up  on  it  with  their  feet.  When  in  position, 
one  end  of  the  trough  is  raised  four  inches  higher  than  the  other. 
The  trough  is  placed  in  an  ordinary  frame  privy  house.  At  the  upper 
end  of  the  trough  there  is  placed  a  galvanized  iron  gutter  of  proper 
height  and  inclination  leading  into  the  trough  to  serve  as  a  urinal. 

"  The  rear  side  of  the  gutter  or  that  attached  to  the  wall  of  the  build- 
ing is  higher  than  the  front  side,  to  prevent  soiling  the  building.  The 
trough  is  prepared  for  the  reception  of  faecal  matter  by  filling  it  Avith 
water  until  a  certain  level,  indicated  by  a  line  on  the  inside  of  the 
trough,  is  reached.  A  measure  for  the  purpose,  and  holding  one-sixth 
of  a  barrel,  is  now  filled  with  quicklime  and  emptied  into  the  water ; 
some  dry  lime  should  also  be  placed  in  the  urinal.  The  lime  in  the 
trough  is  thoroughly  stirred  with  a  wooden  paddle.  This  stirring  is 
repeated  three  times  every  day.  The  wooden  paddle  when  not  in  use 
stands  in  a  pail  filled  with  milk  of  lime.  Toilet  paper  is  provided  for 
the  men's  use  m  the  latrines,  because  large  pieces  of  newspaper  will 
float  on  the  water  holding  masses  of  faecal  matter  above  the  surface, 
thus  exposing  it  to  the  flies  and  other  insects. 

"  Once  a  day  the  contents  of  these  troughs  are  pumped  out  into  an 
odorless  excavator,  carted  away  and  properly  disposed  of.  The  milk 
of  lime  destroys  the  typhoid  bacillus,  and  the  contents  of  the  trough, 
if  properly  cared  for,  will  be  quite  innocuous.  Not  only  is  the  milk 
of  lime  and  faecal  matter  innocuous,  but  its  value  as  a  fertilizer  is  con- 
siderable." 

It  may  be  stated,  however,  that  these  excellent  results  in  sanitary 
police  were  not  brought  about  without  outside  assistance,  for  it  was 
found  advisable  to  employ  a  corps  of  civilian  scavengers  consisting  of 
2  overseers,  22  night  scavengers,  54  day  scavengers,  and  17  teamsters, 
with  5  odorless  excavating  carts,  6  sanitary  cars,  and  12  dust  carts. 
By  means  of  this  outside  force,  the  camp  was  kept  thoroughly  clean, 
and  the  excreta  were  promptly  removed  and  disposed  of.     The  latrine 


THE  DISEASES   OF  THE  SOLDIER.  613 

troughs  were  emptied  twice  in  twenty-four  hours,  and  garbage  and  all 
manner  of  waste  material  were  removed  twice  daily.  The  tent  floors, 
kitchens,  mess  halls,  and  company  streets  were  swept  daily  by  the 
soldiers  themselves,  and  one  man  from  each  company  did  duty  each  day 
in  the  company  latrine  to  keep  it  clean  and  stir  the  lime  solution  fre- 
quently. 

*  The  Diseases  of  the  Soldier. 

While  there  are  no  diseases  peculiar  to  the  soldier,  there  are  many  to 
which  the  circumstances  and  conditions  incident  to  camp  life  render 
him  conspicuously  susceptible.  These  are  mainly  of  the  preventable 
class,  and  may  be  largely  checked  by  proper  regard  to  the  principles  of 
camp  sanitation,  by  avoidance  of  polluted  water,  improper  cooking, 
overcrowding,  and  overwork,  and,  in  some  degree,  by  the  inculcation 
of  the  principles  of  moral  living. 

It  is  difficult  or  impossible  to  determine  how  soldiers  compare  with 
civilians  in  the  amount  of  sickness  which  they  sufPer,  since  we  have  no 
statistics  of  general  morbidity,  especially  of  corresponding  age  periods, 
of  the  civil  population ;  and  even  were  such  available,  it  would  be 
necessary  to  bear  in  mind  that  the  soldier  is  often  on  the  sick  list  with 
ailments  which,  in  civil  life,  would  neither  deter  him  from  attending  to 
his  daily  work  nor  cause  him  to  go  to  the  added  expense  of  medical 
advice.  The  soldier  has  absolutely  free  medical  attendance  and  care, 
and  of  this  he  freely  avails  himself,  excepting,  with  many,  in  case  of 
venereal  troubles. 

Concerning  the  constitution  of  the  medical  corps,  the  hospital  accom- 
modations, and  general  administration,  all  of  which  are  fixed  by  law 
and  regulation,  no  description  or  discussion  is  necessary ;  and  a  brief 
consideration  of  the  prevalence  and  predisposing  causes  of  the  chief 
diseases  of  armies  is  all  that  lies  within  the  scope  of  this  work. 

It  is  a  well-known  fact  that  in  both  war  and  peace  the  greatest  mor- 
tality among  soldiers  is  from  disease,  and  not  from  violence,  the  single 
exception  which  history  records  being  afforded  by  the  German  army  in 
the  war  of  1870  with  France.  In  our  war  with  Mexico,  according  to 
Woodhull,  935  of  the  regular  force  were  killed  or  died  of  wounds,  and 
4714  died  of  disease  in  the  field.  In  the  Civil  War,  99,183  whites 
and  3417  negroes  were  killed  or  died  of  wounds,  and  171,806 
whites  and  29,963  negroes  died  of  disease.  In  our  war  with  Spain 
and  troubles  in  the  Philippines,  during  the  year  from  May  1,  1898,  to 
April  30,  1899,  according  to  the  report  of  the  Surgeon-General,  968 
men  were  killed  or  died  of  wounds,  injuries,  and  accidents,  and  5438 
died  of  disease.  Typhoid  fever  was  responsible  for  more  than  half  the 
deaths  from  disease ;  next  in  order  came  malaria,  followed  by  pneu- 
monia, yellow  fever,  and  smallpox. 

Tuberculosis. — In  the  large  standing  armies  of  the  world,  tubercu- 
losis has  long  playf'd  a  leading  part,  due  largely,  as  has  been  pointed 
out,  to  overcrowding  and  deficient  ventilation,  and  to  the  enlistment  of 
men  in  whom   the  disease   is  latent  before  entrance  and  developed  by 


614 


MILITARY  HYGIENE. 


changes  in  habits  of  life,  climate,  etc.  Yet,  according  to  Colin,^  In- 
spector-General of  Hygiene  in  the  French  Army,  many  persons  with 
latent  tuberculosis  not  only  withstand  the  hardships  of  military  service 
well,  but  even  become  stronger  and  generally  healthier.  According  to 
a  statement  by  Surgeon-General  Schjerning  at  the  Tuberculosis  Con- 
gress in  Berlin  (1899),  a  decided  decrease  in  tuberculosis  has  been 
observed  in  the  German  army,  while  in  other  armies  an  increase  from 
year  to  year  in  loss  of  men  from  this  cause  may  be  looked  for  as 
a  certainty,  especially  when  large  increases  in  enlistment  necessitate 
the  inclusion  of  many  not  fit  for  service.  Colin's  statistics  of  losses 
to  the  French  army  are  corroborative  of  Schjerning's  statement;  espe- 
cially those  for  the  year  1895,  when  a  large  increase  of  the  army, 
necessitating  a  reduction  in  the  quality  demanded,  was  followed  by  a 
more  marked  increase  in  yearly  loss.     The  figures  follow  : 


Year 

Discharges  per  1000 

Deaths  per  1000  army 

Total  loss  per  1000  army 

army  strength. 

strength. 

strength. 

1888 

4.30 

1.18 

5.48 

1889 

4.94 

1.05 

5.99 

1890 

5.70 

1.08 

6.78 

1891 

6.10 

1.33 

7.43 

1892 

6.55 

1.04 

7.59 

1893 

6.33 

0.94 

7.27 

1894 

6.55 

1.01 

7.56 

1895 

8.34 

1.14 

9.48 

1896 

7.34 

0.94 

8.28 

In  the  English  service,  phthisis  is  the  chief  cause  of  mortality  and 
invaliding,  the  annual  loss  averaging  somewhat  below  5  per  1000 
army  strength.  In  the  French  service,  the  disease  stands  second  to 
typhoid  fever. 

In  armies,  as  in  general  life,  tuberculosis  finds  the  greater  number 
of  its  victims  among  those  who  are  most  confined,  and  is  more  frequent 
in  the  garrisons  of  large  towns  than  among  troops  in  the  less  thickly 
settled  parts.  The  most  careful  prophylaxis  is  demanded  to  prevent 
its  spread,  and  the  ideal  measures  would  include  the  discharge  of  all 
persons  capable  of  acting  as  foci  of  the  disease. 

Typhoid.  Fever. — Typhoid  fever  is  very  prominent  as  a  scourge, 
especially  in  time  of  war,  when  large  bodies  of  raw  and  undisciplined 
troops  are  brought  together  in  camps  of  instruction.  Among  large 
bodies  of  men  drawn  from  diiFerent  parts  of  a  country  in  which  the 
disease  is  very  generally  distributed,  it  is  almost  inevitable  that 
there  will  be  some  who  Avill  introduce  the  specific  germ.  The  indi- 
vidual soldier,  owing  to  age  and  the  abrupt  changes  in  the  nature  of 
his  surroundings  and  general  habits  of  life,  is  very  susceptible  to 
infections  in  general.  Statistics  demonstrate  that  the  seasoned  regular 
suifers  much  less  from  disease,  in  proportion  to  numbers,  than  the  un- 
disciplined volunteer  and  raw  recruit.  This  is  due  to  the  fact  that  he 
^  Journal  d'Hygiene,  March  1,  1900. 


THE  DISEASES  OF  THE  SOLDIER.  615 

has  become  accustomed  to  the  mode  of  life,  and,  through  training,  has 
learned  better  how  to  take  care  of  himself  in  all  departments  of 
personal  hygiene.  Great  care  is  necessary  to  isolate  cases  as  soon  as 
recognized,  and  to  treat  excreta  so  that  their  final  disposal  shall  not  be 
a  menace  to  the  safety  of  others. 

Of  the  highest  importance  is  the  prevention  of  access  of  flies  to  the 
discharges,  for,  as  has  been  stated  elsewhere,  these  pests  have  been 
responsible  for  the  spread  of  this  and  other  diseases  by  contaminating 
the  food  supply  after  visiting  the  sinks.  Also  of  the  highest  impor- 
tance is  the  avoidance  of  a  polluted  water  supply  ;  boiling  of  water 
concerning  which  nothing  is  known  should  always  be  done  as  a  matter 
of  routine  precaution,  and  the  attention  of  the  men  should  be  drawn 
to  the  danger  which  they  incur  in  the  indiscriminate  drinking  of 
water  which  has  not  been  thus  treated  or  shown  by  competent 
authority  not  to  require  it.  In  general,  it  may  be  stated  that,  without 
efficient  sanitary  police,  typhoid  fever  among  troops  is  always  to  be 
expected. 

The  origin  and  spread  of  typhoid  fever  in  our  army  during  the 
Spanish  War  (1898)  were  investigated  bv  a  board  consisting  of  Dr. 
Walter  Eeed,  U.  S.  A.,  and  Drs.  Y.  C.  Vaughan  and  E.  O.  Shake- 
speare, U.  S.  v.,  who  reported  that  more  than  90  per  cent,  of  the  vol- 
unteer regiments  developed  the  disease  within  eight  weeks  of  going 
into  camp.  In  certain  regiments  of  regulars,  the  disease  developed 
within  three  to  five  weeks.  Among  the  whole  body  of  troops  there 
were  no  less  than  20,000  cases  between  May  and  September.  The 
causes  included  polluted  Avater  and  dissemination  of  fsecal  matter  by 
flies.  In  some  cases,  camps  were  set  up  despite  the  protests  of  the 
medical  officers  against  the  unfitness  of  the  sites  selected. 

Preventive  inoculation  against  this  disease,  although  in  its  infancy, 
has  given  sufficiently  encouraging  results  to  warrant  trial  on  a  large 
scale.  The  great  majority  of  English  troops  sent  to  war  in  South 
Africa  were  so  treated,  and  statistics  concerning  the  efficacy  of  the  treat- 
ment have  demonstrated  its  value. 

Dysentery, — In  the  South  and  in  our  new  tropical  possessions, 
dysentery  is  one  of  the  most  important  camp  diseases  ;  in  fact,  it  is 
said  that,  within  the  tropics,  dysentery  annually  claims  far  more 
victims  than  Asiatic  cholera.  Once  introduced,  like  typhoid  fever,  it 
is  likely  to  become  epidemic.  Prophylactic  measures  adopted  are  the 
same. 

Malaria. — The  various  forms  of  malarial  diseases  are  always  a  curse 
to  armies,  especially  those  operating  in  hot  climates.  Though  the 
death  roll  from  malaria  may  not  be  great,  sickness  and  consequent 
invaliding  are  commonly  enormous  in  amount,  and  an  army  stricken 
with  malaria  is  an  army  unfit  for  field  operations.  The  infection  weak- 
ens the  natural  power  of  resistance  to  other  infections,  and  is  said  to 
predispose  the  victim  especially  to  infection  by  typhoid  fever,  and  to 
exert  a  particularly  pcrni(;ious  influence  on  those  who  have  already 
acquired  or  su]>sequently  ac(piire  venereal  diseases. 


616  MILITARY  HYGIENE. 

Since  the  confirmation  of  the  discovery  of  the  important  part 
played  by  mosquitoes  in  the  dissemination  of  the  malarial  poison, 
the  necessity  of  the  use  of  netting  against  these  pests  has  been  very 
clearly  demonstrated.  The  preventive  measures  against  malaria  consist 
in  the  avoidance,  if  possible,  of  sites  near  which  the  conditions  are 
favorable  to  the  puddle-breeding  mosquitoes,  the  avoidance  of  unneces- 
sary going  about  during  the  hours  when  mosquitoes  are  most  active, 
prevention  of  access  of  mosquitoes  to  the  sleeping  quarters,  and  the 
systematic  use  of  j)rophylactic  doses  of  quinine  morning  and  night. 
AVhiskey  is  not  needed  as  an  adjuvant,  and  is  more  likely  to  be 
an  injury  than  an  aid.  Hot  tea  and  coffee  are  more  highly  re- 
garded. 

Measles. — In  all  new  levies  of  troops,  measles  is  a  serious  impedi- 
ment to  efficiency,  for,  once  introduced,  the  disease  spreads  rapidly 
through  the  camp,  especially  if  the  troops  are  largely  from  the  country, 
where  they  have  escaped  the  diseases  of  childhood  which  ravage  the 
population  of  cities  and  large  towns.  The  importance  of  the  disease 
appears,  according  to  recent  evidence,  to  be  likely  to  be  underrated  by 
commanding  officers. 

Diarrhoeal  Diseases  in  General. — Because  of  the  lesser  resistance 
to  specific  infectious,  Avhicli  appears  to  accompany  even  mild  conditions 
of  diarrhoea,  it  is  essential  to  take  such  measures  and  precautions  as  are 
possible  to  prevent  them.  Among  the  prominent  causes  may  be  men- 
tioned the  use  of  improj^erly  cooked,  indigestible  food,  and  chilling 
of  the  body,  particularly  at  night  while  sleeping  on  the  ground,  even 
although  separated  from  immediate  contact  therewith  by  rubber  blan- 
kets. The  prevention  of  the  first  cause  needs  hardly  to  be  pointed 
out ;  for  the  prevention  of  the  second,  the  habitual  use  of  light  flannel 
garments  or  abdominal  bands  is  recommended. 

Sunstroke. — This  consequence  of  extreme  heat  or  over-exertion  in 
high  temperatures  is  very  likely  to  be  induced  by  imprudence  in  the 
matter  of  water  supply,  and  by  continuous  work  without  periods  for 
rest  and  recreation.  According  to  Dr.  Smart,  U.  S.  A.,^  "If  the 
allowance  of  water  is  scanty,  it  must,  nevertheless,  be  used  at  regular 
intervals,  but  economically,  lest  it  give  out.  There  is  manifestly  less 
danger  of  a  fulminant  stroke  with  a  stinted  but  steady  supply  than 
with  full  allowance  for  a  given  time  followed  by  a  period  of  enforced 
abstinence.  On  the  other  hand,  if  the  supply  is  liberal,  it  may  be  in- 
dulged in  freely  and  with  advantage  when  the  skin  is  acting  well." 
He  relates  that,  during  a  service  of  four  years  in  the  hot  climate  of 
Arizona,  with  commands  of  v^arying  size,  making  long  marches,  often 
on  scant  allowance  of  water,  he  saw  sunstroke  on  but  one  occasion,  and 
in  this  instance,  the  rule  to  use  the  canteen  in  the  early  part  of  the 
march  with  caution,  as  if  no  more  could  be  had  until  arrival  in  camp, 
was  not  followed.  It  was  the  rule,  when  a  supply  presented  itself  on 
the  line  of  march,  to  use  it  freely,  and  then,  on  proceeding,  to  use  the 
refilled  canteens  with  the  same  caution  as  before.  A  canteen  of  tea, 
^  Philadelphia  Medical  Journal,  January  19,  1901,  p.  158. 


THE  DISEASES   OF  THE  SOLDIER.  617 

not  necessarily  strong,  containing  a  little  lemon  juice,  lime  juice,  or 
vinegar,  is  more  desirable  when  obtainable  than  plain  water. 

Venereal  Diseases. — These  are  responsible  for  a  very  large  amount 
of  sickness  in  all  armies,  and  their  prevention  has  been  the  subject  of 
much  consideration  by  military  authorities  everywhere ;  but  the  reme- 
dies against  the  prevailing  high  figures  of  morbidity,  namely,  scientific 
and  practical  control  of  prostitution,  find  always  and  everywhere  active 
opposition  on  the  part  of  the  public. 


CHAPTER    X. 
NAVAL   AND   MARINE   HYGIENE. 

The  conditions  of  life  at  sea  in  relation  to  health  are  very  different 
in  many  respects  from  those  which  obtain  ashore.  The  seafaring^ 
man,  wherever  he  goes,  travels  in  his  habitation,  in  which,  necessarily, 
his  share  of  cubic  space  is  far  less  in  amount  than  that  which  the  prin- 
ciples of  general  hygiene  stipulate  as  a  permissible  minimum  for  those 
ashore.  His  air-supply  while  at  work  on  and  above  the  deck  is  of  the 
greatest  known  purity,  and  while  below  in  his  sleeping  quarters  it  is 
likely  to  be  at  times  unutterably  foul,  and  under  usual  conditions,  even 
with  the  best  of  care  and  appliances,  is  usually  not  in  conformity  with 
the  generally  accepted  standard.  His  work  exposes  him  to  the  hard- 
ships of  the  most  inclement  weather,  to  extremes  of  heat  in  the  stoke- 
holds of  vessels  propelled  by  steam,  to  long-sustained  muscular  effort 
at  critical  periods  ;  and  involves  short  hours  for  sleep,  and  these  not  in 
one  consecutive  whole,  but  divided  by  intervening  periods  of  duty.  His 
food  supply  for  the  entire  period  from  port  to  port  must  be  transported 
with  him,  must  necessarily  possess  keeping  qualities,  and  hence  con- 
sists largely  of  preserved  instead  of  fresh  meats,  and  dried  and  canned 
vegetables  instead  of  those  fresh  from  the  fields. 

In  the  matter  of  kitchens,  cooking  appliances,  and  fuel,  he  is  circum- 
stanced more  fortunately  than  the  soldier,  since  wherever  he  goes  they 
accompany  him,  and  he  is  independent  of  the  frequently  troublesome 
question  of  transportation  of  supplies  and  appliances  in  time  of  need. 
Thus  it  was  that,  during  the  battle  of  Manila  Bay,  all  hands  could  be 
piped  to  breakfast,  whereas  at  the  fierce  onslaught  by  the  land  forces 
at  San  Juan,  no  such  comfortable  relief  could  be  afforded. 

His  water-supply  must  be  carried  in  proper  storage  or  be  obtained 
by  distillation  from  the  salt  water  in  his  path.  But  he  has  not  to  cope 
with  the  difficulties  which  beset  the  soldier  in  the  matter  of  camp  sani- 
tation, for  his  sewer  is  the  boundless  ocean,  and  the  question  of  disposal 
of  garbage  requires  no  thought. 

NAVAL   RECRUITS. 

The  United  States  Regulation  forbids  the  enlistment  as  a  landsman 
of  any  man  over  25  years  of  age  unless  he  has  learned  some  mechan- 
ical trade,  and  in  this  instance  he  may  not  be  enlisted,  without  special 
authority,  if  over  34  years  of  age.  A  landsman  is  one  who  never 
before  has  gone  to  sea,  or,  having  been  already  at  sea,  does  not  possess 
the  skill  required  of  an  ordinary  seaman.  An  ordinary  seaman  must 
already  have  had  two  years'  experience.     An  able  seaman  is  one  who 

618 


THE  NAVAL  RATION.  619 

has  had  at  least  four  years'  experience  and  understands  the  navigation 
of  ships.  Apprentices  are  enlisted  not  under  16  years  of  age,  and 
serve  as  such  until  21,  when  their  term  expires. 

A  candidate  for  the  service  is  required  to  undergo  a  thorough  ex- 
amination. If  afflicted  with  stricture,  internal  piles,  or  any  serious 
disease,  or  suffering  from  the  results  of  any  former  disease  or  injury, 
or  subject  to  fits,  he  is  debarred  from  the  service.  Applicants  for 
positions  as  skilled  mechanics  must  demonstrate  their  knowledge  of 
their  craft,  and  show  that  they  possess  the  necessary  qualifications  for 
following  it. 

THE   NAVAL   RATION. 

The  naval  ration  is  always  different  from  that  of  the  soldier,  for  rea- 
sons already  given.  The  ration  of  the  United  States  Xavy,  as  pre- 
scribed in  1902,  consists  of  the  following  daily  allowance  of  pro- 
visions to  each  person  :  "  One  pound  and  a  quarter  of  salt  or  smoked 
meat,  with  3  ounces  of  dried  or  6  ounces  of  canned  fruit  and  1 2  ounces 
of  rice  or  8  ounces  of  canned  vegetables,  or  4  ounces  of  dessicated 
vegetables  ;  together  with  1  pound  of  biscuit,  2  ounces  of  butter,  4 
ounces  of  sugar,  2  ounces  of  coffee  or  coca,  or  J  ounce  of  tea,  and  1 
ounce  of  condensed  milk  or  evaporated  cream,  and  a  weekly  allowance 
of  ^  pound  of  macaroni,  4  ounces  of  cheese,  4  ounces  of  tomatoes,  J 
pint  of  vinegar,  J  pint  of  pickles,  ^  pint  of  molasses,  4  ounces  of  salt, 
\  ounce  of  pepper,  and  i^  ounce  of  dry  mustard.  Five  pounds  of  lard 
or  a  suitable  substitute  will  be  allowed  for  every  hundred  pounds  of 
flour  issued  as  bread  and  such  quantities  of  yeast  as  may  be  necessary." 

Preserved  meats,  in  the  meaning  of  the  law,  comprise  canned  beef, 
mutton,  corned  beef,  bacon,  ham,  sausages,  salted  fish,  and  any  other 
smoked  or  salted  meats.  Flour  comprises  wheat,  rye,  oatmeal,  corn- 
meal,  and  hominy.  Dried  fruits  include  apples,  peaches,  pnmes,  raisins, 
dates,  figs,  and  others  susceptible  of  preservation  by  drying. 

From  the  above,  it  will  be  noted  that  our  naval  ration  is  very 
elastic  and  generous,  and,  indeed,  is  said  to  be  superior  in  amount  and 
variety  to  that  of  any  foreign  navy,  just  as  our  army  ration  surpasses 
in  these  respects  those  of  other  armies. 

In  spite  of  the  elasticity  and  abundance  of  the  ration,  considerable 
improvement  and  much  greater  satisfaction  appear  to  be  attained  by 
the  system  of  the  consolidated  mess,  instituted  originally,  in  1889,  by 
Lieutenant  Delehanty,  of  the  U.  S.  S.  Indejiendence.  Not  the  least  of 
its  advantages  is  the  improvement  in  the  preparation  and  serving  of 
the  food.  In  the  ordinary  method  of  messing,  the  ship's  company  is 
divided  into  a  number  of  messes  of  about  twenty  men,  and  each  has  its 
own  cook  and  mess  attendants.  The  preparation  of  the  food  for  all 
is  in  charge  of  the  chief  cook  and  a  number  of  assistants,  and  the 
serving  out  and  the  care  of  the  mess  gear  are  attended  to  by  the  mess 
attendants  or  berth-deck  cooks.    According  to  Lieutenant  B.  C.  Decker,^ 

^  The  Consolidated  Mess  of  the  Crew  of  the  U.  S.  S.  Indiana,  Proceedings  of  the 
U.  S.  Naval  Institute,  XXIIL,  1897,  p.  403. 


620  NAVAL  AND  MARINE  HYGIENE. 

of  the  U.  S.  S.  Indiana,  "  the  present  system  of  messes  with  incom- 
petent and  often  broken-down  landsmen  as  cooks,  ,  .  .  and  with 
general  waste  and  mismanagement,  is  a  failure." 

In  the  consolidated  mess  of  the  Indiana,  as  described  by  Decker, 
the  crew  of  380  men  have  a  common  interest,  and  are  attended  to  by 
seven  cooks,  one  of  the  first  class,  two  of  the  second,  and  four  of  the 
third  class,  a  commissary  yeoman,  and  a  storeroom  keeper.  Funds 
for  provisioning  the  mess  are  derived  from  the  commuted  rations  and 
the  canteen.  (Here  may  be  stated  that,  in  the  discussion  of  the  paper 
noted,  the  canteen  system,  as  it  existed  in  the  Navy,  was  the  subject  of 
severe  criticism  by  officers  of  the  line.     It  is  now  abolished.) 

The  system  saves  much  trouble,  requires  fewer  cooks,  and  by  mak- 
ing possible  the  purchase  of  a  still  wider  variety  of  food  materials,  in- 
sures greater  satisfaction  throughout  at  a  diminished  cost. 

The  principal  defects  of  all  dietaries  for  seafaring  men  comprise 
monotony,  deficiency  m  vegetable  components,  and  excess  of  preserved 
meats.  In  order  to  guard  against  the  results  of  an  insufficient  supply  of 
antiscorbutic  vegetables,  the  Revised  Statutes  require  that  all  vessels  of 
more  than  75  tons  bound  across  the  Atlantic  or  Pacific  or  around  Cape 
Horn  or  Cape  of  Good  Hope,  or  engaged  in  whaling  or  sealing,  shall 
carry  a  sufficient  supply  of  lemon  juice  or  lime  juice,  and  vinegar, 
which  shall  be  served  out  Avithin  ten  days  after  salt  provisions  have 
been  served  out,  the  lemon  juice  or  lime  juice  at  the  rate  of  one-half 
ounce  daily,  and  the  vinegar  at  the  rate  of  one-half  pint  weekly,  per 
man. 

WATER   SUPPLY. 

The  satisfactory  storage  of  water  aboard  ships  is  a  matter  of  some 
difficulty.  Small  vessels,  as  ordinary  merchant  ships  and  similar 
craft,  not  provided  with  distilling  apparatus,  must  necessarily  carry 
a  sufficiency  of  water  for  the  passage  between  ports,  reckoned  at  three 
quarts  daily  per  man  plus  an  amount  sufficient  for  cooking.  Water  is 
stored  in  wooden  casks  and  metallic  tanks.  Storage  in  casks  is  far 
from  satisfactory,  on  account  of  the  deterioration  which  occurs  in  the 
quality  of  the  water.  This  is  due  to  the  action  of  the  water  in  extract- 
ing matters  from  the  wood,  and  to  decomposition  of  these  matters  in- 
duced and  carried  on  by  the  usual  agencies.  Casks  should  not  be  made 
of  soft  wood,  and  the  interior  should  be  very  thoroughly  charred, 
in  order  to  diminish  as  much  as  possible  the  extraction  of  soluble  con- 
stituents and  to  guard  against  decay.  Tanks  are  commonly  made  of 
galvanized  iron,  lined  sometimes  with  cement.  They  should  be  placed 
in  easily  accessible  locations  which  admit  of  ready  inspection  and 
cleansing. 

No  water  should  be  taken  on  board  unless  its  source  is  known  and 
its  quality  is  such  as  to  preclude  the  danger  of  introducing  water- 
borne  diseases.  Large  vessels  and  steamships  provided  with  distilling 
apparatus  do  not,  of  course,  need  to  provide  for  the  storage  of  large 
volumes  of  water.     The  water  yielded  by  a  distilling  apparatus  is,  on 


THE  SAILOR'S  SLEEPING    QUARTERS.  621 

tbe  whole,  far  superior  in  quality  to  that  which,  however  good  origi- 
nally, has  been  stored  for  any  considerable  time.  For  full  considera- 
tion of  the  subject  of  water  and  its  storage,  the  reader  is  referred  to 
the  chapter  devoted  to  that  subject. 

THE    SAILOR'S    SLEEPING  QUARTERS. 

The  sailor  is  berthed  commonly  either  in  deck  houses,  forecastles, 
or  between  decks.  Deck  houses  are  by  far  to  be  preferred,  since  they 
are  well  lighted  and  can  be  well  aired.  They  are  placed  about  mid- 
ships, and  are  most  accessible  and  convenient.  There  are  two  kinds 
of  forecastles  ;  one,  known  as  the  top-gallant  forecastle,  has  side  lights 
and  is  entered  through  a  doorway  ;  the  other,  commonly  found  on 
merchant  vessels  and  small  craft  in  general,  is  entered  from  above 
through  a  hatchway,  and  is  not  lighted.  This  is  the  least  desirable 
lodging  place,  and  is  exceedingly  difficult  to  keep  in  a  cleanly  condition. 
In  fact,  on  merchant  vessels,  it  is  commonly  infested  with  bedbugs  and 
other  vermin,  and  is  the  storehouse  for  wet,  dirty  clothes  and  all  man- 
ner of  rubbish.  Forecastles  are  likely  to  be  damper  than  other  parts, 
on  account  of  the  greater  amount  of  water  shipped  over  the  forepart 
of  the  vessel  when  under  way. 

Cubic  space  per  capita  depends  upon  the  facilities  for  the  convenient 
hanging  of  hammocks  ;  it  can  never  be  generous  :  it  is  always  far  less 
in  amount  than  is  regarded  ashore  as  essential  for  the  maintenance  of 
a  fair  degree  of  health.  In  fact,  sailors  are  almost  always  over- 
crowded :  they  have  nothing  like  the  allowance  which  obtains  in  bar- 
racks, but  rather  that  of  the  tent  in  the  field.  The  fact  that  the 
sailor's  rest  is  broken  in  upon,  so  that  at  no  time  does  he  get  more 
than  four  hours  of  consecutive  sleep,  may  perhaps  be  a  benefit  to  him 
in  that,  in  the  intervals,  he  breathes  the  pure  outside  air,  and  may  thus, 
in  some  measure,  counteract  the  evil  results  of  breathing  the  neces- 
sarily impure  air  below.  The  English  statute  requires  that  a  seaman 
in  the  merchant  marine  shall  have  not  less  than  72  cubic  feet  of  air 
space  and  12  square  feet  of  floor  space,  exclusive  of  that  occupied  by 
the  necessary  articles  of  furniture  and  dunnage. 

In  the  matter  of  cubic  space,  the  crews  of  merchant  vessels  are,  as  a 
rule,  better  off  than  those  of  men-of-war,  since,  on  vessels  of  the  latter 
class,  the  complement  of  men  required  for  all  the  various  duties  is  so 
large  that  overcrowding  is  to  be  looked  upon  as  a  matter  of  course. 
The  sleeping  quarters  of  most  of  the  crew  are  located  below  the  water 
line  on  the  berth  deck.  kSome  are  quartered  on  the  gun  deck,  which 
is  above  the  water  line,  and  consequently  is  circumstanced  better  as  to 
light  and  air. 

T]i(;  sailor  sleeps  in  either  a  hammock  or  a  bunk.  The  hammock  is 
a  haiigijig  bed,  made  of  heavy  canvas,  about  six  feet  long  and  half  as 
wide.  At  each  end,  brass  or  copper  eyelets  are  worked  in,  through 
which  the  nettles  of  the  clews  ])ass  and  are  fastened.  The  clews  end 
in  an  iron  ring,  to  which  the  lashing  for  each  end  is  attached.     In  the 


622  NAVAL  AND  MARINE  HYGIENE. 

hammock  are  placed  a  mattress  and  the  necessary  coverings,  and  on 
this  he  gets  his  modicum  of  rest  in  a  constrained,  unnatural  position, 
bent  into  a  curve,  no  matter  how  he  may  dispose  himself.  Bunks  are 
far  more  rational  and  comfortable,  since  they  permit  of  a  horizontal 
attitude.  They  are  made  of  iron  framework,  wound  with  canvas  or 
other  non-conducting  material,  or  of  wood.  They  possess  the  addi- 
tional advantages  of  occupying  less  space  and  of  being  more  easily  kept 
in  clean  condition.  Commonly,  they  are  placed  in  two  tiers  and  suffi- 
ciently far  apart  to  permit  of  easy  passage  on  either  side.  The  lower 
tier  should  be  not  less  than  nine  inches  from  the  deck. 

Quarters  for  officers  and  passengers  are,  as  may  naturally  be  sup- 
posed, more  favorably  located  and  more  commodious  than  those  as- 
signed to  the  crew. 

THE   DISEASES    OF   SAILORS. 

The  chief  diseases  to  which  persons  on  shipboard  are  subject  include 
diseases  of  the  respiratory  organs  (particularly  tuberculosis),  rheuma- 
tism, diseases  of  the  digestive  apparatus,  venereal  diseases,  and  sea- 
sickness. Of  nervous  troubles,  nostalgia,  melancholia,  and  hypochon- 
driasis are  common.  Skin  diseases  of  various  kinds  are  also  common. 
Cholera  and  yellow  fever  and  other  important  infectious  diseases  appear 
to  be  closely  connected  with  ships,  by  which,  as  elsewhere  noted,  the 
contagion. is  frequently  carried  from  one  country  to  another.  For- 
merly, scurvy  was  associated  especially  with  life  on  shipboard,  but 
since  the  discovery  and  introduction  of  the  proper  prophylactic  remedy, 
the  disease  has  been  practically  eliminated  from  the  list.  In  addition, 
troubles  of  minor  importance,  arising  from  special  duties,  are  of  com- 
mon occurrence,  but  not  lasting  in  character  ;  such,  for  instance,  as  eye- 
strain and  other  disturbances  of  vision,  disturbances  of  hearing,  and 
trauma. 

In  spite  of  improved  hygiene,  diseases  of  the  lungs,  particularly 
tuberculosis,  appear  generally  to  be  on  the  increase  among  seafaring 
men,  instead  of  on  the  decline.  It  is  said  that  in  the  British  Navy, 
between  1883  and  1890,  diseases  of  the  lungs  increased  60  per  cent. 
It  had  been  supposed  that  the  doing  away  with  masts,  sails,  and  rig- 
ging, with  the  consequent  lessened  exposure  of  the  men  to  cold  and 
^vet,  would  have  a  contrary  effect ;  but  its  influence,  if  any  it  had,  has 
been  more  than  counterbalanced  by  the  change  in  conditions  below,  the 
men  living  now  in  a  very  crowded  condition  in  hot  steel  ships. 

Firemen  and  stokers  are  very  prone  to  phthisis,  and  not  infrequently 
the  exhausting  nature  of  their  work  causes  them  to  become  debilitated, 
morbid,  and  inclined  to  suicide.  Among  this  class,  vertigo,  stupor, 
and  convulsions  are  common. 

Hospitals  for  the  treatment  of  the  sick  at  sea  should  not  be  located, 
as  they  usually  are,  on  the  berth  deck  forward,  but  should  be  about 
amidships,  where  they  may  receive  a  sufficient  amount  of  light  and  air. 
The  furniture  should  be  of  iron,  thus  permitting  easy  cleansing. 


VENTILATION   OF    VESSELS.  623 

VENTILATION    OF    VESSELS. 

The  air  of  a  ship  below  the  deck  is  commonly  far  from  meeting  the 
requirements  generally  accepted,  and  is  often  extremely  foul,  and  hence 
wholly  unfit  for  respiration.  The  contributing  causes  of  this  condi- 
tion are  an  excess  of  aqueous  vapor  from  respiration  and  from  water 
used  in  swabbing  decks  or  shipped  over  the  sides  while  under  way ; 
an  excess  of  carbon  dioxide  from  respiration,  combustion  of  illu- 
minants,  and  decomposition  of  organic  matters ;  effluvia  from  the 
bilge-water,  from  oil,  tar,  paint,  and  other  necessary  supplies,  from 
the  components  of  the  cargo,  and  from  other  sources.  The  crew's 
sleeping  quarters,  even  though  protected  by  all  practicable  means 
from  contaminated  air  from  the  hold,  bilges,  and  fore-peak,  are  com- 
monly reached  through  some  channel  by  the  effluvia,  which,  mingling 
with  those  natural  to  the  place,  serve  to  make  a  very  bad  condition 
much  worse. 

The  problem  of  efficient  ventilation  of  vessels  is  exceedingly  com- 
plex, and  is  quite  different  from  that  of  ventilating  dwellings  and 
other  buildings,  since  the  fundamental  conditions  are  so  little  in  agree- 
ment ;  and  it  becomes  more  complicated  with  increase  in  the  size  of 
the  ship.  The  principles  are  the  same  as  in  house  ventilation,  but  the 
application  of  methods  is  surrounded  by  greater  difficulties,  due  to 
peculiarities  of  construction  and  to  external  conditions.  Natural 
ventilation  may  be  effected  under  favoring  conditions  through  the 
medium  of  hatchways,  port  holes,  and  other  openings  ;  canvas  tubes 
or  funnels  with  a  side  opening  at  the  top,  stayed  to  face  the  wdnd  or 
the  ship's  course,  known  as  windsails ;  iixed  ventilating  tubes  acting 
in  the  same  manner,  hollow  masts,  and  other  appliances. 

Hatchways  are  commonly  the  only  openings  for  ventilating  the 
lower  forecastles,  and  in  foul  weather  they  are  kept  closed.  Some- 
times an  outlet,  capped  by  a  cowl,  is  provided,  but  it  is  usually  kept 
closed,  on  account  of  the  discomfort  of  drafts.  Deckhouses  and  top- 
gallant forecastles  are  much  more  efficiently  ventilated  through  the 
side  openings  and  because  of  their  greater  exposure  to  the  external 
air.  Holds  and  spaces  between  decks  are  ventilated  through  hatch- 
ways, fixed  tubes,  and  windsails,  hollow  masts  which  act  as  ventilating 
flues,  funnel  casings  which  act  like  jacketed  stoves,  and  other  means. 

Vessels  of  large  size  cannot  depend  upon  any  system  of  natural  ven- 
tilation, but  must  have  recourse  to  mechanical  methods  of  propulsion 
and  extraction,  and  even  then  only  an  imperfect  result  can  be  hoped 
for.  As  in  the  mechanical  ventilation  of  buildings,  propulsion  is 
likely  to  prove  far  more  effective  than  extraction,,  and  its  efficiency  is 
very  greatly  dependent  upon  the  intelligent  planning  of  the  system  of 
the  channclways  and  valves.  Valves  are  required  not  only  for  the 
])urp!)sc  of  shutting  off  the  air  current  where  it  is  not  at  the  moment 
rccjiiii'cd,  but  also,  on  men-of-war  and  other  large  vessels,  for  the  pro- 
tection of  water-tight  bulkheads  in  case  of  accident,  and  of  different 
compartments  in  case  of  fire. 


624  NAVAL  AND  MARINE  HYGIENE. 

The  ventilation  of  vessels  engaged  in  carrying  passengers  is  pro- 
vided for  in  part  by  legislation.  The  U.  S.  Revised  Statutes  require 
that  vessels  carrying  a  hundred  or  more  passengers  shall  have  for  each 
apartment  two  ventilators,  one  forward  and  one  aft,  of  a  capacity  pro- 
portionate to  the  size  of  the  apartments,  a  tube  12  inches  in  diameter 
being  regarded  as  the  proper  size  for  an  apartment  for  200  persons. 
If  other  means  of  attaining  the  same  measure  of  ventilation  are  pro- 
vided, they  may  be  used  in  place  of  those  stipulated.  Under  the  Eng- 
lish law,  the  provisions  for  lighting  and  ventilating  must  receive  the 
approval  of  the  Emigration  Officer  at  the  port  of  clearance,  and  if 
there  are  as  many  as  a  hundred  passengers  on  board,  the  vessel  must 
be  provided  with  "an  adequate  and  proper  ventilating  apparatus  to 
be  approved  by  such  officer  and  fitted  to  his  satisfaction." 

When  artificial  heating  is  required,  use  is  made  of  stoves  and  steam, 
heating.  In  the  forecastle  of  sailing  vessels,  small  square  stoves  of 
cast  iron  with  a  movable  cover  are  employed.  They  are  dirty,  incon- 
venient, and  generally  unsatisfactory. 


GENERAL    HYGIENE    OF    SHIPS. 

Of  the  very  first  importance  in  the  hygiene  of  ships  is  general 
cleanliness  of  ship  and  personnel.  Cleanliness  of  the  ship  requires 
constant  watchfulness  and  unremitting  attention,  and  daily  inspection 
is  necessary  to  insure  that  cleanliness  is  not  wholly  superficial,  since  it 
often  happens  that,  whereas  the  decks  and  all  visible  portions  are  clean, 
parts  which  are  out  of  sight  are  not  in  a  wholesome  condition.  Naval 
vessels  of  all  countries  are,  as  a  class,  much  more  carefully  looked  after 
in  this  respect  than  those  of  the  merchant  marine. 

In  securing  cleanliness,  it  is  a  mistake  to  use  water  too  frequently  and 
in  too  great  abundance,  and  great  care  should  be  taken  that  all  super- 
fluous water  is  removed  as  quickly  as  possible  from  all  parts  below 
decks,  since  one  of  the  cardinal  directions  is  to  keep  dry,  for  damp 
ships  are  notoriously  unhealthy.  The  dampness  that  condenses  from 
the  moist  air  upon  the  surface  of  metal  plates  and  overhead  beams  is 
a  source  of  great  annoyance  from  its  constant  dripping,  and  keeps  up 
a  continual  dampness.  This  can  be  remedied  only  by  sheathing  or 
coverings  of  non-conducting  material,  such  as  granulated  cork  or  as- 
bestos fiber. 

The  most  difficult  parts  to  keep  in  even  fiiirly  sweet  condition  are 
the  bilges,  in  which  collects  that  most  disagreeable  and  offensive  liquid 
known  as  bilge-wate)],  the  internal  drainage  of  the  ship,  much  of  which, 
in  wooden  ships,  leaks  from  without  inward,  through  the  seams.  The 
disgusting  odor  of  bilge-water  is  due  to  the  decomposition  of  the 
organic  matters  present,  and  to  the  reduction  of  sulphates  of  the  salt 
water  to  sulphides.  The  bilges  require  periodical  pumping,  and 
are  connected  for  this  reason  with  pumps,  known  as  bilge-pumps. 
The  bilge-water  removed  is  discharged  into  the  sea,  and  after  removal, 


GENERAL  HYGIENE  OF  SHIPS.  625 

the  bilges  are  flushed  with  clean  sea-water  and  again  pumped  out; 
sometimes  they  are  regularly  deodorized  and  disinfected. 

Next  in  importance,  on  account  of  their  commonly  unwhole- 
some condition  and  the  difficulty  with  which  they  are  made  clean 
and  kept  so,  are  the  peaks.  In  small  vessels,  the  fore-peak  very 
commonly  causes  fouling  of  the  air  of  the  crew's  quarters  in  the  fore- 
castle. 

From  a  hygienic  standpoint,  the  stoke  holds  of  steamers  are  of  great 
importance,  for  here,  in  a  very  restricted  space,  exposed  to  excessive 
heat  from  the  furnaces,  the  stokers  perform  their  exhausting  office. 
The  air  of  the  stoke  holds  is  commonly  not  only  excessively  hot,  but 
exceedingly  foul,  and  these  conditions  can  be  abated  only  by  proper 
ventilation,  which  may  be  secured  either  by  means  of  mechanical  appli- 
ances or  windsails. 

Water-closets  and  latrines  should  be  of  as  simple  a  type  as 
possible  and  capable  of  effective  flushing.  The  soil-pipes  may  dis- 
charge above  or  below  the  water  line.  Where  closets  must  be  located 
below  the  water  line,  special  pumping  arrangements  are  provided  for 
their  emptying  and  flushing.  Their  placing  differs  according  to  the 
size  and  character  of  the  ships.  Latrines  for  the  crew  are  placed  for- 
ward and  completely  disconnected  from  the  forecastle.  They  are 
supplied  at  the  rate  of  not  less  than  three  for  every  hundred  men. 
Urinals  are  commonly  a  source  of  great  nuisance,  and  hence  require 
extra  care. 

On  passenger  ships,  three  closets  should  be  provided  for  every  hun- 
dred persons  carried,  and  they  should  be  so  located  with  reference  to 
sleeping  quarters  that  they  may  not  give  rise  to  nuisance. 

Whenever  weather  and  other  circumstances  permit,  all  bedding 
should  be  thoroughly  aired,  each  article  being  brought  up  from  below 
and  exposed  separately,  fastened  to  the  rigging  or  upon  the  girt  lines. 
Hammocks  should  be  thoroughly  cleaned  and  dried  about  once  in  every 
fortnight.  Blankets  should  be  washed  with  soap  at  least  every  six 
months ;  hammocks  and  all  articles  of  bedding  should  be,  when  prac- 
ticable, exposed  for  part  of  each  day  to  the  direct  action  of  the  sun- 
light. 

For  methods  of  disinfection  and  general  cleansing,  the  reader  is 
referred  to  the  chapter  on  Quarantine. 

Personal  cleanliness  of  the  men  is  of  even  greater  importance  than 
cleanliness  of  their  surroundings,  and,  indeed,  the  two  go  hand  in  hand, 
for  men  of  cleanly  habits  will  not  permit  their  surroundings  to  be  other- 
wise than  wholesome,  and  those  who  are  not  naturally  so  inclined 
should  be  required  to  keep  themselves  clean.  Each  man  should  be 
allowed  a  sufficient  supply  of  fresh  water  daily,  and  the  necessary 
a))pliances  for  washing  should  be  provided.  In  navies,  the  washing 
of  the  person  is  commonly  made  a  part  of  the  routine.  Special  provi- 
sion for  the  care  of  the  person  is  required  for  those  who  have  the  dirt- 
iest work  to  jK-rform,  namely,  the  firemen  and  stokers,  since  their 
occupation  precliKJes  the  use  of  much  wearing  apparel,  and  the  air  of 

■40 


626  NAVAL  AND  MARINE  HYGIENE. 

the  place  where  they  work  is  laden  with  coal  dust  and  so  hot  that  their 
bodies  are  constantly  bathed  in  perspiration.  Short  bath-tubs  of  gal- 
vanized iron,  a  sufficient  number  of  wash-basins,  and  a  reasonable 
allowance  of  water  and  soap,  should  be  provided.  Given  the  conven- 
iences and  encouragement  to  make  use  of  them,  the  chances  are  that 
they  will  be  appreciated  and  freely  used. 

As  is  the  case  with  soldiers,  it  is  of  very  great  importance  that 
sailors  should  be  kept  busy  and,  at  the  same  time,  should  have  suffi- 
cient time  for  relaxation,  which  they  should  be  encouraged  to  spend  in 
such  pursuits  as  will  conduce  best  to  the  promotion  of  cheerfulness  and 
the  prevention  of  ennui. 


CHAPTEE    XI. 
TROPICAL   HYGIENE. 

THE  SOLDIER  AND  THE  CIVILIAN  IN  THE  TROPICS. 

The  following  pages,  dealing  with  hygiene  in  the  tropics,  have 
greater  general  applicability  to  the  life  of  civilians,  who  have  a  wide 
choice  in  their  mode  of  life  and  distribution  of  their  time,  but  the  main 
principles  are  equally  applicable  to  the  life  of  the  soldier,  even  although 
his  liberty  of  action  in  the  following  of  his  own  inclinations  is  very 
greatly  restricted. 

It  is  a  very  common  mistake  among  persons  reared  in  temperate  cli- 
mates to  suppose  that  the  change  to  a  tropical  climate  means  chiefly  a 
sudden  access  of  heat,  and  that  it  is  simply  this  increased  heat  which  one 
has  to  consider ;  but  it  is  not,  as  a  rule,  the  actual  temperature  which 
affects  the  individual,  for  in  the  North  we  may  have  for  days  at  a  time 
a  higher  temperature  than  obtains  customarily  in  some  parts  of  the 
tropics,  without  suffering  in  the  same  way.  The  principal  difference  lies 
in  the  excessive  tropical  humidity,  but  tropical  climates  are  not  equally 
humid,  some  being  exceedingly  moist,  and  some  exceptionally  dry. 

In  some  parts  of  Australia,  for  example,  the  climate  is  exceedingly 
dry  and  the  temperature  is  very  high,  and  yet  there  is  much  less 
liability  to  sunstroke  and  heat  apoplexy  than  in  some  parts  of  India, 
where  the  temperature  is  less  high,  but  the  atmosphere  exceedingly 
humid.  Since  all  hot  climates  are  not  alike,  the  mode  of  life  also 
varies ;  and  in  any  case  it  is  necessary  to  take  into  consideration  the 
special  local  characteristics  of  climate  and  the  methods  of  life  followed 
by  the  natives,  and  if  one  takes  care  to  adapt  his  clothing,  his  diet, 
and  personal  habits  to  the  conditions  which  surround  him,  life  in  the 
tropics  may  be  bearable,  even  if  not  thoroughly  enjoyable.  On  this 
point.  Dr.  S.  O.  L.  Potter,  U.  S.  V.,^  writing  on  the  spot,  says  :  "  If 
people  can  take  reasonable  care  of  themselves,  and  do  not  give  way  to 
excesses  in  any  form,  drink,  eating,  or  working,  they  will  live  as 
healthily  in  Manila  as  in  New  Orleans  or  St.  Louis  or  New  York." 
But  they  cannot  withstand  the  effects  of  any  tropical  climate  for  long 
without  an  occasional  visit  to  the  temperate  zone,  for  prolonged  resi- 
dence brings  about  an  undoubted  deterioration  of  the  system  in  spite 
of  all  possible  care. 

According  to  Freeman,^  Europeans,  after  some  years'  continuous 
residence  in  a  hot  country,  degenerate,  losing  energy,  initiative,  and 
memory,  which,  from  a  military  point  of  view,  is  not  compensated  for 

'  Notes  on  the  Pliilippines,  T'liiliulelpliia  Medical  Jounial,  April  7, 1900  p.  803, 
"  The  Sanitation  of  Biitisli  Troops  in  India,  London,  18U9. 

627 


628  TROPICAL  HYGIENE. 

by  diminished  liability  to  disease.  Hence  the  necessity  of  furloughs 
at  stated  intervals.  Potter  says,  "  Many  of  our  older  officers  have 
undergone  a  process  of  rapid  aging  here  without  any  definite  ailment 
to  account  for  their  condition.  They  simply  grow  thinner  and  thinner 
day  by  day,  running  down  gradually  in  physical  strength  as  emaciation 
goes  on,  until  finally  tlie  General  takes  pity  and  sends  them  home." 

According  to  a  number  of  observers,  the  body  temperature  of  new 
arrivals  in  hot  climates  is  appreciably  elevated  (0.4—0.9  degree  F.) 
above  the  normal,  and  under  some  conditions  of  high  temperature, 
since  the  body  cannot  radiate  heat  to  hotter  surrounding  air,  the  body 
temperature  may  run  as  high  as  102°  in  health.  The  body  is  then 
dependent  chiefly  upon  evaporation  from  the  surface  for  the  keeping 
down  of  the  temperature  as  nearly  as  possible  to  normal.  But  when 
high  temperature  is  conjoined  with  high  humidity,  the  difficulty  and 
discomfort  are  much  increased.  Continued  moist  heat,  through  its  in- 
fluence on  metabolism  and  the  various  functions  of  the  body,  causes 
great  nervous  exhaustion  and  general  deterioration.  The  respiration  is 
depressed,  the  force  and  rate  of  the  pulse  lowered,  the  mind  becomes 
dulled  ;  the  sweat  is  doubled  in  amount,  and  thirst  increased  in  pro- 
portion ;  the  digestive  function  is  weakened,  and  appetite  for  even  the 
lessened  necessity  for  food  is  diminished  and  requires  constant  stimula- 
tion.    The  body  loses  in  weight,  and  both  body  and  mind  in  energy. 

Dr.  Federico  Montaldo,  of  the  Spanish  Navy,  in  a  practical  hand- 
book ^  written  for  the  use  of  Europeans  intending  to  visit  the  Spanish 
colonies,  published  just  prior  to  the  outbreak  of  our  war  with  Spain, 
urges  upon  those  who  are  not  sure  of  the  soundness  of  their  health 
the  necessity  of  submitting  themselves  for  thorough  physical  examina- 
tion, since  a  trivial  ailment,  easily  corrected  at  home,  may  develop  in 
the  tropics  into  a  trouble  not  easily  managed.  Potter,^  also,  on  this 
latter  point,  remarks  :  "  It  is  all  very  nice  as  long  as  one  is  well,  but 
those  who  get  sick  don't  easily  recover  here.  Convalescence  is  very 
slow  and  very  difficult."  And  again,  "  the  general  climate  of  these 
islands  is  not  pernicious  for  those  who  are  able  to  avoid  exposure,  but 
when  broken  down  by  hardship  or  incidental  disease,  complete  recovery 
is  doubtful  and  convalescence  is  very  slowly  established."  Burot  and 
Legrand,^  also,  lay  stress  on  the  necessity  of  selection  of  healthy  indi- 
viduals for  service  in  the  tropics,  saying  that  if  the  soldier  is  too 
young  or  if  his  constitution  is  not  strong,  he  will  be  an  easy  prey  to 
disease,  while  if,  on  the  contrary,  he  has  been  carefully  selected  in  the 
light  of  the  peculiar  conditions  and  the  demands  upon  his  strength, 
he  will  be  better  able  to  resist  morbid  influences. 

Dr.  Lucca,*  speaking  from  an  experience  of  a  number  of  years  as  a 
military  surgeon  in  Borneo,  urges  the  exercise  of  great  care  to  insure 
the  health  of  troops   on  transports,   so   that  they  may  not  be  landed 

^  Guia  Practica  Higi^nica  y  Medica  del  Europeo  en  los  Paises  Torrid os  (Filipinas, 
Cuba,  Puerto  Kico,  Fernando  Poo,  etc.),  Madrid,  1898,  p.  19. 
^  Loco  citato. 

^  Hygiene  du  vSoldat  sous  les  Tropiques,  Paris,  1898. 
*  Einige  Bemerkungen  iiber  Acclimatisation  und  Leben  in  den  Tropen,  Munich,  1898. 


THE  SOLDIER  AND   THE  CIVILIAN  IN  THE  TROPICS.       629 

already  sick  and  weak  and  ready  for  shipment  home.  Rasch  ^  advises 
all  who  are  prone  to  nervous  disorder,  those  already  suffering,  and, 
above  all,  epileptics,  to  keep  away  from  the  tropics  ;  and  Macleod  ^  offers 
the  same  advice  to  anyone  whose  heart  and  blood-vessels  are  not  wholly 
normal. 

It  is  also  well  to  choose,  if  possible,  the  best  time  of  year  for  land- 
ing. There  are,  it  is  true,  only  two  seasons  in  the  tropics,  the  dry  and 
the  rainy ;  but  there  are,  nevertheless,  transition  periods  of  greater  or 
lesser  duration. 

Residence. — If  one  has  a  choice  in  the  matter  of  residence,  it  is 
well  to  be  cautious  in  its  exercise,  and  to  begin  on  high  land  and  away 
from  the  coast.  The  English  have  long  recognized  the  necessity  of 
sending  their  soldiers  inland  and  to  the  hills,  when  military  require- 
ments are  not  opposed.  After  getting  somewhat  accustomed  to  new 
conditions,  the  lower  parts  and  the  coast  may  gradually  be  ventured 
upon. 

In  some  parts  of  the  tropics,  it  is  customary  to  leave  sleeping  apart- 
ments open  during  the  day  and  closed  at  night ;  but  in  others,  the  con- 
trary is  the  rule,  the  doors  and  windows  being  closed  by  day.  The 
best  form  of  bed  is  that  made  of  not  too  heavy  iron,  with  a  frame  or 
other  device  to  support  a  mosquito  bar.  The  bed  should  be  j^laced 
away  from  the  walls  and  out  of  draughts.  The  legs  should  stand  in 
small  vessels  filled  with  water,  in  order  to  keep  away  small  crawling 
insects.  If  in  the  country  and  neither  bed  nor  hammock  is  to  be  had, 
and  one  is  obliged  to  sleep  on  the  floor  or  ground,  a  rubber  or  other 
waterproof  sheet  or  a  dressed  hide  should  be  spread,  and  the  body 
should  be  well  protected  against  condensing  moisture  and  troublesome 
insects. 

Habits  of  Life. — All  authorities  agree  in  at  least  one  particular,  and 
that  is,  in  urging  moderation  in  all  things — diet,  drink,  work,  exercise, 
dress.  The  diet  should  be  chosen  with  care,  and  iced  drinks  taken  in 
great  moderation,  if  at  all.  The  clothing  should  be  chosen  with  judg- 
ment, both  as  to  protection  from  the  heat  of  the  sun  and  against  chill- 
ing of  the  body. 

Work  should  not  be  excessive,  nor  should  it  be  performed  in  the  sun 
during  the  hottest  part  of  the  day.  Montaldo  ^  advises  one  to  rise 
with  the  sun  and  take  a  quick  cool  bath,  and  then,  after  a  light 
breakfast  of  coffee,  tea,  or  chocolate,  with  a  little  bread,  to  attend  to 
whatever  duties  one  has  to  perform,  until  about  10.30  A.  M.,  when 
luncheon  may  be  had.  This  should  not  be  heavy  as  to  food  or  drink. 
The  latter  may  consist  of  a  little  water  with  claret  or  lemon  juice,  or 
tea  or  coffee.  If  one's  work  is  out  of  doors'  it  should  not  be  resumed 
before  3  in  the  afternoon,  and  in  the  meantime  one  should  rest  indoors. 
After  6.30,  a  substantia],  but  not  too  hearty,  dinner  should  be  taken, 
observing  the  sanui  nioderation  in  the  matter  of  drinking.  One  should 
never  go  out  with  an  empty  stomach  nor  do  work  immediately  after  a 

'  All^'cmeine  Z('itHf:lii-ift  fiii-  Psycliiiitrie,  1897,  p.  745. 

'■'.Journal  of  Tropical  Medicine,  Vcjl.  I.,  No.  1.  "  Loco  citato. 


630  TROPICAL  HYGIENE. 

meal.  After  dinner,  a  walk  or  some  form  of  recreation  until  10.30  or 
thereabouts,  which  is  the  proper  time  for  retiring. 

One  is  advised  strongly  not  to  expose  one's  self  to  the  cool  external 
night  air  ;  to  avoid  cold  bathing  and  cold  drinks  while  perspiring  ;  and 
especially  to  avoid  standing  for  a  long  time  in  the  shade  in  garments 
wet  with  perspiration.  If  one  is  compelled  to  be  exposed  to  the  sun  for 
long,  the  protection  afforded  by  umbrellas  and  colored  spectacles  against 
heat  and  glare  should  be  sought.  The  consequences  of  exposure  may 
be  exceedingly  severe  or  even  fatal.  There  are  various  forms  of 
what  are  commonly  known  as  sunstroke  and  heat  apoplexy.  A  very 
common  form  is  one  of  syncope,  brought  on  by  overexertion  in  the 
direct  sunlight  or. even  within  doors  by  one  already  in  a  depressed  con- 
dition. The  skin  is  moist  and  clammy,  the  pulse  very  feeble  and 
almost  imperceptible,  the  muscular  power  almost  completely  lost.  Death 
may  occur  by  cardiac  failure,  but  recovery  under  appropriate  treatment 
is  the  general  rule.  Another  form,  due  to  direct  action  of  the  sun's 
rays  on  the  brain  and  cord,  is  in  the  nature  of  a  very  sudden  severe 
shock  aflPectingthe  respiratory  and  cardiac  centers,  and  commonly  quickly 
fatal.  Complete  recovery  is  rare.  A  third  form,  commonly  known  as 
heat  apoplexy,  is  due  to  exposure  to  constantly  high  temperature  not 
necessarily  involving  direct  exposure  to  the  sun,  and,  in  fact,  may 
occur  in  cloudy  weather  and  at  night.  The  whole  body  becomes  over- 
heated and  the  temperature  may  exceed  110°  F.  The  skin  is  generally 
dry,  although  sometimes  moist ;  the  pulse  full  and  regular  or  small 
and  irregular ;  respiration  labored.  There  is  intense  restlessness, 
and  epileptiform  convulsions  may  supervene.  These  cases  are  fre- 
quently fatal,  and  if  recovery  occurs,  it  is  not  complete.  In  India, 
according  to  Freeman,^  heat  apoplexy  and  sunstroke  occur  usually 
toward  the  end  of  hot  weather,  although  the  midday  sun  is  strong 
enough  in  most  places  to  cause  severe  headache,  if  not  sunstroke,  the 
year  round. 

For  the  avoidance  of  sunstroke,  in  addition  to  having  proper  head 
covering  and  umbrella,  the  neck  and  spine  should  be  properly  protected 
from  the  sun's  rays.  The  double  pleat  in  the  back  of  the  Norfolk 
jacket  is  intended  as  a  protection  to  the  spine.  A  few  green  leaves  in 
the  hat  are  sometimes  conducive  to  comfort. 

The  commonly  given  advice  to  follow  the  customs  and  habits  of  the 
natives  in  respect  to  diet  and  physical  exercise  can  be  accepted  only  in 
part,  for  the  native  of  the  tropics  is,  as  a  rule,  a  lazy  individual  who 
merely  exists  ;  the  wear  and  tear  of  his  system  require  but  little  in  the 
way  of  repair,  and  his  food  is  of  the  simplest  kind  ;  he  has  no  ambi- 
tion and  no  desire  to  hoard  up  a  fortune  which  he  cannot  use ;  but 
between  his  indolence  and  our  high-pressure  life,  there  is  a  happy  mean, 
especially  in  the  tropics. 

Diet. — The  question  of  diet  in  the  tropics  is  a  very  serious  one,  for 
errors  may  be  followed  by  disastrous  results.  Since  prolonged  heat 
exerts  an  unfavorable  influence  on  digestion,  this  function  should  not 
^  Journal  of  Tropical  Medicine,  Vol.  I.,  No.  1. 


THE  SOLDIER  AND   THE  CIVILIAN  IN  THE  TROPICS.       631 

be  made  to  bear  too  heavy  a  burden,  and  it  becomes  necessary  to  re- 
strict the  diet  in  several  particulars.  No  more  food  should  be  taken 
than  can  comfortably  be  digested,  for  both  dysentery  and  diarrhoea  are 
favored  by  the  irritation  caused  in  the  intestines  by  food  partially 
digested  or  undergoing  fermentative  processes.  But  the  change  from 
the  accustomed  diet  should  not  be  made  with  too  great  abruptness. 

The  natives  depend  chiefly  upon  a  vegetable  diet,  in  which  rice  and 
beans  and  fruits  of  all  kinds  play  prominent  parts.  Meat,  if  eaten  at 
all,  is  taken  usually  in  very  small  quantities.  As  a  rule,  in  hot  climates, 
it  is  not  tender,  for  it  cannot  be  hung  days  and  weeks,  as  with  us,  to 
ripen,  but  must  be  cooked  and  eaten  within  a  very  few  hours  after 
slaughtering.  Fish  should  not  be  used  unless  very  fresh,  and  shell-fish 
of  all  kinds  should  be  avoided.  Fresh  milk  is  ordinarily  not  to  be 
had  or,  at  least,  is  difficult  to  obtain.  It  speedily  sours  and  becomes 
unfit  to  drink.  Condensed  milk  of  good  quality  is  more  to  be  de- 
pended upon.  Vegetables  should  be  thoroughly  cooked,  or  they  will 
seriously  tax  the  digestive  organs.  Fruits  should  be  perfectly  ripe  and 
sound ;  over-ripeness  is  quite  as  objectionable  as  greenness.  Over- 
indulgence in  fruit,  even  of  the  best  quality,  and  especially  in  the  sour 
fruits,  is  particularly  to  be  avoided. 

Tea,  coffee,  and  chocolate  are  advised  in  moderation.  Lime  juice 
with  water  or  cold  tea  makes  a  most  refreshing  drink.  Tamarinds  in 
water  are  also  most  grateful. 

If  alcohol  in  any  form  is  desired,  the  light  wines  diluted  with  water 
are  recommended  more  highly  than  beer.  Spirits  are  generally  con- 
demned, but  there  appears  to  be  no  valid  reason  why,  when  very  largely 
diluted  with  water  or  soda  water,  they  should  exert  a  more  pernicious 
influence  than  wine  only  moderately  extended.  In  any  event,  alcohol 
should  be  taken  only  with  food. 

The  Use  of  Alcohol  in  the  Tropics. — Writers  on  tropical  hygiene 
are  almost  unanimous  in  the  opinion  that,  whatever  may  be  said  for 
and  against  the  use  of  alcoholic  drinks  in  other  climates,  their  use  in 
the  tropics  constitutes  a  distinct  danger,  and  that  much  of  disease 
commonly  attributed  to  climate  is  due  actually  to  alcohol.  Especially 
is  this  true  of  the  various  renal  and  hepatic  troubles.  According  to 
Treille,'  the  abuse  of  alcohol  is  the  chief  cause  of  the  frequency  of  dis- 
eases of  the  liver,  not  alone  among  visiting  Europeans,  but  among 
natives  as  well. 

Dr.  Chr.  Rasch,^  speaking  of  the  futility  of  talk  about  Europeans 
getting  accustomed  to  continued  high  temperature  with  high  humidity, 
and  describing  the  various  steps  in  physical  and  mental  deterioration, 
to  counteract  which,  one  turns  to  alcohol  and  other  stimulants,  says 
that  these,  together  with  insomnia  and  enforced  lack  of  exercise,  bring 
about  a  general  atonic  condition,  or,  in  other  words,  a  lowered  physio- 
logical resistance  to  diseases  in  general.     Dr.  Breiten stern, ^  who  for 

'  I'rincipes  fl'IIygienc  coloniale,  Paris,  1809,  p.  272. 

■^  All«(;ifK;ine  ZeitKchrift  fur  P.sycfiiatrie,  1897,  p.  745. 

•^  Uyi(\itxut  ill  (\vA\  Tropc'ii,  Moiiatssclirift  i'iir  (Jesundheitspflege,  1898,  Nos.  7  and  8. 


632  TROPICAL  HYGIENE. 

twenty  years  served  as  an  army  surgeon  in  the  Malay  Archipelago, 
gives  it  as  his  opinion,  based  on  long  observation,  that  total  absti- 
nence from  alcohol  is  far  preferable  to  even  the  most  moderate  indul- 
gence. 

A  writer  in  Manila  has  pointedly  remarked  concerning  the  health 
of  the  American  troops,  "It  is  not  so  much  the  climate  as  the  glass 
bottle  which  injures  people  out  here,"  which  statement  is  corroborated 
by  another  who  had  seen  actual  service  as  a  member  of  a  company, 
many  of  whose  members  were  total  abstainers  and  the  rest  made  up 
of  moderate  drinkers  and  those  prone  to  excesses,  the  latter  constitut- 
ing 20  to  25  per  cent,  of  the  whole.  Of  the  latter  class,  only  two 
returned  home  in  approximately  the  same  condition  of  health  which 
they  enjoyed  at  the  time  of  enlistment.  Of  the  moderate  drinkers 
who  confined  themselves  to  malt  liquors,  a  large  majority  suffered 
more  or  less  impairment  of  general  health.  But  the  total  abstainers 
returned  almost  to  a  man  in  excellent  health,  having  endured  the 
same  hardships  of  an  active  campaign.  The  same  correspondent, 
speaking  of  the  far  greater  harm  induced  by  the  stronger  alcoholic 
drinks,  relates  that  he  had  repeatedly  seen  American  soldiers,  after 
spending  several  hours  under  shelter,  drinking  round  after  round 
without  perceptible  harm,  fall  over  with  all  the  symptoms  of  sun- 
stroke as  soon  as  they  stepped  into  the  glaring  rays  of  the  hot  sun. 

On  the  other  hand,  in  opposition  to  the  general  opinion  adverse  to 
even  the  moderate  use  of  alcohol  in  the  tropics.  Dr.  C.  E.  Woodruff,^ 
U.  S.  A.,  after  a  careful  survey  of  the  conditions  obtaining  in  the  Phil- 
ippines, declares  that  he  Avould  change  the  statement  in  the  general 
order  from  headquarters  of  the  army,  July  2,  1898,  "The  history  of 
other  armies  has  demonstrated  that  in  a  hot  climate  abstinence  from 
the  use  of  intoxicating  drink  is  essential  to  continued  health  and  effi- 
ciency," to  "  Experience  has  demonstrated  that  in  a  hot  climate  the 
moderate  use  of  intoxicating  drink  is  essential  to  continued  health  and 
efficiency."  He  asserts  that  the  almost  universal  drinking  must  mean 
a  natural  defensive  craving  occasioned  by  the  terrible  nervous  exhaus- 
tion, a  true  neurasthenia,  due  to  long-continued  exposure  to  great  heat 
and  atmospheric  humidity,  indicating  that  waste  is  greater  than  repair. 
He  asserts  that  men  who  want  no  alcohol  at  home  have  this  defen- 
sive craving  for  it  in  the  Philippines,  and  cites  Spanish  authority  that 
a  daily  ration  of  wine  has  been  found  necessary.  Whiskey,  when 
sufficiently  diluted,  is  the  equivalent  of  wine,  and  the  Scotch  variety 
is  regarded  by  him  as  superior  for  the  purpose  to  American,  which 
soon  occasions  nausea.  Beer,  by  reason  of  being  conducive  to  colic, 
diarrhoea,  headache,  loss  of  appetite,  and  general  distress,  he  regards 
as  distinctly  harmful.  While  advocating  the  moderate  use  of  alcohol, 
]ie  believes  that  the  results  of  abuse  are  far  more  serious  than  at 
]iome. 

Concerning  beer  in  the  tropics,  there  is  much  divergence  of  opinion, 
some  regarding  it  as  a  valuable  safeguard  against  abuse  of  stronger 
1  Philadelpliia  Medical  Journal,  April  7,  1900,  p.  768. 


THE  SOLDIER  AND   THE  CIVILIAN  IN  THE  TROPICS.       633 

alcoholics,  others  agreeing  with  Woodruff  that  it  is  harmful.  It  is  said 
that  the  drinking  of  much  beer  followed  by  heavy  sleeping  predisposes 
to  sunstroke  and  heat  apoplexy. 

Clothing, — One  is  advised  to  take  plenty  of  light  cotton,  linen,  and 
merino  underwear,  a  generous  assortment  of  trousers  and  coats  of 
white  duck  or  flannel,  and  light  merino  stockings.  High  boots,  well 
oiled  and  with  hob-nails,  laced  boots,  leggings  of  cloth  and  leather, 
and  light  footwear  for  indoor  and  city  use  should  be  included.  Light 
waterproof  outer  garments  with  cape  and  hood  are  recommended,  and 
for  protection  against  the  sun,  white  umbrellas  lined  with  blue  or  green 
material,  and  spectacles  with  green  or  blue  colored  glasses. 

The  head-covering  should  be  selected  with  the  double  consideration 
of  comfort  and  protection  for  the  head  and  neck.  The  material  of 
which  it  is  made  should  be  chosen  with  regard  to  local  climatic  con- 
ditions. In  a  particularly  dry  hot  climate,  for  instance,  pith  is  the 
most  suitable  material,  being  lighter  than  either  cork  or  felt ;  but  a 
hat  made  of  this  material  is  absolutely  worthless  in  a  wet  climate,  since 
on  being  exposed  to  rain  it  absorbs  water,  becomes  exceedingly  heavy 
therefrom,  and  is  reduced  to  a  worthless,  shapeless  pulp.  Hats  should 
be  properly  ventilated  in  the  crown,  and  there  should  be  a  generous 
space  for  the  free  passage  of  air  between  the  head-band  and  the 
inner  side  of  the  hat ;  that  is  to  say,  the  head-band  should  be  fastened 
to  the  crown  of  the  hat  at  only  a  limited  number  of  ^^oints  and  with 
intervening  small  pieces  of  wood  or  other  material,  so  that  the  band 
shall  keep  its  proper  shape.  All  head-covering  of  whatever  form 
should  afford  proper  protection  for  the  sides  of  the  head  and  the  ears, 
as  well  as  for  the  front  and  back.  A  puggery  affords  additional  pro- 
tection. 

The  brim  of  the  head-covering  should  be  lined  with  some  material 
of  a  bluish  or  green  color,  as  a  relief  to  the  eyes.  The  outside  should 
be  light  in  color.  The  head-band  is  made  of  leather,  and  is  easily 
saturated  with  perspiration,  and  then  hardens  on  drying;  while  it  is 
wet,  it  is  exceedingly  uncomfortable.  •  If  covered  with  fine  flannel,  it 
will  be  found  to  be  much  more  comfortable. 

Jackets  and  other  outer  garments  should  afford  perfect  freedom  of 
action  in  both  riding  and  walking.  The  Norfolk  jacket  is  a  favorite 
form,  and  may  be  made  of  duck,  khaki,  or  similar  material.  It  is 
well  to  leave  a  few  inches  of  the  arm-scyes  unstitched  for  the  sake  of 
ventilation.  For  shirts,  a  mixture  of  silk  and  wool,  known  as  kashmir, 
is  regarded  as  the  best  material,  being  very  light  in  texture  and  per- 
fectly absorbent.  Gauze  undershirts  with  short  sleeves,  or  with  no 
sleeves  at  all,  shoidd  be  worn  beneath  the  shirt.  Elastic  cotton  and 
jean  are  the  best  materials,  so  far  as  comfort  and  durability  are  con- 
cerned, for  drawers. 

If  one  is  to  do  much  riding,  it  is  advised  that  as  much  care  be  ex- 
prindod  in  the  selection  of  a  saddle  as  in  selecting  boots,  since  comfort 
in  liorH(;back  riding  in  the  tropics  is  very  largely  dependent  upon  the 
fit  of  the  Kiulrllc. 


634  ■  TROPICAL  HYGIENE. 

Care  of  the  Person.— The  imtating  effect  of  hot  wmcls,  which  fre- 
quently cany  fine  particles  of  sand  and  dust,  and  the  glare  of  the  sun, 
which  conduces  to  troubles  with  the  eyes,  should  be  guarded  against.. 
Not  infrequently  the  ears,  too,  are  affected  injuriously  by  hot  winds,, 
but  they  are  easily  protected  by  external  coverings  or  by  cotton-wool 
plugs.  The  nose  and  lips  are  subject  to  cracking  and  uncomfortable 
dryness,  which  may  be  helped  by  cold  cream  or  some  similar  applica- 
tion. The  nails  should  be  kept  closely  pared,  since  they  become  brittle 
and  crack  off. 

The  skin,  having  a  very  important  function  to  fulfil,  should  be  kept 
thoroughly  clean,  if  on  no  other  account ;  but  bathing  in  too  cold  water 
or  for  too  long  a  time  should  be  avoided.  Parasites  abound  in  tropical 
climates,  and  should  be  looked  for  on  the  person  and  removed  with  all 
care.  Among  these  may  be  mentioned  the  chigoe,  or  jigger,  an  exceed- 
ingly troublesome  small  flea  (^SarcopsyUa  penetrans)  which  burrows 
beneath  the  skin,  particularly  of  the  feet,  and  beneath  the  nails.  At 
first,  it  causes  only  itching,  but  if  not  then  removed,  sharp  pain  and 
inflammation  ensue.  A  half  teaspoonful  of  flowers  of  sulphur  inside 
the  shoe  is  said  to  be  an  efficient  preventive.  Another  parasite  of  far 
greater  importance,  especially  to  the  troops  in  the  Philippines,  is  that 
which  occasions  the  dhobie  itch,  which  can  be  avoided  only  by  very 
great  attention  to  personal  cleanliness  and  frequent  changing  of  under- 
clothes. It  first  attacks  the  perineum  and  axillae,  and  when  the  acute 
stage  passes  by  and  the  inflammation  somewhat  subsides,  the  scales 
become  rubbed  off  and  reach  the  feet,  where  the  trouble  spreads  rap- 
idly, causing  intense  itching  with  consequent  scratching  and  the  evil 
consequences  thereof. 

Diarrhoea  and  constipation  are  alike  to  be  avoided.  The  former  should 
be  checked  at  once,  and  should  on  no  account  be  allowed  to  continue 
without  treatment.  It  is  easily  brought  on  by  improper  or  ill-cooked 
foods,  impure  water,  green  and  over-ripe  fruit,  sudden  changes  in  the 
weather,  and  intemperance.  Constipation  should  be  avoided  by  the 
acquirement  of  a  regular  habit.  Sometimes,  a  cup  of  tea  or  coffee  on 
rising  will  act  beneficially,  and  oatmeal  and  coarse  bread,  figs  and 
prunes  may  be  found  to  assist,  but  purgatives  and  enemata  should  be 
avoided,  if  possible  to  get  along  without  them. 

Tropical  Diseases. — It  is  beyond  the  scope  of  this  work  to  enter 
upon  the  field  of  tropical  medicine,  but  it  may  be  said,  in  general,  that 
the  diseases  of  hot  climates  are  exceedingly  varied.  Some  of  them  are 
peculiar  to  certain  districts  ;  some  are  exaggerated  forms  of  what  we  in 
the  temperate  zone  regard  as  simple  maladies.  In  general,  it  may  be 
said  that  in  the  tropics  one  meets  nearly  all  the  diseases  of  the  tem- 
perate zone  plus  a  great  variety  of  others,  but  some  of  our  most  com- 
mon diseases  may  be  very  rare  in  certain  places.  Thus,  scarlet  fever 
and  diphtheria  are  rare  in  the  tropics  as  a  whole,  tuberculosis  is  rare 
in  parts  of  India  and  common  and  quickly  fatal  in  other  parts  of 
the  tropics.  Rabies  is  more  common  in  India  than  in  England,  and 
the  victims  are  almost  always  Europeans.      Leprosy,  beri-beri,  and 


THE  SOLDIER  AND   THE  CIVILIAN  IN  THE  TROPICS.       635 

elephantiasis  are  common  among  the  natives,  but  very  rare  among 
Europeans. 

Throughout  the  tropics,  dysentery  kills  many  more  people  annually 
than  cholera,  and  works  greater  havoc  in  armies  than  the  contending 
forces.  Typhoid  fever  always  appears  sooner  or  later  in  camps  of 
soldiers  from  temperate  climates,  and  the  new  arrivals  are  commonly 
observed  to  be  the  most  susceptible.  This  disease  and  cholera,  accord- 
ing to  Freeman,  rarely  occur  in  India  during  the  hottest  months,  when 
the  burning  rays  of  the  sun  act  as  a  germicide ;  but  when  the  rains 
come  and  sweep  the  accumulated  surface  dirt  into  the  water  courses, 
they  quickly  appear. 

For  a  most  interesting  description  of  the  diseases  observed  in  the 
tropics,  the  reader  is  referred  to  Dr.  Patrick  Hanson's  Tropical  Dis- 
eases (second  edition,  1900). 


CHAPTEK    XII. 
THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

Although  a  supposed  relationship  between  insects  and  the  spread 
of  diseases  has  been  considered  in  greater  or  lesser  detail  by  writers  of 
all  times,  it  is  only  Mithin  the  most  recent  years  that  the  possible  con- 
nection has  been  regarded  as  entitled  to  most  serious  consideration.  It 
is  not  strange  that  the  bare  statements  of  ancient  writers  concerning 
the  influence  of  flies  and  other  insects  as  disseminators  of  plague  and 
other  diseases  were  not  received  with  any  degree  of  credence,  for  until 
recent  advances  in  the  fields  of  bacteriology  and  zoology  made  demon- 
stration of  the  connection  possible,  there  was  no  more  reason  for  accept- 
ing them  than  for  accepting  similar  unsupported  assertions  concerning 
the  action  of  clouds  and  things  supernatural.  But  as  our  knowledge 
of  the  exciting  causes  of  diseases  grew  with  bacteriological  and  zoologi- 
cal research,  so,  also,  came  an  appreciation  of  the  fact  that  these  same 
causes  might  be  disseminated  by  insects  and  other  lower  forms  of  ani- 
mal life. 

Disregarding  the  not  infrequent  reports  of  sickness  and  death 
attributed  to  insect-bites,  which,  so  far  as  one  may  know,  may  have 
become  secondarily  infected,  it  may  be  said  that  serious  attention  was 
not  drawn  to  insects  as  bearers  of  infection  until  the  early  90's.  And 
although  Nott,  in  1848,  had  suggested  the  mosquito  as  a  cause  of 
malaria  and  yellow  fever,  and  Finlay,  in  1881,  had  asserted  that  the 
latter  disease  was  transmitted  from  infected  to  non-infected  man  by 
these  insects,  it  was  not  until  the  closing  years  of  the  century  that 
these  theories  were  demonstrated  as  correct. 

The  insects  which  have  been  most  extensively  studied  are,  naturally, 
those  which  have  the  greatest  opportunity  for  contact  with  human 
l)eings,  namely,  flies,  fleas,  bedbugs,  and  mosquitoes ;  but  others  have 
been  the  subject  of  more  or  less  extensive  investigation  which  has 
demonstrated  their  capacity  for  conveying,  externally  or  within  their 
bodies,  virulent  bacteria  of  many  kinds.  That  insects,  coming  in  con- 
tact with  material  containing  pathogenic  bacteria,  may  convey  the  same 
directly  to  wounds  or  food-stuffs  upon  which  they  may  alight,  needs 
hardly  to  be  demonstrated,  whether  the  organisms  are  adherent  to  the 
body,  limbs,  or  proboscis  ;  but  how  long  the  bacteria  may  retain  their 
virulence  during  carriage,  and  whether,  if  taken  into  the  insect's  ali- 
mentary canal,  they  can  survive  the  process  of  digestion  and  be  dis- 
charged in  the  faeces,  can  be  determined  only  by  direct  experiment ; 
and  it  was  with  such  problems  that  the  first  researches  on  the  agency 
of  insects  in  the  transmission  of  disease  were  engaged.  It  has  been 
636 


FLIES.  637 

found  that  certain  species  of  bacteria  are  digested  by  certain  insects ; 
but  it  must  be  borne  in  mind  in  practice  that  this  should  not  be 
accepted  as  the  inevitable  or  even  usual  result,  for  although  flies,  for 
example,  will  digest  certain  bacteria,  they  cannot  always  be  depended 
upon  to  do  so,  and  may  excrete  them  with  other  undigested  food. 

Besides  transmitting  specific  bacteria,  the  insect  world  is  responsible 
for  the  spread  of  parasitic  organisms  belonging  to  the  animal  kingdom, 
now  recognized  as  the  causes  of  malaria,  filariasis,  and  yellow  fever,  as 
will  be  shown. 

FLIES. 

Although  the  possibility  of  the  spread  of  such  diseases  as  cholera, 
dysentery,  and  typhoid  fever  was  demonstrated  as  early  as  1892, 
the  matter  did  not  receive  particular  attention  until  the  unusual 
prevalence  of  typhoid  fever  in  the  great  military  camps  in  the  South 
in  1898  was  made  the  subject  of  a  careful  inquiry,  which  led  to  the 
conclusion  that  the  great  swarms  of  flies  which  infested  the  camps 
were  largely  responsible.  A  series  of  interesting  experiments  on  the 
subject  of  infection  through  the  agency  of  flies  was  conducted  by  Sawt- 
chenko  ^  with  pure  cultures  of  cholera  bacilli.  The  bacilli,  fed  to  two 
kinds  of  flies,  were  found  in  the  excreta  and  bowels  as  late  as  four  days 
after  ingestion  ;  removed  on  the  third  day  and  inoculated  into  guinea- 
pigs,  they  were  found  to  be  as  active  as  the  pure  cultures  themselves. 
Similar  results  were  obtained  when,  instead  of  pure  cultures,  the  dis- 
charges of  cholera  patients  were  employed  as  feeding  material.  Some 
of  the  experiments  indicated  that  the  bacilli  probably  multiply  within 
the  fly,  which  thus  acts  as  a  breeder  and  distributing  agent  at  the  same 
time.  A  fly,  caught  in  the  autopsy  room  at  Hamburg  during  the  great 
cholera  epidemic  of  1892,  was  examined  by  Simmonds,^  and  yielded 
numerous  bacilli.  This  suggested  an  inquiry  into  the  length  of  time 
the  poison  could  retain  its  activity  when  adherent  to  flying  insects, 
and  experiment  showed  that  it  remained  virulent  for  at  least  an  hour 
and  a  half  after  drying.  Surgeon-General  Sir  William  Moore  ^  drew 
attention,  in  1893,  to  the  fact  that,  in  India,  flies  abound  most  exten- 
sively during  the  time  and  season  of  greatest  prevalence  of  cholera ; 
he  suggested  that  they  might  act  as  carriers  of  typhoid  fever,  phthisis, 
and  ophthalmia.  He  instanced  an  epidemic  of  anthrax  spread  by  flies 
which  had  covered  the  carcass  of  a  dog  thrown  into  a  ditch.  It  ap- 
pears that  the  specific  bacteria  of  this  disease  resist  the  digestive  proc- 
ess, and  may,  therefore,  be  deposited  from  the  e5!ternal  surface  or  in  the 
faeces.  According  to  Nuttall,*  who  was  the  first  to  present  from  the 
exceedingly  scattered  literature  a  general  view  of  the  part  played  by 
insects  and  other  low  forms  in  the  transmission  of  human  and  other 
diseases,  fiics  do  not  convey  anthrax  by  biting,  but  may  become  crushed 
upon  the  skin,  and  thus  convey  the  organism  to  the  wound.     From  a 

'  CentmlV)liitt  fiir  Biikterinlofitie  nnd  PMrasitenkunde,  XII.,  p.  983. 

^  Deufsclie  mwlif'inisclK"  WocljenHchrift,  1892,  No.  41. 

'  Medical  MiiKiizinc-,  .inly,  W.)?,. 

*  .Johns  IIopkiriH  Hospital  Reports,  Vlir.  (1899),  Nos.  1  and  2,  p.  1. 


638         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 


study  of  the  cases  cited,  it  appears  likely  that  in  many  instances  the 
specific  organism  may  have  been  present  on  the  skin  prior  to  the 
advent  of  the  fly  or  other  insect. 

An  instance  of  strong  presumptive  evidence  of  an  outbreak  of  cholera 
through  the  agency  of  flies  is  furnished  by  Buchanan/  who  relates  that 
in  June,  1896,  9  cases  of  the  disease  occurred  in  Burdwan  jail,  where, 
prior  to  and  after  the  attack,  there  was  exceptional  freedom  from  bowel 
complaints.  The  water  supply  was  above  suspicion  and  was  the  same 
for  all  the  inmates,  who  numbered  190,  and  were  divided  into  two 
groups,  the  ordinary  prisoners  and  the  "infirm  gang."  The  latter 
worked,  slept,  and  associated  generally  with  the  former,  but  their  food 
was  cooked  specially,  and  they  were  fed  in  a  separate  place  in  the  hos- 
pital compound.    The  ordinary  prisoners — and  it  was  among  these  that 

Fio.  99. 


FEEDING 
PLACES 


COOK 
HOUSE 


s.w.  B 

GANG  AT  A  WERE  ATTACKED. 
GANG  AT  B   ESCAPED. 

Plan  of  grounds  of  Burdwan  jail,  where  cholera  is  supposed  to  have  been  carried  by  flies. 

all  the  cases  occurred — had  their  food  prepared  and  were  fed  at  the 
extreme  opposite  comer,  diagonally  from  the  hospital.  Over  the  wall 
at  their  corner  were  a  deserted  compound,  and  a  row  of  dirty  huts 
where  cholera  had  existed  during  the  preceding  year.  At  the  time,  the 
city  was  more  than  usually  infested  with  swarms  of  flies,  and  just  before 
the  outbreak,  a  storm  had  occurred,  during  which  a  strong  E.N.E. 
wind  blew  across  the  jail  yard  from  the  locality  mentioned.  All 
who  were  seized  were  among  those  who  were  known  to  have  had  their 
evening  meal  in  the  corner  during  the  storm,  and  it  was  believed  that 
swarms  of  flies  were  blown  from  the  huts,  and  on  reaching  the  trees 
and  corner  of  the  high  jail  wall,  obtained  shelter  from  the  storm  and 
settled  upon  the  food  exposed  in  the  plates  before  the  gang.  The 
accompanying  figure  shows  the  relative  positions  of  the  two  gangs  at 
^  Indian  Medical  Gazette,  March,  1897. 


FLIES.  639 

their  meal,  and  of  the  compound  and  huts  from  which  the  flies  were 
supposed  to  have  come.  The  evidence  here  is  purely  circumstantial, 
but  it  is  to  be  noted  that  all  of  the  sick  belonged  to  the  same  gang  ;  that 
all  had  been  more  than  a  month  in  jail,  excepting  2,  who  had  been 
there  seven  and  twelve  days  respectively ;  that  there  had  been  no 
prevalence  of  diarrhoea  before,  during,  or  after  the  outbreak ;  that  the 
water  and  milk  supply  were  the  same  for  all,  and  that  the  outbreak 
was  very  limited  in  extent. 

The  ability  of  flies  to  infect  food  was  well  demonstrated  in  1892  by 
Ufielmann,^  who  allowed  a  cholera-infected  fly  to  drink  from  a  glass 
of  sterile  milk,  and  then  shook  the  latter  and  kept  it  at  70°  F.  for 
sixteen  hours,  at  the  end  of  which  time  each  drop  contained  about  a 
hundred  organisms. 

The  prevalence  of  typhoid  fever  among  Europeans  in  India  has  been 
attributed  by  Surgeon-Major  Battersby^  to  the  agency  of  flies,  since, 
year  by  year,  outbreaks  occur  which  are  most  difficult  or  impossible  to 
trace  to  a  water-borne  cause,  the  water  supply  being  in  many  instances 
above  suspicion,  and  even  of  exceptional  purity.  During  our  war 
with  Spain,  investigation  of  the  great  prevalence  of  typhoid  fever  in 
the  large  camps  in  the  South  showed  the  abundant  opportunity  which 
exists  for  infection  by  flies,  and  demonstrated  the  necessity  of  thorough 
camp  sanitation,  and  of  excluding  them  from  contact  with  both  excreta 
and  foods.  Visiting  the  "  sinks  "  at  one  time  and  the  mess-tables  at 
another,  they  have  the  widest  opportunity  for  spreading  infection. 

The  presence  of  plague  bacilli  in  the  intestines  of  flies  has  been 
demonstrated  repeatedly  within  recent  years,  first  by  Yersin  in  1894, 
who,  noting  the  large  number  of  dead  flies  where  the  victims  were 
being  autopsied,  crushed  one  fly  and  inoculated  it  into  a  guinea-pig, 
which  died  of  the  disease  in  forty-eight  hours.  Further  investigation 
showed  the  bacilli  present  in  the  intestines  of  the  living  fly,  and  led 
to  the  conclusion  that  they  actually  multiply  therein.  Nuttall  ^  proved 
that  flies  may  carry  the  disease,  and  that  they  themselves  die  of  it. 
It  is  interesting  to  note  that  the  statements  of  early  writers  to  this 
effect  were,  therefore,  correct.  Most  of  these  were  vague,  and  gave  no 
intimation  of  how  the  contagion  was  carried ;  but  a  Venetian,  Mer- 
curialis,  in  1577,  wrote  (De  Pestilentia)  that  flies  go  to  infected  houses, 
alight  upon  the  sick,  and  then  convey  the  contagion  to  other  houses 
and  deposit  it  on  bread  and  other  foods. 

That  flies  may  play  a  part  in  the  spread  of  tuberculosis,  too,  seems 
probable,  for  the  specific  bacilli  have  repeatedly  been  found  in  virulent 
condition  both  in  their  intestines  and  in  their  excrements.  They  are 
believed,  also  to  carry  leprosy  and  various  conjunctival  diseases. 

The  larv£e  of  the  common  house-fly  are  sometimes  found  in  the  ali- 
mentary tract.     Thus,  Cohen  "*  reports  finding  them  in  the  dejections 

1  lierliner  klinisclie  Wochenschrift,  1892,  p.  1213. 

2  ?>j-iti.sh  Medireil  .JoiiriiJil,  Au^nist  10,  1895. 

■•' C<,ntrii]l)latt  fur  Ikkteriolofrie,  etc.,  XXII.  (1897),  No.  4,  and  XXIII.  (1898), 
No.  15. 

*  Deutsche  medicinisc^lie  Wi)cliciisclirift,  March  24,  1898. 


640         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

of  a  nursing  infant,  the  ova  having  probably  been  deposited  in  its- 
mouth  ;  and  Bachmann  ^  found  them  in  the  vomitus  of  a  hard  drinker, 
and  later,  after  the  administration  of  an  infusion  of  pyrethrum,  in 
large  numbers  in  his  faeces. 

Flies  may  also  transport  the  eggs  of  Tcenia  solium,  Tricocej^halus 
dispar,  Ascaris  Iwnbricoides,  and  other  parasites,  and  deposit  them  on 
foods. 

FLEAS. 

In  1898,  Simonds^  advanced  the  idea  that  fleas  from  rats  sick  with 
plague  might  spread  the  disease  to  other  rats,  and  even  to  man.  He 
found  the  specific  bacilli  in  such  fleas,  as  did  also  Ogata.^  But  Nut- 
tall  *  has  shown  that  fleas  do  not  inoculate  bacteria  when  they  bite,  but 
by  sucking  remove  any  already  present  at  the  point  of  application. 
His  experiments  were  made  with  fleas  found  on  mice  sick  with  anthrax 
and  mouse  septicaemia,  and  then  transferred  to  healthy  mice.  The  re- 
sults were  negative.  In  other  experiments,  fleas  were  placed  upon 
healthy  mice  from  which  the  hair  had  been  shaved  in  spots,  whereon 
anthrax  bacilli  were  smeared.  Individual  animals  bitten  by  as  many 
as  eight  fleas  failed  to  become  infected.  Inoculation  into  healthy  ani- 
mals of  the  organs  of  fleas  infected  with  anthrax,  mouse  septicsemia, 
and  chicken  cholera  eight  hours  after  infection  gave  negative  results. 
He  concluded  that  infection  by  fleas  can  occur  only  when  the  person 
bitten  slaps  and  crushes  the  insect,  and  then  scratches  the  spot. 
Simond's  paper  was  assailed  by  Bruno  Galli-Valerio,^  who  contends 
that  Siniond  failed  to  distinguish  between  the  flea  which  attacks  man 
and  that  which  infests  rats  and  mice.  Of  48  species  of  common  fleas, 
6  infest  rats,  and  of  these,  but  2  will  bite  man.  One  of  the  latter 
[Pulex  serraticeps)  is  not  common  on  rats,  and  the  other  (P.  erinacei) 
will  not  bite  readily. 

jN^uttall''  speaks  of  the  possibility  of  transmission  of  Tcenia  cucu- 
merina  through  fleas.  The  adult  worm  is  found  in  dogs,  occasionally 
in  cats,  and  rarely  in  man.  The  larval  stage  is  found  in  dog  fleas  and 
lice,  and  even  in  the  flea  that  infests  man  (P.  irritans) ;  but  the  dog 
flea  is  the  usual  host,  and  may  carry  as  many  as  50  larvee.  Dogs 
infest  themselves  by  devouring  their  fleas  and  lice,  and  children  may 
become  infested  by  playing  with  and  kissing  dogs,  the  vermin  being 
unconsciously  swallowed.  The  larvse  are  liberated  in  the  intestine 
through  digestion  of  the  body  of  the  insect,  and  they  then  exvaginate 
and  take  on  their  definite  form. 

BEDBUGS. 

But  few  cases  of  transmission  of  disease  by  bedbugs  are  known. 

Nuttall  quotes  Dewevre's  ^  report  of  a  case  of  transmission  of  tuber- 

^  Deutsche  medicinische  Wochenschrift,  Marcti  24,  1898. 

^  Annales  de  I'lnstitut  Pasteur,  XII.,  p.  625. 

^  Centralblatt  fiir  Bakteriologie,  etc.,  XXI.,  p.  769. 

*  Ibidem,  XXII.,  p.  625.  ^  Ibidem,  January  6, 1900. 

^  .lohns  Hopkins  Hospital  Reports,  VIII.,  Nos.  1  and  2. 

'  Eevue  de  Mddecine,  XII.,  1892,  p.  291. 


MOSQUITOES.  641 

culosis  after  disinfection  of  a  room  in  which  a  young  man  had  died  of 
the  disease.  After  the  process  was  completed,  the  room  and  bed  were 
occupied  by  a  brother  of  the  deceased,  and  he,  too,  died.  Investigation 
showed  his  body  to  be  much  bitten  by  bedbugs,  and  the  bed  to  be 
swarming  with  the  vermin.  At  this  time,  the  floor  was  soiled  with 
sputum,  and  had  not  been  cleaned  for  many  weeks.  The  contents  of 
30  bugs  were  inculated  into  3  guinea-pigs  with  positive  results  :  all 
died  of  tuberculosis.  Virulent  bacilli  were  obtained  from  60  per  cent, 
of  the  bugs  examined. 

Nuttall's  experiments  with  bedbugs  were,  as  with  fleas,  negative  in 
results.  Allowed  to  bite  animals  dying  with  or  dead  from  anthrax, 
chicken  cholera,  and  mouse  septicaemia,  and  then  transferred  to  healthy 
mice,  they  caused  no  sickness,  although  10  mice  were  bitten  by  136 
infected  bugs.  The  dejections  of  those  fed  on  anthrax  blood  contained 
living  bacilli  only  during  the  first  twenty-four  hours  after  feeding. 
Inoculations  with  their  viscera,  however,  were  uniformly  successful, 
and  it  is  probable,  therefore,  that  infection  may  occur  when  the  bug  is 
crushed  where  it  is  biting.  Miihling  ^  agrees  that  no  danger  of  infection 
is  to  be  apprehended  from  either  bedbugs  or  leeches,  both  of  which 
suck  without  introducing  anything  into  the  wound,  and  will  do  no 
harm  so  long  as  they  are  not  crushed. 

MOSQUITOES. 

Certain  genera  of  mosquitoes  have  been  definitely  proved  to  be  the 
intermediate  cause  of  several  of  the  most  disastrous  human  scourges, 
and  their  connection  with  others  has  been  suggested,  and  may  at  any 
time  become  demonstrated.  The  diseases  w^hich  have  been  definitely 
connected  with  these  pests  are  malaria,  yellow  fever,  and  filariasis. 

Mosquitoes  appear  to  be  ubiquitous  ;  they  are  found  not  alone  in  the 
torrid  and  temperate  zones,  but  in  the  arctic  regions,  where,  according 
to  good  authority,  they  are,  in  their  season,  even  more  of  a  pest  than 
in  warmer  latitudes.  In  Siberia,  they  hibernate  under  the  moss ; 
and  in  all  inhabited  places  they  hibernate  in  cellars,  outhouses,  and 
other  retreats.  The  larvae,  also,  may  hibernate,  being  frozen  in 
the  ice  on  the  approach  of  winter,  and  able,  when  thawed  out,  to  re- 
sume growth.  Gorman  ^  found  living  larvae  in  water  beneath  ice  at 
Providence,  R.  I.,  in  December ;  and  Wright  ^  found  Anopheles  larvae 
beneath  ice  in  Aberdeenshire.  Nuttall  has  known  larvae  to  live  from 
seven  to  eight  months.  The  adult  mosquito  may  be  found  in  the  open, 
even  when  the  weather  is  wintry.  Thus,  Sterling  *  saw  mosquitoes  at 
Mackinaw  in  March,  1844,  when  snow  covered  the  ground  to  a  depth 
of  two  to  four  feet.  But  it  is  only  in  warm  weather  that  mosquitoes 
appear  to  have  any  part  in  the  transmission  of  disease,  for  temperature 
has  very  great  influence  on  the  life  and  development  of  the  parasites 

^  Centralblatt  fiii-  BakterioloKie,  etc.,  XXV.,  p.  703. 
''■  .Journal  of  tlie  Bowton  Sf)ciety  of  tlie  Medical  Sciences,  V.,  p.  330. 
3  British  Medical  .Journal,  April  13,  IVIOl,  p.  882. 
*  Jiwect  J.ife,  III.,  p.  403. 
41 


642 


THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 


which  they  spread,  and  upon  their  own  activity  and  inclination  to  bite. 
The  parasite  of  the  tropical  sestivo-autumnal  type  of  malaria,  for 
example,  will  fail  to  thrive  in  a  temperature  not  too  low  for  that  of  the 
tertian;  and  the  latter  will  not  live  at  65°  F,,  which  temperature  is 
not  too  low  for  that  of  the  quartan  type.  Malaria  rarely  develops 
below  59°  F.,  and  is  completely  checked  at  32°,  at  which  temperature 
mosquitoes  are  very  sluggish  and  do  not  bite. 

We  have  in  this  country,  according  to  Dr.  L.  O.  Howard,^  9  genera 
of  mosquitoes,  represented  by  about  24  species,  the  larger  number  of 
which  belong  to  the  genus  Culex,  and  are  quite  harmless.  We  have  3 
of  the  8  or  more  species  of  malaria-bearing  Anopheles,  and  Stegomyia 
fasciata  (formerly  known  as  Culex  faselatus),  the  carrier  of  yellow 
fever. 

Mosquitoes  and  Malaria. — The  indigenous  malarial  species  are  as 
follows  : 

1.  Anopheles  maculipennis  {A.  quadrimaculatus,  A.  claviger)  (Figs. 


Fig.  100. 


Fig.  101. 


Anopheles  maculipennis.    Male. 


Anopheles  maculipennis.    Female. 


100  and  101)  has  the  "  dappled  wings  "  described  by  Ross.     The  palpi 
are  black. 

2.  Anopheles  punctipennis  has  a  yellowish-white  spot  extending 
about  three-fourths  of  the  length  of  the  front  margin  of  the  wing. 
(Figs.  102  and  103.) 

3.  Anopheles  crucians. — The  scales  of  the  last  wing- vein  are  white, 
marked  with  three  black  spots.  The  palpi  are  marked  with  white  at 
the  bases  of  the  last  four  joints.      (Figs.  104  and  105.) 

A.  maculipennis  and  A.  punctipennis  are  distributed  very  widely, 
1  Mosquitoes,  New  York,  1901,  p.  230. 


MOSQUITOES.  643 

being  found  in  greater  or  lesser  abundance  throughout  the  country.  The 
former  is  the  most  common  Anopheles  in  the  malarial  districts  of 
Africa  and  Southern  Europe,  and  is  found  in  Great  Britain,  Germany, 
France,  and  elsewhere. 

Fig.  102. 


/ 

Anopheles  punctipennis.    Male.    (After  Howard.) 


A.  crucians  is  a  Southern  form,  believed  to  be  the  carrier  of  the  per- 
nicious, tropical,  sestivo-autumnal  fever,  but  not  the  only  one,  for  in 
St.  Lucia,  for  example,  where  the  great  majority  of  cases  of  malaria 
are  of  the  pernicious  type,  the  common  mosquito  is  A.  albipes. 


Fig.  103. 


Anopheles  punctipennis.    Female.    (After  Howard.) 

Unlike  C'ullces  and  Stefjomyia,  the  Anopheles  do  not  breed  in  rain- 
water barrels,  troughs,  cisterns,  tin  cans,  pitcher  plants,  and  other 
small  receptacles,  but  in  pools,  juiddles,  ditches,  canals,  and  other 
bodies  of  stagnant  or  Ijut  very  slowly  moving  water.     The  larv£e  thrive 


644         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

in  clean  or  foul  water,  but  not  in  that  which  is  so  foul  as  to  stink ;  they 
cannot  live  in  salt-  or  very  brackish  water,  nor  where  there  is  rapid 
movement. 

Fig.  104. 


Anopheles  crucians.    Male. 


It  is  only  the  female  imago  that  sucks  human  blood,  and  she  is 
active  only  at  night.     She  enters  dwellings  about  sundown  or  later, 


Fig.  105. 


Anopheles  crucians.    Female. 


and,  unless  leaving  before  morning,  seeks  out  the  darkest  corner  in 
which  to  pass  the  day. 

According  to  Nuttall,^  Anopheles  are  attracted  variously  by  different 

1  British  Medical  Journal,  September  14,  1901,  p.  668. 


MOSQUITOES.  645 

colors,  navy  blue  being  the  most  attractive,  followed  by  dark  red,  red- 
dish brown,  scarlet,  black,  and  slate  gray.  Yellow,  orange,  white,  and 
ochre  proved  to  attract  the  least.  Joly  is  quoted  as  stating  that  mos- 
quitoes in  Madagascar  are  attracted  more  to  brown  than  to  red  soil  or 
white  sand ;  that  wearers  of  black  shoes  and  stockings  are  bitten  more 
than  those  who  wear  white  ;  that  blacks  are  bitten  more  than  whites, 
and  black  dogs  than  yellow.  Nuttall  noted  in  his  experiments  that, 
while  the  imagines  frequently  flew  up  and  settled  on  persons  entering 
the  room  clad  in  dark  clothes,  they  never  did  when  the  dress  was  white. 
He  suggests  the  employment  of  boxes  colored  dark  inside,  in  which 
the  pests  may  be  caught  and  destroyed.  The  influence  of  color  is 
noted  also  by  Osborne  Brown,^  who  holds  that  walls,  furniture,  etc., 
should  be  of  light  color,  and  advises,  among  other  measures,  the  put- 
ting away  of  all  dark  clothes.  Anopheles  appear  to  be  attracted  also  by 
odors,  according  to  the  testimony  of  Stephens  and  Christophers,^  who 
found  that  when  native  Africans  slept  in  a  tent  previously  occupied  by 
Europeans,  the  insects  congregated  there  more  numerously.  During 
European  occupancy,  2  Anopheles  were  usually  found  in  the  morning  ; 
but  after  the  first  night  of  African  occupancy,  19  were  caught,  and 
after  the  second  night,  no  less  than  62  were  found. 

The  Malarial  Parasite. — The  malarial  parasite  was  discovered  in  1880, 
by  Laveran,  a  French  military  surgeon  stationed  in  Algeria,  but  until 
some  years  later  its  method  of  development  Avas  not  demonstrated,  and 
only  recently  has  anything  been  known  definitely  as  to  the  manner  of 
its  entrance  into  the  human  body.  Before  proceeding  to  an  account  of 
the  researches  by  which  this  was  determined,  it  may  be  well  to  describe 
the  development  of  the  parasite  within  the  human  subject  and  within 
the  mosquito. 

The  several  malarial  j^arasites  belong  to  the  lowest  order  of  the  ani- 
mal kingdom,  the  protozoa,  suborder  Hcemosporidia.  The  different 
forms  corresponding  to  the  clinical  varieties  of  the  disease  were  difler- 
entiated  in  1886  by  Golgi,  one  of  the  most  prominent  of  the  Italian 
biologists,  who,  between  1885  and  1890,  were  the  first  to  pay  especial 
attention  to  Laveran's  discovery,  and  study  the  life  cycle  of  the  para- 
site in  the  red  blood-corpuscle.  In  this  it  appears  as  an  amoebula, 
which  grows,  digesting  the  red  coloring  matter,  until  it  occupies  nearly 
the  whole  volume  of  the  corpuscle  and  shows  spots  of  pigment  in  its 
interior.  Then  the  nucleus  divides  and  forms  spores,  which,  when  the 
cell  wall  bursts,  are  liberated  into  the  blood  plasma.  This  point  marks 
the  Ijeginning  of  the  malarial  chill.  The  spores  enter  into  other  cor- 
puscles, develop  into  mature  organisms,  segment,  and  produce  new 
spores,  which  on  being  liberated  proceed  to  infect  other  corpuscles,  and 
so  the  process  continues.  In  the  tertian  form  of  fever,  this  process  of 
sporulatiou  occurs  at  intervals  of  forty-eight  hours  ;  in  the  quartan 
form,  which  is  comparatively  rare,  the  intervals  are  seventy-two  hours  ; 
in  the  pernicious  sestivo-autumnal  form,  the  intervals  are  very  irregu- 

1  JoniTiiil  of  Tcoj)if!il  Mcdic^ine,  Oftober  1,  1901. 

H^iioted  by  Nuttall,  Journal  of  Hygiene,  January,  1901,  p.  7. 


646  THE  RELATION  OF  IMSECTS  TO  HUMAN  DISEASES. 

lar,  and  the  successive  processes  of  sporulation  may  occur  so  rapidly 
that  the  fever  becomes  continuous. 

After  a  number  of  generations  of  these  asexual  forms,  male  and 
female  parasites  appear,  which  are  incapable  of  further  reproduction 
within  the  human  subject,  but  require  external  conditions  which  they 
find  within  the  body  of  Anopheles  mosquitoes.  The  female  parasites 
are  known  as  macrogametes,  homologous  with  ova ;  the  male  organisms 
are  known  as  microgametocytes.  They  give  off  flagella  or  microgametes, 
homologous  with  spermatozoa.  In  the  next  cycle,  discovered  by  Ross, 
these  adult  sexual  forms,  when  sucked  up  in  the  blood  by  the  mosquito, 
coalesce  in  its  stomach.  The  fertilized  organisms  attach  themselves  to 
the  walls  and  penetrate  to  the  outer  muscular  Avail,  where  they  increase 
in  size  and  become  mature  zygotes  {sporocysts),  upon  the  surface  of 
which,  clear  spaces,  centromeres,  begin  to  appear.  In  a  short  time, 
these  become  surrounded  by  minute  spindle-shaped  cells,  sporohlastSy 
which  divide  into  minute  rods,  sporozoites,  which  soon  fill  the  whole 
cyst,  which  bursts  and  liberates  them  through  the  outer  wall  into  the 
abdominal  cavity.  They  then  rapidly  penetrate  the  tissues  to  the 
salivary  duct,  and  thence  into  the  proboscis,  from  which  they  are  dis- 
charged with  the  salivary  secretion  into  the  blood  of  the  next  person 
bitten.  From  the  time  of  entrance  of  the  sexual  forms  into  the 
mosquito  to  the  completion  of  the  process,  about  ten  days  elapse,  and 
since  the  period  of  incubation  in  man  is  the  same,  it  follows  that,  under 
favoring  conditions  of  temperature  (for  in  cool  weather  the  process 
within  the  mosquito  is  slower),  about  twenty  days  must  elapse  between 
the  appearance  of  a  first  case  and  that  of  another  connected  therewith. 
The  inoculated  sporozoites  give  rise  to  the  successive  asexual  genera- 
tions above  described. 

The  tertian  parasite  invades  the  whole  corpuscle ;  the  quartan, 
nearly  the  whole  ;  the  ffistivo-autumnal,  from  a  fifth  to  a  fourth  of  its 
volume.  The  pigment  granules  in  the  tertian  form  are  fine ;  in  the 
quartan,  coarse  ;  in  the  sestivo-autumnal,  very  fine. 

Not  alone  man,  but  many  of  the  lower  animals,  as  cattle,  sheep, 
monkeys,  dogs,  various  species  of  birds,  frogs,  snakes,  turtles,  lizards, 
etc.,  are  subject  to  malaria ;  but  the  parasites  are  peculiar  to  each 
species,  and  are  not  transferable  from  one  to  another. 

Some  years  after  Golgi  and  others  of  the  Italian  school  had  dif- 
ferentiated the  several  malarial  parasites  and  traced  their  life  cycle 
within  the  human  subject,  Manson,  who  had  done  much  work  in  the 
investigation  of  mosquitoes  as  a  causative  agent  of  filariasis,  announced, 
in  1894,  his  belief  that  malaria  was  caused  by  drinking  water  infected 
by  mosquitoes  or  dust  from  the  dried  mud  left  on  evaporation  of  the 
water  in  which  they  had  bred.  He  believed  that  the  female,  already 
infested  with  the  protozoon,  laid  her  eggs  and  then  died  in  the  water, 
and  was  later  devoured  by  the  larvse.  Bignami  opposed  this,  aud 
asserted  that  the  infection  was  conveyed  directly  by  inoculation  in  the 
process  of  sucking  blood. 

In  1895,  Ross  discovered  the  malarial  crescents  in  the  stomachs  of 


MOSQUITOES.  647 

mosquitoes  that  had  bitten  a  malarial  subject,  and  followed  them  in 
their  development  into  spheres  and  flagellated  bodies,  but  was  unable 
to  find  them  in  the  body  cavity  or  observe  any  metamorphosis  there. 
For  two  years,  Ross  ^  endeavored  to  cultivate  the  parasite  in  mosquitoes, 
but  without  success,  and  he  then  ceased  experimenting  with  the 
"  brown  and  gray"  species  (Culex),  and  began  anew  with  a  few  speci- 
mens of  a  larger  kind  having  four  black  spots  on  the  wings  (^Anopheles). 
After  these  had  fed  on  malarial  blood,  he  observed,  on  examination  of  one 
of  them,  certain  pigmented  cells,  "  the  pigment  absolutely  identical  in 
appearance  with  the  well-known  characteristic  pigment  of  the  malarial 
parasite."  In  a  second  mosquito,  killed  a  day  later,  the  cells  were 
observed  to  be  larger.  The  supply  of  Anopheles  having  become  ex- 
hausted, he  worked  with  other  kinds,  but  with  no  results  ;  but  later  ^ 
he  announced  that  he  had  found  the  pigmented  cells  in  a  third  "  dapple- 
winged  "  mosquito  fed  on  crescent-containing  blood.  In  the  mean- 
time, MacCallum,  of  Johns  Hopkins,^  announced  his  discovery  that 
with  halteridum,  a  parasite  of  birds  strictly  analogous  to  the  malarial 
parasite  of  man,  the  function  of  the  flagellum  is  that  of  true  sperma- 
tozoa. Ross  then  took  up  the  study  of  bird  parasites  {Halteridium  and 
JProteosoma),  especially  of  the  proteosoma  of  sparrows,  larks,  and  crows, 
and  was  successful  in  growing  the  parasites  in  mosquitoes  that  had 
bitten  sick  sparrows,  and  in  reproducing  the  disease  in  other  birds 
bitten  by  them.  He  observed  the  liberation  of  the  sporozoites  from 
the  zygotes,  their  passage  into  the  body  cavity  of  the  insects,  and  their 
presence  in  the  salivary  glands.  His  belief  that  Anopheles  acts  as  a 
carrier  of  the  malarial  parasites  was  proved  by  Grassi,  Bastianelli,  and 
Bignami,  who  allowed  different  kinds  of  mosquitoes,  including  A.  macu- 
lipje finis,  to  bite  persons  af9icted  with  the  gestivo-autumnal  type  of 
fever,  and  found  only  in  the  species  mentioned  the  developmental 
changes  described  by  him.  Later,  Bignami  *  reported  that  he,  Grassi, 
and  Bastianelli  had  caught  a  number  of  specimens  of  this  mosquito 
in  a  malarious  district  twenty-two  miles  from  Rome,  and  had  re- 
leased them  at  the  Santo  Spirito  Hospital  in  a  room  occupied  for 
some  years  by  a  man  who  had  been  under  constant  observation  and  had 
had  no  kind  of  fever  whatever.  The  experiment  yielded  positive  re- 
sults, for  the  volunteer  subject  acquired  the  fever  and  yielded  para- 
sites in  his  blood.  The  demonstration  of  the  agency  of  these  pests 
was  thus  complete,  and  the  connection  has  been  proved  repeatedly 
on  a  much  larger  scale.  Thus,  Ross  ^  reports  that  of  21  persons  in  a 
camp  near  Calcutta,  17  who  slept  without  the  protection  of  mosquito- 
netting  were  seized  with  malaria,  while  the  others  who  slept  under 
nets  escaped.  Grassi's  experience  is  equally  convincing,  although  with- 
out a  control.  For  eight  consecutive  days,  accompanied  by  a  family  of 
seven,  he  left  Rome  each  day  at  5.30  in  the  afternoon  and  went  to  a 

»  Uritish  Medical  .Toiirnal,  December  18,  1897,  p.  178G. 

■^  Ibidem,  Februaiy  26,  1898,  p.  550. 

'  .Joiii-nal  of  Expei-irnental  Medicine,  January  7,  1898. 

*  Builctino  d(dla  R.  Accad.  Med.  di  Roma,  XXV.,  1898-1899. 

s  Rritish  Medical  .Journal,  .July  22,  1899. 


648         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

cottage  in  a  notoriously  malarious  district  between  Rome  and  Civita- 
vecchia, where  they  passed  the  nights  in  a  cottage,  the  windows  of 
which,  screened  with  perforated  zinc,  were  left  open  all  the  time.  Not 
one  of  the  party  was  in  the  least  aifected. 

The  longer  experiment  of  Sambon  and  Low  in  an  equally  malarious 
district  is  even  more  convincing.  They  spent  several  months,  includ- 
ing the  summer  of  1900,  with  malaria  raging  all  about  them,  but 
were  themselves  not  affected.  They  took  no  drugs  by  way  of  pro- 
phylaxis, and  went  about  freely  by  day,  but  kept  indoors  between  sun- 
set and  sunrise,  protected  by  nettings  and  screens. 

In  1901,  an  interesting  experiment  was  tried  by  the  Japanese  gov- 
ernment w^ith  two  battalions  of  soldiers  stationed  together  in  Formosa. 
One  battalion  was  completely  protected  from  mosquitoes  for  161  days 
during  the  malarial  season,  and  not  a  man  had  the  disease.  In  the 
other  battalion,  which  was  not  protected,  259  cases  were  observed. 

Another  interesting  experiment  was  that  conducted  by  Fermi  and 
Cano-Brusco,^  who  took  16  persons,  ranging  from  eighteen  to  thirty 
years  of  age,  who  had  had  no  malaria  within  a  year,  to  a  malarious 
place  in  Sardinia  and  kept  them  there  eight  days.  Half  were  pro- 
tected from  mosquitoes  at  night,  and  the  others  not.  Of  the  non- 
protected, 5  were  seized ;  of  the  8  protected,  not  one. 

The  most  convincing  proof  of  the  agency  of  mosquitoes  may  be 
said  to  be  the  occurrence  of  the  disease  in  a  non-malarious  country 
through  inoculation  by  mosquitoes  imported  from  another  where  ma- 
laria abounds.  Such  an  instance  is  reported  by  Manson,"  whose  son 
was  bitten  in  London  on  three  different  days  by  infected  mosquitoes 
brought  from  Italy.  Within  a  few  days  of  the  third  inoculation, 
the  characteristic  symptoms  of  tertian  malarial  fever  appeared  and 
the  parasites  were  found  in  the  blood. 

For  the  spread  of  malaria,  two  factors  are  thus  evidently  essential : 
the  parasite  in  human  blood  and  the  Anopheles  mosquito.  Either 
alone  is  impotent.  There  are  many  places  where  Anopheles  are  com- 
mon and  malaria  unknown.  Indeed,  if  the  Anopheles  alone  could 
cause  the  disease,  no  place  would  be  safe,  for  although  they  are  not 
strong  fliers,  they  may  be  transported  through  hundreds  and  even 
thousands  of  miles  by  the  vehicles  of  ordinary  travel.  Thus  Grassi 
relates  that,  during  a  drive  lasting  two  hours,  he  caught  200  speci- 
mens inside  the  coach ;  and  others  have  noted  their  presence  in  rail- 
road cars  and  passenger  ships.  Whether  they  would  be  able  to  breed 
aboard  ship  is  doubtful,  although  instances  of  breeding  of  other  mos- 
quitoes in  this  manner  are  known.  Thus,  Dr.  Gumming,  of  the 
Marine-Hospital  Service,  reported  on  August  2,  1901,  to  the  Super- 
vising Surgeon-General,  the  case  of  the  Spanish  barque  Ilaria  Blan- 
quer,  which  was  free  from  mosquitoes  until  the  twenty-second  day  out 
from  Rio  de  Janeiro,  when  some  were  noticed  in  the  water  tank  when 
it  was  opened,  after  which  the  crew  were  attacked  so  persistently  by 

1  Centralblatt  fiir  Bakteriologie,  etc.,  XXIX.,  p.  985. 
=  British  Medical  Journal,  September  29,  1900. 


MOSQUITOES.  649 

them  that  they  were  obliged  to  cover  themselves  to  get  any  sleep. 
After  fumigation  of  the  forecastle,  the  dead  mosquitoes  could  be 
scooped  up  in  the  hand.  Howard  relates  that  mosquitoes  were  intro- 
duced into  the  Hawaiian  Islands  by  sailing  vessels  from  the  United 
States,  and  deems  it  probable  that  they  bred  more  or  less  continuously 
in  the  water  barrels  during  the  voyage. 

Mosquitoes  may  be  blown  along  by  the  wind  through  long  distances, 
but  ordinarily  they  take  shelter  on  the  leeward  side  of  any  object  as 
soon  as  the  wind  begins  to  be  strong.  Howard  cites  an  instance  of 
mosquitoes  crossing  a  strip  of  water  a  mile  wide,  aided  by  gentle  and 
continuous  wind,  and  another  in  which  a  migratory  cloud  of  the  insects, 
extending  three  miles  in  width,  traversed  60  miles ;  and  Dr.  Kallock, 
of  the  Gulf  Quarantine  Station,  reports  (August  2,  1901)  that  the  cap- 
tain of  the  ship  America  stated  that  mosquitoes  came  aboard  the  vessel 
when  she  was  at  least  10  miles  from  land.  But  Anopheles  are  not 
likely  to  fly  far  from  their  birthplaces.  They  are  not  such  strong  fliers 
as  Culices.  Stephens  and  Christophers  ^  believe  that  Anopheles  in  Sierra 
Leone  may  fly  a  quarter  of  a  mile  or  farther,  but  in  Freetown  they  found 
them  scarce  at  a  distance  of  200  yards  from  their  breeding-places. 

As  stated  above,  there  are  many  places  in  this  country  and  elsewhere 
where  Anopheles  are  common  and  malaria  unknown,  although  formerly 
the  disease  may  have  raged  most  extensively.  In  England,  for  ex- 
ample, where  malaria  was  once  one  of  the  great  national  scourges  and 
is  now  seen  only  rarely,  NuttalP  and  his  associates  found,  in  1900, 
specimens  either  of  the  imago  or  of  the  larvae  in  no  less  than  173  dif- 
ferent places.  In  some  of  these  places,  malaria,  so  far  as  known,  has 
never  existed  ;  in  others,  it  once  had  raged  extensively.  In  France,  Ser- 
gent^  has  found  A.  maculipennis  and  A.  bifwrcatus  in  great  abundance 
where  malaria  was  formerly  common,  but  now  is,  and  for  twenty  years 
has  been,  unknown  ;  and  in  Germany,  Pfeiffer*  has  found  them  in  great 
numbers  in  formerly  malarious  districts,  but  none  of  them  showed  the 
presence  of  the  parasite.  In  Italy,  too,  where  Grassi  has  held  that  the 
geographical  distribution  of  Anopheles  is  identical  with  that  of  malaria, 
Celli^  has  found  the  insects  in  situations  where  malaria  has  never  been 
known. 

To  what  the  disappearance  of  malaria  in  England,  Scotland,  parts  of 
the  United  States,  France,  Germany,  and  other  countries,  is  due,  is  not 
easily  explained.  To  a  very  large  extent,  it  is  doubtless  due  to  drain- 
age of  the  land  and  general  sanitary  improvement,  the  drying  of  the 
soil  diminishing  the  opportunity  for  puddle-breeding  mosquitoes  to 
multiply.  But  this  explanation  will  not  apply  generally,  for  in  many 
places  now  free  from  malaria  the  same  conditions  of  soil,  wetness,  and 
mosquitoes  are  found  to-day  as  existed  when  the  disease  was  endemic. 
It  is  interesting  to  note  that,  in  England,  the  Anopheles,  although  fairly 

'  Loco  citato. 

^Journal  of  Hygiene,  January,  1901,  p.  4. 

•^  AnnaloH  de  rinHtitut  Pasteur,  XV.,  Oct.  25,  1901. 

*Correspon(lenzhlatt  des  allgemeinen  Jirztliclien  Vereins  von  Thiiringen,  1901,  No.  7. 

5  Central  Watt  fur  Dakteriologie,  etc.,  XXVIII.,  j).  Tj.'M. 


650  THE  RELATION   OF  INSECTS  TO  HUMAN  DISEASES. 

common,  does  not  bite ;  at  least  Nuttall  states  that  neither  he  nor  any 
of  his  associates  was  bitten  while  collecting,  and  that  Mr.  Theobald,  of 
the  British  Museum,  wrote  that  he  had  never  known  them  to  bite  in 
England.  (It  is  to  be  remembered  that  mosquitoes  are  naturally 
vegetarians.) 

Nuttall  suggests  as  a  second  reason  for  the  disappearance  of  malaria 
from  England  the  reduction  of  the  population  of  the  infected  districts 
by  emigration  at  about  the  time  of  the  disappearance.  This  would, 
of  course,  reduce  the  number  of  infected  individuals  and  lessen  the 
chance  of  the  Anopheles  becoming  infected.  Koch  and  many  others  are 
strongly  of  the  opinion  that  the  use  of  quinine  has  had  more  to  do 
with  the  disappearance  of  malaria  than  anything  else,  but  it  is  probable 
that  there  is  some  other  as  yet  unrecognized  cause,  and  that  all  the  influ- 
ences mentioned  have  contributed  in  different  degrees.  That  there  is 
some  such  undiscovered  local  condition,  must  be  very  evident  when  we 
consider  the  following  facts  published  by  Celli  and  Gasperini  :  ^  Certain 
localities  in  Tuscany,  which  less  than  thirty  years  ago  were  very  mala- 
rious, are  to-day,  so  far  as  can  be  ascertained,  in  precisely  the  same 
general  condition  as  obtained  before  malaria  disappeared  therefrom. 
The  stagnant  marsh-water  swarms  with  Anopheles  larvse,  and  the  air 
above  with  myriads  of  the  imagines.  There  is  no  lack  of  the  malarial 
parasite  for  infection  of  the  mosquitoes,  for  the  people  go  to  other 
districts  and  return  with  malaria ;  and  yet,  in  spite  of  the  presence  of 
the  essential  factors  for  an  extensive  epidemic,  no  outbreak  occurs.  The 
children  are  robust  and  healthy,  the  adult  population  shows  no  eifects 
of  malaria,  and  many  who  have  lived  there  all  their  lives  have  never 
had  the  slightest  attack  of  the  fever.  This  freedom  is  not  due  to 
acquired  immunity,  for  the  inhabitants  take  the  disease  when  they  go  to 
malarious  districts  for  Mork.  The  mosquitoes  are  not  insusceptible  to 
infection,  for  specimens  captured  there  are  readily  infected  by  malarial 
blood  in  Rome.  Quinine  cannot  be  credited  with  being  the  cause  of 
the  exemption,  for  it  is  not  used  more  extensively  than  elsewhere.  In 
India,  too,  there  are  districts  which  were  formerly  malarious,  but  are 
now  comparatively  healthy  in  spite  of  apparently  unchanged  conditions. 

But  although  Anopheles  may  exist  where  malaria  is  unknown,  the 
converse  is  not  true,  for  where  malaria  is,  there,  also,  are  mosquitoes. 
The  assertion  that  in  Java  there  are.  places  where  malaria  abounds 
without  mosquitoes,  has  been  investigated  by  Koch,  who  found  that 
mosquitoes  were  everywhere  present  where  malaria  prevailed.  He  found 
also  a  place  in  East  Africa  with  all  the  conditions  favorable  to  malaria 
excepting  mosquitoes,  but  with  no  evidence  of  the  disease.  In  many 
of  the  islands  of  Polynesia,  where  marshes  are  very  extensive  and  all 
malarial  conditions  are  present  at  their  maximum,  with  the  exception  of 
mosquitoes,  no  malaria  is  known. 

It  seems  reasonable  to  assume  that,  given  the  necessary  species  of 
mosquitoes,  the  introduction  of  infected  persons  into  a  district  would 
probably  be  followed  by  the  appearance  of  other  cases  ;  but  there  are, 
1  Centi-alblatt  fur  Bakteriologie,  etc.,  Oct.  23,  1901,  p.  623. 


MOSQUITOES.  651 

fortunately,  a  number  of  conditions  which  must  be  fulfilled  in  order  to 
bring  this  about.  First,  the  Ano-pheles  must  be  blood-drinkers  ;  sec- 
ond, they  must  bite  the  infected  individuals ;  third,  they  must  then 
develop  the  parasite  within  themselves ;  and,  fourth,  they  must  live  to 
bite  another  person  when  the  sporozoites  are  still  present  in  the  salivary 
duct.  In  addition,  certain  favoring  conditions  of  temperature  are 
required,  both  for  the  activity  of  the  mosquito  and  for  the  development 
of  the  parasite.  Should  cold  weather  come  on  shortly  after  the  malarial 
subject  is  bitten,  no  harm  might  follow,  for  about  ten  days  are  required 
before  the  mosquito  becomes  fully  infective,  and  in  a  cold  atmosphere 
she  is  sluo-o^ish  and  will  not  bite. 

Preventive  Measures. — In  order  to  prevent  multiplication  of  Anoph- 
eles, measures  should  be  taken  to  diminish  the  number  of  breeding- 
places  by  drainage  and  other  means,  and  the  larvse  should  be  destroyed 
where  it  is  not  possible  to  accomplish  removal  of  the  water.  The 
natural  enemies  of  the  larvse  may  be  introduced  at  very  slight  expense 
and  with  a  minimum  of  trouble.  Among  these,  Howard  mentions  as 
most  efficacious,  sunfish,  sticklebacks,  and  top-minnows.  Where  fish 
cannot  be  introduced,  the  application  of  the  cheapest  kerosene  at  regu- 
lar intervals  will  not  only  kill  all  larvse,  but  will  prevent  the  impreg- 
nated female  from  laying  her  eggs.  Kerosene  spreads  easily  and  does  not 
evaporate  too  quickly,  and  a  barrel  will  suffice  for  an  area  larger  than 
two  acres.  A  single  application  by  means  of  mops  or  watering-pots — 
about  an  ounce  to  fifteen  square  feet,  enough  to  give  a  very  thin 
film — will  remain  for  at  least  a  week,  and  generally  a  fortnight ;  and 
since  a  week  must  elapse  for  eggs  to  develop  into  pupse,  a  second  appli- 
cation need  not  be  made  until  about  seventeen  days  have  elapsed. 

The  sick  should  be  protected  by  mosquito-netting,  and  the  same 
means  should  be  employed  to  prevent  access  to  the  houses  of  the  well, 
and  for  the  protection  of  those  who  may  be  obliged  to  sleep  in  the  open. 
Local  applications  to  the  skin  (oil  of  pennyroyal,  oil  of  eucalyptus,  etc.) 
are  not  of  much  value. 

Fermi  and  Tonsini  ^  have  rej)orted  a  noteworthy  instance  of  diminu- 
tion in  the  amount  of  malaria  after  systematic  destruction  of  the  larvse 
of  mosquitoes.  The  Island  of  Asinara,  inhabited  solely  by  convicts 
and  their  guards,  has  often  been  ravaged  by  malaria.  The  larvse  of 
different  species  of  mosquitoes  were  found  in  many  wells  and  horse- 
ponds,  and  were  treated  with  kerosene  a  number  of  times.  Screens 
were  placed  in  the  windows  and  doors  of  the  dormitories.  The  results 
were  most  satisfactory,  only  9  cases  of  malaria  occurring  during  the  year, 
against  99  in  the  year  preceding. 

If  Anopheles  gain  access  to  houses,  they  may  be  destroyed  by  fumi- 
gation with  sul];hur  dioxide,  employing  1  pound  of  sulphur  for  each 
1000  cubic  feet  of  air  space. 

For  prophylaxis  by  means  of  quinine  sulphate,  the  daily  ingestion  of 
2.5  to  5  grains  is  advised.  However  efficacious  this  may  be,  it  will 
have  to  be  admitted  that  it  is  an  expensive  measure,  for  the  mini- 
^  ZJeitschrift  fiir  Hygiene  iind  rnfectionskriinkheiten,  XXX.,  p.  534. 


652  THE  BELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

muni  dose  advised  would  require  the  annual  use  of  no  less  than  65  tons 
per  million  population. 

Mosquitoes  and  Yellow  Fever. — Since  1693,  when  yellow  fever 
made  its  first  appearance  in  this  country,  there  have  been  no  less  than 
95  epidemics  of  greater  or  lesser  magnitude  within  the  United  States. 
According  to  Reed  and  Carroll,^  since  1793  the  disease  has  been  the 
cause  of  no  less  than  100,000  deaths,  41,348  of  which  have  occurred 
in  New  Orleans,  10,038  in  Philadelphia,  and  7759  in  Memphis 
(1855,  '73,  '78,  '79).  Between  1851  and  1883,  it  caused  23,338 
deaths  at  Rio  de  Janeiro,  where,  according  to  Gouvea,^  previous  to  1849 
it  was  unknown,  being  introduced  in  that  year  by  the  Brazil  from  New 
Orleans  and  Havana,  and  by  the  Navarre  from  Bahia.  From  Rio  it 
spread  to  all  the  towns  in  the  bay.  Between  1853  and  1900,  it  caused 
35,952  deaths  at  Havana,  where  it  had  flourished  continuously  for 
more  than  a  century,  and  where,  after  a  practical  application  of  the 
knowledge  concerning  the  method  of  its  dissemination — the  outcome 
of  brilliant  work  on  the  part  of  Reed  and  his  associates,  of  the  United 
States  Army — it  was  demonstrated  that  it  could  be  completely  eradicated, 
and  that  even  though  outbreaks  should  occur  on  ships  arriving  from  in- 
fected ports,  removal  of  the  victims  to  the  fever  hospital  need  give  rise 
to  no  new  cases. 

Inability  to  control  the  spread  of  the  disease  has  hitherto  been  due 
to  the  fact  that  the  manner  of  its  dissemination  was  not  known,  and 
that  all  efforts  to  control  it  were  exerted  in  the  wrong  direction,  in 
the  belief,  now  shown  to  have  been  unfounded,  that  fomites,  filth,  and 
soil  conditions  were  the  distributing  agencies. 

It  was  in  1848  that  Dr.  Josiah  JS^ott,  of  Mobile,  suggested  that 
mosquitoes  might  be  responsible  for  or  connected  with  the  spread  of 
yellow  fever,  but  the  idea  appears  to  have  been  received  with  indiffer- 
ence. In  1881,  Dr.  Finlay,  of  Havana,  announced  his  theory  of  mos- 
quito transference,  and  began  his  experiments,  but  it  remained  for 
Reed  and  his  associates  to  demonstrate  conclusively  that  mosquitoes 
are  the  principal,  if  not  the  sole,  carriers  of  the  exciting  cause,  and  that 
fomites  and  filth  have  absolutely  no  influence  whatever. 

The  experiments  proving  both  statements  are  exceedingly  interest- 
ing. In  October,  1900,  Reed  ^  reported  positive  results  of  experi- 
ments conducted  by  himself  and  Drs.  Carroll,  Agramonte,  and  Lazear 
with  mosquitoes,  Stegomyia  fasciata,  furnished  by  Dr.  Finlay.  Carroll 
was  bitten  by  one  that  had  bitten  four  yellow  fever  patients,  alternately 
severe  and  mild  cases,  respectively,  twelve,  six,  four,  and  tM^o  days 
jn'cviously.  Four  days  afterward  he  took  to  his  bed,  and  on  the  fifth 
day  his  disease  was  diagnosed  as  yellow  fever.  Another  subject  was 
bitten  by  the  same  mosquito,  and  by  three  others  that  had  previously 
bitten  patients  with  the  disease,  and  in  seven  days  he  also  had  the 
fever.     Dr.  Lazear  was  bitten  without  result  by  an  infected  mosquito 

1  Medical  Eecord,  October  26,  1901,  p.  641. 

2  Bulletin  medical,  October  12,  1901,  p.  861. 

*  Philadelphia  Medical  Journal,  October  27,  1900. 


MOSQUITOES.  653 

on  August  16th,  and  by  another,  an  accidental  stranger,  on  September 
13th.  In  five  days,  he  had  a  chill ;  on  the  day  following,  the  diagnosis 
of  yellow  fever  was  made,  and  in  a  week,  the  case  terminated  fatally. 
Between  August  17th  and  October  13th  (fifty-seven  days),  these  three 
were  the  only  cases  which  occurred  among  1400  non-immune  Ameri- 
cans at  Quemados. 

On  November  20,  1900,  an  experiment  station,  Camp  Lazear,  was 
established  at  Columbia  Barracks,  Cuba,  under  the  direction  of  Reed, 
who,  with  his  former  associates,  continued  the  work  with  gratifying 
results.  A  very  strict  quarantine  was  established,  and  no  non-immune 
was  subjected  to  mosquito  inoculation  (with  one  exception)  who  had 
not  passed  the  full  period  of  incubation  of  yellow  fever  under  close 
observation,  nor  was  any  non-immune  who  left  the  camp  permitted 
to  return  under  any  circumstances.  Twenty-one  subjects  presented 
themselves,  mostly  immigrant  Spaniards  seeking  immunity,  and  the 
result   in   each   case   was   positive. 

Experiments  with  fomites  ^  were  equally  convincing  in  results. 
Three  large  boxes  of  sheets,  pillow-slips,  blankets,  etc.,  contaminated 
with  the  discharges  of  yellow  fever  patients,  many  of  them  purposely 
soiled  with  black  vomit,  urine,  and  faeces,  were  placed  in  a  building 
of  2800  cubic  feet  capacity,  tightly  ceiled  and  battened,  with  small 
windows  to  prevent  thorough  circulation  of  air  and  wooden  shutters  to 
prevent  the  disinfectant  action  of  sunlight.  The  windows  were 
screened  with  wire  gauze,  and  the  entrance  with  a  screen  door.  The 
articles  were  unpacked  by  Dr.  Cooke  and  two  privates,  and  they  were 
shaken  so  that  the  specific  agent  might  be  disseminated  throughout  the 
room,  if  it  were  present.  They  were  then  used  on  the  three  beds  pro- 
vided, and  some  were  hung  about  the  room  and  near  the  beds.  For 
twenty  consecutive  nights,  the  three  slept  in  the  uninviting  beds,  and 
every  morning  they  packed  the  filthy  articles  back  into  the  boxes, 
and  every  evening  unpacked  and  distributed  them  again.  They  passed 
their  days  in  tents  in  quarantine.  During  their  tour  of  service,  other 
bedding,  soiled  with  the  bloody  stools  of  a  fatal  case,  was  received  in  a 
most  offensive  stinking  condition,  and  used  with  the  rest.  Then  other 
non-immunes  repeated  the  experiment  for  twenty-one  nights,  sleeping 
in  the  very  garments  which  had  been  used  by  patients.  Then  these 
subjects  were  followed  l)y  others,  who,  for  fourteen  nights  out  of  tw^enty, 
slept  with  pillows  covered  with  towels  that  had  been  thoroughly  soiled 
with  blood  drawn  from  a  case  of  well-marked  yellow  fever  on  the  first 
day  of  the  disease.  The  result  of  the  exposure  of  these  non- 
immunes in  relays  for  nine  weeks  was  wholly  negative,  for  not  one  had 
the  first  symptom  of  yellow  fever.  Not  so,  however,  in  the  case  of 
a  man  who  was  exposed  in  a  building  of  similar  size,  thoroughly 
ventilated,  and  containing  only  disinfected  articles  plus  infected  mos- 
quitoes. On  December  15,  1900,  15  of  the  insects  were  set  free,  and 
he  was  soon  bitten  several  times.  Later,  he  was  bitten  again,  and  also 
on   the  following  day.      He  contracted  the  disease  ;  but  2   men  who 

'  Ke[)orted  in  Medical  Record,  October  26,  11)01,  and  in  other  American  journals. 


654         THE  BELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

slept  for  eighteen  niglits  in  a  half  of  the  room  which  was  screened  from 
the  other  and  from  the  mosquitoes  by  netting,  had  no  symptoms. 

Whatever  the  nature  of  the  parasite,  its  life  cycle  would  appear  not 
to  need  the  passage  of  the  parasite  through  the  intermediate  host,  for 
E-eed  ^  and  his  associates  succeeded  in  producing  the  disease  by  injec- 
tion of  blood  drawn  from  the  general  circulation.  Although  the  specific 
causa  morbi  has  not  yet  been  discovered,  it  appears  to  be  definitely 
settled  that  it  is  not  Sanarelli's  B.  ideroides. 

The  conclusions  arrived  at  by  Reed,  Carroll,  and  Agramonte,  and 
reported  to  the  American  Medical  Association,  are,  in  brief,  as  follows  : 
The  intermediate  host  is  the  Stegomyia  fasciata,  which  is  capable  of 
transmitting  the  disease  after  an  interval  of  about  twelve  days  or 
longer  after  becoming  contaminated  by  biting  a  person  already  sick. 
The  disease  can  be  caused  by  subcutaneous  injection  of  blood  from  the 
general  circulation  during  the  first  or  second  day  of  sickness.  Im- 
munity is  not  conferred  by  the  bite  of  a  mosquito  at  an  earlier  period 
after  contamination  ;  but  when  the  disease  is  produced  through  the 
agency  of  a  mosquito,  the  subject  is  immune  against  infection  by  sub- 
cutaneous injection  of  blood.  The  period  of  incubation  in  cases  of 
induced  fever  varied  from  forty-one  hours  to  five  days  and  seventeen 
hours.  The  disease  is  not  conveyed  by  fomites,  and  hence  disinfection 
of  a  house,  except  as  to  mosquitoes,  is  unnecessary.  The  spread  of 
the  disease  can  be  controlled  most  effectually  by  measures  directed  to 
the  destruction  of  mosquitoes  and  to  protection  of  the  sick  against  them. 

That  not  less  than  twelve  days  are  required  for  the  contaminated 
mosquito  to  acquire  the  power  to  transmit  the  disease,  is  borne  out  by 
the  observations  of  Dr.  H.  R.  Carter,^  who  found  that,  in  sixteen  houses 
in  which  95  secondar}'-  cases  of  yellow  fever  occurred,  the  interval  be- 
tween the  first  and  second  cases  ranged  between  twelve  and  twenty- 
three  days. 

The  Yellow  Fever  Mosquito,  Stegomyia  fasciata  (Figs.  106  and  107), 
formerly  known  as  Culex  fasciatus,  is,  in  this  country,  confined  princi- 
pally to  the  tropical  and  subtropical  regions  along  the  Atlantic  Ocean 
and  Gulf  of  Mexico,  but  may  be  transferred  from  one  region  to  another 
bv  the  usual  vehicles  of  travel.  It  is  found  in  all  the  principal  cities 
and  some  of  the  smaller  towns  of  Cuba  ;  in  Jamaica,  Isle  of  Pines, 
and  Nicaragua ;  in  Louisiana,  especially  in  New  Orleans  ;  in  Eastern 
Texas ;  in  various  places  in  other  Southern  States ;  in  a  number  of 
towns  and  cities  in  Brazil,  and  in  certain  other  hot  countries.  It  is  not 
essentially  an  American  species,  for  Mr.  Theobald,  of  the  British  Mu- 
seum, states  that  he  has  received  specimens  from  Italy,  Greece,  Spain, 
Portugal,  and  Malta.  Its  presence  in  Spain  may  explain  the  occurrence, 
in  1800,  of  a  very  extensive  epidemic  of  yellow  fever  in  the  province 
of  Andalusia,  and,  in  1821,  of  another  at  Barcelona.  Wherever  it  is 
found,  it  appears  to  prefer  the  larger,  populous  centres,  and  to  be  but 
little  common  in  rural  districts. 

1  Philadelphia  Medical  Journal,  .July  6,  1901. 
•'  Medical  Kecord,  June  15,  1901,  p.  933. 


MOSQUITOES. 


655 


The  Sfegomyia  breeds,  like  Culices,  in  small  collections  of  water. 
Reed  and  Carroll  found  the  larvse  in  rain-water  barrels,  sagging  gut- 
ters containing  rain-water,  cesspools,  tin  cans  used  for  removing  ex- 
creta, tin  cans  placed  about  table  legs  to  prevent  inroads  of  red  ants, 
horse-troughs,  leaves  of  the  Agave  Americana,  and  generally  in  any 
collection  of  still  water.  The  New  Orleans  Mosquito  Commission^ 
found  the  larvse  in  128  of  210  cisterns  examined  by  them.  According 
to  this  authority,  the  life  cycle  of  Stegomyia  is  somewhat  different  from 
that  of  other  genera,  and  these  differences  may  necessitate  more 
stringent  measures  than  will  suffice  for  the  suppression  of  Culices  and 
Anopheles,  for  the  eggs  hatch  earlier  (ten  to  twenty-four  hours),  and 
the  larval  (six  and  one-half  to  eight  days)  and  pupal  stages  (two  days) 
are  much  shorter,  so  that  full  development  requires  from  two  to  four 
days  less  than  for  Culex  pungens,  and  two  weeks  less  than  for  any 
species  of  Anopheles.     According  to  Reed  and  Carroll,  the  eggs  begin 


Fig.  106. 


Fig.  107. 


Stegomyia  fasciata.    Male.    (After  Howard.) 


Stegomyia  fasciata.    Female.    (After  Howard.) 


to  hatch,  as  a  rule,  on  the  third  day,  and  the  process  may  last  about 
a  week  ;  the  larval  stage  lasts  seven  or  eight  days  and  the  pupal  stage 
two  days ;  the  shortest  time  for  complete  development  observed  by 
them  was  nine  and  one-half  days.  At  an  average  temperature  of 
75°  F.  or  higher,  the  species  multiplies  abundantly,  but  exposure  to  a 
lower  temperature  for  even  a  short  time  daily  causes  much  retardation, 
and  eggs  kept  at  68°  F.  do  not  hatch.  They  found  that  newly 
hatched  larvse  kept  at  68°  F.  develop  slowly,  and  require  twenty  days 
to  reach  the  pupal  stage  ;  kept  at  50°  F.,  they  fail  to  reach  the  pupal 
stage. 

Although  low  temperatures  are  destructive  of  the  larvse,  it  is  other- 
wise with  the  eggs,  which  Reed  and  Carroll  found  to  be  very  resistant 
to  the  influ(!nce  of  dryness  and  cold.      They  observed  that  eggs  which 
had  \)een  dried  on  filter-paper  and  kcjit  ninety  days  hatched  promptly 
'  New  Orleans  Medical  and  Surgical  Journal,  January,  1902. 


656         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

on  being  placed  in  water.  Dried  eggs,  brought  from  Havana  to 
Washington  in  February,  were  easily  hatched  in  May,  and  furnished 
about  60  per  cent,  of  the  usual  number  of  iarvse  hatched  from  fresh 
eggs.  Eggs  frozen  for  an  hour,  thawed  out  at  room  temperature,  and 
placed  in  an  incubator  at  95°  F.,  began  to  hatch  on  the  sixth  day,  and 
furnished  active  larvae  on  the  eighth  ;  while  others,  frozen  for  a  half 
hour  on  two  successive  days,  began  to  hatch  under  the  same  conditions 
on  the  third  day.  Thus  it  would  appear  that  eggs  may  survive  the 
Havana  winter,  and  that  the  presence  of  hibernating  females  is  not 
necessary. 

The  female  imago,  when  impregnated,  is  generally  ready  to  bite  on 
the  second  or  third  day.  In  New  Orleans,  according  to  the  Mosquito 
Commission,  the  mosquitoes  are  active  during  the  day,  and  particularly 
in  the  afternoon.  In  Cuba,  Reed  and  Carroll  found  them  to  be  especially 
active  from  4  p.  m.  until  midnight,  although  in  captivity  the  hungry 
impregnated  female  will  bite  at  any  hour.  When  freed  in  a  room,  she 
does  not  appear  to  bite  a  second  time  within  five  to  seven  days. 

Having  bitten  a  yellow  fever  patient,  it  appears  that  the  mosquito  is 
incapable  of  inducing  the  disease  before  twelve  days  have  passed. 
Those  which  failed  to  infect  on  the  eleventh  day  were  successful  on  the 
seventeenth.  How  long  the  ability  to  infect  continues,  was  not  deter- 
mined, but  successful  inoculation  was  brought  about  as  late  as  fifty- 
seven  days  after  contamination. 

How  long  the  infected  mosquito  will  live,  is  not  known.  The  speci- 
men which  conveyed  the  disease  on  the  fifty -seventh  day  lived  seventy- 
one  days,  others  have  been  known  to  live  five  months,  but  the  majority 
die  in  captivity  within  five  weeks.  In  a  state  of  freedom  their  length 
of  life  depends  largely  upon  access  to  water. 

At  temperatures  below  62°  F.,  Stegomyia  will  not  bite,  and  thus 
Reed  accounts  for  the  decline  in  epidemics  of  yellow  fever  at  New 
Orleans  in  November,  when  the  mean  temperature  is  61.8°  F.,  and 
their  cessation  in  December,  when  it  falls  to  55.3°. 

Preventive  Measures. — To  avoid  epidemics  of  yellow  fever.  Reed 
advocates  the  prevention  of  importation  of  cases  of  the  disease  from 
infected  localities,  and,  when  cases  do  appear,  the  application  of  meas- 
ures to  protect  the  sick  from  attacks  of  mosquitoes.  Screens  should 
be  used  for  this  purpose,  and  even  the  dead  should  be  thus  protected, 
for  Stegomyia  will  bite  even  these.  All  mosquitoes  in  a  house  where 
a  case  occurs  should  be  caught,  and  search  should  be  made  for  them  in 
all  the  houses  in  the  immediate  vicinity.  They  may  be  destroyed  by 
fumigation  with  sulphur  dioxide  (1  pound  of  sulphur  for  each  1000 
cubic  feet  of  air-space),  which  Rosenau  ^  finds  far  superior  for  this  pur- 
pose to  formaldehyde,  for  very  small  amounts  of  the  dry  gas  will  kill 
them,  even  when  they  are  protected  by  four  layers  of  towelling,  while 
formaldehyde  acts  feebly  and  with  uncertainty.  Pyrethrum  (Dalmatian) 
powder  may  be  burned  in  the  same  proportion,  and  will  either  kill  or 
stupefy  them,  so  that  in  three  hours  they  may  be  swept  up  and  burned. 
1  Bulletin  No.  6,  Hygiene  Laboratory  of  the  U.  S.  M.-H.  S.,  September,  1901. 


MOSQUITOES.  657 

Nou-inimunes  entering  infected  houses  are  advised  to  rub  all  exposed 
surfaces/  including  the  ankles,  with  spirits  of  camphor,  oil  of  penny- 
royal, or  5  per  cent,  menthol  ointment ;  but  these  agents  exert  only  a 
temporary  protective  influence  against  being  bitten. 

Of  very  great  importance  is  the  destruction  of  larvse  and  of  breed- 
ing-places. The  results  of  systematic  work  in  this  direction  and  of 
other  preventive  measures  are  manifest  in  the  immense  improvement  in 
the  sanitary  condition  of  Havana.  Under  the  direction  of  Dr.  W.  C. 
Gorgas,  U.  S.  A.,^  the  "Stegomyia  Brigade"  began  its  work  of  in- 
spection in  March,  1901,  when,  in  16,000  houses  examined,  larvse  were 
found  "at  the  rate  of  100  per  cent.  This  does  not  mean  that  every 
house  examined  had  larvse ;  many  houses  were  found  that  had  several 
receptacles  which  contained  larvse."  During  December,  1901,  16,121 
houses  were  inspected,  and  in  but  1.5  per  cent,  were  the  larvse  found. 
From  May  7  to  July  1  (fifty-four  days),  no  case  of  the  disease  oc- 
cured  ;  then  it  was  introduced  from  Santiago  de  las  Vegas,  and  later  from 
other  places,  and  yet,  during  July,  there  were  but  4  cases,  and  in 
August,  but  8.  During  the  whole  year  (1901),  there  were  but  18  deaths 
from  yellow  fever,  and  12  of  these  occurred  in  January  and  February, 
before  the  work  of  prevention  was  begun.  During  the  preceding 
forty-five  years,  the  average  number  of  deaths  therefrom  was  751.44, 
the  minimum,  51,  occurring  in  1866. 

Mosquitoes  and  Filarial  Disease. — In  1872,  Dr.  Timothy  Lewis, 
of  Calcutta,  discovered  that  human  blood  is  the  normal  habitat  of  the 
embryo  nematode  discovered,  in  1863,  by  Demarquay,  in  the  milky 
fluid  from  chylous  dropsy  of  the  tunica  vaginalis,  and  named  it  Filaria 
sanguinis  hominis.  Later,  Manson,  in  consequence  of  the  discovery  of 
other  filarise  in  the  blood,  renamed  this  parasite  Filaria  nocturna,  and 
named  the  others  F.  diiirna,  F.  perstans,  F.  Demarquaii,  and  F.  Ozzardi. 
The  most  important  of  these  is  F.  Nocturna,  which  is  the  embryo  of 
F.  Bancrqfti,  discovered  in  1876  by  Bancroft,  of  Australia,  in  patients 
with  lymph-scrotum,  and  named  in  his  honor  by  Cobbold.  The  par- 
ental form  is  a  hair-like  nematode,  from  3  to  4  inches  long,  which 
infests  small  cyst-like  dilatations  of  the  distal  lymphatics,  lymphatic 
varices,  the  larger  lymphatic  trunks  between  the  glands,  the  lymphatic 
glands,  and  the  thoracic  duct.  The  embryos,  which  are  about  an 
eightieth  of  an  inch  in  length,  and  about  as  broad  as  the  diameter  of 
a  red  blood-corpuscle,  are  found  in  the  blood  of  persons  afflicted  with 
filariasis  from  just  before  the  approach  of  night  until  about  8,  or  9,  or 
10  o'clock  in  the  morning.  They  enter  the  general  circulation  as  night 
approaches,  and  increase  gradually  in  number  until  about  midnight, 
after  which  they  gradually  decrease  until  the  time  above  mentioned, 
when  they  disap]icar  from  the  peripheral  circulation.  According  to 
Manson,  it  is  not  unusual  to  find  at  midnight  as  many  as  300  to  600 
in  a  single  drop  of  blood,  from  which  he  concludes  that,  at  that  honr, 
as  many  as  40  or  50  millions  of  them  may  be  circulating  simultaneously 
1  Public  Health  Reports,  Febrnaiy  14,  1902,  p.  363. 

42 


658         THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES 

in  the  blood-vessels.  During  the  day,  they  may  be  found  in  the  larger 
arteries  and  in  the  lungs. 

The  parasite  is  found  indigenous  in  almost  all  tropical  and  sub- 
tropical countries,  and  in  this  country  as  far  north  as  Charleston,  S.  C. 
In  many  places,  a  half,  and  even  more,  of  the  population  are  found  to 
be  infested. 

According  to  Manson,  the  following  diseases  are  known  to  be  pro- 
duced by  this  parasite :  abscess ;  lymphangitis ;  varicose  groin  and 
axillary  glands  ;  lymph-scrotum  ;  cutaneous  and  deep  lymphatic  varix  •, 
orchitis ;  chyluria ;  elephantiasis  of  the  leg,  scrotum,  vulva,  arm, 
mammse,  and  elsewhere ;  chylous  dropsy  of  the  tunica  vaginalis ;  chy- 
lous ascites  ;  chylous  diarrhoea ;  and  probably  other  diseases  due  to 
obstruction  or  varicosity  of  the  lymphatics  or  to  the  death  of  the 
parent  worm. 

In  1878,  Manson,  having  conceived  the  idea  that  mosquitoes 
might  be  instrumental  in  spreading  the  disease  by  acting  as  an  inter- 
mediate host,  observed  the  development  of  filariae  in  a  sjjecies  of 
Culex  (C  ciliaris,  vel  ptpiews),  which  was  allowed  to  bite  an  infected 
person.  Within  a  few  hours,  the  blood  plasma  in  the  mosquito's 
stomach  becomes  thickened,  but  not  coagulated,  and  some  of  the 
embryos  manage  to  escape  from  their  sheaths  and  then  move  freely 
in  the  blood,  and  finally  escape  from  the  stomach  and  enter  the  tho- 
racic muscles,  where  they  remain  a  number  of  days  and  undergo  a 
process  of  metamorphosis,  which  results  in  the  formation  of  a  mouth, 
an  alimentary  canal,  a  peculiar  trilobed  tail,  and  great  increase  in 
size. 

It  was  Manson's  idea  that  the  infested  mosquito  repaired  to  some 
body  of  water,  laid  her  eggs,  and  died  ;  and  that  the  parasites  freed 
themselves  from  the  dead  body,  lived  in  the  water,  and,  being  received 
into  the  stomach  of  man  through  drinking,  bored  their  way  through 
the  tissues  and  entered  the  lymphatic  trunks,  where,  attaining  sexual 
maturitv,  fecundation  occurred,  resulting  in  clue  course  of  time  in 
new  generations  of  embryos  to  be  poured  into  the  lymph,  then 
through  the  glands  or  by  the  lymphatics  into  the  general  circulation. 
Bancroft,  however,  suggested  that  the  parasite  is  transmitted  back  to 
man  not  through  drinking-water,  but  by  the  bite  of  the  mosquito ; 
and  in  1900,  G.  C.  Low  discovered  that  the  metamorphosed  worm 
makes  its  way  to  the  insect's  head,  and  finally  into  the  root  of  the 
proboscis,  in  which  it  lies  until  the  mosquito  bites  another  person,  when, 
stimulated  into  activity  by  the  warmtb  of  the  encompassing  tissues, 
it  moves  from  its  position  in  the  proboscis  and  enters  the  M^ound. 
The  worms  thus  introduced  undergo  farther  development  in  their 
new  position  in  the  skin  and  become  adults,  and  proceed  to  breed 
embryos,  which  enter  the  lymph  spaces  or  vessels. 

According  to  Manson,  in  most  cases  of  infection  the  parasite  exer- 
cises no  manifest  injurious  influence  whatever,  and  in  those  cases  in 
which  injury  is  caused,  the  trouble  is  due  in  the  main  to  obstruction 
of  the  lymphatics  by  the  parent  worms. 


MOSQUITOES.  659 

At  first  it  was  believed  that  the  intermediate  host  was  CuLex  ciliaris 
(yel  pipiens)  alone,  but  a  number  of  other  mosquitoes  are  now  known 
to  act,  including  species  of  Culex  and  Anopheles.  These  include, 
according  to  James,  A.  Rossii,  C.  albopundatus,  and  C  raicroannu- 
latus ;  and,  according  to  Low,^  C.  fatigans  ;  and  to  Vincent,^  A.  albi- 
manus.  Low  reports  that,  in  Barbadoes,  neither  malaria  nor  any  spe- 
cies of  Anopheles  is  known,  but  that  there  are  much  filarial  disease  and 
an  extraordinary  abundance  of  C.  fatigans.  In  600  blood  examina- 
tions of  persons  taken  at  random,  12.66  per  cent,  yielded  F'daria 
noeturna.  In  Trinidad,  Vincent  found  in  500  cases  taken  at  random, 
5  per  cent,  infested  with  filariffi  and  6.6  per  cent,  with  elephantoid 
disease.  In  Culex  fatigans,  it  was  observed  that  the  final  stage  of 
metamorphosis  was  reached  between  the  sixteenth  and  nineteenth  days, 
but  with  A.  albimanus,  since  none  of  the  specimens  lived  in  captivity 
beyond  the  twelfth  day,  it  was  not  possible  to  determine  definitely 
when  the  final  stage  is  reached.  In  the  case  of  C.  ciliaris,  Bancroft 
prolonged  the  life  of  the  insect  and  followed  the  development  of  the 
parasite  to  the  last  stage  of  its  metamorphosis,  which  occurred,  under 
favorable  conditions  of  temperature,  at  about  the  sixteenth  or  seven- 
teenth day  after  feeding. 

Filaria  diurna  is  a  form  which  is  detected  in  the  blood  only  by 
day,  and  it  has  been  supposed  to  be  a  distinct  species,  although  nothing 
is  known  about  its  life  history  or  pathological  significance.  Accord- 
ing to  the  findings  of  the  jSTigeria  Malaria  Expedition,^  however,  there 
are  so  many  points  of  resemblance  between  the  two  forms  that  it  is 
possible  that  they  may  be  identical.  It  is  pointed  out  that  the  geo- 
graphical distribution  of  the  two  forms  is  in  close  agreement,  although 
in  many  places  where  F.  noeturna  is  known  to  exist,  F.  dmrna  has 
not  been  noted ;  but  the  latter  is  not  known  to  exist  where  the  former 
is  absent.  Furthermore,  in  some  of  the  Pacific  islands  where  ele- 
phantiasis is  exceedingly  common  and  F.  noeturna  is  found,  there  is 
none  of  the  characteristic  nocturnal  periodicity.  Where  both  were 
found,  the  members  of  the  expedition  were  unable  to  distinguish  in 
any  way  the  one  form  from  the  other.  In  some  cases,  embryos  were 
found  during  both  day  and  night.  It  is  known  that  when  persons 
infested  with  F.  noeturna  change  ther  habits,  so  that  they  sleep  by 
day  and  keep  about  by  night,  the  filarise  are  found  in  the  peripheral 
circulation  only  during  the  day. 

Filaria  iJemarquaii  resembles  F.  diurna  and  F.  noeturna  in  shape, 
but  not  in  size,  being  about  half  as  large.  It  is  present  in  the  blood 
botli  l>y  day  and  by  night  in  the  peripheral  circulation.  Low  *  has 
attempted,  without  success,  to  determine  the  intermediate  host  neces- 
sary for  the  development  of  the  embryos  to  the  point  where  they  are 
capable  of  farther  growth  in  man,  but  is  of  the  oi^inion  that  the  inter- 
mediate host  is  a  blood-sucking  insect. 

Mosquitoes  and  Dengue. — Concerning  the  etiology  of  this  disease 

'  Kritish  Mwliral  .Jr.iinial,  .Septeniber  14,  lOOl,  p.  687.         ^  Ibidem,  January  25,  1902. 
=*  Memoir,  IV.,  ]>.  8'J.  ••  I5i-iti.sh  Medical  Journal,  January  25,  1902. 


660  THE  RELATION  OF  INSECTS  TO  HUMAN  DISEASES. 

of  tropical  climates,  nothing  has  ever  been  known,  although  many  hy- 
potheses, diifering  widely,  have  been  advanced.  Recently,  however,  an 
investigation  conducted  by  Dr.  Harris  Graham,^  in  the  vicinity  of  Bey- 
routh, in  Syria,  implicates  the  mosquito  as  an  important  factor  in  its 
spread.  At  the  place  mentioned,  the  disease  is  very  prevalent,  and 
mosquitoes  of  the  genus  Culex  are  a  serious  pest.  Graham  observed 
that  the  disease  occurred  in  persons  under  observation  only  when  they 
were  bitten  by  infected  mosquitoes,  and  that,  when  they  were  bitten, 
the  disease  invariably  followed.  For  example  :  he  applied  mosquitoes 
to  a  person  suifering  from  it,  and,  after  they  had  bitten,  carried  them 
in  a  paper  box  to  a  village,  high  up  on  a  mountain,  where  there  was 
no  case  of  the  disease.  There  they  were  allowed  to  bite  two  apparently 
healthy  persons,  in  whom,  in  four  and  six  days,  respectively,  typical 
attacks  occurred.  In  a  large  number  of  cases,  he  made  examinations 
of  the  blood,  and  in  every  instance  he  found  in  the  red  corpuscles  an 
amoeboid  parasite  which  bore -considerable  resemblance  to  the  malarial 
organism,  but  required  a  much  longer  time  for  its  cyclic  development 
and  showed  no  pigment  at  any  stage.  The  organisms  were  found  at 
times  also  in  the  blood  plasma.  Flagellated  forms  were  observed  also 
in  some  cases  when  the  blood  had  stood  for  some  time. 

Further  observation  and  study  are  obviously  desirable  and  necessary. 

Mosquitoes  and  Distomiasis. — In  a  recent  communication.  Dr.  F. 
Martirano  ^  gives  certain  facts  which  suggest  that  the  principal  malarial 
mosquito  may  serve  as  an  intermediate  host  for  distomal  diseases  as 
well.  At  the  request  of  Professor  Celli,  he  examined  a  large  number 
of  Anopheles  maculipennis  to  ascertain  whether  the  hibernating  insects 
contained  malarial  parasites  in  their  stomach  and  salivary  ghinds.  Up 
to  the  fifteenth  day  of  JSIarch,  he  found  from  1  to  5  per  cent,  of  the 
mosquitoes  to  be  infected,  and  from  that  time  until  the  end  of  May 
the  examination  was  completely  negative.  In  his  examinations  it  hap- 
pened frequently  that  he  found  in  the  abdominal  cavity  a  diminutive 
trematode,  which  on  close  study  proved  to  be  a  distomum.  In  May 
and  June,  fully  half  of  the  specimens  examined  proved  to  be  infested. 
The  distomum  was  rarely  found  singly ;  sometimes  five  or  ten  were 
found  in  one  mosquito.  Frequently,  they  were  in  the  rearmost  segment 
of  the  abdomen,  but  he  found  them  also  in  the  salivary  ducts.  Some- 
times they  were  free  in  the  thorax  and  in  the  abdomen,  but  in  the 
majority  of  cases  they  were  encysted  on  the  outer  wall  of  the  stomach 
and  oesophagus  and  on  the  inner  wall  of  the  abdominal  cavity.  The 
distomum  nearly  filled  the  cyst,  was  very  motile,  and  endeavored  to 
breai<:  through  its  envelope  by  butting  with  its  forepart.  Several  times 
he  found  not  only  the  distoma,  but  filarial  infection  as  well.  The 
possibility  that  the  parasite  may  be  communicated  to  man  through  the 
wound  made  .in  biting  is  obvious,  and  thus  may  be  explained  the  sup- 
posed entrance,  through  the  skin,  of  Bilharzia  hcematobia. 

1  Medical  Eecord,  February  8,  1902. 

2  Centralblatt  fiir  Bakteriologie,  etc.,  XXX.,  Dec.  24,  1901,  p.  849. 


CHAPTER   XIII. 
HYGIENE  OF  OCCUPATION. 

The  influence  of  occupation  on  health  and  length  of  life  has  been 
the  subject  of  much  investigation  since  attention  was  first  called  to  its 
importance  by  Professor  Bernardino  Pamazzini,  of  Padua,  in  1700,  but 
more  particularly  during  the  last  half  century.  Although  his  work 
was  translated  anonymously  into  English  as  early  as  1705,  the  subject 
appears  to  have  been  one  that  did  not  appeal  with  any  special  force  to 
English  social  scientists  and  medical  men,  for  the  first  English  work 
of  any  importance  was  that  by  Mr.  C.  Turner  Thackrah,  a  practitioner 
of  Leeds,  on  The  Effects  of  the  Principal  Arts,  Trades  and  Professions, 
and  of  Civic  States  and  Habits  of  Living,  on  Health  and  Longevity, 
published  in  1831.  A  French  translation  of  the  work  of  Ramazzini 
appeared  in  1777,  and  formed  the  groundwork  of  P.  Patissier's  Traits 
des  Maladies  des  Artisans  et  de  celles  qui  Pesultent  des  Diverses  Pro- 
fessions, d'apres  Ramazzini,  which  was  published  at  Paris  in  1822. 
It  was  translated  early  also  into  German ;  but  the  first  work  of  any 
importance  on  the  subject  by  a  German  writer  was  that  of  Halfort, 
Entstehung,  Verlauf,  und  Behandlung  der  Krankheiten  der  Kiinstler  und 
Gewerbetreibenden,  published  at  Berlin  in  1845. 

Since  the  awakening  of  interest  in  the  subject  in  England,  France, 
Germany,  and  other  European  countries,  and  the  United  States,  it  has 
been  extensively  and  minutely  studied  in  all  its  aspects,  and  to-day 
its  bibliography  includes  thousands  of  titles,  mostly,  however,  as  Avould 
naturally  be  supposed,  of  monographs  and  memoranda  pertaining  to 
individual  callings.  From  this  vast  amount  of  material  from  all 
sources,  numerous  tables  have  been  constructed,  showing,  it  is  generally 
supposed,  how  the  various  occupations  stand  relatively  in  the  amount 
of  influence  which  they  exert  on  the  longevity  of  those  engaged  in 
them.  From  these  tables  it  appears,  for  example,  that  those  who 
follow  some  particular  calling  are  more  prone  to  contract  certain  dis- 
eases than  those  engaged  in  another ;  that  in  each  hundred  individuals 
of  some  one  class,  a  greater  number  of  deaths  will  occur  in  a  year  than 
in  each  hundred  of  another ;  that  the  average  age  at  death  of  those 
engaged  in  one  employment  is  lower  or  higher  than  that  of  those  in 
another,  and  so  on. 

As  in  all  findings  based  upon  groups  of  units  with,  pcrha])s,  but  one 
common  bond,  each  unit  being  subject  to  a  variety  of  outside  influences, 
the  conclusions  drawn  frf)m  this  vast  mass  of  matijrial  are  influenced 
largely  by  fallacy,  and   inchide  wheat  and  chafl^',  fact  and  fimcy.     In 

661 


662  HYGIENE  OF  OCCUPATION. 

many  cases,  general  statements  are  based  upon  such  a  slight  founda- 
tion as  to  indicate  that  their  authors  are  possessed  of  that  degree  of 
genius  which  has  been  defined  as  the  ability  to  generalize  from  a 
single  instance.  In  many  others,  they  are  based  upon  facts  and  con- 
ditions which  no  longer  exist,  the  methods  followed  in  the  manufacture 
of  the  particular  article  concerned  having  undergone  a  complete  change. 
For  example,  a  process,  formerly  carried  on  by  men  in  small  establish- 
ments run  by  Avater-power  in  the  country,  may  have  been  concen- 
trated in  large  mills  run  by  steam  and  situated  in  crowded  cities  ;  the 
machinery  is  diflFerent  and  more  perfect,  and  requires  nothing  more 
than  feeding,  and  this  may  be  done  by  a  boy  or  girl,  instead  of  an 
adult  man.  Here,  the  older  facts  may  no  longer  apply  in  any  way, 
and  for  present  purposes  should  be  abandoned  as  belonging  to  an  ex- 
tinct occupation. 

It  is  often  difficult  or  impossible  in  the  study  of  the  effects  of  occu- 
pation to  eliminate  outside  influences  which  may  affect  the  health  of 
the  worker  as  much  as  or  more  than  the  circumstances  of  his  trade. 
A  hundred  men,  for  example,  from  different  strata  of  society — some 
married,  others  single  ;  some  living  in  comfortable  houses,  others  in 
cheerless,  unsanitary  tenements ;  some  spending  their  evenings  in  whole- 
some recreation  amid  wholesome  surroundings,  others  doing  evening 
work  in  places  of  public  entertainment  and  elsewhere,  or  spending 
their  time  and  wages  in  the  paths  of  vice ;  some  naturally  robust,  and 
others  inclined  to  disease — engage  in  the  same  occupation  at  the  same 
time.  During  the  year,  there  is  considerable  sickness  among  them,  and 
some  of  them  die  ;  perhaps  these  include  mainly  young  men.  Shall 
it  be  said  without  a  careful  analysis  of  all  the  circumstances  of  their 
lives  and  of  the  immediate  causes  of,  their  deaths,  that  their  calling 
is  necessarily  inimical  to  health  and  longevity?  This  one  died  of 
smallpox  ;  this  one  of  consumption  ;  this  one  of  a  blow  on  the  head 
while  drunk ;  this  one  was  drowned  ;  two  were  victims  of  typhoid 
fever  and  two  of  pneumonia ;  eight  in  all — truly  a  large  percentage, 
but  shall  the  trade  be  blamed  ? 

It  must,  of  course,  be  self-evident  that  certain  occupations  are 
intrinsically  dangerous  to  health,  because  of  the  nature  of  the  sub- 
stances with  which  the  workers  are  brought  in  contact ;  and  these  are 
properly  classed  as  dangerous  trades.  Many  others  are  so  classed,  not 
because  of  any  intrinsic  danger,  but  on  account  of  the  peculiar  con- 
ditions under  which  they  are  ordinarily  carried  on,  these  tending  to 
reduce  the  physiological  resistance  to  disease.  Still  others  are  classed 
as  dangerous  to  health  which  are  merely  dangerous  to  life,  the  iixlivid- 
ual  being  subject  to  mechanical  violence  while  in  the  enjoyment  of 
perfect  health.  These  also  are  properly  to  be  included  among  the 
dangerous  trades.  But  the  great  majority  of  callings  are  neither  intrin- 
sically dangerous  nor  carried  on  under  peculiar  conditions  favoring  a 
low  state  of  health,  yet  many  of  these  figure  in  statistical  tables  in  such 
a  way  as  to  lead  to  the  conclusion  that  those  engaged  in  them  may 
have  little  hope  of  green  old  age,  while  others  in  occupations  of  practi- 


HYGIENE  OF  OCCUPATION.  663 

cally  the  same  character,  but  under  diiferent  names,  give  promise  of  a 
full  period  of  usefulness. 

Statistical  tables  of  longevity  of  groups  of  individuals  engaged  in 
the  various  callings  should  be  used  with  much  circumspection  and  with 
a  due  regard  to  the  various  circumstances  which  determine  the  choice 
of  trade,  the  age  of  the  individual  at  the  time  of  engaging  upon  it,  the 
length  of  time  which  one  may  serve  before  engaging  in  another,  the 
peculiar  conditions  under  which  the  calling  is  pursued,  and  the  prob- 
able character  of  the  influences  which  affect  the  well-being  of  the  in- 
dividual while  he  is  not  immediately  engaged ;  that  is  to  say,  his  home 
surroundings,  his  personal  habits,  the  nature  of  his  relaxations,  the 
quality  of  his  food,  and  other  factors.  Tables  based  on  foreign  statis- 
tics should,  furthermore,  be  not  too  freely  accepted  as  applicable  to  home 
conditions,  owing  to  differences  in  racial  peculiarities  and  of  conditions 
under  which  those  engaged  work  and  live,  for  one  can  hardly  suppose 
that  any  one  class  works  and  lives  under  the  same  conditions  in  all 
countries. 

The  conditions  which  govern  the  choice  of  an  occupation  are  of  very 
great  importance.  Many  callings  demand  men  of  robust  build  and 
good  health,  and  manifestly  are  unsuited  to  the  weakling,  who  natu- 
rally is  attracted  to  other  occupations  of  a  lighter  character.  On  this 
score  alone,  statistics  may  be  grossly  fallacious.  For  example,  in  cer- 
tain tables  it  will  be  observed  that  the  class  designated  as  clerks  have 
a  low  average  age  at  death,  and  from  this  it  may  be  inferred  that  the 
calling  is  one  which  is  intrinsically  incompatible  with  long  life.  But 
is  it  fraught  with  danger?  Is  it  conducted  under  peculiar  conditions 
which  tend  to  bring  its  unfortunate  followers  to  an  early  grave  ?  Or 
is  it  not  rather  the  fact  that  it  is  the  refuge  of  a  great  number  of  those 
whose  physical  powers  are  such  that  they  are  unsuited  to  employments 
which  call  for  greater  robustness,  and  who,  inevitably  marked  for  an 
early  death,  regardless  of  their  calling,  reduce  the  average  age  at  death 
of  the  entire  class. 

On  the  other  hand,  certain  occupations  involving  much  severe  mus- 
cular effort  appear  to  be  conducive  to  long  life,  in  spite  of  the  condi- 
tions under  which  they  are  pursued.  Here  must  be  borne  in  mind 
that  in  these,  the  weaker  individuals  and  those  whose  powers  begin  to 
fail  are  forced  into  other  occupations,  and  that  those  who  remain 
until  the  end  show  an  average  age  at  death  which  is  eloquent  of  the 
benign  influence  of  the  calling.  It  is  undoubtedly  true  that  muscular 
effort,  carried  to  excess,  will  undermine  the  health  ;  but  not  forced 
beyond  reasonable  limits,  and  particularly  if  carried  on  under  good 
hygienic  surroundings,  instead  of  being  in  itself  prejudicial  to  health, 
is  promotive  of  it.  Those  who  are  forced  into  lighter  occupations  may 
find  the  change  advantageous ;  or,  on  the  other  hand,  entering  upon 
them  already  broken  in  health,  may  help  to  reduce  the  average  age  at 
death  of  all  those  engaged  therein. 

Anotiier  influence  having  a  bearing  on  the  choice  of  occupation  is 
tlio  high  wage  offered  to  attract  workmen  to  trades  vvhich  are  properly 


664  HYGIENE  OF  OCCUPATION. 

conceded  to  be  dangerous  to  health.  These  are  naturally  unattractive 
to  men  of  sound  body  and  mind,  to  whom  health  and  life  are  sweet, 
and  hence  they  find  their  recruits  among  the  broken-down  and  vicious, 
to  whom  the  rate  of  pay  offers,  in  the  one  case,  immediate  much-needed 
and  otherwise  unattainable  financial  relief, 'and,  in  the  other,  opportunity 
for  a  short  period  of  unrestrained  license. 

Statistics  concerning  occupations  entered  upon  at  an  early  age  and 
followed  for  but  a  limited  number  of  years  as  a  preliminary  ti^aining 
for  other  callings,  and  those  which  from  their  very  nature  demand 
men  of  wide  experience,  hence  well  matured,  can  be  of  little  or  no 
value  unless  the  occupations  are  in  some  way  of  intrinsic  danger.  We 
find,  for  exam])le,  in  certain  statistical  tables  dealing  only  with  individ- 
uals above  the  age  of  20  years,  that  the  average  age  at  death  of  students 
is  about  23  years,  while  that  of  professors  exceeds  50.  The  manifest 
absurdity  of  attempting  comparisons  of  the  healthfulness  of  these  two 
occupations  is  brought  out  still  farther  by  reversing  the  case,  and  sup- 
posing the  professors  to  die  oif  at  23  and  the  students  at  50.  Since 
even  advanced  students  in  the  professional  schools  pass,  as  a  rule,  out 
of  the  student  class  and  into  their  chosen  fields  of  usefulness  long  before 
their  thirtieth  year,  it  cannot  cause  surprise  that  those  who  die  before 
their  training  is  completed  do  not  show  a  high  average  age  at  death  ; 
and,  on  the  other  hand,  since  men  of  learning  are  not  ordinarily  called 
upon  to  assume  the  duties  of  professors  until  they  have  passed  through 
the  lower  grades  which  lead  to  that  rank,  it  is  to  be  expected  that  their 
average  age  at  death  will  be  fairly  high.  To  compare  lieutenants  and 
major-generals,  ship])ing-clerks  and  retired  merchants,  apprentices  and 
master  carpenters,  would  be  no  more  absurd.  The  average  age  at 
death  of  any  one  calling  must  be  largely  influenced  by  the  relative 
number  of  individuals  of  the  different  age  periods  engaged  therein,  just 
as  is  the  case  with  the  population  in  general. 

Another  fact  that  affects  the  age  at  which  work  is  undertaken 
is  a  very  low  wage  offered  even  in  times  of  prosperity,  so  low  as 
to  be  no  inducement  to  heads  of  families,  but  sufficiently  high  to  cause 
them  to  help  out  their  financial  condition  by  making  use  of  their 
offspring. 

Before  proceeding  to  a  classification  of  occupations  according  to  the 
circumstances  which  determine  their  healthfulness,  it  is  desirable  to 
consider  the  significance  of  the  somewhat  loosely  applied  term,  occupa- 
tion diseases.  Every  form  of  occupation  and  every  form  of  life  of 
leisure  has  some  attendant  circumstances  which  may  at  some  time,  in 
one  way  or  another,  bring  about  a  predisposition  to  some  form  of 
disease ;  and  to  regard  every  disease  of  an  artisan,  tradesman,  or  pro- 
fessional man  as  attributable  to  his  particular  calling,  is  to  fall  into  a 
common  inexcusable  error,  for  workers  and  drones  have  most  diseases 
in  common.  It  is  beyond  dispute  that  certain  pathological  conditions 
are  caused  and  others  promoted  by  certain  occupations,  and  it  is  equally 
true  that  most  diseases  already  acquired  may  be  influenced  for  better 
or  worse  by  one  or  another  calling. 


HYGIENE  OF  OCCUPATION.  665 

The  true  occupation  disease  is  that  which  in  all  probability  would 
not  have  been  acquired  had  the  individual  not  engaged  in  his  par- 
ticular calling  or  some  other  in  which  the  conditions  are  essentially 
similar.  As  an  instance,  may  be  cited  the  lead  paralysis  of  the  house 
painter,  potter,  compositor,  and  file-cutter.  Certain  diseases  of  com- 
mon occurrence  in  the  population  at  large  are  promoted  by  the  condi- 
tions under  which  various  callings  are  carried  on,  but  these  cannot 
properly  be  called  occupation  diseases,  since  the  exciting  cause  is  in  no 
way  a  part  of  the  business,  and  under  better  hygienic  management, 
combined  with  more  favorable  outside  influences,  might  be  avoided. 
As  a  conspicuous  instance  of  this  class,  may  be  cited  the  tuberculosis 
of  dressmakers,  cutlery  grinders,  and  operatives  in  the  cotton  and  flax 
industries,  promoted  by  overcrowding  and  inhalation  of  dust  while 
at  work,  and  by  all  extraneous  conditions  tending  to  lower  vitality. 
The  plying  of  the  needle  is  in  itself  in  no  way  inimical  to  the  in- 
tegrity of  the  lungs ;  the  grinding  of  the  steel  implement  on  the  wheel 
and  the  running  of  the  loom  send  forth  none  of  the  specific  bacilli ; 
but  the  overcrowding  in  the  one  case,  and  the  unavoidable  inhalation  of 
irritating  dust  in  the  others,  bring  about  the  conditions  which  offer 
fertile  soil  to  the  germ  of  the  disease. 

Certain  conditions  are  influenced  for  better  or  worse  by  different 
occupations,  as  has  been  stated.  Among  these  may  be  mentioned 
anaemia,  which  not  uncommonly  is  classed  among  the  diseases  of  occu- 
pation. Under  the  conditions  of  many  indoor  callings,  this  state  is 
easily  brought  about,  or,  if  already  existing,  increased ;  but,  on  the 
other  hand,  under  those  of  outdoor  occupation,  it  is  not  likely  to  be 
induced,  and,  if  already  existing,  may  be  made  to  disappear.  Many 
occupations,  for  easily  explainable  reasons,  draw  their  workers  largely 
from  that  portion  of  the  population  which  is,  if  not  already  diseased, 
predisposed  by  heredity,  habit,  and  home  surroundings  to  anaemia,  tu- 
berculosis, and  other  disorders,  the  onset  of  which  may  be  hastened  or 
delayed,  according  to  circumstances.  In  these,  and  in  occupations  in 
general,  it  is  not  an  easy  matter  to  determine  correctly  the  amount  of 
influence  properly  chargeable  to  the  calling  when  disease  appears,  since 
the  conditions  under  which  a  trade  is  carried  on  may  be  widely  vari- 
able, and  their  influence  for  good  or  evil  exceedingly  complex.  Among 
these  conditions  may  be  mentioned  indoor  confinement,  nature  of  ma- 
terials, geographical  location,  and  M^ages  paid. 

Whether  an  occupation  is  carried  on  indoors  or  outdoors,  is  of  much 
importance,  for,  other  things  being  equal,  outdoor  employment  is  far 
more  conducive  to  health  than  is  confinement,  even  in  well-venti- 
lated factories,  in  which,  with  the  best  of  systems,  the  air  cannot  be 
maintained  in  the  condition  of  purity  which  obtains  outside.  Even 
those  callings  which  subject  their  followers  to  great  vicissitudes  of 
weather  appear  to  be  more  conducive  to  robustness  than  those  carried 
on  indoors,  particularly  if  tlie  nature  of  the  work  is  such  as  to  call 
for  freedom  of  movement  and  great  bodily  activity.  The  sailor,  the 
letter-carrier,   or   the   farm    hniid,   for   example,   working  in  the  open 


666  HYGIENE  OF  OCCUPATION. 

air,  in  lieat  and  cold  and  in  all  kinds  of  weather,  is  better  circum- 
stanced in  many  ways  than  the  loom-tender,  the  entry  clerk,  and 
the  salesman  at  the  ribbon  counter.  He  works,  perhaps,  in  a  broil- 
ing sun,  rather  than  in  an  overheated  room  filled  with  impure  air ; 
the  air  he  inhales  contains  some  dust,  perhaps  much,  but  it  is  a 
less  harmful  dust,  less  abundant,  and  not  continuous.  The  air  of  the 
factory  and  workshop  may  be  almost  as  pure  as  that  out  of  doors,  or  it 
may  be  laden  with  fumes,  gases,  foul  odors,  or  dust  of  a  special  nature, 
according  to  the  materials  used.  The  outdoor  worker  is  also  much  less 
oppressed  by  the  monotony  which  is  so  conspicuously  a  concomitant  of 
indoor  work.  He  can,  at  least,  see  sorne  part  of  his  world  in  ever- 
changing  conditions,  while  the  mill  operative  tends  his  machine,  of 
which  he  is  perhaps  only  a  minor  part,  day  in  and  day  out,  seeing  it  do 
the  same  thing  with  mechanical  exactness  so  many  times  per  minute  or 
per  hour,  with  no  more  sense  of  responsibility  than  might  reside  in  an 
automaton. 

Geographical  location  of  the  place  of  employment  has  an  important 
sanitary  bearing  on  the  condition  of  the  workers,  since  it  determines 
very  largely  the  outside  influences  to  which  they  are  subjected.  Loca- 
tion in  country  districts  is  likely  to  insure  better  and  cheaper  homes 
than  can  be  found  in  crowded  cities,  with,  perhaps,  a  patch  of  garden 
which  may  be  M'orked  for  pleasure,  profit,  and  variety  in  the  diet.  It 
is,  furthermore,  farther  removed  from  the  influence  of  the  tippling-shop 
and  other  unhealthy  influences  of  the  city. 

The  wages  paid  affect  the  health  of  the  working  classes  in  several 
ways.  A  small  wage  means  necessarily  a  small  expenditure  for  rent, 
clothing,  and  food ;  it  means  overcrowded  tenements,  lack  of  ventila- 
tion, insufficient  protection  of  the  body  by  clothing  of  inferior  quality, 
inadequate  food — usually  improperly  prepared  and  hastily  bolted — 
personal  and  general  uncleanliness  and  other  conditions  which  lower 
the  mental,  moral,  and  physical  well-being  of  the  workers  and  all  who 
are  dependent  upon  them.  It  means  more  beside  :  it  means  the  utili- 
zation of  child-labor  and  the  breaking-down  of  women,  who  perform 
the  double  duty  of  looking  after  the  home  and  assisting  in  its  main- 
tenance. All  these  circumstances  promote  the  morbidity-  and  mortality- 
rates,  and  the  particular  occupations,  perhaps  intrinsically  wholesome, 
are  then  said  to  be  inimical  to  health,  when  it  is  not  the  nature  of  the 
callings,  but  the  attendant  circumstances,  that  are  at  fault.  Thus,  it 
often  happens  that  the  conditions  leading  to  the  most  serious  evils  may 
be  traced  to  some  circumstance  or  combmation  of  circumstances  which 
are  wholly  external. 

Classification  of  Occupations. — In  a  general  way,  we  may,  from  a 
sanitary  standpoint,  classify  occupations  as  follows  :  1.  Those  which 
are  intrinsically  dangerous  to  health  by  reason  of  the  nature  of  the 
materials  involved.  2.  Those  which  are  carried  on  under  conditions, 
avoidable  or  unavoidable,  which  promote  susceptibility  to  disease.  3. 
Those  which,  involving  exposure  to  mechanical  violence,  are  dangerous 
to  life  and  limb  rather  than  to  health.     4.  Those  neither  intrinsically 


CLASSIFICATION  OF  OCCUPATIONS.  667 

dangerous  to  health  or  life  nor  carried  on  necessarily  under  peculiar 
avoidable  or  unavoidable  circumstances. 

The  first  and  second  of  these  classes  are  of  especial  interest  to  the 
sanitarian,  whose  efforts  are  directed  toward  the  removal  of  all  unsani- 
tary influences  of  whatsoever  kind  attending  any  and  all  occupations. 
The  third  class  includes  occupations  which  involve  the  possibility  of 
injury  due  to  circumstances  bearing  no  relation  to  hygiene.  Thus,  no 
effort  of  the  hygienist  can  prevent  a  brakeman  from  falling  beneath  the 
wheels  of  a  train  or  the  operatives  in  a  dynamite  industry  from  being 
blown  into  eternity  by  the  force  of  an  explosion  due  to  carelessness. 
The  fourth  class — and  this  includes  a  great  variety  of  perfectly  color- 
less callings — presents  nothing  of  especial  hygienic  interest,  since  the 
physical  condition  of  the  individual  would  be  essentially  the  same 
whether  he  were  engaged  in  one  or  another  of  the  different  fields,  and 
only  those  which  are  carried  on  under  peculiar  conditions  can  be  studied 
to  advantage.  Therefore,  only  the  first  two  classes  will  be  considered 
here,  and  since  the  dividing  line  between  the  two  is  often  difficult  to 
define,  and  since  some  occupations  may  be  said  to  belong  to  both,  the 
two  may  be  merged  into  one  for  the  sake  of  convenience,  and  then 
subdivided  as  below  : 

The  occupations  which  are  of  particular  hygienic  interest  embrace 
those  which  involve  exposure  to — 

1.  Air  vitiated  by  respiration. 

2.  Irritating  and  poisonous  gases  and  fumes. 

3.  Irritating  and  poisonous  dusts. 

4.  Infective  matter  in  dust. 

5.  Offensive  gases  and  vapors. 

6.  Extremes  of  heat. 

7.  Dampness. 

8.  Abnormal  atmospheric  pressure. 

Of  distinct,  but  minor,  importance  are  those  which  involve — 

9.  Constrained  attitude. 

10.  Over-exercise  of  parts  of  the  body, 

11.  Sedentary  life. 

Some  occupations  are  conducted  under  such  conditions  that  they 
may  very  properly  be  regarded  as  belonging  to  a  number  of  these 
groups.  Mining,  for  example,  may  be  considered  under  groups  2,  3, 
6,  7,  9,  and  10,  and  cigar-making  under  groups  1,  2,  3,  9,  and  11. 

To  attempt  to  describe  the  conditions  which  surround  each  individual 
industry,  and  to  give  the  details  of  the  countless  processes  involved, 
would  be  beyond  the  scoj>e  of  a  work  of  this  nature,  and  quite 
unnecessary  for  a  general  understanding  of  the  relation  of  occupation 
to  health.  Therefore,  in  the  following  pages,  only  the  most  conspicu- 
ously characteristic  examples  will  be  cited  by  way  of  illustration  of  the 
dangers  to  which  workers  are  exposed. 


668  HYGIENE  OF  OCCUPATION. 

1.  Occupations  Involving  Exposure  to  Air  Vitiated  by 
Respiration, 

This  class  may  be  made  to  include  any  indoor  calling  carried  on  in 
overcrowded,  ill-ventilated  rooms,  in  which  the  air  is  vitiated  only  by 
the  processes  of  the  body,  and  not  by  adventitious  gases  or  dust.  These 
occupations,  therefore,  are  not  in  themselves  dangerous,  but  are  made 
so  by  a  preventable  cause. 

As  examples,  may  be  cited  the  callings  of  tailoring  and  dressmaking, 
which,  only  too  commonly,  are  conducted  in  rooms  in  which  fresh  air 
and  cubic  space  per  capita  are  at  a  minimum.  The  workers  are  packed 
into  quarters  no  larger  than  absolutely  necessary  for  the  performance 
of  their  daily  task,  impossible  of  proper  ventilation  without  an  expen- 
sive mechanical  system,  so  great  is  the  overcrowding,  and,  as  is 
naturally  to  be  supposed,  overheated.  Here,  the  unfortunates  spend  a 
fairly  long  day,  leaving  at  night  to  go  to  homes  perhaps  no  less 
unsanitary.  If  not  already  so  M'hen  they  begin,  they  become,  after  a 
time,  aua?mic,  dyspeptic,  and  depressed,  these  conditions,  as  in  many 
other  callings,  being  promoted  by  lack  of  exercise,  by  ill-chosen  and 
badly  cooked  food,  and  by  absence  of  healthful  recreations.  They 
become  greatly  susceptible  to  cold,  and  hence  opposed  to  the  admission 
of  fresh  air  from  without.  Breathing  excremental  air  by  day  and 
night,  denying  themselves  proper  food,  their  minds  depressed,  it  is  not 
to  be  wondered  at  that  their  condition  invites  disease,  more  particularly 
the  one  which  stands  forth  conspicuously  as  a  consequence  of  over- 
crowding; namely,  pulmonary  consumption.  The  onset  is  insidious. 
Beginning  with  a  cold  that  resists  being  "  thrown  off,"  the  cough  be- 
comes chronic ;  they  continue  to  lose  weight  and  strength,  and  the  end 
can  be  foreseen.  It  is  not  to  be  understood  that  these  callings  are 
always  or  even  usually  associated  with  these  conditions ;  but  when 
they  are,  the  result  is  generally  the  same. 

2.  Occupations  Involving  Exposure  to  Irritating  and  Poisonous 

Gases  and  Fumes. 

This  class  includes  a  great  variety  of  callings  which  may  or  may 
not  be  intrinsically  dangerous,  according  to  individual  circumstances. 
In  many  cases,  the  danger  may  be  much  lessened  by  due  regard  to 
personal  hygiene  and  by  the  use  of  respirators.  These  are  simple 
pieces  of  apparatus  designed  to  remove  noxious  matters  from  the 
air,  on  its  way  to  the  respiratory  passages.  It  is  the  rule,  however, 
that  workmen  refuse  to  wear  them  after  the  first  days,  even  though 
well  aware  of  the  possible  consequences  of  laying  them  aside.  One 
reason  for  this  is  that  not  one  of  the  several  forms  invented  can  be 
worn  with  any  degree  of  comfort.  They  demand  faster  respiration, 
soon  get  wet  with  expired  moisture,  and  cause  excessive  perspiration, 
furthermore,  they  cannot  be  made  to  fit  tightly,  and  so,  even  ^vheu 
conscientiously  worn,  they  only  partially  perform  their  office.     The 


IRRITATING   GASES  AND  FUMES.  669 

majority  of  them  are  designed  to  filter  out  dust,  but  all  are  made  on 
essentially  the  same  principle,  those  intended  for  noxious  fumes  con- 
taining spongy  or  other  absorbent  material,  wet  with  agents  which 
exert  a  neutralizing  influence. 

One  form  consists  of  a  muzzle  of  fine  wire  gauze,  single  or  double, 
on  a  metallic  frame.  If  made  with  a  single  layer,  it  is  lined  with  cot- 
ton-wool, kept  in  place  by  a  very  loosely  woven  fabric  stitched  to  the 
wire  meshes ;  if  made  double,  the  intervening  space  is  occupied  by  a 
piece  of  thin  flannel.  Another  form  is  made  of  woven  or  knitted  stuif, 
instead  of  wire.  This  is  said  to  be  even  hotter  than  the  first  mentioned, 
particularly  in  summer,  and  both  are  extremely  uncomfortable.  A 
third  form,  made  of  pieces  of  flat  sponge  large  enough  to  cover  the 
nose  and  mouth,  interferes  very  much  with  free  respiration.  Another, 
consisting  of  a  large  bag  of  fine  cambric,  is  said  to  be  less  objection- 
able, but  is  difficult  to  fasten  tightly. 

Aside  from  the  discomfort  caused  by  respirators  of  whatever  form, 
the  operatives  have  another,  a  senseless,  objection  to  their  use,  women 
complaining  that  they  are  made  to  "  look  ridiculous,"  and  men  being 
moved  to  discard  them  by  the  gibes  of  their  more  reckless  fellows. 

(a)  Irritating-  Gases  and  Fumes. — As  examples  of  irritating  gases 
or  fumes,  may  be  cited  ammonia,  chlorine,  sulphur  dioxide,  hydro- 
chloric acid,  and  nitrous  fumes.  In  small  amounts,  they  cause,  per- 
haps, no  more  disturbance  than  a  slight  tickling  cough,  but  in  large 
amounts,  they  bring  about  great  discomfort  and  acute  and  chronic 
catarrhal  conditions. 

Chlorine,  which  is  used  or  given  off  very  extensively  in  a  number  of 
industries,  is  unimportant  when  it  is  present  in  the  air  in  very  small 
traces ;  but  when  in  large  amounts,  it  is  said  to  cause  minor  catarrhal 
troubles  and  diminution  or  even  loss  of  the  sense  of  smell.  It  is  said 
by  Pettenkofer  that  from  1  to  5  parts  of  chlorine  in  100,000  of  air  are 
sufficient  to  affect  the  lungs ;  that  40  to  60  parts  in  100,000  will  pro- 
duce alarming  symptoms  ;  and  that  more  than  60  parts  will  cause  death. 
It  is  given  off  in  the  processes  of  making  and  using  bleaching  powder, 
in  the  operation  of  glazing  bricks,  and  in  various  other  processes. 
Among  the  workmen  who  make  use  of  bleaching  powder,  the  occur- 
rence of  bronchitis,  asthma,  and  caries  of  the  teeth,  is  noticeably 
frequent. 

Hydrochloric  acid  fumes  are  given  off  in  various  industries,  and  es- 
pecially from  alkali  works,  the  immediate  neighborhood  of  Avhich  is 
likely  to  be  barren  of  vegetation  in  consequence  thereof.  They  are 
given  off  also  in  the  process  of  galvanizing  iron,  the  first  part  of  the 
work  consisting  in  "pickling"  the  iron  in  the  acid  to  clean  it  and  to 
prevent  the  pnjsence  of  oxide  on  the  surface  when  it  is  dipped  into  the 
molten  zinc.  These  fumes  act  much  less  energetically  on  the  respira- 
tory passages  than  chlorine.  Pettenkofer  states  that  as  much  as  1  part 
in  1,000  of  air  can  be  borne  without  difficulty  by  men  who  are  accus- 
tomed to  it,  but  that  this  amount  cannot  bo  exceeded.  In  the  galvan- 
izing process,  the  workmen  are  exj)osed  also  to  the  dense  fumes  arising 


670  HYGIENE  OF  OCCUPATION. 

from  the  sal  ammoniac  which  is,  from  time  to  time,  thrown  upon  the 
surface  of  the  molten  zinc.  These  are  more  insupportable  than  the 
acid  fumes. 

Sulphur  dioxide  is  evolved  in  the  smelting  of  various  ores,  in  pre- 
paring hops,  in  the  manufacture  of  sulphuric  acid  and  of  ordinary 
matches,  and  is  used  extensively  as  a  bleaching  agent.  In  small 
amounts,  it  causes  cough,  and,  by  those  unaccustomed  to  it,  cannot  be 
tolerated.  Those  who  are  exposed  to  it  in  their  daily  work  establish  a 
gradual  tolerance  and  take  no  notice  whatever  of  an  atmosphere  in 
which  it  is  present  to  such  an  extent  that  persons  unaccustomed  to  it 
cannot  breathe  it.  The  weight  of  evidence  concerning  the  relation  of 
this  gas  to  health  indicates  that  its  effects  are  neither  serious  nor  past- 
ing, and  are  exerted  more  on  the  digestive  than  on  the  respiratory 
function.  In  some  individuals,  a  small  amount  in  the  atmosphere 
causes  epigastric  pain  and  heartburn  very  quickly. 

Bromine  is  exceedingly  irritating  to  the  respiratory  passages  and  to 
other  mucous  membranes  with  which  it  may  come  in  contact.  In  small 
amounts,  it  causes  cough,  dizziness,  and  a  feeling  of  general  malaise ; 
in  large  amounts,  spasm  of  the  glottis  and  asphyxia.  Bronchial 
astlima  is  commonly  observed  among  those  constantly  exposed.  The 
fumes  of  iodiue  act  practically  in  the  same  way,  although  to  a  much  less 
marked  extent.  In  occupations  in  which  these  two  substances  are 
used,  men  with  a  tendency  to  pulmonary  troubles  should  not  be  j)er- 
mitted  to  work. 

There  is  no  evidence  that  ammonia  in  small  amounts  produces  any- 
thing more  than  temporary  irritation  of  the  air-passages,  but  it  is  a 
general  belief  that  it  is  conducive  to  emphysema. 

Xitrous  fumes,  given  oif  in  a  number  of  processes  involving  contact 
of  metals  with  nitric  acid,  are  also  of  no  very  great  importance  in  small 
amounts,  but  it  is  said  that  those  who  are  exposed  are  especially  sub- 
ject to  phthisis,  in  the  causation  of  which  it  is  conceded  that  the  con- 
strained attitude  and  lack  of  ventilation  have  a  large  influence.  It  is 
noted  that  the  tendency  is  greatest  in  those  exposed  to  the  largest 
amounts. 

(6)  Poisonous  Gases  and  Fumes. — This  class  includes  a  very  large 
number  of  occupations,  since  poisonous  gases  are  an  incident  of  proc- 
esses without  number. 

Carbon  monoxide  is  one  of  the  most  important  of  the  poisonous 
gases,  and  this  is  given  off  in  many  manufacturing  operations,  usually 
in  company  with  other  gases,  and  it  is,  therefore,  not  always  an  easy 
matter  to  determine  what  proportion  of  the  effects  noticed  are  due  to 
any  one  constituent  of  the  mixture.  The  constant  inhalation  of  even 
very  small  amounts  of  carbon  monoxide  causes  disturbances  of  the 
digestive  function,  general  weakening  of  the  system,  and  diminished 
mental  power.  The  one  class  in  which  one  would  naturally  expect  to 
find  the  greatest  evidence  of  injury,  namely,  laborers  in  gas  plants, 
yields  very  little. 

Carbon  disulphide  is  much  used  as  a  solvent  for  fats,  but  its  chief 


POISONOUS  GASES  AND  FUMES.  671 

use  is  as  a  solvent  and  vulcanizing  agent  for  India-rubber.  The  very 
peculiar  effects  produced  upon  the  operatives  in  rubber  factories,  espe- 
cially when  the  work  is  carried  on  in  imperfectly  ventilated  rooms,  have 
been  attributed  generally  to  the  use  of  this  agent.  There  is  at  first  a 
dull  headache,  which  increases  much  in  severity  toward  the  close  of 
day  ;  sight  becomes  somewhat  confused  ;  vertigo  and  epileptiform  con- 
vulsions, pains  in  the  extremities,  and  formication  are  common.  In 
the  early  stages,  an  unrestrainable  inclination  to  talk  is  almost  invari- 
ably observed,  and,  coincidently,  a  stimulation  of  sexual  desire.  Soon, 
the  victim  becomes'  moody,  irritable,  and  subject  to  violent  outbreaks 
of  anger ;  vision  becomes  further  impaired ;  the  sense  of  smell  is  much 
diminished.  During  this  stage,  obstinate  insomnia  is  the  rule.  Next 
occurs  a  stage  of  depression,  in  which  the  loquacity  and  increased  sex- 
ual desire  give  way  to  impaired  memory,  feebleness  of  mind,  taciturn- 
ity, and  diminution  of  sexual  desire  and  power  even  to  complete  abol- 
ishment, with  intense  headache,  either  somnolence  or  wakefulness,  and 
local  areas  of  anaesthesia.  Sometimes  cough,  dyspnoea,  and  paraplegia 
are  observed.  As  a  rule,  however,  no  permanent  injury  is  caused, 
since,  from  the  very  nature  of  the  symptoms,  the  victims  are  unable 
to  continue  to  work  ;  and  removal  from  the  cause,  with  appropriate 
medication,  in  which  phosphorus  is  highly  regarded,  usually  brings 
about  a  perfect  cure.  This  train  of  symptoms  seems  to  be  peculiar  to 
workers  in  rubber  factories  ;  and  since  the  evidence  at  hand  shows  that 
those  who  make  carbon  disulphide  do  not  suffer  in  the  same  way,  it  seems 
reasonable  to  suppose  that  other  agents  than  this  one  are  to  be  consid- 
ered in  the  etiology.  It  happens  that,  in  this  same  industry,  naphtha 
is  very  much  used  as  a  solvent.  The  vapors  of  this  substance  cause 
embarrassment  of  respiration,  and  also  dizziness  and  mental  confusion. 
In  France,  the  employment  of  women  under  eighteen  in  rubber  fac- 
tories, and  in  any  work  which  exposes  them  to  the  combined  fumes  of 
naphtha  and  carbon  disulphide,  is  prohibited.  Santesson  ^  has  reported 
9  cases  of  naphtha-poisoning,  4  of  which  were  fatal.  They  occurred 
in  a  rubber  factory  where  a  solution  of  rubber  in  naphtha  was  used. 
The  symptoms  were  headache,  dizziness,  vomiting,  palpitation,  and 
hemorrhages.  In  those  cases  which  recovered,  the  symptoms  lasted 
several  weeks.  All  the  victims  were  young  women.  In  1  fatal  case, 
the  autopsy  showed  fatty  degeneration  of  the  heart,  liver,  kidneys,  and 
other  parts.  Naphtha  is  used  very  extensively  also  in  cleansing  wool- 
len and  other  un washable  clothing,  and  young  women  employed  in 
establishments  devoted  to  this  kind  of  work  suffer  from  dizziness, 
nausea  and  vomiting,  headache,  insomnia,  and  hysteria.  They  find  it 
necessary  to  go  frequently  into  the  open  air  in  order  to  avoid  hysteri- 
cal outbreaks. 

Another  much  more  poisonous  substance  is  nitrobenzol,  which  is 
very  insidious  in  its  effects.  It  is  used  in  making  aniline,  like  which 
it  is  a  narcotic  poison,  and  in  the  manufacture  of  roburite  and  other 

'  Gazette  liehdomadaire  de  Medccine  et  de  Cliinirgie,  August  26,  1897. 


672  HYGIENE  OF  OCCUPATION. 

of  the  newer  explosives.  Long  exposure  to  small  amounts  produces  a 
train  of  symptoms  which  include  headache,  dyspnoea,  drowsiness,  diz- 
ziness, nausea  and  vomiting,  and  loss  of  muscular  strength,  and  which 
terminate  in  stupor  and  not  infrequently  in  death.  Death  sometimes 
occurs  within  a  few  hours  of  the  onset.  Aniline  vapor  itself  is  dan- 
gerous to  health  when  present  in  the  air  to  the  extent  of  0.1  per  cent. 

The  most  prominent  of  all  the  poisonous  vapors  in  manufacturing 
processes  are  those  of  mercury  and  phosphorus.  It  is  hardly  neces- 
sary here  to  enumerate  the  effects  of  exposure  to  these  poisons,  since 
they  are  so  universally  well  known ;  but  it  is  not  so  commonly 
recognized  that  operatives  in  industries  in  which  metallic  mercury  is 
used  extensively  appear  to  be  very  subject  to  phthisis,  and  that,  among 
the  women,  miscarriage  is  very  common.  It  is  said  that  the  offspring 
show  the  eifects  of  the  poison,  and  that  two-thirds  or  more  of  those 
born  at  term  die  without  completing  a  year  of  life ;  but  it  is  well  to 
consider  that  among  the  classes  from  which  the  operatives  for  this  and 
similar  occupations  are  drawn,  child  life,  at  best,  labors  under  great 
disadvantages. 

Mercury  is  commonly  supposed  to  be  used  chiefly  in  the  manufact- 
ure of  mirrors,  and  in  gilding  and  silvering.  This,  however,  is  far 
from  being  the  case.  In  fact,  the  processes  of  making  mirrors  and  of 
gilding  have  been  so  revolutionized  that,  in  these  industries,  mercurial 
aflFections  have  been  practically  eliminated.  At  present,  one  of  the 
most  common  sources  of  mercurial  poisoning  is  the  industry  of  felt- 
ing, in  which  it  has  been  discovered  that  the  conev  and  other  hairs 
used  make  better  felt,  if  they  have  a  preliminary  treatment  in  a  bath 
of  mercuric  nitrate.  In  a  later  process,  the  raw  product  is  heated  to  a 
temperature  sufficient  to  volatilize  the  mercury.  Other  occupations  in 
which  mercury  is  used  extensively  include  the  manufacture  of  ther- 
mometers, barometers,  and  certain  forms  of  electric  batteries,  and  the 
bronzing  of  plaster  casts  with  an  amalgam  containing  tin,  bismuth,  and 
mercury. 

Phosphorus  is  a  substance  of  much  more  importance  to  the  public 
health  than  mercury.  The  only  industry  of  any  magnitude  in  which 
phosphorus  is  used  extensively  is  that  of  match-making,  in  which  in- 
dustry the  operatives  suffer  from  the  well-known  lesions  which  phos- 
phorus produces.  This  is  a  danger  which  has  received  much  legisla- 
tive attention  in  England  and  other  European  countries,  and  much 
has  been  done  to  avert  it  by  more  strict  attention  to  hygiene  and  the 
introduction  of  machinery  to  take  the  place  of  human  beings.  In 
Switzerland,  indeed,  even  the  use  of  any  matches  other  than  those 
made  with  amorphous  phosphorus  is  absolutely  forbidden. 

Common  phosphorus  gives  off  poisonous  fumes  at  ordinary  tempera- 
tures, provided  the  air  contains  moisture.  Amorphous,  or  red,  phos- 
phorus is  not  poisonous,  and  gives  off  no  fumes  under  usual  condi- 
tions. It  cannot  be  used  in  the  same  way  as  common  phosphorus, 
and  is  employed  only  in  the  manufacture  of  matches  that  strike  only 
on  the  box  or  on  a  specially  prepared  surface ;   this  is  obviously  a 


POISONOUS  GASES  AND  FUMES.  673 

disadvantage,  since  a  match  that  will  strike  anywhere  is  much  more  con- 
venient. It  is  said  that,  in  England  alone,  no  less  than  60  tons  of  white 
phosphorus  are  consumed  annually,  against  4  tons  of  the  red  variety. 

It  is  a  very  common  notion  that  most  of  the  workmen  suiFer  exten- 
sively from  the  effects  of  the  poisonous  fumes,  and  that  necrosis  of  the 
jaw  is  exceedingly  common.  It  appears,  however,  that,  while  this 
class  of  workmen  are  in  general  anaemic  and  badly  nourished,  the  ex- 
tensive lesions  that  formerly  were  noticed  have  been  of  late  years  much 
less  common.  In  1897—8,  in  the  United  Kingdom,  more  than  1,500 
persons  were  engaged,  but  in  the  four  years,  1894-8,  only  36  cases  of 
necrosis  of  the  jaw  were  recorded,  21  of  which  occurred  in  1890  ;  but 
possibly  more  may  have  occurred.  This  reduction  is  due  to  precautions 
taken  to  carry  oif  the  fumes  by  thorough  ventilation,  and  to  prevent 
their  production  as  far  as  possible  by  the  use  of  substances  like  tur- 
pentine, and  by  drying  the  matches  as  quickly  as  possible  after  they 
have  been  dipped,  since  the  fumes  are  given  otf  only  in  the  presence 
of  moisture.  Again,  much  of  the  work  of  dipping  is  done  in  closed 
hoods.  It  is  said  that  the  most  difficult  part  of  prevention  lies  in  the 
handling  of  the  work-people  themselves,  since  they  are  of  a  class  that 
can  rarely  be  made  to  understand  the  importance  of  cleanliness  and  of 
attention  to  the  condition  of  the  teeth.  Persons  with  decayed  teeth 
should  be  excluded  from  the  business,  since  caries  is  known  to  increase 
enormously  the  risk  of  poisoning.  They  cannot,  for  reasons  already 
explained,  be  persuaded  to  use  respirators. 

In  the  industry  of  brass-founding,  fumes  are  given  oif  which  cause 
what  is  commonly  known  as  "brass-founders'  ague,"  which  is  a  dis- 
order occurring  sooner  or  later — usually,  within  a  very  short  time — to 
all  engaged.  The  trouble  begins  with  a  feeling  of  malaise,  headache, 
stiffness,  great  muscular  pain,  and  soreness  of  the  chest.  A  chill  comes 
on,  which  lasts  generally  about  a  quarter  of  an  hour,  after  which  the 
patient  falls  into  a  profuse  perspiration.  The  symptoms  then  begin  to 
abate  and  within  a  day  or  two  disappear.  Although  this  train  of 
symptoms  does  not  commonly  recur,  a  more  or  less  marked  chronic 
poisoning  is  common,  in  which  the  most  prominent  symptoms  are 
anaemia,  cough,  tachycardia,  headache,  neuralgia,  disordered  digestion, 
progressive  emaciation,  and  annoying  eruptions  of  the  skin.  The  acute 
and  chronic  poisoning  suffered  by  this  class  of  workmen  are  supposed 
by  some  to  be  due  to  zinc,  by  some  to  copper,  by  some  to  both  together, 
and  by  others  to  arsenic,  which  is  an  important  constituent  of  some 
kinds  of  brass  and. an  impurity  of  others.  Some  incline  to  the  belief 
that  brass-founders'  ague  is  a  true  infection,  for  which  the  poisoned  air 
prepares  the  ground  and  paves  the  way. 

Fumes  of  arsenic  are  given  off  in  various  smelting  operations,  but 
the  chief  danger  from  this  substance  is  met  with- in  occupations  to  be 
considered  later,  in  which  it  is  given  off  in  the  form  of  dust.  A  pecu- 
liar source  of  poisoning  by  arseniui'cttcd  hydrogen  has  been  brought  to 
jjublic  notice  by  Maljean,^  wlio  observed  a  number  of  cases  of  icterus 
'  Archives  de  M<5(lecine  militaire,  February,  1900,  p.  12. 
43 


674  HYGIENE  OF  OCCUPATION. 

among  the  balloonists  of  a  regiment  of  engineers.  The  cause  was 
traced  by  him  to  the  hydrogen  gas  used  in  tilling  the  balloons,  which 
was  made  by  the  action  of  ordinary  commercial  sulphuric  acid  on  com- 
mercial zinc,  both  of  which  contain  arsenic  in  variable  amounts,  in 
consequence  of  which  the  product  contained  arseniuretted  hydrogen. 
The  impure  gas  was  liberated  through  the  valve  of  the  balloon,  but 
the  main  source  of  danger  was  the  habit  of  smelling  at  the  stopcock 
during  filling,  to  ascertain  when  the  air  in  the  j)ipes  had  been  expelled 
by  the  gas.  In  the  cases  observed,  the  onset  was  marked  by  great 
malaise,  headache,  nausea,  stiffness  of  the  joints,  jaundice,  and  hemo- 
globinuria. The  symptoms  subsided  in  a  few  days,  leaving  the  patients 
in  a  condition  of  antemia  and  pronounced  malnutrition. 

The  vapors  of  wood  alcohol  have  within  recent  years  attracted  con- 
siderable attention  by  reason  of  their  disastrous  effects  upon  vision. 
Since  1899,  many  cases  of  blindness  have  been  reported  in  the  journals 
devoted  to  ophthalmology  as  due  to  the  vapors  and  to  the  internal  use 
of  preparations  such  as  essences  of  ginger,  peppermint,  etc.,  which  are 
very  commonly  made  with  wood  alcohol,  and  extensively  consumed  in 
places  where  the  sale  of  liquor  is  prohibited.  When  wood  alcohol  as 
such  is  consumed,  as  it  often  is,  with  fatal  results,  it  will  be  noted  that 
the  victims  are  generally  quite  blind  before  death  approaches.  Wiir- 
demann  ^  has  reported  a  case  of  wood-alcohol  blindness  due  to  the  in- 
halation of  fumes  from  varnish.  The  subject  was  a  moderate  user  of 
tobacco  and  stimulants,  whose  sight  had  always  been  good.  After 
working  six  days,  he  was  obliged  to  quit  work  on  account  of  nausea, 
dizziness,  and  severe  frontal  headache.  On  the  following  day,  he  had 
dimness  of  sight,  and  then  became  totally  blind  for  twenty-four  days, 
when  his  sight  began  to  improve.  In  another  case  reported  by  Patillo,^ 
and  quoted  by  Wurdemann,  the  material  worked  with  was  the  same, 
and  total  blindness  occurred  on  the  sixth  day.  This  lasted  a  week, 
then  sight  improved,  but  in  two  weeks  it  began  again  to  fail.  Inhala- 
tion of  the  vapor  is  believed  to  cause  retrobulbar  neuritis,  producing 
partial  atrophy  of  the  optic  nerve,  especially  of  the  central  fibers. 

3.    Occupations   Involving   Exposure   to   Poisonous   and 
Irritating   Dusts. 

Dust  is  of  very  great  importance  in  its  influence  on  health.  Its 
production  is  a  prominent  feature  of  many  occupations,  in  some  of 
which  so  much  is  caused  as  to  be  of  the  highest  possible  importance. 
It  may  be  divided  into  poisonous  and  irritating,  and  the  latter  may  be 
subdivided  into  mineral,  metallic,  vegetable,  and  animal. 

(a)  Poisonous  Dusts. — The  most  important  of  the  poisonous  dusts 
are  arsenic  and  lead. 

One  of  the  most  dangerous  of  arsenical  trades  is  the  grinding  of  the 
well-known  green  pigments,  Scheele's  green  (arsenite  of  copper)  and 

'  American  Medicine,  December  21,  1901,  p.  995. 
,  ^  Ophthalmic  Kecord,  December,  1899,  p.  599. 


POISONOUS  DUSTS.  675 

Schvveinfurt  green  (aceto-arsenite  of  copper).  These  and  many  other 
arsenical  colors  are  used  in  printing  wall-papers,  cretonnes,  and  other 
decorations,  and  in  the  manufacture  of  artificial  flowers.  The  latter  is 
an  especially  dangerous  occupation,  since  after  the  leaves  have  been  cut 
to  the  proper  shape,  they  are  smeared  with  gum,  the  green  pigment  is 
then  dusted  on  from  a  dredging-box  and  much  of  the  substance 
becomes  suspended  in  the  air.  Much  of  the  green  glazed  paper  used 
for  covering  boxes  is  made  with  these  pigments,  and  other  papers  and 
articles  of  paper  in  green  and  other  colors  (playing  cards,  etc.),  are 
made  with  arsenical  pigments.  Arsenite  of  sodium  is  a  very  common 
mordant,  and  white  arsenic  is  much  used  in  taxidermy.  In  fact,  the 
list  of  processes  in  which  arsenic  is  used  is  almost  endless.  The  symp- 
toms produced  may  be  acute,  but  ordinarily  are  chronic  in  character. 
Workmen  of  this  class  frequently  suffer  from  eczematous  sores  and 
obstinate  ulcers.  The  symptoms  of  chronic  poisoning  are  too  well 
known  to  need  description. 

Lead  is  infinitely  more  disastrous  in  its  effects  upon  health,  and  is  by 
far  the  most  important  of  all  industrial  poisons,  because  of  the  great 
diversity  of  its  use.  Among  the  many  occupations  in  which  it  figures 
may  be  mentioned  all  the  processes  involved  in  obtaining  lead  in  its 
commercially  pure  state  from  ores,  the  making  of  white  and  red  lead, 
the  glazing  of  many  kinds  of  papers  ;  type-founding  and  setting,  glass- 
cutting  and  polishing,  file-cutting ;  enamelling,  dyeing  and  printing, 
working  in  weighted  silk ;  plumbing,  painting,  leather  varnishing ; 
making  artificial  flowers,  leaves,  and  jewels  ;  and  several  of  the  proc- 
esses used  in  the  making  of  earthenware  and  china.  In  many  of 
these,  the  lead  gains  access  to  the  system  through  inhalation,  and  in 
some  it  is  carried  into  the  mouth  by  the  soiled  fingers.  The  latter 
method  of  introduction  is  very  commonly  the  case  with  compositors, 
plumbers,  workers  in  lace  and  silk  weighted  with  lead  acetate,  and 
others. 

In  Paris  alone,  it  is  said,  there  are  more  than  30,000  of  the  working 
classes  following  callings  which  expose  them  to  this  very  deleterious 
substance.  In  England,  the  great  importance  of  the  subject  of  indus- 
trial lead-poisoning  has  led  to  extensive  investigations,  resulting  in 
stringent  legislation  ;  and  in  the  year  1895,  it  was  required  that  all 
cases  of  lead-poisoning  should  be  reported  to  the  authorities.  During 
the  year  1897,  the  number  reported  was  1,124,  and  in  1898,  1,278. 
The  largest  number  of  cases  are  reported  from  the  china  and  earthen- 
ware trades.  It  appears  to  be  a  fact,  wherever  the  matter  is  inves- 
tigated, that  women  suffer  less  than  men.  This  is  explainable  in  two 
ways  :  first,  that  women  are  naturally  more  cleanly  in  their  habits  ; 
and  second,  that  women  are  more  likely  to  give  up  their  work  after 
the  occurrence  of  th^  first  symptoms  and  before  the  affe(!tion  becomes 
chronic.  Men  appear  to  be  able  to  work  longer  without  showing 
evidence   of  injury. 

Particular  att(!iition  lias  been  given  of  late  years  in  England,  France, 
and   (;is(;where   to  tin;   j)f)tt('ry  industry,  in  which   lead  is  used   in   the 


676  HYGIENE  OF  OCCUPATION. 

glazes,  the  flux  being  made  of  litharge,  clay,  and  flint.  Much  atten- 
tion has  been  given  to  the  possibility  of  finding  a  glaze  which  shall 
be  free  from  lead.  In  the  manufacture  of  ordinary  white  porcelain,  no 
lead  glaze  is  required,  and  the  danger  of  lead-poisoning  arises  almost 
wholly  in  the  work  of  decoration,  the  powder  which  is  dusted  on  and 
ofP  the  transfer  paper,  containing  lead  compounds.  According  to  a 
report  of  a  committee  of  the  master  potters  of  Staifordshire,  it  is  not 
possible  to  substitute  a  leadless  glaze  for  ordinary  china  and  earthen- 
ware, but  this  is  said  to  be  only  partly  true. 

In  Limoges,  where  16,000  people,  of  whom  2,500  are  children,  are 
employed  in  sixteen  pottery  establishments,  the  workers  are  much  less 
subject  to  lead-poisoning  than  those  in  Staffordshire,  and  in  one  of  the 
establishments  where  the  ware  produced  is  of  the  same  kind  as  made 
in  Staffordshire,  the  glaze  contains  only  8  per  cent,  of  lead  carbonate 
against  13  to  24  m  that  used  in  Staffordshire.  It  has  been  pointed 
out  that  where  lead  glazes  are  necessary,  the  danger  can  be  very  much 
diminished,  if  the  lead  is  used  in  the  form  of  a  double  fritted  silicate. 
In  the  Limoges  factories,  the  lead  is  used  in  this  condition,  and  to  this 
fact,  part  of  the  difference  in  the  amount  of  poisoning  is  probably  due. 
In  English  potteries,  the  tendency  is  toward  the  abandonment  of  the 
old  methods  and  the  adoptiou  of  fritted  lead. 

Lead  is,  however,  not  the  only  danger  to  health  with  which  Avork- 
men  in  potteries  have  to  contend.  In  certain  of  the  operations,  large 
amounts  of  mineral  dust  are  given  off,  and  in  consequence  they  suffer 
from  the  effects  of  not  only  poisonous,  but  irritating,  dust ;  in  fact,  the 
occupation  is  regarded  from  a  sanitary  standpoint  as  one  of  the  least 
desirable.  The  flint-grinders,  mIio  belong  to  this  class,  are,  according 
to  Hirt,  quite  low  down  in  the  scale  of  longevity.  It  is  said  that  the 
dust  which  is  given  off  in  the  operation  of  grinding  kaolin  is  unusually 
irritating  to  the  lungs — worse,  even,  than  steel  dust.  The  most  com- 
mon diseases  among  potters  are  bronchitis,  phthisis,  rheumatism,  and 
lead-poisoning. 

As  another  example  of  an  industry  in  which  the  workmen  suffer 
largely  from  lead-poisoning  may  be  cited  that  of  file-making,  in  which, 
as  in  pottery -making,  the  operative  is  subjected  to  the  action  of  dust 
both  poisonous  and  irritating.  The  best  files  are  those  cut  by  hand, 
no  machinery  having  yet  been  invented  to  produce  so  satisfactory  an 
article  as  the  hand-made.  While  being  cut,  the  file  is  held  upon  a 
leaden  bed,  called  the  "  stiddy,"  which  offers  sufficient  resistance  to  the 
blow,  without  at  the  same  time  being  so  unyielding  as  to  cause  a 
recoil.  As  fast  as  it  is  cut,  it  is  brushed  off,  and  the  air  becomes 
charged  with  a  combination  of  steel,  lead,  chalk,  and  charcoal,  and 
granite  from  the  block,  or  "  stock,"  upon  which  the  "  stiddy "  is 
secured.  The  danger  of  lead-poisoning  is  thus  always  present,  and  its 
occurrence  is  hastened  by  the  careless  habits  of  the  workman,  who,  in 
handling  the  leaden  bed,  constantly  wets  the  thumb  and  forefinger  of 
his  left  hand  with  his  tongue.  Doubtless,  if  rnore  attention  were  paid 
to  personal  hygiene,  a  smaller  proportion  would  suffer  from  colic  and 


IRRITATING  DUSTS.  677 

paralysis  of  the  extensor  muscles  of  the  wrist  and  thumb.  It  Ls  said 
that  a  robust  file-cutter  is  rarely  seen  ;  as  a  class,  they  are  sallow, 
anaemic,  and  dull,  and  the  majority  show  the  blue  line  of  chronic  lead- 
poisoning. 

A  more  modern  industrial  danger  is  that  involved  in  making  and 
chararing;  storage  batteries  of  a  certain  kind.  Dr.  Talamon  ^  relates 
that,  during  a  single  year  of  hospital  service,  he  saw  30  cases  of  lead- 
poisoning  among  workmen  so  engaged.  The  work  consists  largely  in 
spreading  red  lead  and  litharge  over  lead  plates  with  the  bare  hands, 
and  the  results  on  the  system  are  doubtless  due  in  greatest  part  to 
absorption  through  the  alimentary  tract,  the  lead  being  conveyed  to  the 
mouth  by  the  hands.  The  symptoms  come  on  much  more  rapidly  and 
are  much  more  acute  than  with  painters,  type-setters,  and  others.  Many 
of  the  men  fall  victims  within  three  or  four  weeks  from  the  beginning 
of  their  service. 

(6)  Irritating  Dusts. — The  irritating  dusts  act  with  variable  inten- 
sity, according  to  their  nature.  It  is  generally  thought  that  that  of 
vegetable  origin  is  the  most  irritating  of  all ;  then,  in  order,  metallic, 
animal,  and  mineral.  The  disease  which  is  conspicuously  common 
among  dust-workers — more  common  than  among  any  other  large 
class — is  phthisis,  a  predisposition  to  which  is  favored  by  constant 
irritation  by  the  dust,  assisted  by  poor  ventilation,  constrained  atti- 
tude, and  other  unsanitary  circumstances.  In  general,  the  first  effects 
of  an  abnormal  amount  of  dust  in  the  air  are  cough  and  increased 
secretion  of  mucus.  Then  the  cough  becomes  chronic,  and  when 
the  soil  has  been  properly  prepared,  the  specific  bacillus  finds  a 
lodgement  and  soon  produces  its  results.  Many  of  the  dust-workers' 
disorders  are  traceable  not  to  a  single  kind  of  dust,  but  to  a  mixt- 
ure. Thus,  the  condition  formerly  known  as  "grinders'  asthma" 
is  superinduced  by  a  mixture  of  metallic  particles  from  the  imple- 
ment ground  and  mineral  matter  from  the  stone,  and  to  which,  if  either, 
of  the  two  kinds  the  prepondering  influence  belongs,  cannot  be 
stated. 

The  relative  frequency  with  which  diseases  of  the  lungs  occur  in  the 
different  classes  of  dust-workers  and  in  those  whose  occupation  creates 
no  unusual  amount  of  dust  was  determined  by  Hirt  ^  from  a  large  mass 
of  material,  in  which,  of  course,  the  value  of  the  primary  factors  can 
hardly  be  determined  ;  nor  that  of  collateral  circumstances,  such  as 
habits,  heredity,  and  locality.  But  his  facts,  which,  to  say  the  least, 
are  coincidences  of  occupation  and  disease,  show  that  the  different 
classes  of  dust-workers  suffer  from  pneumonia  and  phthisis  in  varying 
degrees,  and  much  more  frequently  than  those  not  exposed  to  dust,  and 
that  in  the  frequency  of  diseases  of  the  digestive  system,  on  the  other 
h:md,  there  is  practically  no  difference.  In  the  following  table,  com- 
])iled  from  his  figures,  the  relative  frequency  of  these  diseases  per  100 
workmen  is  shown  : 

'  L:i  M(5rlec-ine  moderne,  Fel).  7,  1900. 

''■  Die  Kranklic'iten  der  Arbeiter,  BreKlai],  1871. 


678 


HYGIENE   OF  OCCUPATION. 


Pneumonia. 


Phthisis.         Digestive  disorders. 


Workers  in  metallic  dust  .  . 
"  "  mineral  "  .  . 
"  "  vegetable  "  .  . 
"  "  animal  "  .  . 
"  "  mixed  "  .  . 
"         "  non-dusty  trades 


17.4 
5.9 
9.4 
7.7 
6.0 
4.6 


17.8 
16.6 
15.7 
20.2 
15.2 
16.0 


With  regard  to  the  mfluence  of  the  different  kinds  of  dust  occu- 
pations, one  ruust  not  lose  sight  of  the  fact  that  quantity  as  well  as 
quality  should  be  considered,  and  that  local  conditions  of  ventilation 
have  a  very  decided  bearing. 

Among  the  occupations  in  which  metallic  dust  is  given  off  in  not- 
able amounts,  that  which  stands  forth  most  conspicuously  as  dan- 
gerous is  steel-grinding.  In  this  work,  the  danger  varies  inversely 
with  the  size  of  the  object  ground  ;  that  is  to  say,  the  smaller  the 
object,  the  greater  the  danger.  This  is  because  large  objects  can 
be  ground  in  the  wet  way,  but  very  small  ones,  as  needles,  must  be 
ground  dry  and  require  constrained  attitude  and  close  inspection,  and 
thus  the  grinder  constantly  inhales  the  very  fine,  sharp  particles  of 
steel  that  are  thrown  off  in  the  process.  These,  by  constant  irritation 
of  the  mucous  membranes  of  the  air-passages,  prepare  them  for  the 
reception  of  the  specific  organisms  of  pneumonia  and  jihthisis.  At 
first,  the  cough  is  dry,  but  in  a  short  time  is  accompanied  by  exj^ectora- 
tion.  Among  those  individuals  Avho  have  followed  the  work  for  a  year 
or  longer  under  the  usual  conditions,  a  sound  man  is  rare.  Their 
average  age  at  death  is  stated  variously  betAveen  twenty-five  and  forty 
years.  The  danger  may  be  much  reduced  by  the  use  of  respirators, 
and  by  the  employment  of  a  blast  of  air  to  carry  the  dust  away  from 
the  grinder  into  an  appropriate  exit. 

Not  all  metallic  dust  is  as  irritating  as  that  given  off  in  cutlery- 
grinding,  and  in  some  occupations  in  which  it  is  given  off  even  more 
abundantly,  there  is  no  noticeable  tendency  to  phthisis,  although,  perhaps, 
the  subject  has  not  been  investigated  with  sufficient  thoroughness.  In 
the  operation  of  bronzing  in  the  manufacture  of  show  cards,  Christmas 
cards,  and  the  like,  the  bronze  powder,  which,  under  the  microscope 
shows  sharp  angles,  is  applied  to  the  pattern,  printed  in  sizing,  by  means 
of  a  soft  pad  worked  largely  by  hand.  The  dust  adheres  tenaciously 
to  the  skin  and  causes  much  local  irritation,  and  is  inhaled  and  causes 
catarrh  of  the  upper  air-passages.  In  addition,  the  workers  suffer 
from  headache,  bad  taste  in  the  mouth,  anorexia,  nausea,  vomiting,  and 
diarrhoea,  from  absorption  and  local  action  in  the  alimentary  canal. 
When  the  operations  of  dusting  on  and  off  are  done  by  machinery,  the 
evolution  of  dust  is  very  much  lessened. 

The  dusts  of  many  of  the  metallic  salts  produce  more  or  less  serious 
local  effects,  aside  from  the  results  due  to  absorption  into  the  system. 
In  the  manufacture  and  use  of  potassium  dichromate,  for  example, 
great  irritation  of  the  nasal  mucous  membrane  is  caused,  followed  by 
ulceration,  which  in  most  instances  ends  in  perforation  of  the  septum. 


IRRITATIXG  DUSTS.  679 

Ulcers  are  produced  wherever  the  skin  is  abraded,  and  especially  on  the 
scalp,  where  action  is  promoted  hy  the  scratching  which  the  irritation 
calls  forth.     Xo  local  effects  appear  to  be  caused  in  the  lungs. 

As  an  example  of  a  calling  in  which  mineral  dust  is  given  off  in 
abundance,  that  of  glass-grinding  may  be  mentioned.  This  is  much 
like  cutlery -grinding,  in  a  general  way,  and  the  dust  produced  is  nearly, 
if  not  quite,  as  sharp  and  irritating.  In  addition,  the  workmen  are 
often  subject  to  lead-poisoning,  due  to  the  use  of  putty  powder  con- 
taining 70  per  cent,  of  lead  oxide.  It  is  as  rare  to  find  sound  men 
among  this  class,  as  among  needle-grinders.  Gem  polishers  and 
potters  belong  in  this  same  category.  Stonecutters  and  quarr\-men 
are  exposed  to  coarser  kinds  of  mineral  dust,  but  their  work  being 
conducted  in  the  open  air  or  in  open  sheds,  they  are  by  no  means 
so  prone  to  diseases  of  the  lungs.  Some  stone  is  much  dustier  than 
others,  and  hence  may  cause  more  marked  effects.  Mica  dust  is 
exceedingly  irritating,  and,  like  the  sharp  particles  of  glass  and  steel, 
prepares  indoor  workers  for  the  reception  of  the  bacillus  of  tubercu- 
losis. In  the  wall-paper  industry,  it  is  applied  to  obtain  the  effect 
of  "frosting,"  and  assists  or  is  assisted  in  its  action  on  the  opera-, 
tives  by  another  very  fine  dust  made  of  finely  chopped  or  ground  lambs' 
wool,  which  is  applied  to  the  pattern  printed  in  size  in  much  the  same 
manner  as  obtains  in  bronzing  cards.  The  workers  are  very  prone  to 
phthisis. 

Vegetable  dust  is  of  very  many  varieties,  which  affect  the  system 
with  varying  degrees  of  intensity.  Ordinary  wood  dust  appears  to  be 
quite  innocent  of  injurious  action  on  the  lungs  of  carpenters,  whose 
employment  is  very  largely  out  of  doors,  and  of  cabinet-makers,  who, 
on  the  other  hand,  work  in  confinement.  Grain  threshers,  millers,  and 
many  others  exposed  to  vegetable  dust  present  no  great  evidence  that 
their  callings  are  markedly  inimical  to  health.  Certain  others,  how- 
ever, offer  important  and  interesting  facts,  indicating  that,  either  alone 
or  as  one  of  a  group  of  influences,  some  of  the  vegetable  dusts  are  as 
disastrous  in  their  effects  as  some  of  the  most  irritant  of  those  of 
metallic  nature.  Among  the  most  unhealthy  classes  of  workpeople 
are  those  engaged  in  cotton  and  linen  factories.  Cotton  dust,  or  ''flue," 
is  very  irritant  to  the  upper  air-passages,  and  causes  diwness  of  the 
throat,  followed  by  cough  and  expectoration.  In  some  operations,  a 
sized  cotton  thread  containing  kaolin  is  used,  and  then  the  air  is  laden 
also  with  this  very  irritating  substance.  Flax  dust,  or  "  ponce,"  is  even 
more  irritating  than  cotton. 

In  the  linen  factories  of  Belfast,  which,  according  to  G.  H.  Ferris,^ 
employ  oO,000  persons,  five-sixths  of  whom  are  women,  the  deaths 
from  phthisis  and  other  respiratory  diseases  have  been  sho^^^l  to  out- 
number those  from  all  other  diseases  by  about  two  to  one.  Among 
the  women  below  thirty  years  of  age,  the  death-rate  from  phthisis  is 
three  or  four  times  as  high  as  among  women  of  the  same  ages  engaged 
in  other  employments.  In  1892,  the  phthisis  death-rate  reached  the 
'  Journal  of  State  Medicine,  March,  1895. 


680  HYGIENE  OF  OCCUPATION. 

enormous  height  of  41.1  per  10,000,  against  14.6  for  the  whole  of 
England  and  Wales,  and  21.6  for  all  Ireland.  Apart  from  the  intrin- 
sic danger  of  the  occupation,  however,  it  must  be  noted  that  the  city 
itself,  from  the  nature  of  the  soil  and  climate,  cannot  be  a  healthy 
place,  but,  on  the  other  hand,  it  must  be  said  that  overcrowding,  which 
is  so  great  a  factor  in  the  causation  of  the  disease,  cannot,  in  this 
instance,  be  charged  with  an  unusual  amount  of  influence,  since  in  no 
other  city  in  Great  Britain  and  Ireland  are  there  so  many  houses  in 
proportion  to  the  population. 

Workers  in  tobacco  are  exposed  not  alone  to  irritating  and  poisonous 
dust,  but  to  fumes  as  well.  They  are  much  subject  to  nasal  and  bron- 
chial catarrhs  and  disorders  of  the  digestive  apparatus  and  nervous 
system.  The  women  engaged  are  said  to  abort  very  commonly,  on 
account  of  the  death  of  the  fcetus.  Many  assert  that  the  occupation  in 
itself  is  not  an  unhealthy  one,  and  that  it  possesses  certain  advantages 
in  that  it  renders  the  individual  less  susceptible  to  infective  agents. 
As  evidence  of  this,  it  is  said  that,  during  the  great  cholera  epidemic  at 
Hamburg,  in  1892,  there  were  but  8  cases  of  the  disease,  with  4  deaths, 
among  the  5,000  cigarmakers  there  resident. 

Animal  dust  is  given  off  in  the  numerous  industries  in  which  wool, 
silk,  feathers,  fur,  bristles,  hair,  horn,  bone,  shell,  ivory,  and  other  sub- 
stances of  animal  origin  are  used.  These  substances  are  irritating  to 
different  extents,  as  would  naturally  be  sujjposed  from  their  very 
diverse  character,  some,  as  wool,  feathers,  and  silk,  resembling  in  action 
cotton  and  flax,  and  others,  as  shell,  bone,  and  ivory,  acting  more  like 
the  mineral  dusts.  The  operatives  in  woollen  mills,  appear,  on  the 
whole,  to  be  rather  less  subject  to  phthisis  than  those  engaged  in  the 
cotton  and  flax  industries.  Among  the  others  of  this  class,  those 
making  brushes  and  buttons,  esjDecially  pearl  buttons,  are  regarded  as 
taking  greater  risks  than  the  rest.  Most  statistics  of  these  industries 
are  faulty  and  inconclusive. 

4.  Occupations  Involving"  Exposure  to  Infective  Matter  in  Dust. 

This  class  includes  those  having  to  do  with  rags,  wool,  horsehair, 
hides,  and  other  materials  likely  to  be  infected.  The  importance  of 
rags  as  a  vehicle  for  infection  has  been  much  overrated,  but  the 
danger  is,  nevertheless,  a  real  one,  as  the  experience  of  paper-makers 
has  often  demonstrated.  The  only  method  of  insuring  freedom  from 
infection  through  the  handling  of  rags  is  thorough  disinfection,  a  proc- 
ess involving  an  expense,  it  is  asserted,  much  disproportionate  to  the 
results  achieved. 

The  most  common  disease  connected  with  infected  raw  material  is 
anthrax,  or  "  wool-sorters'  disease,"  the  spread  of  which  is  often  traced 
to  horsehair,  wool,  and  hides.  Nichols^  reported  26  cases  of  this  dis- 
ease as  occurring  in  one  curled  hair  factory  in  three  years.     Ravenel  ^ 

'  Second  Annual  Keport  o£  the  State  Board  of  Plealth  of  Massachusetts,  p.  86. 
^  Eeport  and  Papers  of  the  American  Public  Health  Association,  Vol.  24,  p.  302. 


INHALATION  OF  OFFENSIVE  GASES  AND    VAPORS.  681 

collected  12  cases  occurring  in  men  and  60  in  cattle  in  three  localities 
in  Pennsylvania,  during  the  summer  and  autumn  of  1897.  All  of  the 
men  worked  in  tanneries,  and  all  of  the  cattle  were  pastured  in  mead- 
ows watered  by  streams  which  received  waste  products  from  tanyards. 
The  skins  at  fault  came  from  China. 

According  to  Dr.  S.  Leduc,^  imported  horsehair  is  the  most  danger- 
ous material  brought  into  France.  The  French  market  is  supplied  by 
South  America,  whence  it  is  shipped  in  bales  compressed  by  hydraulic 
pressure.  Unpacking  the  bales  and  sorting  the  contents  according  to 
color  are  alike  regarded  as  dangerous.  After  being  sorted,  the  hair  is 
beaten,  and  in  this  process  much  dust  is  caused.  It  is  then  carded 
and  spun  into  ropes.  The  precautions  to  be  taken  include  removal  of 
dust  by  special  blower  apparatus,  perfect  cleanliness,  and  great  watch- 
fulness. Disinfection  of  the  hair  without  impairing  its  commercial 
value  or  unduly  increasing  its  cost  is  said  to  be  impracticable. 

Naturally,  the  danger  of  infection  by  the  spores  of  anthrax  on  iiides, 
hair,  and  the  many  kinds  of  wools  coming  from  countries  where  the 
disease  is  common  cannot  in  any  individual  case  be  foreseen.  From 
ordinary  sheep's  wool,  the  danger  is  slight,  and  from  native  wools  is 
practically  non-existent.  When,  for  any  reason,  danger  is  appre- 
hended, workmen  with  sores,  cuts,  or  abrasions  on  their  hands,  arms, 
faces,  or  necks,  should  not  be  employed,  ventilation  should  be  thor- 
ough, and  all  precautions  should  be  taken  to  prevent  dissemination 
of  the  dust. 


5.  Occupations  Involving  the  Inhalation  of  Offensive  Gases 

and  Vapors. 

This  class  of  occupations  includes  a  great  variety  of  what  are  known 
as  "  offensive  trades,"  having  to  do  with  organic  matter  largely  of 
animal  origin,  such  as  tanning  and  currying,  soap-making,  glue-making, 
fertilizer-making,  fat-rendering,  bone-boiling,  keeping  animals,  etc. 
While  there  can  be  no  doubt  that  these  offensive  trades  are  a  frequent 
source  of  nuisance  to  the  community  at  large,  evidence  of  injurious  in- 
fluence on  the  health  of  those  actively  engaged  and  of  the  population 
in  the  immediate  vicinity  of  the  works  is  decidedly  slender.  There 
can  be  no  doubt  of  the  disadvantage  of  having  such  establishments 
located  in  the  midst  of  thickly  settled  communities,  and  hence  their 
supervision  constitutes  a  most  important  part  of  the  duty  of  public 
authorities.  The  workmen  are  likely  at  first  to  suffer  from  nausea, 
vomiting,  loss  of  appetite,  and  headache,  but  these  evidences  of  dis- 
turbance disappear  within  a  short  time,  and  do  not  recur. 

Contrary  to  general  opinion,  these  occupations  not  only  do  not 
appear  to  shorten  life,  but  from  such  facts  as  are  ]iresented  by  the 
mortality  statistics  of  oecupations,  it  may  be  inferred  that  they  con- 
duce to  longevity,  for,  as  a  class,  their  average  age  at  death  is  quite 
'  Public  Health  Reports,  May  25,  1900,  p.  130G. 


682  HYGIENE  OF  OCCUPATION. 

high.     It  is  hardly  necessary  to  go  into  the  details  of  the  processes 
involved  in  the  different  callings. 

6.  Occupations  Involving-  Exposure  to  Extremes  of  Heat. 

Exposure  to  extreme  heat  is  a  concomitant  of  a  number  of  other 
unsanitary  influences  which  affect  the  health  of  the  worker  in  a  variety 
of  occupations,  which  include  those  of  engineers,  stokers,  cooks,  bakers, 
miners,  foundrymen,  weavers,  employees  in  rolling  mills,  wire  mills, 
sugar  refineries,  glass  factories,  and  others.  The  effects  of  great  heat 
alone  are  exhaustion  and  thermic  fever,  and  when  to  these  are  added 
those  of  vitiated  air,  dust,  irritating  fumes,  and  dampness,  the  conse- 
quences may  be  very  grave.  Sudden  chilling  of  the  body  and  pro- 
longed exposure  without  intervals  of  rest  are  especially  to  be  guarded 
against.  The  workmen  of  this  class  are  commonly  affected  with 
catarrhal  and  rheumatic  troubles,  diseases  of  the  kidneys,  and  skin 
eruptions. 


7.  Occupations  Involving  Exposure  to  Dampness. 

Exposure  to  indoor  dampness  is  usually  only  one  of  a  number  of 
debilitating  influences,  the  effects  of  any  one  of  which  are  not  suscep- 
tible of  correct  measurement.  Outdoor  dampness  is  probably  far  less 
influential  for  evil ;  but  continued  exposure,  coexistent  with  exhausting 
labor,  is  conducive  to  rheumatism  and  bronchial  troubles.  With  ordi- 
nary care,  however,  those  exposed  to  vicissitudes  of  weather  and  to 
wetness  from  other  causes — drivers,  boatmen,  fishermen,  and  trench 
diggers,  for  example — enjoy  good  health  and  are,  as  a  class,  long  lived. 

8.    Occupations  Involving  Exposure  to  Abnormal  Atmospheric 

Pressure. 

The  principal  calling  of  this  group  is  that  of  caisson  workers,  who 
suffer  from  what  is  known  as  the  caisson  disease,  the  pathology  of  which 
is  by  no  means  clear.  A  caisson  may  be  defined  as  a  large  inverted 
water-tight  box  in  which  work  is  performed  below  the  water-level,  as 
in  the  laying  of  foundations  for  the  piers  of  bridges.  It  is,  in  fact,  a 
diving  bell  on  a  large  scale.  It  is  provided  at  the  top  with  a  shaft  for 
ingress  and  egress,  communicating  with  which  and  with  the  interior  is 
a  chamber  with  two  sets  of  doors,  known  as  an  air-lock.  Placed  in 
position  and  heavily  weighted  with  masonry,  it  sinks  into  the  mud 
beneath.  The  air  in  its  interior  is  compressed  by  the  action  of  the 
surrounding  water,  and  the  thereby  diminished  air  space  is  restored  by 
downward  displacement  of  water  through  the  agency  of  powerful  air 
pumps.  The  deej^er  the  caisson  sinks,  the  greater,  of  course,  the  at- 
mospheric pressure  within.  As  the  work  of  excavation  progresses,  the 
apparatus  sinks  deeper  and  deeper,   being  assisted  in  its  downward 


CONSTRAINED  ATTITUDE.  683 

movement  by  the  weight  of  the  superimposed  masonry  ;  and  when  the 
proper  geological  formation  is  reached,  the  interior  is  filled  with  con- 
crete, which  thus  forms  the  solid  foundation,  and  the  box  is  left  there. 
In  entering  the  caisson,  the  workman  goes  first  into  the  air-lock  and 
closes  the  door.  The  pressure  in  this  compartment  is  then  gradually 
equalized  with  that  of  the  caisson  chamber  by  means  of  an  inlet  pipe 
controlled  by  a  valve,  after  which  he  opens  the  inner  door  and,  enter- 
ing the  chamber,  closes  it  again.  In  emerging,  the  process  is  reversed  : 
the  pressure  in  the  air-lock  being  raised,  he  enters  and  closes  the  door ; 
by  means  of  another  valve,  the  pressure  is  lowered  gradually  to  normal, 
and  tlien  the  outer  door  is  opened.  The  operations  of  locking  in  and 
out  must  be  conducted  gradually.  In  locking  out,  the  rule  is  to  allow 
at  least  one  minute  for  each  6  pounds  of  pressure  within  the  chamber. 
Attention  must  be  paid  also  to  the  lowering  of  temperature  which 
accompanies  the  expansion  of  the  air  within  the  lock. 

The  symptoms  of  the  peculiar  disturbance  do  not,  as  a  rule,  appear 
until  the  pressure  equals  20  pounds,  and  some  time,  measured  in  min- 
utes or  even  hours,  after  emerging.  In  some  cases  in  which  cerebral 
and  spinal  symptoms  are  severe  from  the  beginning,  death  occurs  within 
a  short  time.  The  symptoms  include  headache,  pain  in  the  ears,  rapid 
pulse,  sweating,  severe  pains  in  the  legs,  back,  and  epigastrium,  and, 
later,  paralysis  of  the  motor  nerves,  generally  of  the  legs,  sometimes  of 
the  arms,  and  not  infrequently  of  the  bladder  and  rectum.  The  motor 
nerves  are  in  some  instances  involved  before  the  sensory  disturbances 
appear.  The  epigastric  pain  is  accompanied  sometimes  by  vomiting, 
more  or  less  severe  in  character.  Mild  cases  of  the  disease  last  from  a 
few  hours  to  a  week  or  longer ;  but,  whether  mild  or  severe,  complete 
recovery  is  the  rule.  Where  electric  lighting  is  not  employed,  irrita- 
tion of  the  bronchial  mucous  membrane,  cough  and  expectoration,  due 
to  soot,  are  not  uncommon. 

The  cause  of  the  main  symptoms  has  been  the  subject  of  consider- 
able speculation,  and  whether  it  is  an  excess  of  oxygen  in  the  tissues, 
which  seems  improbable,  or  congestion  of  the  central  nervous  system, 
or  some  other  condition,  appears  to  be  incapable  of  elucidation.  The 
use  of  intoxicants  appears  to  be  a  predisposing  influence ;  hence, 
drinking-men  should  not  be  employed.  Thin  men  are  much  less  sus- 
ceptible than  the  stout  and  full-blooded.  Work  should  never  be  per- 
formed on  an  empty  stomach,  and  periods  of  absolute  rest  should  be 
frequent  when  the  pressure  is  unusually  high. 

8ul>marine  divers  are  subject  in  a  lesser  degree  to  the  same  train  of 
symj)toms. 

9.  Ocoupations  Involving'  Constrained  Attitude. 

These  include  a  wide  variety  of  trades  leading  to  various  deformities, 
the  most  important  of  vvhicli  is  constriction  of  the  chest.  Vitiated 
air  is  a  common  coexistent  condition,  and  phthisis  is  a  frequent  cause 
of  death. 


684  HYGIENE  OF  OCCUPATION. 

10.  Occupations  Involving  Overexercise  of  Parts  of  the  Body. 

The  occupations  of  this  class  bring  about  a  variety  of  deformities 
and  of  fatigue  neuroses  characterized  by  disturbance  of  the  functional 
activity  of  groups  of  muscles  trained  by  practice  in  highly  specialized 
coordinated  movements.  These  include  such  conditions  as  the  cramps 
of  writers,  telegraphers,  pianists,  violinists,  engravers,  seamstresses, 
and  others,  and  localized  paralyses  and  tremors.  The  pathology  of 
these  conditions  is  very  obscure ;  but  in  certain  of  the  cases,  especially 
those  in  which  the  larynx  is  overexercised,  the  element  of  hysteria 
enters  to  a  considerable  extent.  These  abnormal  conditions  are  of  far 
less  hygienic  importance  than  any  that  have  been  considered,  and  are 
of  interest  chiefly  to  the  specialist. 

11.  Occupations  Involving-  Sedentary  Life. 

Certain  callings  are  commonly  set  down  as  sedentary  occupations  ; 
but,  strictly  speaking,  this  class  is  closely  interwoven  with  several  of 
those  already  mentioned.  For  instance,  a  very  large  number  of  indoor 
occupations,  carried  on,  perhaps,  uuder  conditions  peculiar  to  them- 
selves, are  at  the  same  time  sedentary  in  their  nature. 

The  abnormal  conditions  brought  about  by  sedentary  life  are  those 
induced  by  a  lack  of  general  exercise  of  the  body.  This  brings  about 
a  general  sluggishness  of  the  functions,  which  is  ordinarily  most 
marked  in  those  of  the  abdominal  organs  and  heart.  The  consequences 
of  too  close  confinement  and  lack  of  exercise  are  too  w^ell  known  to 
need  detailed  mention.  Ordinarily,  they  can  be  expressed  by  the 
term  "general  debility."  There  is  no  particular  reason  why  sedentary 
occupations  should  injure  health,  and  it  will  be  found  in  almost  all  in- 
stances of  impaired  function  that  the  sedentary  habit  is  not  peculiar 
to  the  individual  while  at  work,  but  during  both  work  and  leisure 
hours.  The  sedentary  worker  has  the  matter  of  prophylaxis  in  his 
own  hands,  and  should  take  a  reasonable  amount  of  exercise  daily, 
preferably  in  the  open  air.  It  is  common  to  include  brain-workers  in 
this  class,  and  to  attribute  to  the  sedentary  side  of  their  lives  the  con- 
sequences of  overexertion  of  the  mind.  It  must  be  remembered  that 
activity  of  the  mind  has  no  shortening  influence  on  life ;  but  abuse  of 
the  mental  powers,  and  especially  mental  worry,  conduce  to  headache, 
insomnia,  and  general  breaking  down  of  the  nervous  system  and  of 
the  general  health. 

PROPHYLAXIS  IN  GENERAL. 

In  w^hat  has  gone  before,  it  will  be  noticed  that  the  disastrous  effects 
attributed  to  occupations  are  in  very  large  part  due  to  non-observance 
of  the  principles  of  general  hygiene,  and  chiefly  to  inattention  to  that 
most  important  sanitary  measure,  perfect  ventilation.  It  will  have  been 
noted  that  in  Groups  1,  2,  3,  4,  5,  and  6,  the  conditions  which  bring 


EMPLOYMENT  OF  WOMEN  AND  CHILDREN.  685 

about  impairment  of  health  may  be  reduced  very  largely  by  a  con- 
stant supply  of  fresh  air.  With  proper  attention  to  this  matter  and 
improvement  in  the  home  and  home  influences,  greater  attention  to  the 
character  and  preparation  of  food,  and  a  more  general  observance  of 
the  beneficial  influence  of  active  outdoor  exercise,  no  very  great  differ- 
ences would  be  noted  in  the  health  of  the  various  classes  of  work- 
people, and  the  expression  occupation  diseases  would  lose  whatever 
significance  it  now  has. 

Employment  of  Women  and  Children. 

In  view  of  the  dangers  and  conditions  incident  to  a  great  variety  of 
occupations  directly  or  indirectly  inimical  to  health,  it  is  of  the  utmost 
importance  to  protect  the  health  of  women  and  children  by  restricting 
them  in  the  daily  nu-mber  of  hours  which  they  may  give,  and  prohibit- 
ing their  employment  in  distinctly  dangerous  surroundings,  for  women 
and  children  are  more  delicately  organized  and  less  resistant  to  weak- 
ening influences.  Particularly  should  women  be  protected  during  the 
child-bearing  age,  so  that  they  may  be  insured,  so  far  as  is  possible,  a 
healthy  progeny.  It  hardly  needs  to  be  said  that  children  should  be 
protected  most  carefully  during  the  period  of  their  full  development,  in 
order  that  they  may  come  to  maturity  in  a  fit  condition  to  take  on  the 
responsibilities  of  the  family. 

Inattention  to  the  very  great  importance  of  conserving  the  health  of 
women  and  children  is  bound  sooner  or  later  to  result  in  degeneration, 
and  this  fact  has  received  the  attention  of  the  law-making  bodies  of 
all,  or  nearly  all,  civilized  countries.  In  this  country,  it  is  constitu- 
tionally a  matter  for  legislation  by  individual  States,  in  many  of  which 
not  only  is  their  physical  welfare  protected,  but  the  moral  aspects  of 
trades  as  well  receive  due  attention. 

By  legal  enactment,  the  employment  of  women  in  certain  kinds  of 
work  is  prohibited  absolutely,  and  in  many  others  is  restricted  as  to 
number  of  hours  according  to  the  nature  of  the  work.  The  very  great 
value  of  most  of  the  legislation  regulating  labor  by  children  and 
women  is  too  clear  to  need  demonstration. 


CHAPTER    XIV. 

VITAL   STATISTICS. 

The  science  of  vital  statistics  comprises  the  analysis  and  synthesis 
of  facts  concerning  the  life-history  of  populations.  It  points  out  where 
and  to  what  extent  disease  and  death  are  on  the  increase,  and  suggests, 
therefore,  the  inauguration  of  combative  sanitary  effort,  the  efficiency 
of  which  it  enables  us  to  measure.  It  furnishes  the  basis  for  the  study 
of  all  the  various  social  problems  which  affect  increase  and  diminution 
in  numbers. 

It  is  axiomatic  that  the  facts  employed  must  be  numerous  and 
accurately  stated  and  classified,  in  order  that  the  information  supplied 
therefrom  shall  be  trustworthy  and  of  value.  These  facts  comprise 
those  which  are  yielded  by  the  census,  as  numbers,  age,  sex,  color,  oc- 
cupation, und  conjugal  relations,  and  those  reported  to  and  recorded  by 
local  and  central  authorities  concerning  infectious  diseases,  marriages, 
births,  and  deaths. 

The  study  of  these  facts  and  their  correct  interpretation  are  by  no 
means  simple.  In  census  years,  it  is  not  difficult  to  obtain  practically 
accurate  information  of  the  size  of  the  po})ulation,  and  the  ratios  of 
births,  marriages,  and  deaths,  and  at  all  times  to  know  the  degree  of 
prevalence  of  notifiable  disease ;  but  the  intelligent  interpretation  of 
these  facts  is  often,  if  not  usually,  a  most  complex  problem.  In  the 
hands  of  those  who  understand  the  fallacies,  the  numerous  sources  of 
error,  the  corrections  to  be  applied,  and  the  comparative  values,  statis- 
tics can  be  made  to  yield  knowledge  of  immense  value  to  sanitary 
science ;  but  in  the  hands  of  the  unskilled  or  unscrupulous,  they  may 
be  more  productive  of  harm  than  absolute  ignorance,  for  it  is  better 
not  to  know  at  all  than  to  be  misinformed. 

It  is  well  known  that  it  is  often  possible  apparently  to  prove  two 
direct  opposites  with  the  same  statistics,  the  fallacies  being  unobserved, 
and  to  this  fact  is  due  the  low  estimate  in  which  all  statistical  studies 
are  held  by  those  incapable  of  distinguishing  the  false  from  the  true. 
Statistics  may  be  made  to  lie  while  they  appear  to  tell  the  truth,  and 
they  have  been  raised  to  superlative  rank,  therefore,  among  falsifiers 
of  all  degrees. 

As  has  been  said,  the  interpretation  of  statistics  is  no  simple  matter. 
It  requires,  in  fact,  a  mind  not  only  naturally  logical,  but  trained  in 
drawing  scientific  inferences,  in  the  recognition  and  avoidance  of  the 
influence  of  fallacy,  and  in  the  correct  estimation  of  the  value  of  dif- 
ferent factors  and  disturbing  influences.  But  even  with  several  such 
mmds  working  on  the  same  mass  of  material,  decided  differences  may 

68fi 


THE  CENSUS.  687 

be  found  in  their  respective  conclusions,  some  apparently  small  fact 
being  overlooked  by  one  or  being  credited  with  undue  importance  by 
another.  Therefore,  in  publishing  facts  and  inferences,  it  is  well  to 
give  as  much  as  possible  of  details,  and  to  bring  out  clearly  the  thread 
of  the  reasoning  leading  to  the  final  conclusions,  for  then,  other  anal- 
ysts may,  by  pointing  out  debatable  issues,  assist  in  deducing  the 
absolute  truth. 

The  Census. — The  very  foundation  of  vital  statistics  is  a  knowledge 
of  the  size  of  the  population  and  of  the  ages  of  the  units  of  which  it  is 
composed.  In  census  years  this  may  be  regarded  as  substantially  ac- 
curate ;  but  in  the  intervening  years  it  is  necessary  to  make  estimates 
based  on  past  and  present  indications,  which  may  lead  to  wide  varia- 
tions from  the  truth,  not  susceptible  of  correction  until  the  next 
enumeration.  The  census  is  taken  in  all  civilized  countries  at  stated 
intervals,  usually  of  five  or  ten  years.  In  France  and  in  Germany,  it 
is  taken  every  five  years ;  in  this  country  and  in  Great  Britain,  every 
ten  years.  In  this  country,  many  of  the  individual  States  have  an  in- 
dependent enumeration  in  the  middle  of  the  intercensal  period,  so  that 
the  census  is  virtually  quinquennial.  The  census  gives  the  population 
of  each  community,  and  also  important  facts  as  to  age  distribution,  sex 
distribution,  race,  occupations,  and  civil  state. 

From  the  very  nature  of  the  work,  dealing  in  a  very  short  time  with 
vast  numbers  of  individual  sources  of  information,  no  census  can  be 
absolutely  accurate,  but  under  present  methods  the  results  obtained 
may  be  regarded  as  being  as  nearly  accurate  as  possible.  It  is  prob- 
able that,  in  a  large  degree,  the  errors  counterbalance  one  another,  but 
how  far,  can  be  only  a  matter  of  conjecture. 

The  sources  of  error  in  census-taking  are  intentional  frauds  and  neg- 
ligence on  the  part  of  the  enumerators,  ignorance  and  wilful  misstate- 
ment on  the  part  of  those  inteiTogated,  absence  of  residents  when  called 
upon,  and  inclusion  of  transient  visitors.  In  1890,  it  is  well  Ipiown, 
in  certain  cities  gross  frauds  were  practised  in  "  padding  "  the  returns 
so  as  to  increase  the  fees  due  the  individual  enumerators  concerned.  In 
one  case,  a  hotel  register,  running  back  seven  years,  is  known  to  have 
served  as  an  aid  in  the  manufacture  of  population  returned.  During 
the  same  census,  many  complaints  were  made  that  whole  streets  and 
districts  were  omitted,  the  inference  being  that  the  enumerators  either 
did  not  regard  the  work  as  sufficiently  remunerative,  or  made  up  their 
reports  regardless  of  the  facts,  and  without  the  disagreeable  necessity 
of  going  from  house  to  house  for  information  only  slowly  obtained. 

Ignorance  on  the  part  of  the  person  questioned  is  doubtless  a  more 
fruitful  source  of  error  than  intentional  misstatement.  Many  persons 
do  not  know  their  age,  and  give,  therefore,  only  a  guess,  which  is  most 
commonly  expressed  in  multiples  of  five  and  ten,  more  especially  the 
latter.  This  tendency  appears,  in  general,  only  after  the  twenty-fifth 
year,  and  is  shown  graphically  by  means  of  the  accomjxmying  diagram 
(Fig.  108)  by  Mr.  R.  H.  Hooker^  taken  from  Newsholme's  VitalSta- 
tistics.     Again,  many  data  concerning  the  occupants  of  a  house  are 


VITAL  STATISTICS. 


given  by  persons  not  qualified  to  know ;  thus,  the  returns  for  a  whole 
family  may  be  based  upon  the  statement  of  a  servant  not  long  in  the 
place. 

Intentional  misstatement  is  most  common  with  regard  to  age  and 
occupation,  many  wishing  to  appear  younger,  others  older,  than  they 
really  are,  and  many  being  reluctant  to  state  correctly  the  occupations 
of  themselves  and  of  members  of  their  households,  preferring,  perhaps, 
to  record  others  more  "  genteel  "  or  important.  Other  wilful  misstate-, 
iments  are  due  very  commonly  to  that  over-development  of  the  sense  | 
I  of  humor  that  disposes  its  unfortunate  possessor  to  regard  extravagant 
lying  as  the  acme  of  wit. 

The   intentional  misstatement  of  age  is   more  commonly  a  fault  of 
women  than  of  men.     Women  are  prone  to  understate  their  age  after 


Fig.  108. 

60  70 


NO.  AT 
EACH 
AGE 

1000 

sooo 

2000 
1000 

s,-.. 

\ 

'1 

A-/\, 

/[ 

I, 

'-< 

f ' 

«    ' 

^' 

- 

N-.'\ 

^'\  ],. 

Number  of  persons  in  Tasmania  living  at  each  year  of  age,  according  to  the  census  schedule, 
showing  the  tendency  to  cluster  at  round  decennial  periods. 

passing  twenty-five ;  with  men,  the  tendency  is  to  add  rather  than 
subtract.  After  twenty-five,  many  women  become  sensitive,  and  give 
their  ages  as  under  that  age,  and  do  not  progress  for  several  years. 
This  is  shown  statistically  by  the  British  census  returns,  from  which  it 
appears  that  the  girls  of  10  to  15  years  of  one  census,  who  become 
women  of  20  to  25  years  of  the  next  census,  reach  these  latter  age 
periods  without  suffering  any  loss  in  number  through  death  and  emi- 
gration ;  but,  on  the  contrary,  with  an  augmentation,  while  the  women 
of  20  to  25  years,  who  become  30  to  35  years  old  at  the  next  census, 
show  a  very  great  diminution  in  number. 

Thus,  as  shown  by  Dr.  Farr,  the  Registrar-General,  in  1 841,  the 
number  of  girls  of  10  to  15  years  was  1,003,119,  and  in  1851,  the 
number  of  women  of  20  to  25  years  was  1,030,456,  or  27,337  more, 
while  the  women  of  20  to  25  years  in  1841  numbered  973,696  and 
yielded  in  1851  only  768,711 — a  loss  of  204,985.     It  is  inconceivable 


ESTIMATED  POPULATION.  689 

that  the  losses  among  the  younger  group,  due  to  death  and  emigration, 
should  have  been  more  than  offset  by  immigration  to  the  extent  of 
27,337,  and  that  the  same  influence  should  have  failed  to  the  extent 
of  204,985  to  do  the  same  thing  for  those  of  the  later  age  periods. 
This  discrepancy  is  said  to  be  capable  of  demonstration  by  compari- 
son of  the  returns  of  any  two  consecutive  subsequent  enumerations. 
Children's  ages  are  very  commonly  overstated  in  the  earliest  years ; 
then,  as  the  limit  of  age  for  free  transportation  in  public  conveyances  is 
passed,  they  are  understated  as  long  as  possible.  Finally,  when  the 
statutory  minimum  of  age  is  the  only  bar  to  the  utilization  of  children 
in  the  various  trades,  the  years  held  back  are  restored  with  some 
additions. 

Estimated  Population. — In  intercensal  years,  it  is  necessary  to 
estimate  as  nearly  as  possible  the  growth  or  decline  of  a  population, 
making  use  of  such  factors  as  can  be  obtained  by  comparison  of  the 
two  preceding  enumerations  and  from  other  observed  influences.  This 
is  done  very  commonly  by  dividing  the  difference  between  the  figures 
of  the  two  by  the  number  of  years  of  the  interval,  thus  obtaining  the 
yearly  increase  or  diminution,  and  reducing  it  to  a  percentage  which  is 
assumed  to  be  the  rule  obtaining  until  the  next  census.  This,  of 
course,  is  merely  a  guess  which  may  be  near  or  very  wide  of  the 
truth,  since  very  many  influences  may  be  in  operation  to  bring  about 
conditions  actually  very  different.  But  one  must  work  with  the  best 
data  available  and  eliminate  as  much  of  error  as  possible ;  hence  the 
ratio  of  increase  or  diminution  is  assumed  to  hold  until  the  next 
census,  and  in  the  meantime  errors  must  be  diminished  as  much  as 
possible. 

One  of  the  first  errors  into  which  one  falls  is  in  assuming  a  fixed 
ratio,  based  upon  the  above-mentioned  method  of  calculation.  Let  it 
be  asskumed,  for  example,  that  the  annual  increase  in  the  population  of 
a  city  of  100,000  inhabitants,  determined  by  a  comparison  of  the  two 
preceding  enumerations,  is  2  per  cent. ;  if  we  reckon  that  in  5  years' 
time  the  population  will  have  increased  5  times  2  per  cent.,  that  is  to 
say,  from  100,000  to  110,000,  we  fall  at  once  into  error,  for  the 
increase  proceeds  not  by  simple  but  by  compound  interest,  since  in 
reckoning  by  simple  interest  no  allowance  is  made  for  the  augmentation 
of  capital,  so  to  speak,  due  to  the  annual  increase  in  the  number  of 
persons  arriving  at,  the  nubile  period. 

The  method  generally  adopted  is,  therefore,  based  on  the  assumption 
that  population  increases  in  geometrical  rather  than  arithmetical  pro- 
gression, and  the  formula  employed  is  P'  =  P(l  +  ry,  in  which  P' 
represents  the  estimated  population,  P  the  population  according  to  the 
last  census,  r  the  annual  rate  of  increase  per  unit  of  population,  ascer- 
tained by  comparison  of  two  successive  enumerations,  and  n  the 
number  of  the  intercensal  year  in  question.  On  the  basis  of  a  2  per 
cent,  annual  increase,  the  population  at  the  end  of  the  first  year  would 
be  102,000 ;  at  the  end  of  the  second,  it  would  be  102,000  plus  2  per 
cent.,  or  104,040 ;  at  the  end  of  the  third,  106,121  ;  at  the  end  of  the 

44 


690  VITAL  STATISTICS. 

fourth  108,243;  and  at  the  end  of  the  fifth,  110,408,  or  an  increase 
of  408  over  the  original  estimate. 

As  an  ilkistration  of  the  manner  of  applying  this  formula  in  the 
estimation  of  the  population  at  the  expiration  of  the  fifth  iutercensal 
year,  in  this  instance  of  an  original  population  of  100,000  increasing 
at  the  rate  of  2  per  cent.,  the  following  may  serve  :  The  formula 
is  P'=  100,000  X  (1  +  0.02)^;  (1  +  0.02)^=  1.10408.  100,000  X 
1.10408  =  110,408  =  P'  as  given  above.  Much  time  is  saved  in  the 
calculation  by  recourse  to  logarithms.  For  a  proper  estimation  of  the 
population  at  any  particular  period  in  the  year  on  this  basis,  due  allow- 
ance should  be  made  for  the  fraction  of  the  uncompleted  year. 

Population  is  sometimes  estimated  by  using  as  a  factor  the  average 
number  of  persons  per  habitation  according  to  the  preceding  census 
returns,  and  multiplying  this  by  the  number  of  houses  found  to  be 
occupied  at  the  time.  Sometimes,  also,  the  number  of  registered  voters 
is  used  as  a  basis  of  c9,lculation,  and  again  the  birth-rate,  and  again 
the  number  of  children  in  attendance  at  the  several  schools.  These 
methods,  however,  are  very  faulty,  and  often  even  quite  valueless. 

Whatever  the  method  adopted,  and  notwithstanding  the  calculations 
of  the  amount  of  influence  exerted  by  emigration,  immigration,  unusual 
prevalence  of  or  freedom  from  infective  diseases  and  other  factors, 
estimation  of  population  is  very  frequently  wide  of  the  truth.  AVithin 
recent  years,  for  example,  the  most  careful  estimate  of  the  population 
of  London  by  the  Registrar-General  was  found  by  the  census  returns 
to  be  no  less  than  a  quarter  of  a  million  in  excess  of  the  truth.  With 
errors  in  estimation  come  necessarily  errors  in  all  the  ratios  of  births, 
marriages,  and  deaths,  and  these  must,  therefore,  undergo  correction  at 
the  proper  time. 

Increase  of  Population. — The  growth  in  population  due  to  excess 
of  births  over  deaths  is  known  as  the  natural  increase.  That  which  is 
due  to  excess  of  births  plus  immigration  over  deaths  plus  emigration, 
is  known  as  the  actual  increase.  Fluctuations  in  natural  increase  are 
caused  by  changes  in  mortality-  and  birth-rates ;  thus,  a  decline  may 
be  due  to  a  diminution  in  the  number  of  births,  or  to  an  increase  in 
the  number  of  deaths,  or,  more  markedly,  to  both.  Fluctuations  in 
actual  increase  are  caused  by  the  same  influences  plus  those  of  immi- 
gration and  emigration.  Growth  may,  therefore,  be  slow  or  fast,  and 
steady  or  varied  and  spasmodic,  according  to  ever-possible  changing 
conditions,  governed  largely  by  commercial  prosperity  or  depression'. 
Decline  in  population  may  be  due  to  excess  of  deaths  over  births,  but 
is  commonly  the  consequence  of  emigration. 

Population  Constitution. — \Yhat  is  known  as  the  constitution  of 
a  population  shows  the  relative  proportions  of  males  and  females  and 
of  persons  of  different  age  periods.  These  facts  are  obtained  only  from 
the  census  returns,  and  are  commonly  accepted  as  holding  good  until 
the  next  census  gives  different  figures.  In  cities  and  large  towns, 
the  proportion  of  females  is  generally  considerably  higher  than  that 
of  males  ;  while  in  country  districts  the  reverse  is  true  or  the  excess  is 


REGISTRARS'  RETURNS.  691 

slight.  This  is  explained  in  several  ways  :  In  the  first  place,  women 
are,  in  general,  longer  lived  than  men ;  in  the  second,  men  are  more 
prone  than  women  to  return,  when  advanced  in  years,  to  countiy  dis- 
tricts from  which  they  originally  sprang ;  and  again,  under  the  con- 
ditions obtaining  in  crowded  communities,  men  wear  out  more  rapidly 
than  women.  In  the  population  at  large,  males  are  more  numerous 
than  females. 

Age  distribution  has  a  very  important  bearing  on  the  death-rate, 
since,  as  is  well  known,  the  highest  death-rates,  so  far  as  age  is  con- 
cerned, occur  always  in  the  earlier  age  periods.  Therefore,  the  prepon- 
derance of  individuals  of  one  and  another  age  period  has  a  very  great 
influence  in  demonstrating  apparent  differences  in  salubrity  of  different 
localities,  when  the  actual  sanitary  conditions  are  identical.  With  such 
agreement  in  sanitary  conditions,  a  community  which  includes  a  much 
larger  proportion  of  young  children  will  sIioav  a  larger  death-rate  and 
a  smaller  marriage-rate  than  another  in  which  the  population  is  made 
up  more  largely  of  young  adults.  In  consequence,  it  is  necessary,  in 
instituting  comparisons  between  two  localities,  to  take  into  account  (and 
make  corrections  therefor)  the  differences  in  age  distribution,  and  to 
reduce  the  respective  populations  to  a  common  standard. 

Registrars'  Returns. — Returns  concerning  births,  marriages,  deaths 
and  causes  thereof,  and  cases  of  infective  diseases,  are  made  to  local 
authorities,  such  as  boards  of  health,  and  city  or  town  clerks  or  regis- 
trars. In  conjunction  with  census  returns  or  estimates  of  population, 
they  reveal  the  sanitary  and  sociological  conditions  obtaining  from 
week  to  week,  month  to  month,  and  year  to  year,  in  any  community 
in  which  they  are  made.  Through  them  we  are  enabled  to  watch  the 
death-rate  from  all  causes  and  from  any  one  cause,  the  amount  of  pre- 
ventable disease,  the  probable  fluctuations  in  populations,  and  other 
facts  of  interest  concerning  communities  and  groups  thereof.  They 
convey  information  as  to  sanitary  conditions,  and  suggest  wherein 
improvement  in  various  directions  is  possible. 

The  individual  facts  must,  of  course,  be  accurately  observed  and 
stated.  This  is  particularly  true  of  causes  of  death  and  distribution 
of  infective  diseases.  The  importance  of  proper  groupings  is  well 
shown  by  the  worthlessness  of  the  lax  returns  not  infrequently 
observed.  For  example,  it  is  not  unusual,  especially  in  the  older 
tables,  to  find  "  dropsy  "  standing  side  by  side  with  "  heart  disease," 
"  kidney  disease,"  Bright's  disease,   and  other  general  or  vague  terms. 

The  value  of  the  aggregate  facts  depends  very  largely  upon  the 
length  of  time  during  which  they  have  been  gathered,  since  only  with 
tlie  lapse  of  time  can  comparisons  be  instituted  and  the  influence  of 
temporary  conditions  eliminated  or  minimized.  They  must  be  suffi- 
ciently numerous  to  yield  correct  averages,  for  the  larger  the  number 
of  facts,  the  smaller  the  fluctuations  caused  by  individual  units ;  and, 
conversely,  the  smaller  the  nunil)er,  the  greater  the  influence  of  single 
units,  and  the  greater  the  chancti  of  error  ;  or,  more  definitely  stated, 
accuracy  increases  as  tlie  squan;  root  of  tlie  number  of  units.     Thus, 


692  VITAL  STATISTICS. 

400  units  will  yield  but  half  the  error  of  100,  and  900  will  yield  but 
a  third.  In  no  way,  perhaps,  can  the  great  influence  of  individual  com- 
ponents of  a  small  aggregate  and  the  small  influence  of  the  unit  when 
the  aggregate  progressively  increases  be  better  illustrated  than  by  the 
daily  fluctuations  in  the  comparative  standing  of  a  number  of  athletic 
organizations,  such  as  ball  clubs  and  bowling  clubs,  in  competition 
among  themselves  for  a  prize  or  championship.  In  the  beginning, 
single  events  may  cause  entire  rearrangement,  and  the  fluctuations  are 
wide  and  the  curves  most  irregular ;  then,  as  the  number  of  events 
increases,  the  fluctuations  are  less  abrupt  and  the  changes  in  the  curves 
are  gradual. 

In  order  that  statistics  may  be  useful,  they  must  admit  of  compari- 
son with  similar  figures  obtained  in  other  years  and  also  at  other  places. 
But  correct  deductions  can  be  drawn  only  when  the  conditions  are  at 
least  apparently  the  same  or  when  there  is  but  one  essential  difference. 
One  may  not,  for  example,  compare  the  death-rate  of  New  York  for 
the  winter  of  1898  with  that  of  Detroit  for  the  summer  of  1875,  and 
expect  to  obtain  thereby  information  of  value.  In  order  to  measure 
the  full  influence  of  any  one  important  condition,  the  other  conditions 
must  be  in  agreement,  or  it  must  be  possible  to  make  correct  allowance 
for  any  degree  of  divergence. 

Again  one  must  not  ignore  the  effect  of  temporary  local  conditions, 
such,  for  example,  as  an  accident  in  a  small  community  whereby  a 
number  of  persons  are  killed  at  once  and  others  die  later  from  the 
effects  of  their  injuries.  The  death-rate  of  that  town  for  that  year 
would  be  abnormally  high,  and  the  sanitary  condition  of  the  place 
might  be  made  by  figures  to  appear  much  inferior  to  that  of  an  adjoin- 
ing one  where  sickness  and  death  from  preventable  diseases  are  much 
higher  all  the  time. 

Marriage -rates. — Statistics  as  to  marriage  vary  considerably  from 
year  to  year,  according  to  various  circumstances,  and  especially  with 
changing  conditions  in  the  prosperity  of  the  general  population.  The 
rate  is  commonly  greater  in  cities  and  towns  than  in  country  districts, 
not  that  country-bred  people  are  less  inclined  to  marry,  but  because 
large  numbers  of  them  are  attracted  to  populous  centers  after  arriving 
at  the  wage-earning  age,  and  there  they  marry. 

The  marriage-rate  is  usually  expressed  as  so  many  per  1,000  of  pop- 
ulation ;  but  this  is  commonly  open  to  objection,  in  that  it  may  convey 
false  impressions  concerning  inclination  or  disinclination  to  assume  the 
new  responsibilities,  and  also  concerning  the  communal  prosperity. 
Here,  the  importance  of  the  population  constitution  as  to  age  periods 
and  sex  is  very  clear,  for  in  a  community  made  up  largely  of  old  per- 
sons, young  children,  and  domestic  servants  from  without,  the  number 
of  marriages  occurring  among  the  marriageable  element  might  be  very 
considerable,  and  yet  the  rate  per  1,000  of  population  would  be  low. 
Therefore,  a  more  instructive  method  of  expression  would  be  a  state- 
ment of  the  rate  obtaining  among  those  of  marriageable  age.  Again, 
the  number  per  1,000  of  population  does  not  admit  of  proj)er  compari- 


BIRTH-RATES.  693 

son  of  different  communities  in  this  particular,  unless  their  population 
constitution  is  substantially  the  same. 

Fluctuations  in  marriage-rates  are  due  to  other  causes  than  commer- 
cial prosperity  and  depression.  It  has  been  observed,  for  example,  that 
a  condition  of  war  diminishes  the  rate  by  withdrawing  from  the  mar- 
riageable ranks  of  wage-earners  large  numbers  of  able-bodied  active 
men.  With  return  of  peace  and  its  attendant  release  of  the  troops  to 
civil  life,  the  rate  is  augmented.  Thus,  during  1870,  when  France  and 
Germany  were  at  war,  the  marriage-rates  sank  respectively  to  12.1  and 
14.8  ;  two  years  later  (1872)  they  advanced  to  19.5  and  20.7.  Age 
constitution,  too,  has  necessarily  an  important  influence  in  causing 
fluctuations.  Thus,  in  a  community  largely  made  up  of  youths  and 
maidens,  the  time  comes  when  an  unusual  amount  of  marriageable 
material  becomes  available,  and  the  rate  at  once  advances. 

A  period  of  unusual  increase  in  the  rate,  from  whatever  cause,  is 
commonly  followed  by  a  corresponding  decline,  just  as  business  pros- 
perity and  depression  are  marked  by  regular  waves  ;  but  the  general 
trend  is  unmistakably  toward  a  diminution.  For  nearly  thirty  years, 
a  very  gradual  decline  has  obtained  in  nearly  all  highly  civilized  coun- 
tries. 

That  more  women  marry  than  men,  sounds  paradoxical,  but  it  is, 
nevertheless,  true ;  for  men  are  more  prone  than  women  to  second  and 
third  marriages,  and  statistics  show  that  the  tendency  of  widowers  to 
marry  spinsters  is  much  more  marked  than  that  of  bachelors  to  marry 
widows. 

The  age  at  which  marriage  occurs  has  a  very  important  bearing  on 
the  natural  increase  of  population,  since  whether  a  woman  marries  early 
or  late  in  the  child-bearing  period,  determines,  other  conditions  being 
the  same,  the  extent  of  fruitfulness  and,  more  particularly,  the  interval 
between  successive  generations.  Statistics  indicate  that,  among  the 
native-born  of  this  country,  particularly  in  those  parts  longest  settled, 
and  in  Great  Britain  and  other  countries  in  which  the  highest  degree 
of  civilization  has  been  reached,  the  average  age  at  marriage  is  steadily 
increasing.  This  has  been  attributed  to  an  intelligent  selfishness, 
tending  to  defer  the  assumption  of  responsibility  for  the  maintenance 
of  others,  thus  insuring  an  unrestricted  enjoyment  of  the  fruits  of  labor ; 
and  to  the  wider  opportunities  for  jDrofitable  employment  of  w^omen, 
with  consequent  lessened  dependence  upon  marriage  as  a  means  of 
support. 

Birth-rates. — Statistics  as  to  births  are  expressed  in  the  same  manner 
as  those  concerning  marriage ;  namely,  as  so  many  per  1000  of  popu- 
lation. This  ratio  is  known  as  the  crude  birth-rate,  and  conveys  no 
information  concerning  the  proportion  of  women  of  the  child-bearing 
ag(;  who  have  added  to  the  population.  Here,  again,  a  more  accurate 
and  instructive  method  of  expression  might  be  based  upon  a  comparison 
of  the  number  of  legitimatf;  births  with  the  number  of  married  women 
bf'low  forty-five  years  of  age,  and  of  the  number  of  illegitimate  births 
with   the  number  of  single  women  of  the  same  limit  of  age.     Under 


694  VITAL  STATISTICS. 

any  system,  still-births  are  not  included  in  either  the  births  or  deaths, 
although  they  are  certified. 

Birth-rates  naturally  vary  very  greatly  in  different  communities,  the 
same  as  marriage-rates,  and  for  the  same  reasons.  Ordinarily,  they 
are  higlier  in  cities  than  in  the  country,  and  during  and  immediately 
following  periods  of  prosperity  than  during  times  of  depression.  A 
higher  rate  is  to  be  expected  of  a  manufacturing  and  commercial  center 
than  of  a  purely  residential  town,  where  a  large  number  of  unmarried 
domestics,  employed  by  the  well-to-do  and  rich,  swell  the  population 
and  lower  the  rates  of  both  marriages  and  births  in  the  manner  already 
mentioned.  In  the  latter  case,  the  married  inhabitants  may  be  unusu- 
ally prolific,  and  the  birth-rate,  expressed  per  1000  of  married  women 
below  forty-five,  would  be  very  high ;  yet,  the  crude  birth-rate  would 
be  low.  So,  in  comparing  two  communities  in  respect  to  births,  accuracy 
demands  that  they  shall  be  reduced  to  a  common  basis. 

The  higher  birth-rate  in  cities  and  large  towns  is  due  to  the  greater 
proportion  of  women  of  child-bearing  age,  the  higher  marriage-rate, 
and  the  earlier  marriage  age  that  there  obtain  among  people  of  the 
lower  classes. 

Since  the  proportion  of  deaths  in  the  earliest  years  of  childhood  is 
very  high,  it  follows  that  a  high  birth-rate  is  always  associated  with  a 
high  death-rate ;  but  at  the  same  time,  a  high  birth-rate  implies  a  large 
proportion  of  married  persons  in  the  full  vigor  of  life  at  that  age  period 
which  is  associated  with  a  low  rate  of  mortality,  and  thus  the  influence 
on  the  death-rate  is  more  or  less  corrected.  A  continued  high  birth- 
rate necessarily  implies  a  large  proportion  of  growing  children  who, 
year  by  year,  swell  the  ranks  of  the  reproductive. 

A  low  birth-rate,  by  causing  a  relative  increase  in  the  proportion  of 

•  persons  of  the  age  periods  of  low  mortality,  may  bring  about  a  low 

death-rate ;  but  if  it  continues  long  enough  to  bring  the  population  to 

a  high  average  age,  it  will  be  succeeded  by  a  rapid  increase  in  the 

death-rate  due  to  diseases  of  advancing  years. 

The  birth-rates  of  many  countries,  like  the  marriage-rates,  have  for 
some  years  shown  a  steady  decline.  This  is  due  somewhat  to  the  in- 
creasing average  age  at  marriage,  which  reduces  the  period  of  repro- 
duction, but  largely  to  artificial  restrictions  and  economic  considera- 
tions. The  great  decline  in  the  birth-rate  of  France  has  attracted 
widespread  attention,  and  has  become  the  subject  of  grave  concern  to 
the  authorities  and  other  thinking  people  of  that  country.  A  hundred 
years  ago,  more  than  a  quarter  of  the  population  of  what  are  known  as  the 
Great  Powers  was  French  ;  to-day,  notwithstanding  the  marked  disin- 
clination of  that  people  to  emigrate  and  seek  new  homes,  the  propor- 
tion has  fallen  to  about  one-eighth.  In  1891,  according  to  census 
returns,  of  every  hundred  families,  22  had  but  2  children,  and  24,  but 
1  child,  apiece.  The  decline  in  births  is  not  due  to  poverty,  for  it  is 
among  the  poorest  there,  as  elsewhere,  that  the  largest  families  are  raised. 
The  same  influences  appear  to  have  been  in  operation  for  some  years  in 
England  and  Wales,  where,  since  1876,  when  the  birth-rate  was  36.3, 


DEATH-RATES.  695 

it  fell  progressively  in  twenty  years  to  29.7,  and  showed  in  the  last 
years  of  the  century  a  more  striking  decrease  than  in  any  other  country 
of  Europe. 

In  our  own  country,  among  the  descendants  of  the  original  colonists 
and  earlier  immigrants,  the  same  decline  is  most  evident.  Whereas  in 
colonial  times  and  in  the  earlier  years  of  national  independence,  fami- 
lies of  a  dozen,  fifteen,  and  more  were  exceedingly  common  ;  nowa- 
days, one  of  six  or  eight  becomes  a  subject  for  comment,  surprise,  and 
even  ridicule.  The  large  families  of  to-day  are  mainly  those  of  the 
more  recently  arrived  immigrants  and  of  their  first  generation.  In  Mas- 
sachusetts, the  statistics  for  1898  show  that  the  greatest  proportion  of 
the  number  of  births  belongs  to  the  foreign-born,  the  children  of 
native  parentage  on  both  sides  representing  32.36,  those  of  mixed 
parentage,  19.42,  and  those  of  foreign-born  parentage,  48.22  per  cent, 
of  the  total  births.     The  crude  birth-rate  was  27.37. 

Death-rates. — Death-rates  are  calculated  in  the  same  way  and  ex- 
pressed in  the  same  terms  as  birth-  and  marriage-rates,  that  is,  by  mul- 
tiplying the  number  reported  by  1000  and  dividing  the  product  by 
the  population,  or  by  dividing  the  reported  number  by  the  number  of 
thousands  of  population,  the  result  in  either  case  being  the  rate  per 
1000  of  population.  This  is  known  as  the  general,  gross,  or  crude 
death-rate,  and  is  affected  by  so  many  factors  that,  without  careful 
study  and  due  allowance  for  disturbing  influences,  it  may  prove  to  be 
a  very  faulty  index  of  the  health  of  the  people  and  of  the  sanitary  con- 
dition of  the  place.  When  used  as  a  basis  for  comparison  of  different 
places,  the  death-rates  must  first  be  corrected  by  making  careful 
allowances  for  differences  in  age,  sex,  and  race  distribution,  and  for 
abnormal  influences. 

Influence  of  Sex. — Sex  exerts  a  decided  influence,  since,  in  general, 
females  live  longer  than  males  and  their  mortality  is  lower  at  all  age 
periods,  excepting  from  the  tenth  to  the  twentieth  year.  So,  of  two 
places  equal  in  sanitary  and  all  other  conditions  excepting  sex  consti- 
tution, the  one  with  the  greater  proportion  of  females  will  have  the 
lower  death-rate.  Except  in  newly  settled  places,  there  is,  as  a  rule, 
a  preponderance  of  females  over  males,  although  everywhere  the  births 
of  males  exceed  in  number  those  of  females,  the  preponderance  being 
the  result  of  the  higher  mortality  that  obtains  among  males,  except  at 
the  age  periods  above  mentioned. 

Influence  of  Age. — The  influence  of  age  distribution  is  far  greater 
than  that  of  sex,  since,  for  example,  the  mortality  per  1000  of  chil- 
dren under  5  years  of  age  is  more  than  ten  times  that  of  persons 
between  5  and  25,  and  more  than  six  times  that  of  adults  between  25 
and  45.  Thus  it  may  be  seen  that  the  greater  the  proportion  of  popu- 
lation belonging  to  the  earliest  aixl  latest  periods  of  life,  the  higher 
will  be  the  death-rate.  One  would  expect,  for  example,  a  higher 
mortality  in  a  community  made  up  largely  of  elderly  people  or  young 
children  than  in  one  unusually  rich  in  young  adults,  or,  to  reduce  the 


696  VITAL  STATISTICS. 

matter  to  its  simplest  terms,  in  a  foundling  asylum  or  retreat  for  the 
aged  than  in  a  college  for  young  men. 

Influence  of  Race. — To  a  certain  extent,  racial  peculiarities  have  an 
influence  on  vitality,  and  especially  on  susceptibility  to  certain  diseases. 
Thus,  the  negro  is  far  less  prone  to  some  and  far  more  susceptible  to 
other  morbid  influences  than  the  white.  As  between  diiferent  peoples 
of  the  same  race,  the  differences  are  not  so  wide.  In  those  parts  of 
this  country  where  the  negro  population  is  considerable  or  preponder- 
ant, this  influence  can  never  be  disregarded,  and,  indeed,  it  is  com- 
monly the  practice  to  calculate  separate  rates  for  the  whites  and  for 
the  blacks.  According  to  Hoffman,^  the  mortality  of  whites  and 
blacks  in  ten  southern  cities,  including  Baltimore,  Washington,  Rich- 
mond, Memphis,  Louisville,  Atlanta,  Savannah,  Charleston,  Mobile, 
and  New  Orleans,  during  the  years  1890-94,  was  expressed  as  20.1 
and  32.6,  respectively.  This  divergence,  it  is  pointed  out,  would  be 
still  greater,  if  correction  were  made  for  age  distribution. 

The  excess  of  negro  mortality  obtaining  at  all  age  periods  is  espe- 
cially noticeable  in  the  earlier  ones.  Thus,  in  1890,  in  Washington 
and  Baltimore,  the  death-rates  of  pegro  children  under  5  and  between 
5  and  15  years  of  age  were  more  than  double  those  of  white  children 
of  the  same  age  periods ;  in  the  age  periods  from  the  fifteenth  to  the 
forty-fifth  year,  the  rates  for  both  races  naturally  diminish  very  much, 
but  the  ratio  is  nearly  the  same.  After  the  forty-fifth  year,  the  dif- 
ference begins  to  be  much  less,  but  the  excess  is  always  with  the 
negro. 

As  instances  of  the  differences  in  white  and  black  death-rates,  the 
following  are  presented : 


C  December, 

1899, 

White, 

23.49 ; 

Colored, 

28.59 

New  Orleans 

4  January, 

1900, 

" 

28.28 ; 

44.80 

i  March, 

1900, 

a 

22.50 ; 

39.60 

November 

1899, 

a 

13.42 ; 

22.30 

Baltimore     . 

December, 

1899, 

u 

15.00 ; 

29.38 

January, 

1900, 

a 

17.90 ; 

30.60 

Whole  year. 

1900, 

a 

17.48; 

33.42 

Atlanta     .    . 

Whole  yeai", 

u        '  u 

1900, 
1899, 

11.59 ; 
10.50 ; 

19.50 

Augusta,  Ga. 

31.00 

r 

5  wks.  ending  Jan. 

6. 

,  1900, 

u 

15.70 ; 

33.23 

Charleston    < 

4      " 

"      Feb. 

3,' 

1900, 

u 

12.60 ; 

27.50 

1 

2      " 

"      Feb. 

24, 

1900, 

a 

19.81 : 

32.94 

The  difference  between  white  and  black  mortality  is  believed  to  be 
due  more  largely  to  race  degeneration  than  to  sanitary  conditions.  In 
the  North,  the  negro  shows  an  excess  of  deaths  over  births,  and  holds 
his  own  only  by  influx  of  recruits  from  the  South. 

According  to  Dr.  Scale  Harris,^  before  the  Civil  War  the  negro 
death-rate  in  the  South  was  less  than  that  of  the  whites.  For  exam- 
ple, in  Charleston,  S.  C,  from  1822  to  the  beginning  of  the  war  the 

^  Kace  Traits  and  Tendencies  of  the  American  Negro.  Publications  of  the  Amer- 
ican Economic  Association,  New  York,  1896. 

"  The  Futui-e  of  the  Negro  from  the  Standpoint  of  the  Southern  Physician,  Amer- 
ican Medicine,  Sept.  7,  1901. 


INFLUENCE  OF  DENSITY.  697 

average  death-rate  of  the  whites  was  25.98,  and  of  the  blacks  24.05  ; 
but  from  1865  to  1894,  although  the  rate  was  but  slightly  higher  in 
the  case  of  the  whites  (26.77),  it  had  nearly  doubled  (43.29)  with  the 
blacks. 

From  what  has  been  said,  it  must' be  evident  that  crude  death-rates 
cannot  be  relied  upon  as  a  basis  of  mortality  comparison  of  two  places, 
unless  the  respective  populations  are  in  substantial  agreement  in  age, 
race,  and  sex  constitution,  nor  for  comparison  of  the  conditions  obtain- 
ing at  the  same  place  in  different  years,  unless  these  factors  are  prac- 
tically unchanged. 

Other  Influences. — Crude  death-rates  are  influenced  by  errors  in 
estimated  population,  by  the  presence  of  various  kinds  of  public  insti- 
tutions, such  as  hospitals,  state  almshouses,  and  asylums  for  foundlings 
and  the  aged  ;  by  migratory  movements  ;  by  density  of  population,  and, 
as  has  been  stated,  by  the  birth-rate.  An  important  source  of  error  lies 
in  the  return  of  persons  afflicted  with  incurable  diseases  to  their  old 
homes,  where  they  die ;  their  deaths  are  registered  there,  instead  of  at 
the  places  where  the  causes  thereof  had  their  origin  or  where  the  sani- 
tary conditions  were  such  as  to  favor  susceptibility. 

Influence  of  Density. — Death-rates,  especially  those  of  the  very 
3^oung,  are  much  higher  in  crowded  localities  than  where  the  population 
has  plenty  of  room  ;  and  it  is  commonly  accepted  that,  other  things  being 
equal,  increased  density  means  increased  mortality.  To  a  certain 
extent  this  is  undoubtedly  true,  particularly  where  increased  density 
means  overcrowding ;  but  it  is  not  necessarily  true  of  a  large  population 
spread  out  over  a  territory  capable  of  accommodating  twice  as  many 
people  very  comfortably.  Thus,  in  Massachusetts,  for  example,  where, 
in  1855,  the  population  averaged  136  to  the  square  mile,  the  general 
death-rate  was  about  the  same  as  obtained  forty  years  later,  when  the 
average  population  per  square  mile  had  more  than  doubled,  the  slight 
difference  being  in  favor  of  the  later  period.  During  the  decennium 
just  prior  to  the  outbreak  of  the  Civil  War,  the  average  rate  was  18.25  ; 
during  the  period  1887-1897,  it  was  about  19.50  ;  and  in  1898,  it  was 
but  17.55,  which  was  the  lowest  annual  rate  for  thirty -two  years. 

In  densely  populated,  overcrowded  localities,  such  as  the  slums  of  large 
cities,  we  find  all  the  conditions  which  favor  a  high  mortality  ;  namely, 
poverty,  immorality,  ignorance,  intemperance,  unsanitary  habitations, 
high  l)irth-rate,  carelessness,  filth,  and  improper  and  insufficient  food. 
In  fact,  the  slums  are,  in  very  great  measure,  the  cause  of  the  differences 
observed  in  the  death-rates  of  small  and  large  communities.  In 
country  districts,  small  towns,  large  towns,  and  cities  situated  within 
the  same  district,  where  climatic  and  other  natural  conditions  are  essen- 
tially the  same,  it  is  commonly  observed  that  the  higher  average  rates 
obtain  in  the  larger  communities,  and  the  lower  in  the  smaller  places, 
where  slums  are  unknown  ;  while  the  very  highest  occur  in  manufact- 
uring centers,  where  the  main  poj)ulation  consists  of  mill  operatives, 
who  work  by  day  under  unsanitary  conditions  and  ])ass  their  nights  in 
crowded  tcnciiuints.      8(k  jiIso,  hiirhcr  rates  obtain  in  old  niaiiiiiactnriny: 


698  VITAL  STATISTICS. 

places,  in  which  a  larger  proportion  of  population  of  a  weak  and 
degenerated  type  is  to  be  found,  than  in  others  more  recently  estab- 
lished. 

Weekly  Death-rates,  etc. — The  death-rate  for  any  particular  week  is 
obtained  by  multiplying  the  number  of  deaths  occurring  during  that 
period  by  52.14  (the  number  of  weeks  in  365  days)  and  dividing  the 
product  by  the  number  of  thousands  of  population  as  estimated  for  the 
middle  of  the  year.^  The  same  method  of  reckoning  may  be  employed 
for  determining  the  rates  for  other  fractions  of  a  year,  and  for  rates  of 
birth,  marriage,  zymotic  disease,  and  other  matters  of  statistical  inter- 
est. These  weekly  and  other  periodical  rates  are  highly  unreliable 
data  upon  which  to  base  comparisons  with  those  of  other  places  and  of 
other  parts  of  a  year,  since  seasonal  influences  and  temporary  condi- 
tions must  not  be  ignored ;  their  principal  value  is  in  comparing  the 
rates  obtaining  at  the  same  place  at  corresponding  periods  of  different 
years. 

In  the  same  way,  the  weekly  death-rate  from  any  given  cause,  or  the 
weekly  number  of  cases  of  any  particular  notifiable  disease,  such  as 
diphtheria,  scarlet  fever,  or  measles,  may  be  determined. 

Zymotic  Death-rate. — The  zymotic  death-rate  is  the  death-rate  due 
to  the  seven  principal  so-called  zymotic  diseases  ;  namely,  smallpox, 
scarlet  fever,  measles,  diphtheria,  whooping-cough,  typhoid  fever,  and 
diarrhoeal  diseases.  It  is  expressed  in  terms  per  1000  of  population, 
like  the  gross  death-rate.  The  rate  for  any  disease  may  be  similarly 
obtained  and  expressed. 

Infantile  Death-rate. — The  infantile  mortality  is  not  expressed  in 
terms  per  1000  of  the  whole  population,  but  as  the  number  of  deaths 
of  children  under  one  year  of  age  to  each  1000  births  registered  during 
the  year.  It  is  assumed  that  the  efflux  of  living  children  whose  births 
have  been  registered  with  the  local  authorities  is  counterbalanced  bv  the 
influx  of  others  whose  births  are  registered  elsewhere. 

Infantile  mortality  is  always  high,  owing  to  a  variety  of  causes,  and 
it  is  particularly  high  in  slums  and  in  manufacturing  towns  where 
women  are  largely  employed  in  factories,  and  so  are  unable,  even  though 
so  inclined,  to  give  that  personal  attention  to  their  offspring  as  is 
bestowed  by  mothers  whose  lives  are  purely  domestic.  In  Massa- 
chusetts, for  example,  the  infantile  death-rate  averaged,  in  the  decade 
1881-1890,  174.9  in  the  cities  and  129.5  in  the  country,  and  the 
extremes  for  the  cities  were  239.7,  at  Fall  River,  preeminently  a  "  mill 
town,"  with  all  that  the  term  implies,  and  111.9  at  Newton,  where 
manufacturing  is  at  a  minimum  and  overcrowding  practically  unknown. 
Lowell  and  Lawrence,  also  "  mill  towns,"  showed  respectively  222.5 
and  213.9,  while  Boston,  commercial,  manufacturing,  and  residential, 
showed  188.2. 

'  Many  statisticians  employ  the  factor  52.17747,  the  number  of  weeks  in  the  solar 
year  of  365  days,  5  hours,  48  minutes,  and  46  seconds.  This  exaggeration  of  exactness 
in  small  things  seems  all  the  more  absurd  when  we  consider  that  the  estimation  of  popu- 
lation at  the  middle  of  the  year  is  nothing  more  than  a  fairly  reasonable  guess,  and 
often  proves  to  be  wide  of  the  truth. 


INFANTILE  DEATH-RATE.  699 

lu  the  three  cities  with  the  highest  rates,  Fall  River,  Lowell,  and 
Lawrence,  the  population  is  largely  French-Canadian  oj^eratives  of 
cotton  and  woollen  mills,  housed  in  crowded  tenements.  The  so-called 
"shoe  towns,"  Haverhill,  Marlboro,  Brockton,  and  Lynn,  have  a  very 
different  kind  of  population,  much  better  paid  and  not  inclined  to  a 
tenement-house  life,  and  show  respectively  157.1,  154.6,  146.9,  and 
140.7,  all  of  which  rates  are  below  that  of  the  State  at  large,  160.4.^ 
Similarly,  in  England  and  Wales,  where  in  1894  the  rate  was  137,  and 
in  1896,  147.5,  Preston,  which  can  claim  one  of  the  blackest  records 
in  all  respects  among  mill  towns,  showed,  in  the  former  year,  229,  and 
in  the  latter,  262,  while  in  London  the  rate  was  but  159. 

The  chief  factors  in  the  causation  of  high  infant  mortality  are 
premature  births,  heredity,  intemperance,  early  marriages,  neglect, 
carelessness,  ignorance,  improper  food,  unsanitary  surroundings,  indus- 
trial conditions,  illegitimacy,  and,  perhaps,  infant  life  insurance.  The 
immediate  causes  are  chiefly  inanition,  diarrhoeal  diseases,  measles, 
whooping-cough,  and  other  infective  diseases,  and  violence.  The  influ- 
ence of  premature  birth,  heredity,  neglect,  carelessness,  ignorance,  and 
unsanitary  surroundings  needs  no  elucidation.  Industrial  conditions 
figure  largely  in  the  neglect  of  infants,  since  mothers  in  employment 
return  as  soon  as  possible  after  confinement  to  their  work,  and  entrust 
their  offspring  to  the  care  of  older  children  and  others,  by  whom  they 
are  improperly  fed  and  looked  after.  During  pregnancy,  also,  the 
woman  remains  at  work  up  to  the  last  possible  moment,  so  that  her 
absence  is  limited  to  that  period  during  which  she  is  absolutely  in- 
capacitated. 

The  age  of  the  parents  has  much  influence  on  the  vitality  of  infants, 
those  of  mothers  under  20  dying  off  appreciably  faster  than  those  of 
others  between  20  and  30.  Between  30  and  35,  the  vitality  of  the 
offspring  is  still  greater ;  but  after  this  age  period  it  begins  to  decline. 
The  first  children  of  very  young  fathers  also  are,  as  a  general  rule, 
weaker  than  those  begotten  later.  To  this  influence  of  the  parents' 
age,  conjoined  with  that  of  ignorance  and  inexperience,  may  be 
attributed  the  excessive  mortality  which  obtains  among  the  first-born. 

Illegitimacy  has  a  very  great  influence  on  the  chance  of  survival  to 
even  the  early  period  of  childhood,  for  the  infant  is  in  an  unfavorable 
position  as  regards  care  and  home  surroundings  from  the  beginning. 
Abandoned  by  the  mother  to  the  care  of  whomsoever  may  be  willing  to 
accept  the  charge,  or  "  farmed  out "  among  persons  whose  interest  in 
its  welfare  is  wholly  financial  and  subject  to  immediate  decline  on  the 
cessation  or  tardiness  of  payments,  it  has  even  less  chance,  perhaps, 
than  when  kept  at  home,  an  unwelcome  addition  both  to  the  family 
circle  and  to  the  expense  account. 

Infant  insurance  is  generally  believed  to  be  an  influence  in  diminish- 
ing the  amount  of  care  and  solicitude  for  the  health  of  the  very  young, 

'  These  figures  are  taken  from  a  commrinication  from  Dr.  S.  W.  Abbott,  vSecretary  of 
the  State  Boaixl  of  Jleallh  of  Massachusetts,  on  "  Infant  Mortality  in  Massachusetts." 
Journal  of  tlie  Massachusetts  Association  of  I'oanls  of  ITcaltli,  December,  1898,  p.  134. 


700  VITAL  STATISTICS. 

and,  therefore,  has  been  the  subject  of  considerable  legislation,  by 
which  the  maximum  amount  of  the  policy  is  kept  at  a  low  figure,  as, 
for  instance,  the  actual  expense  of  burial.  AVhether  insurance  has  more 
than  an  insignificant  bearing,  cannot  be  determined  by  trustworthy 
statistics. 

Beyond  doubt,  the  most  fruitful  single  cause  of  high  infant  mortality 
is  improper  feeding,  due  partly  to  the  necessity  of  supplying  an  arti- 
ficial substitute  for  breast  milk  and  partly  to  ignorance.  The  breast- 
fed infant,  carelessly  looked  after,  has  a  far  better  chance  than  the 
l)ottle-fed  more  carefully  tended.  The  former  receives  its  natural  food 
at  a  uniform  temperature  and  practically  sterile ;  the  latter  is  fed  upon 
another  kind  of  milk,  differently  constituted  and  of  a  different  degree 
of  digestibility,  which,  under  the  best  of  circumstances,  is  com- 
paratively rich  in  ordinary  bacteria,  and  is  administered  at  different 
temperatures,  sometimes  very  hot,  sometimes  cold.  With  lack  of  care, 
the  danger  is  increased,  for  the  milk  may  be  stale  and  dirty,  and  act  as 
the  vehicle  for  the  exciting  cause  of  cholera  infantum,  which  is  respon- 
sible to  a  greater  extent  than  any  other  morbid  condition  for  the  deaths 
in  mill  towns  of  infants  whose  mothers  are  employed  in  the  various 
industries.  Besides  dirty  and  stale  cows'  milk,  a  variety  of  cereal  and 
sugar  substitutes  are  provided,  which  may  or  may  not  be  digestible 
and  nutritious. 

Ignorance  of  what  is  proper  for  introduction  into  an  infant's  stomach 
is  responsible  for  much  influitile  mortality,  even  when  breast-feeding 
is  followed.  Who  has  not  seen  fond,  but  ignorant,  mothers,  in  public 
conveyances,  keeping  their  infants  quiet  with  bananas,  seed  cakes, 
cookies,  and  other  food  materials  unsuited  to  a  digestive  system  which 
can  have  difficulty  enough  with  milk  alone  ?  It  seems  unlikely  that 
such  practices  are  restricted  to  the  time  spent  in  travel,  when  consid- 
eration for  the  comfort  of  strangers  suggests  the  avoidance  of  fretting 
and  crying. 

Death-rates  of  children  under  five  years  of  age  are  expressed  in  the 
same  terms  as  infantile  mortality,  that  is  to  say,  as  the  proportion  of 
deaths  per  1000  children  of  that  age  period. 

High  and  Low  Death-rates. — In  the  absence  of  any  unusual  general 
unsanitary  condition  or  of  unusual  prevalence  of  epidemic  diseases,  an 
abrupt  rise  in,  or  a  very  high,  death-rate  is  not  infrequently  only 
apparent,  being  based  upon  an  underestimated  population.  A  very  low 
death-rate  is  always  open  to  suspicion,  although  sometimes,  as  in  newly 
settled  communities  with  a  very  high  proportion  of  young  male  adults, 
for  a  limited  term  of  years,  it  is  perfectly  possible  and  natural.  A  rate 
of  15  per  1000,  for  example,  in  large  cities,  is  so  low  as  to  suggest 
that  the  population  has  been  very  much  overestimated.  Within 
recent  years,  the  authorities  of  a  rapidly  growing  Western  city  noted 
with  great  pride  the  gigantic  strides  in  the  estimated  population,  and 
were  naturally  much  elated  to  find  that  the  death-rate  based  thereon 
entitled  the  city  to  a  position  in  the  first  rank  of  the  cities,  large  and 
small,  of  the  whole  world.      The  census  of  1900  dispelled  the  illusion. 


CORRECTION  OF  DEATH-RATES. 


701 


lor  the  population  had  been  grossly  exaggerated,  and  the  actual  death- 
rate  was  comparatively  high. 

Death-rates  as  low  as  10  and  12  are  sometimes  noted.  A  continued 
rate  of  10  in  a  stationary  population  would  mean  that  the  inhabitants 
would  average  100  years  of  age  at  death  ;  one  of  12  would  mean  an 
average  age  of  over  83  ;  one  of  15  would  mean  an  average  of  nearly  37. 

As  examples  of  high  and  low  death-rates,  the  following  for  the  same 
quarter  of  the  same  year  (1897)  may  be  cited : 


High. 

Dublin 39.9 

Moscow 36.9 

Bucharest 33.2 

Belfast 31.3 

St.  Petersburg 31.0 


Low. 
Frankfort  on  the  Main  .    .    .  15.6 

The  Hague 16.2 

Berlin 17.0 

Christiania 17.7 

Amsterdam 17.8 


The  influence  of  improved  sanitation  in  the  lowering  of  the  mortality 
of  any  given  place  cannot  be  disputed,  but  in  attributing  the  whole  or 
even  the  greater  part  of  the  diiference  in  the  rates  of  any  two  places  or 
of  the  same  place  in  diiferent  years,  one  should  be  careful  not  to  ignore 
factors,  already  mentioned,  that  exert  influences  beyond  the  control  of 
sanitary  authorities.  Permanent  decline  in  mortality-rate  is  a  matter 
of  slow  growth,  and  is  the  combined  result  of  sanitary  effort  and  miti- 
gation of  the  occupational  and  social  conditions  tending  to  lower  vital- 
ity. In  Elizabethan  times,  the  death-rate  of  London  was  about  40  ; 
at  the  beginning  of  the  reign  of  Victoria,  it  was  24,  and  at  the  end 
of  the  century,  about  19. 

Correction  of  Death-rates. — The  impossibility  of  making  a  fair  com- 
parison of  the  death-rates  at  different  places  without  taking  into  con- 
sideration the  constitution  of  the  respective  populations  as  to  age,  sex, 
and  race,  has  been  sufficiently  pointed  out ;  and  since  two  places  abso- 
lutely alike  with  regard  to  occupational  influences,  wealth,  density  of 
population,  climate,  soil,  water-supply,  sanitary  administration,  and 
general  sanitary  condition,  but  discrepant  as  regards  the  distribution 
of  the  sexes,  age  periods,  and  race,  may  show  very  different  death- 
rates,  perhaps  magnifying  the  salubrity  of  the  one  and  exaggerating  the 
unhealthiness  of  the  other,  it  becomes  necessary  to  have  some  method 
of  bringing  them  to  a  common  basis.  In  the  matter  of  race  influence, 
the  best  plan  is  to  separate  the  statistics  absolutely,  having  one  set  for 
the  white  and  another  for  the  colored  population,  and  to  compare  white 
with  white  and  negro  with  negro. 

The  method  commonly  recommended  for  correcting  according  to 
sex  and  age  is  the  one  in  use  in  the  office  of  the  Registrar-General  for 
England  and  Wales  ;  this  may  briefly  be  described  as  follows  : 

The  mean  annual  death-rate  of  the  country  for  each  sex  at  each  of 
the  eleven  age  periods,  namely,  below  5,  5-10,  10-15,  15-20,  20-25, 
25-35,  35-45,  45-55,  55-65,  65-75,  and  75  and  upw^ard,  during  the 
last  preceding  ten  years,  is  obtained  and  multiplied  by  the  number  of 
those  of  (jach  sex  at  each  corresponding  age  |)criod  in  the  territory 
under   consideration,   according   to  the   retnrns  of  the  last  preceding 


702  VITAL  STATISTICS. 

census.  Each  product  thus  obtained,  divided  by  1,000,  gives  the  cal- 
culated number  of  deaths  for  the  respective  sex  and  age  periods. 
These  22  results,  added  together,  represent  the  calculated  number  of 
deaths  for  the  place  in  question  in  one  year.  The  total  calculated 
number  of  deaths,  divided  by  the  number  of  thousands  of  population 
or  multiplied  by  1,000  and  divided  by  the  population,  gives  the  stan- 
dard death-rate. 

The  next  step  is  to  obtain  a  factor  for  correction,  by  determining  the 
ratio  which  the  standard  death-rate  of  the  place  bears  to  the  death-rate 
of  the  whole  country.  This  is  obtained  by  the  rule  of  simple  propor- 
tion, the  second  mean  being  unity.  The  recorded  death-rate  for  the 
year,  multiplied  by  this  factor,  gives  the  corrected  death-rcde,  which 
will,  therefore,  be  above  or  below  the  recorded  rate,  according  as  the 
factor  is  above  or  below  unity.  By  dividing  the  corrected  death-rate 
by  the  death-rate  of  the  whole  country,  and  multiplying  the  quotient 
by  1,000,  the  comparative  mortality  figure  is  obtained ;  that  is  to  say, 
the  number  of  deaths  which  will  occur  in  the  same  number  of  the  local 
population  as,  in  the  general  population,  will  yield  1,000  deaths. 

Classification  of  Causes  of  Death. — In  the  registration  of  causes  of 
death,  a  certain  amount  of  error  is  inevitable,  for  several  reasons.  In 
the  first  place,  even  the  most  competent  practitioners  are  not  infallible 
in  diagnosis,  and  it  is  not  always  possible,  when  one  pathological  state 
is  complicated  by  the  advent  of  another,  to  determine  which  was  the 
actual  cause  of  the  fatal  termination.  Next,  the  nomenclature  of  dis- 
eases is  faulty,  although  ever  tending  toward  ultimate  perfection.  Again, 
the  true  cause  of  death  frequently  is  misrepresented  intentionally  for 
private  or  family  reasons ;  thus,  apoplexy,  instead  of  suicide,  and 
peritonitis,  when  the  actual  cause  of  the  peritonitis  is  criminal 
interference. 

Lastly,  it  is  sometimes  the  case  that  no  cause  whatever  is  assignable, 
even  after  careful  autopsy,  and,  obviously,  such  cannot  be  classified. 
With  the  existence  of  an  indeterminate  amount  of  error,  it  folloNvs  that 
caution  should  be  exercised  in  comparing  results  representing  a  series 
of  years,  and  allowances  should  be  kept  in  mind  with  changes  in 
nomenclature,  when  drawing  deductions  from  what  has  been  described 
as  the  classification  of  the  more  or  less  reliable  guesses  of  a  large  num- 
ber of  more  or  less  skilled  observers. 

Registration  of  Sickness,  if  it  were  possible,  would  afford  a  far  more 
efficient  index  of  the  sanitary  condition  of  the  population  than  the 
registration  of  deaths,  which  gives  us  simply  the  number  of  cases  of 
sickness  which  ended  fatally,  but  no  idea  of  the  duration  thereof  or  of 
the  number  of  persons  temporarily  incapacitated.  A  disease  ordinarily 
regarded  as  fairly  dangerous  may  prevail  very  extensively  in  a  mild 
form,  and  be  attended  by  a  very  low  death-rate,  and,  again,  may  exist 
to  a  lesser  extent,  but  in  an  unusually  severe  form,  with  a  high  propor- 
tion of  fatalities.  Many  diseases,  again,  are  temporarily  disabling  and 
often  Avidely  prevalent,  but  play  a  small  part  m  mortality  returns. 
Tonsillitis,  for  example,  is  responsible^  for  much  discomfort  and  lost 


EXPECTATION  OF  LIFE.  703 

time  :  its  prevalence  has  some  meaning,  but  its  death  roll  is  exceedingly 
small.  Rheumatism  is  much  more  widespread  than  mortality  returns 
would  imply  ;  chickenpox  is  relatively  unimportant,  but  in  some  places 
its  notification  is  required  as  a  safeguard  against  the  spread  of  small- 
pox incorrectly  diagnosed  as  varicella  ;  gonorrhoea,  without  being  fatal, 
does  more  harm  than  commonly  is  supposed ;  and  syphilis,  also  not 
immediately  and  directly  fatal,  sends  its  victims  into  the  mortality 
returns  through  various  avenues.  But  however  desirable  such  regis- 
tration may  be,  the  obstacles  in  the  way  of  its  accomplishment  are  too 
numerous  to  admit  even  of  hope,  and,  excepting  in  the  case  of  infective 
diseases,  which  law  requires  shall  be  reported,  there  is  no  satisfactory 
method  of  obtaining  an  accurate  idea  of  the  health  of  a  community. 

Duration  of  Life. — Several  expressions  and  methods  are  employed 
to  denote  and  measure  the  duration  of  life,  a  problem  with  which  the 
science  of  vital  statistics  is  largely  engaged.  One  of  the  most  falla- 
cious indications  of  longevity  and  sanitary  condition  is  the  3Iean  age  at 
Death  or  Mean  Lifetime,  which  is  the  sum  of  the  ages  at  death  divided 
by  the  number  of  deaths.  This  is  unreliable,  because  it  fluctuates  very 
widely,  according  to  age  distribution ;  for'in  a  community  containing 
a  large  proportion  of  children  and  in  which  the  birth-rate  and,  conse- 
quently, the  infantile  mortality  are  high,  the  average  age  at  death  will 
be  lower  than  in  another,  equally  healthy,  in  which  these  conditions  do 
not  obtain.  Hence,  it  can  only  be  employed  with  any  degree  of  safety 
where  the  population  constitution  is  uniform  in  all  respects,  and  when 
the  observations  are  carried  along  over  a  long  period.  The  mean  age 
at  death,  not  of  a  few  hundreds  or  thousands  of  individuals,  but  of  an 
entire  generation  of  population,  is  necessary  to  show  accurately  the 
mean  duration  of  life,  and  this  is  determined  only  by  means  of  life 
tables. 

Probable  Duration  of  Life  signifies  the  age  at  which  half  of  any  num- 
ber of  children  born  will  have  died,  so  that  they  have  equal  chances  of 
dying  before  and  after  that  age.  It  is  also  called  the  vie  jyfobable  and 
the  equation  of  Life ;  but  all  of  these  terms  are  ill-chosen,  for  every 
possible  duration  of  life  has  a  certain  probability,  which  may  be  deter- 
mined by  life  tables. 

Mean  Duration  of  Life  is  another  ill-chosen  term  with  which  the  last- 
mentioned  is  often  confounded,  but  which  has  an  entirely  different 
meaning.  It  is  meant  to  express  the  probable  duration  of  life  from' 
the  date  of  birth.  In  an  ordinary  population,  subjected  to  the  usual 
disturbing  influences  of  migration,  it  means  present  age  plus  the  prob- 
able length  of  life  after  passing  a  given  point,  and  is  called  commonly 
the  eocper-tation  of  life  or  mean  after-lifetime.  It  is  a  term,  which,  by 
reason  of  its  indefiniteness  and  looseness  of  application,  it  would  be  well 
to  eliminate  altogether. 

Expectation  of  Life,  or  Mean  After-lifetime,  is  the  average  number  of 
years  which  an  individual  at  any  given  age  will  continue  to  live,  as 
shown  by  a  life  table.  As  ap])iied  to  whole  communities,  it  is  the 
mean  duration  of  life  of  a  generation  of  individuals  from  birth  to  death, 


704  VITAL  STATISTICS. 

and  is  regarded  as  the  only  true  measure  of  the  health  of  entire  popu- 
lations. Like  others  which  have  gone  before,  it  is  an  unfortunate 
expression  tending  to  confusion.  "  The  term  does  not  imply  that  an 
individual  may  reasonably  expect  to  live  a  given  number  of  years. 
The  excess  of  those  who  die  late  is  distributed  among  those  who  die 
early,  '  those  who  live  longer  enjoying  as  much  more  in  proportion  to 
their  number  as  those  who  fall  short  enjoy  less  of  life.'  Thus  the 
expectation  of  life  has  no  relation  w^hatever  to  the  most  probable  life- 
time of  any  given  individual."      (Newsholme.) 

"  Expectation  of  life  is  an  incorrect  term  :  the  time  which  it  is  expected 
a  person  will  live  is  the  time  which  it  is  an  even  chance  he  will  live ; 
it  is  the  vie  probable  of  the  French,  and  is  correctly  expressed  by 
'probable  lifetime.'  The  after-lifetime  can  only  be  the  same  as  the 
probable  lifetime  on  Demoivre's  hypothesis — that  the  surviving  form 
an  arithmetical  progression.  The  term  '  expecstation  of  life/  first  used 
by  Demoivre,  is  correct,  on  that  supposition,  which  is,  however,  in 
itself  quite  erroneous.  The  idea  intended  to  be  expressed  by  '  expec- 
tation of  life '  is  the  mean  time  which  a  number  of  persons  at  any 
instant  of  age  will  live  after  that  instant :  it  is  the  French  vie  moyenne; 
and  this  technical  idea  is  strictly  and  shortly  expressed  by  after-lifetime, 
a  pure  English  word,  formed  on  the  same  analogy  as  after-life,  cfter- 
times,  after-age,  after-hours.  The  after-lifetime  of  men  at  the  age  of  30 
is  33  years  by  the  English  Life  Table  :  33  years  is  not  the  precise 
time  probably  that  anyone  of  that  age  will  live,  but  the  average 
time  that  a  number  of  men  of  that  age  will  live,  taken  one  with 
another.  Age  -f-  after-lifetime  =  Lifetime.  At  30  this  is  30  +  33  =  63, 
the  average  age  which  men  now  aged  30  will  attain.  At  bu-th 
this  is  0  +  40  =  40 ;  when  lifetime  and  after-lifetime  are  the  same 
thing. 

"  The  lifetime  simply,  without  the  addition  at  a  given  age,  will 
serve  to  express  in  one  word  what  is  improperly  called  the  expectation 
of  life  at  birth  ;  thus  the  lifetime  of  males  in  England  is  40  years,  the 
lifetime  of  males  in  3Ianchester  is  24  years.  Those  who,  from  habit, 
prefer  '  expectation  of  life,'  can  always  substitute  it  for  after-lifetime ; 
from  the  use  of  which,  in  this  paper,  no  ambiguity  can  arise." 
(Dr.  William  Farr,  Eighth  Annual  Report  of  the  Kegistrar-General, 
p.  279.) 

Life  Tables. — A  life  table,  according  to  Dr.  Farr,  is  an  instrument 
of  precision.  "  It  may  be  called  a  hiometer,  for  it  gives  the  exact 
measure  of  the  duration  of  life  under  given  circumstances. 
A  life  table  represents  a  generation  of  men  passing  through  time  ;  and 
time  under  this  aspect,  dating  from  birth,  is  called  age.  In  the  first 
column  of  a  life  table,  age  is  expressed  in  years,  commencing  at  0 
(birth),  and  proceeding  to  100  or  110  years,  the  extreme  limit  of 
observed  lifetime." 

In  order  to  construct  a  life  table,  it  is  essential  to  have,  as  material, 
a  knowledge  of  the  size  of  the  population  and  its  age  and  sex  distribu- 
tion, and  the  returns  of  death  for  a  year,  or  a  series  of  years,  arranged 


LIFE-TABLES.  705 

according  to  age  at  death  and  sex  ;  and  for  tools,  certain  abstruse 
mathematical  formulae  which  it  is  hardly  necessary  to  consider  here. 
The  principle  upon  which  the  tables  are  based  is  that  if  a  large  number 
of  persons,  100,000,  for  instance,  born  at  the  same  time,  were  followed 
from  birth  to  the  grave,  and  their  deaths  recorded  in  the  usual  manner, 
the  average  age  lived  could  be  obtained  by  dividing  the  sum  of  their 
ages  at  death  by  their  original  number,  and  the  number  of  deaths  and 
of  survivors  at  each  period  would  be  known.  Another  lot  of  the  same 
size,  observed  elsewhere  and  living  under  diiferent  conditions,  would 
give  different  results,  and  thus  the  influence  of  the  discrepant  conditions 
could  be  measured. 

To  insure  as  great  accuracy  as  possible  in  constructing  life  tables,  it 
is  best  to  take  the  death  returns  for  the  entire  intercensal  period  of  five 
or  ten  years,  and  the  mean  population,  for  the  experience  of  a  single 
year  may  be  exceptional.  Tables  can  be  constructed  comprising  each 
year  of  life  or  according  to  quinquennial  periods,  and  are  made  for  each 
sex.  From  them  may  be  determined  the  probable  proportion  of  a 
given  number  that  will  arrive  at  different  ages,  the  probability  of  living 
a  given  time  at  each  year  or  period  of  age,  the  mean  after-lifetime  at 
the  end  of  any  given  year  or  period,  and  the  aggregate  future  lifetime 
of  the  survivors  at  the  end  of  each  year  or  age  period,  or  what  is 
known  as  the  life  capital  of  the  entire  community. 

The  probability  of  living  a  given  time  for  each  year  of  life  or  age 
period  equals  the  number  of  survivors  at  the  beginning,  into  the  num- 
ber at  the  end  of  the  year  or  period.  The  probable  number  of  sur- 
vivors at  each  year  or  period  is  obtainable  directly.  The  mean  after- 
lifetime  at  the  end  of  any  given  year  or  period  is  obtained  by  adding 
together  the  years  lived  by  the  w^hole  life-table  population  beyond  the 
year  or  period,  and  dividing  the  sum  by  the  number  of  survivors  at 
that  particular  time.  The  life  capital  of  a  community,  divided  by  the 
population,  gives  the  average  future  lifetime  ;  and  into  a  hundred  times 
the  population,  gives  the  percentage  of  annual  expenditure  of  life  capi- 
tal, since  the  mean  population  equals  years  of  life  expended  in  a  year. 

For  further  information  concerning  this  branch  of  vital  statistics, 
and  for  further  consideration  of  statistical  methods,  values,  and  errors, 
the  reader  is  referred  to  the  many  standard  works  dealing  with  the 
subject. 

45 


CHAPTER   XV. 

PERSONAL   HYGIENE. 

In  addition  to  the  barriers  which  public  hygiene  interposes  for  the 
protection  of  the  health  of  communities  by  protecting  water  supplies, 
disposing  of  sewage  and  other  wastes,  excluding  exotic  diseases  by 
means  of  quarantine,  providing  for  isolation  of  communicable  diseases, 
destroying  infectious  matter  by  disinfection,  regulating  the  conduct  of 
dangerous  occupations,  providing  for  the  inspection  of  foods,  and  throw- 
ing out  other  safeguards,  the  individual  owes  it  to  himself  and  to  the 
community,  of  which  he  constitutes  a  more  or  less  valuable  unit,  to 
erect  such  other  barriers  for  his  own  protection  as  he  can,  by  due  re- 
gard to  such  habits  of  life  as  conduce  to  a  healthy  existence.  It  is  his 
duty  to  maintain  habits  of  personal  cleanliness,  to  regulate  his  diet, 
avoiding  all  excesses  in  eating  and  drinking  ;  to  protect  his  body  by 
suitable  clothing  ;  to  take  sufficient  exercise  in  the  open  air  ;  to  keep  his 
system  in  perfect  working  order  throughout ;  to  devote  a  sufficient 
part  of  each  twenty -four  hours  to  needful  rest  of  mind  and  body  ;  and 
to  keep  his  immediate  surroundings  in  as  cleanly  a  state  as  his  own 
person.     This  is  the  domain  of  personal  hygiene. 

Section  1.     CARE  OF  THE  PERSON. 

It  is  hardly  necessary  to  impress  upon  intelligent  people  the  impor- 
tance of  personal  cleanliness,  for  with  such  it  is  a  matter  almost  of  in- 
stinct. In  the  case  of  the  naturally  dirty,  the  attempt  to  educate  in 
this  particular  is,  as  a  rule,  a  hopeless  task,  and  with  such,  the  mainte- 
nance of  cleanliness  of  body  and  surroundings  can  be  obtained  only  by 
compulsion.  There  is  in  every  civilized  community  an  all-too-large 
proportion  of  persons  who  never  bathe,  and,  indeed,  regard  a  bath  as 
a  positive  danger  to  health,  as  every  physician  who  has  had  experi- 
ence as  a  hospital  interne  or  in  practice  among  the  ignorant  poor  can 
abundantly  testify. 

Bathing  is  of  importance  to  health,  both  for  its  action  in  removing 
dirt  and  infectious  matter  of  external  origin,  and  for  its  influence  in 
keeping  the  skin  free  from  waste  products  of  the  system  and  in  a  con- 
dition for  the  proper  exercise  of  its  natural  functions ;  for  the  skin  is 
one  of  the  most  important  natural  defences. 

Baths, — By  an  arbitrary  division  of  temperatures,  cold  baths  are 
those  in  which  the  water  has  a  temperature  beloAV  65°  F.  ;  cool,  be- 
tween 65°  and  80°  ;  tepid,  between  80°  and  90°  ;  warm,  between  90° 

706 


CABE  OF  THE  PERSON.  707 

and  the  normal  temperature  of  the  body  ;  and  hot,  above  this  limit  as 
high  as  the  system  can  bear.  Cold  bathing  is  essentially  stimulant : 
the  cutaneous  vessels  contract  at  once,  and  send  the  superficial  blood 
supply  inward  ;  the  respiration  is  momentarily  gasping  in  character,  and 
then  slowed  and  increased  in  depth.  The  whole  nervous  system  and 
all  of  the  mental  faculties  receive  an  immediate  powerful  stimulus. 
The  pulse  is  somewhat  slowed.  On  emerging  from  the  cold  water,  the 
respiration  and  pulse  return  to  their  normal  rates,  the  cutaneous  vessels 
relax  and  dilate,  and  the  return  of  the  blood  in  increased  volume  to  the 
surface  gives  a  sensation  of  warmth,  which  is  increased  by  the  process 
of  "  rubbing  down."     This  is  known  as  the  ''  normal  reaction." 

The  cold  bath  is  taken  best  in  a  tub  in  which  the  whole  body  may 
be  immersed ;  but  in  default  of  the  necessary  means,  a  sponge,  satu- 
rated with  water,  applied  repeatedly  to  the  various  parts  and  squeezed 
out,  forms  a  desirable  substitute.  A  shower  bath  is  better  still,  espe- 
cially one  admitting  of  regulation  of  the  temperature. 

The  proper  time  for  cold  bathing  is  on  rising  in  the  morning  ;  never 
on  retiring  for  the  night.  Cold  baths  should  not  be  taken  by  those 
advanced  in  years,  in  whom  the  arteries  are  atheromatous,  nor  by  those 
with  abnormal  circulation,  who  do  not  quickly  react. 

Not  the  least  in  importance  of  the  effects  of  cold  bathing  is  the  im- 
munity which  its  devotees  appear  to  enjoy  against  taking  cold.  Many 
of  those  who  practise  cold  bathing  the  year  round  have  no  experience 
whatever  with  colds,  and  can  withstand  exposure  which,  to  others,  is 
productive  of  much  illness. 

In  sea  bathing,  the  element  of  enjoyment  has  a  most  important  in-, 
fluence.  The  salts  are  commonly  supposed  to  be  the  chief  source  of 
benefit,  and,  in  consequence  of  this  belief,  many  persons  are  in  the 
habit  of  dissolving  in  their  daily  bath  in  the  household  a  quantity  of 
more  or  less  dirty  material,  sold  at  a  price  which  insures  at  least  a  fair 
pecuniary  return,  and  known  as  sea  salt.  The  influence  of  the  salts 
contained  in  sea  water  is  nil,  and  the  benefits  of  sea  bathing  are 
the  result  of  the  physiological  action  of  cold,  the  attendant  exercise  of 
swimming,  the  pure  air,  the  absence  of  domestic  and  business  cares  (if 
on  vacation),  and  the  sense  of  enjoyment. 

Warm  and  hot  bathing  cause  dilatation  of  the  cutaneous  vessels 
and  more  or  less  profuse  perspiration.  Respiration  and  pulse  are 
increased  in  frequency,  and  a  general  soothing  effect  is  produced.  Hot 
bathing  is  a  most  grateful  means  of  reducing  soreness  of  the  muscles 
after  violent  exercise  and  a  valuable  assistant  in  the  treatment  of 
insomnia.  For  purposes  of  personal  cleanliness,  warm  and  hot  baths 
are  more  suited  than  cold,  since  they  can  be  borne  longer  with  comfort, 
and  the  relaxation  of  the  skin  which  they  induce  is  more  favorable  to 
complete  removal  of  the  adherent  matters. 

If  means  for  complete  bathing  are  not  at  hand,  the  individual  should 
in  any  event  give  daily  attention  to  careful  cleansing  of  the  axillae, 
groins,  genitals,  and  feet,  as  well  as  of  tlic  hands  and  face. 


708  PERSONAL  HYGIENE. 

Section  2.     REGULATION  OF  THE  DIET. 

It  is  obviously  impossible  to  formulate  any  system  of  rules,  applic- 
able to  all  classes,  for  the  selection  of  diet  and  the  regulation  of  hours 
■with  reference  to  the  daily  duties  of  life,  but  general  rules  concerning 
some  aspects  of  the  question  may  be  laid  down.  The  suggestion  of 
light  breakfasts,  somewhat  more  substantial  luncheons,  and  hearty  din- 
ners at  close  of  day,  with  periods  of  mental  and  physical  rest  after  each 
meal,  is  easy  to  make ;  but  the  busy  lives  which  the  great  majority  of 
the  population  lead,  and  the  widely  different  conditions  of  life  and  oc- 
cupation, make  its  general  acceptance  and  adoption  quite  beyond  the 
bounds  of  possibility.  It  is  a  common  habit  of  writers  on  personal 
hygiene  to  compose  menus  for  the  several  daily  meals,  to  suggest  the 
amount  of  time  which  should  be  devoted  to  the  consumption  of  each, 
and  to  recommend  the  avoidance  of  physical  or  mental  labor  for  vary- 
ing periods  before  and  after  each  meal,  in  order  that  the  digestive  appa- 
ratus may  proceed  with  its  work  under  the  most  favorable  conditions 
for  its  uninterrupted  completion. 

The  adoption  of  most  of  such  recommendations,  however,  presup- 
poses a  curious  state  of  the  conditions  of  life,  including  an  absence  of 
any  marked  preferences  in  the  matter  of  articles  of  diet,  a  complete 
mastery  of  one's  time  without  reference  to  the  demands  of  occupation, 
and  pecuniary  independence. 

General  rules  may  be  offered  to  the  effect  that  the  diet  should  con- 
sist of  wholesome  articles  of  food  ;  that  these  should  be  consumed  in 
sufficient,  but  not  excessive,  amounts ;  that  they  should  not  be  hur- 
riedly bolted  ;  and  that  as  much  time  as  is  consistent  with  the  needs 
of  one's  occupation  should  be  allowed  after  each  meal,  before  proceed- 
ing to  a  continuance  of  work.  Obviously,  in  these  particulars  each 
person  must  be  a  law  unto  himself,  and  the  greater  the  observance  of 
general  hygienic  principles,  the  better  the  physical  and  mental  well- 
being. 

Section  3.     REST  AND  RECREATION. 

For  the  repair  of  the  daily  wear  and  tear  of  a  busy  life,  a  reasonable 
period  of  rest  of  body  and  mind  is  indispensable.  Nervous  and  mental 
breakdown  result  from  overwork  and  absence  of  recreation,  but  it  is 
impossible  to  make  any  rule  as  to  what  may  be  regarded  as  a  safe  limit 
of  the  amount  of  work  which  may  be  performed.  Monotony  of  life  is, 
perhaps,  as  potent  a  factor  in  mental  breakdown  as  overwork,  as  is 
evidenced  by  statistics  showing  the  high  percentage  of  insanity  among 
farmers  and  farmers'  wives  in  sparsely  settled  districts.  Mental  worry, 
also,  is  far  more  potent  than  mere  mental  activity  in  causing  physical 
and  mental  degeneration.  Eecreation  is  a  most  important  remedy, 
therefore,  for  the  prevention  of  monotony  and  worry. 

It  is  impossible  to  lay  down  any  rule,  governing  the  amount  of  sleep, 
that  can  apply  to  all  persons  indifferently,  since  active  minds  may  need 
much  less  than   what  commonly  is  regarded  as  a  minimum  general 


PHYSICAL  EXERCISE.  709 

requirement,  and  persons  of  conspicuously  low  mental  capacity  may  re- 
quire much  more.  It  is  generally  accepted,  however,  that  for  the  repair 
of  waste,  the  average  man  needs  to  pass  at  least  one-third  of  his  time, 
namely,  eight  hours  a  day,  in  sleep. 

Section  4.     PHYSICAL  EXERCISE. 

It  is  essential  to  the  maintenance  of  a  completely  healthy  condition 
that  a  well-nourished  body  shall  be  exercised  properly  in  all  its  parts. 
The  muscular  effort  involved  in  what  we  designate  as  physical  exercise 
and  in  the  pursuit  of  certain  callings  which  necessitate  bodily  activity 
aifects  not  alone  the  general  musculature,  but  all  the  organs  of  the  body 
as  well ;  the  heart,  the  lungs,  the  digestive  apparatus,  the  skin,  the 
kidneys,  the  brain,  and,  in  short,  every  part.  The  heart  and  lungs 
being  stimulated  to  increased  action,  an  increased  supply  of  oxygenated 
blood  is  sent  to  every  part,  bringing  with  it  the  essentials  to  full  nutri- 
tion and  conveying  to  the  elirainative  channels  the  ultimate  products 
of  metamorphosis.  The  special  stimuli  of  the  various  organs  are 
excited,  and  thus  the  several  functions  are  maintained  in  a  normal  state 
of  activity. 

In  order  to  gain  a  full  appreciation  of  the  benefits  of  physical  exer- 
cise, one  needs  but  to  compare  the  rugged  condition  of  the  well-nour- 
ished laborer  in  the  fields  or  of  the  student  or  man  of  business,  who, 
in  the  intervals  away  from  his  daily  work,  seeks  recreation  in  outdoor 
exercise  or  indoor  gymnastics,  with  that  of  the  pent-up,  sedentary 
operative  or  the  indolent  seeker  after  pleasures  involving  inaction. 
Whether  the  work  of  the  individual  be  that  of  the  hands  or  brain,  it 
is  sustained  better,  if  the  system  is  kept  active  in  all  its  functions  and 
parts. 

Effects  of  Active  Exercise. 

Circulation  and  Respiration. — Muscular  effort  causes  the  heart  to 
beat  more  rapidly  and  with  greater  force,  so  that  more  blood  is  sent 
through  the  lungs  and  all  parts  of  the  body,  including  the  substance  of 
the  heart  itself.  Unless  the  exercise  is  excessive  in  duration  or  violence, 
the  increased  action  is  regular  and  equal,  and  cessation  of  the  exercise 
is  followed  by  gradual  slowing,  until  the  rate  is  below  the  normal ; 
and  then  by  return  to  the  natural  rate.  With  excess  of  muscular 
effort,  the  pulse  becomes  quick,  small,  and,  often,  more  or  less  irregular, 
and  even  during  the  fall  in  rate  in  the  interval  of  rest,  it  may  be  inter- 
mittent. Excessive  rapidity,  irregularity  in  pulsation,  and  inequality 
of  volume  are  indicative  of  the  necessity  of  rest  and  of  danger  from 
continuance. 

The  increase  in  the  pulmonary  circulation  is  accompanied  by  increase 
in  respiratory  action,  so  that  a  larger  volume  of  blood  is  forced  through 
the  lungs  and  comes  in  contact  with  an  increased  air  supply,  from 
which  it  receives  the  necessary  increase  in  oxygen  for  conveyance  to 
the  tissues,  and  to  which  it  gives  up  its  carbon  dioxide,  aqueous  vapor, 
and  other  waste  products,  for  removal  from  the;  ))()dy.     According  to 


710  PERSONAL  HYGIENE. 

the  researches  of  Pettenkofer  and  Voit,  the  oxygen  absorbed  during 
an  ordinary  working  day,  with  the  usual  interval  for  rest,  is  about  one- 
third  greater  in  amount  than  during  a  day  -of  inaction,  and  the  carbon 
dioxide  produced  and  eliminated  is  increased  about  two-fifths.  During 
exertion,  the  action  of  the  chest  should  be  impeded  as  little  as  possible 
by  tightly  fitting  clothing  and  other  restrictions. 

Excessive  exercise  causes  labored  breathing  and  sighing,  which  are 
indications  that  the  lungs  are  too  much  congested,  and  that  rest  is 
required. 

Continued  excessive  exercise  may  bring  about  palpitation,  dilatation, 
hypertrophy,  and  even  valvular  lesions  of  the  heart,  and  congestion  of 
the  lungs,  accompanied,  sometimes,  by  haemoptysis.  Sudden  unusual 
elFort  may  cause  rupture  or  other  injury  of  the  blood-vessels,  and, 
rarely,  even  rupture  of  the  heart. 

Deficient  exercise  favors  weakening  of  the  heart's  action,  dilatation, 
and  fatty  degeneration  ;  and  in  those  with  inherited  predisposition,  the 
preparation  of  suitable  soil  for  the  reception  and  development  of  the 
organism  of  tuberculosis. 

Skin. — In  consequence  of  the  increased  blood  supply  sent  through 
the  cutaneous  vessels,  the  latter  dilate  aud  the  skin  becomes  reddened. 
Heat  is  brought  from  the  interior  of  the  body  and  radiated  from  the 
surface,  and  a  farther  cooling  effect  is  caused  by  the  evaporation  of  the 
sweat  which  is  poured  out  by  the  sweat  glands.  Thus  the  excess  of 
heat  produced  in  the  system  through  exercise  of  its  various  parts  is 
eliminated  and  the  body  temperature  kept  in  a  state  of  equilibrium. 
The  amount  of  Avater  given  oif  by  the  lungs  and  skin  during  a  day  of 
average  work  was  shown  by  Pettenkofer  and  Voit  to  be  nearly  twice 
and  a  half  that  eliminated  during  the  same  period  of  rest. 

With  the  water  of  the  sweat,  the  body  loses  salts,  especially  sodium 
chloride,  and  fiitty  acids  and  other  organic  substances. 

During  exercise,  while  the  skin  is  active,  there  is  little  danger  of 
chill,  even  though  the  skin  be  lightly  covered  or  even  exposed ;  but  as 
soon  as  the  body  rests,  the  temperature  falls,  and  sweating  aud  evapo- 
ration continue,  so  that  it  is  important  to  protect  the  body  against  sud- 
den checking  of  the  skin's  action  and  chilling  of  the  surface.  This  is 
done  best  by  means  of  clothing  of  low  heat  conductivity,  preferably 
woollen. 

With  normal  action  of  the  skin,  the  body  temperature  remains  fairly 
constant,  the  heat  of  the  blood,  even  during  most  violent  exercise, 
rarely  rising  much  more  than  a  degree  Fahrenheit  above  the  normal. 
During  work,  a  decided  rise  in  temperature  indicates  lessened  evapo- 
ration from  the  skin  and  points  to  possible  danger  from  heat  apoplexy. 

Nervous  System. — It  is  a  common  belief  that  exercise  has  no  effect 
in  increasing  the  powers  of  the  mind,  this  belief  being  based  on  the 
supposition  that  the  greater  expenditure  of  nervous  energy  called  for 
in  the  exercise  of  the  muscles  is  opposed  to  intellectual  development  or 
accomplishment.  In  support  of  the  idea  that  great  muscular  power 
and  exertion  are  incompatible  with  marked  mental  attainments,   the 


EFFECT  OF  EXERCISE  ON   WEIGHT,  711 

fact  is  often  cited  that  trained  athletes,  as  pugilists  and  wrestlers,  are 
conspicuously  stupid.  But  admitting  that  this  is  true,  it  may  also  be 
said  that  these  persons  are  stupid  in  spite  of  rather  than  because  of 
their  physical  development  and  training  ;  and  the  fact  may  be  pointed 
out  that  in  our  schools  and  colleges  the  chosen  athletic  representatives 
rank,  as  a  class,  even  higher  than  the  average  of  their  non-athletic 
brethren.  Intellectual  ability  is  incompatible  with  the  embracing  of 
pugilism  as  a  calling,  but  is  quite  consistent  with  a  high  degree  of 
physical  perfection  and  bodily  exercise.  Furthermore,  a  reasonable 
degree  of  activity  appears  to  be  necessary  to  the  performance  of  men- 
tal labor,  for  without  proper  nutrition  and  exercise  of  the  system,  the 
nerves  and  nerve  centers  must  suffer  with  other  parts,  even  as  they 
must  share  in  the  benefits  of  healthy  and  vigorous  living. 

One  part  of  the  general  system  cannot  monopolize  the  benefits  of 
training  :  the  muscles,  for  example,  cannot  be  trained  without  the  par- 
ticipation of  the  nervous  system  in  the  good  results,  nor,  on  the  other 
hand,  can  they  be  abused  without  injury  to  other  parts  as  well,  for 
motor  activity  is  the  result  of  nervous  energy,  and  all  fatigue  is  nerv- 
ous fatigue.  As  evidence  of  the  beneficial  influence  of  exercise  on 
the  nerves  may  be  cited  the  greater  readiness  with  which  trained  mus- 
cles respond  to  volition. 

Deficient  exercise  is  a  common  cause  of  morbid  excitability,  mani- 
fested by  irritability  of  temper,  sensitiveness,  and  that  form  of  nervous 
unrest  commonly  known  as  fidgets. 

Digestive  Apparatus. — The  great  increase  in  the  excretion  of  car- 
bon dioxide  and  in  general  cellular  activity  causes  a  demand  for  food, 
and  the  appetite  is  increased,  especially  for  proteid  matter  and  fats. 
Digestion  is  assisted,  and  absorption  is  hastened.  The  volume  of  the 
excreta  is  lessened  by  reason  of  a  diminished  content  of  water,  due  to 
increased  elimination  through  the  skin  and  lungs.  Lack  of  exercise,  on 
the  other  baud,  tends  to  diminish  appetite  and  the  powers  of  digestion. 

Kidneys. — The  amount  of  urine  is  lessened  by  reason  of  increased 
loss  of  water  through  the  skin  and  lungs.  The  inorganic  salts  are  com- 
monly increased,  both  relatively  and  absolutely.  Urea  is  not  increased^ 
and  may  even  be  diminished,  as  shown  by  Petteukofer  and  Voit,  in 
which  case,  a  more  than  compensatory  increase  occurs  during  the  inter- 
val of  rest. 

Effect  of  Exercise  on  Weight. — The  effect  of  systematic  regular 
exercise  on  weight  is  by  no  means  constant,  but  is  influenced  by  the 
condition  of  the  body  in  the  beginning,  and  by  the  amount  and  variety 
of  the  food  ingested.  Many  persons  shortly  after  beginning  a  course 
of  training  for  the  reduction  of  weight  or,  more  correctly,  of  size,  find 
that  a  reduction  in  girth  is  accompanied  by  an  increase  rather  than  a 
diminution  in  weight.  This  means  simply  that  the  system  has  drawn 
upon  its  stored  fat  for  fuel,  this  fat  being  most  conspicuously  placed 
in  the  vicinity  of  the;  waist  line,  and  has  built  up  tissues  elsewhere  for 
the  increased  work  of  moving  the  various  levers  of  the  body.  This  in- 
crease has  its  limitations,  and  wIhsii  the  maximum  has  been  reached, 


712  PERSONAL  HYGIENE. 

the  fall  in  weight,  due  to  utilization  of  surplus  fat,  may  continue  until 
a  point  is  reached  when  the  curve  of  weight  approximates  a  horizontal 
line,  and  the  person  may  be  said  to  be  in  perfect  physical  condition. 
The  marked  losses  in  weight  which  occur  during  violent  exercise  are 
soon  counterbalanced  by  ingestion  and  absorption  of  food  and  drink. 

Amount  of  Exercise  Required. — Since,  in  the  ordinary  routine  of 
life,  a  considerable  and  varying  amount  of  physical  work  is  performed, 
it  is  impossible  to  fix  any  rule  concerning  the  exact  daily  amount  of 
exercise  which  a  healthy  normal  adult  should  take.  With  the  vast 
majority  of  persons,  all  the  exercise  needed  is  taken  as  an  inseparable 
element  of  their  regular  occupation,  and  any  additional  work  is  per- 
formed as  a  means  of  recreation.  On  no  other  ground  can  be  explained, 
for  example,  the  evening  bicycle  ride  of  the  letter-carrier  after  the 
monotony  of  his  daily  rounds  on  foot,  or  the  game  of  ball  begun  at  the 
close  of  the  day's  work  by  the  hands  from  the  mill  or  foundry. 

A  fair  day's  work  for  an  adult  may  be  said  to  be  equivalent  to  about 
300  foot-tons,  a  hard  day's  work  to  400,  and  a  very  hard  day's  work 
to  500  foot-tons.  The  latter  is  about  the  amount  of  work  performed 
by  a  soldier  of  average  weight  marching  at  ease  with  his  kit  twenty 
miles  over  a  level  surface  at  the  rate  of  three  miles  an  hour. 

It  has  been  reckoned  by  Haughton  that,  in  walking  on  the  flat,  one 
performs  an  amount  of  work  equivalent  to  raising  a  certain  proportion 
of  his  weight  through  the  distance  travelled,  the  proportion  varying 
according  to  speed.  The  work  perfonued  is  reckoned  by  the  fol- 
lowing formula  : 

{W+  TT"MX-D  ^  (7=  number  of  foot-tons. 
2240 

W      =^  weight  of  the  person. 

TP     =  weight  carried. 

D       =  distance  in  feet. 

2240   =  number  of  pounds  in  a  long  ton. 

C        =  coefficient  of  traction. 

The  coefficients  of  traction,  as  determined  by  Haughton  for  different 
rates  of  speed,  are  as  follows : 

Miles  per  hour.  Coefficient. 

1.818 —^ 

28.27 
1 
^•^^^ 15.70 

'»■■"' •■ ylr 

From  these,  the  coefficients  for  any  rate  may  be  determined.  For 
two,  three,  four,  and  five  miles  per  hour,  they  are  approximately 
2T'  "=5^?  iV'  ^^^  TTi'  respectively.  Thus,  a  man  weighing  175  pounds, 
walking  10  miles  at  the  rate  of  4  miles  per  hour  and  carrying  25 
pounds,  would,  according  to  the  formula,  do  nearly  300  foot-tons  of 
work — 

(175  +  25)X52,800         1    _  295.25 
2240  ^  16 


KINDS   OF  EXERCISE— GOLF.  713 

In  ascending  a  height,  a  man  lifts  his  entire  weight  through  the 
vertical  distance  travelled.  Thus,  the  same  man,  carrying  the  same 
weight,  climbing  six  flights  in  an  ordinary  office  building,  would  do 
about  8  foot-tons  of  work,  reckoning  the  distance  climbed  as  90  feet. 

For  those  who  do  no  regular,  ordinary  physical  labor,  it  has  been 
estimated  by  different  authorities  that  exercise  equivalent  to  from  100 
to  150  foot-tons  is  sufficient  for  the  maintenance  of  a  fair  state  of 
health.  But  this  should  not  be  pushed  to  the  extent  of  being  exhaust- 
ing or  irksome.  When,  in  the  course  of  exercise,  the  body  begins  to  be 
fatigued  or  the  heart  and  respiration  to  be  embarrassed,  rest  is  required ; 
for  excessive  exercise  confers  no  benefit.  Severe  prolonged  exercise 
may  cause  dilatation  of  the  heart,  aneurysm,  and  respiratory  disorders. 

Kinds  of  Exercise. — Exercise  as  a  hygienic  measure  maybe  divided 
into  outdoor  work,  including  walking,  riding,  and  athletic  sports,  and 
indoor  work,  or  systematic  gymnastic  exercises.  The  former,  preferred 
by  all  English-speaking  people,  are  carried  on  under  far  more  healthy 
conditions  and  bring  with  them  a  much  greater  measure  of  enjoyment 
than  the  latter,  which  are  preferred  on  the  Continent,  more  especially 
by  Swedes  and  Germans.  Indoor  work  in  the  gymnasium  is,  as  a 
rule,  purely  work,  without  the  element  of  pleasure  either  in  anticipation 
or  during  its  continuance,  and  is  performed  as  a  serious  duty.  It  is 
carried  out  from  day  to  day  for  a  longer  period,  if  done  in  company 
with  others,  as  in  a  class  ;  in  which  case,  emulation  may  stand  in  the 
place  of  actual  enjoyment.  But  ordinary  indoor  exercise  with  Indian 
clubs,  dumb-bells,  chest-weights,  and  similar  appliances,  carried  on 
alone  in  one's  room,  is  usually  most  unsatisfactory  in  its  results. 

There  are  some,  doubtless,  who  regularly  take  a  certain  amount  of 
this  class  of  exercise,  enjoy  it,  and  profit  by  it ;  but,  commonly,  the 
enthusiasm  which  attends  the  purchase  of  the  appliances  declines  in  a 
marked  degree  by  the  end  of  the  third  or  fourth  day  of  use,  and  has 
disappeared  in  a  week.  Soon  the  exercise,  simply  a  duty,  develops 
into  a  bore,  for  the  monotony  of  this  kind  of  work,  into  which  no 
sense  of  achievement  enters,  except  that  from  the  accomplishment  of 
a  wearisome  round  of  strokes  measured  by  hundreds,  produces  a  dis- 
taste ;  and  soon  the  work  becomes  spasmodic,  the  intervals  growing 
longer  and  longer,  and  finally  is  abandoned  completely. 

Grolf. — This  exceedingly  popular  game  appears  to  be  an  ideal  form 
of  exercise  for  all  ages  above  early  childhood,  and  j^articularly  for  those 
whose  lives  are  essentially  sedentary  or  whose  age  precludes  them 
from  following  the  more  violent  games.  The  amount  of  work  per- 
formed in  going  once  over  a  course  is  very  considerable,  but  it  is  done 
in  such  a  way  and  under  such  surroundings,  with  ever-changing  scene, 
that,  at  the  time,  it  is  hardly  appreciated.  The  mind  is  pleasantly 
engaged  in  speculation  as  to  the  possibility  of  achieving  certain  results, 
and  is  filled  with  ])lc'asural)le  emotions  when  the  effort  is  crowned  with 
success  ;  the  body  is  gently  exercised  in  all  its  parts  by  a  form  of  work 
performed  because  it  is  so  essentially  a  means  of  enjoyment.    It  cannot 


714  PERSONAL  HYGIENE. 

be  abused  as  are  so  many  other  sports,  and  there  is  no  necessity  for 
quick  and  violent  action,  as  in  tennis  and  football. 

Wheeling. — Wheeling  involves  very  largely  the  entire  muscular  sys- 
tem, and  brings  into  play  groups  of  muscles,  the  existence  of  which 
has  not  before  been  appreciated  by  the  beginner.  With  the  wheel,  one 
may  take  any  desired  amount  of  gentle,  moderate,  or  violent  exercise. 
It  gives  a  constant  change  of  scene  and  the  pleasurable  sense  of  motion, 
both  of  which  are  of  value  to  the  tired  mind.  It  is  not  the  particular 
form  of  muscular  exertion  that  is  the  incentive  to  long  exercise  on  the 
wheel,  but  the  pleasure  which  it  gives  ;  for  no  more  monotonous  exercise 
can  be  devised  than  riding  a  stationary  bicycle  in  a  gymnasium,  while, 
on  the  other  hand,  many  who  would  regard  an  errand,  involving  a 
walk  of  a  mile,  as  a  hardship,  will,  without  demur,  wheel  five  times 
that  distance  for  the  same  end. 

Tennis,  etc. — Tennis,  football,  baseball,  and  other  outdoor  sports  are 
comparatively  violent  for  the  majority  of  people.  They  bring  the 
whole  body  into  action  and  are  valuable,  if  not  pushed  too  far.  They 
do  not  admit  of  varying  the  pace  according  to  the  fatigue  of  individual 
players,  in  which  respect  golf  and  wheeling  possess  an  advantage. 

Rowing  is  also  a  very  healthful  form  of  exercise,  but  the  violent  exer- 
tion required  in  the  sustained  effort  of  racing  is  not  always  a  benefit. 

Section  5.     CLOTHING. 

The  objects  of  clothing  are,  aside  from  motives  of  decency,  to  pro- 
tect the  body  from  the  sun's  rays  in  hot  weather,  from  the  chilling 
influence  of  winds  in  all  weathers,  from  rain  and  other  forms  of  wet, 
and  from  mechanical  and  other  external  injuries  and  discomforts  ;  to 
conserve  the  body  temperature  and  prevent  interference  with  the 
natural  functions  of  the  skin  ;  and,  finally,  to  adorn  the  person.  The 
proper  fulfilment  of  these  various  objects  is  dependent  upon  the  nature 
of  the  material,  the  looseness  of  its  texture,  its  color,  its  hygroscopicity 
and  heat  conductivity,  and  its  special  adaptability  to  some  particular 
purpose. 

Color. — The  heat  of  the  sun's  rays  is  absorbed  to  the  greatest  extent 
by  black  materials,  and  least  by  white.  Next  to  black  come  the  dark 
shades  of  blue,  and  then,  in  order,  green,  red,  and  yellow.  Heat  is 
reflected  most  by  white,  and  then,  in  order,  the  light  shades  of  yellow, 
red,  green,  and  blue.  The  color  of  undergarments  (not  exposed  to  the 
rays  of  the  sun)  exercises  no  influence  whatever. 

Texture. — The  looser  the  texture,  the  greater  the  amount  of  air  in 
the  interstices  ;  and  air  being  a  very  poor  heat  conductor,  other  things 
being  equal,  a  loosely  woven  fabric  prevents  loss  of  body  heat  in  a 
still  air  more  than  one  of  closer  texture.  Thus  it  is  that  a  thin, 
loosely  woven  garment  of  woollen  is  warmer  to  the  body  in  a  still, 
cold  atmosphere  than  an  equal  amount  of  closely  woven  material  of 
the  same  or  other  kinds.  The  same  result  is  attained  by  wearing  a 
number  of  garments,  one  over  another,  so  that,  having  layers  of  con- 


MATERIALS.  715 

fined  air  between,  they  act  in  the  same  way  as  double  windows  on  a 
house.  The  value  of  furs  as  conservators  of  heat  is  largely  due  to 
the  amount  of  air  retained  between  the  individual  hairs. 

Impermeable  materials,  being  absolutely  wind-proof,  and  hence  per- 
mitting no  natural  ventilation  through  their  substance,  are  very  warm, 
but  have  serious  disadvantages,  the  most  important  of  which  is  the 
retention  of  the  transpired  moisture  of  the  body,  which  collects  on  the 
surface  and  is  absorbed  only  in  part  by  the  clothing  next  thereto. 
Against  rain  and  cold  winds,  impermeable  materials  afford  very  great 
protection.  Winds  act  in  two  ways  to  chill  the  body  :  by  constant 
removal  of  the  air  in  contact  with  the  body  and  warmed  by  reason  of 
contact,  and  by  hastening  evaporation  of  the  moisture  within  the  sub- 
stance of  the  clothing. 

Heat  Conductivity. — Materials  vary  widely  in  their  power  of  heat 
conduction.  Among  the  textiles,  linen  and  cotton  are  by. far  the  best 
conductors,  and  wool  the  poorest ;  but  since  the  conductivity  of  a  gar- 
ment is  governed  mainly  by  the  looseness  of  texture,  it  follows  that 
the  same  amount  of  a  good  conductor,  loosely  woven,  may  be  warmer 
than  wool  woven  very  closely.  But  the  fabrics  made  of  the  best  con- 
ductors are  commonly  very  closely  woven,  and  of  wool  are  of  varying 
degrees  of  looseness. 

Hygroscopicity. — Fabrics  hold  moisture  in  two  ways  :  first,  by 
retaining  it  in  the  interstices  between  the  fibers  ;  and,  secondly,  by 
absorption  directly  into  the  substance  of  the  fibers.  The  moisture 
held  in  the  interstices  gives  the  sensation  of  dampness  or  wetness,  and 
may  be  largely  removed  by  pressure,  as  in  wringing ;  that  absorbed 
into  the  fiber  may  be  very  large  in  amount  without  giving  any  sen- 
sation of  dampness,  and  it  cannot  be  expelled  by  pressure.  The 
latter  is  known  as  hygroscopic  moisture. 

Materials  of  animal  origin  are  more  hygroscopic  than  those  from  the 
vegetable  world,  and  while  they  absorb  water  readily,  they  part  with 
it  more  slowly  by  evaporation.  Thus  it  happens  that  a  person,  sweat- 
ing to  the  same  extent  and  under  the  same  general  conditions,  feels 
less  sensation  of  chill  on  resting  from  his  exercise  or  work  when 
clothed  in  woollen,  than  when  his  dress  is  linen  or  cotton.  In  the 
latter  instance,  the  moisture  is  held  more  largely  in  the  interstices, 
and  the  garment  may  be  distinctly  wet,  and  then  adheres  to  the  skin, 
which,  as  evaporation  proceeds,  becomes  chilled  through  rapid  abstrac- 
tion of  the  heat  required  in  the  process ;  whereas,  in  the  former,  the 
evaporation  is  gradual  and  the  chilling  much  less  perceptible  or 
unnoticeable.  But  here,  again,  a  hygroscopic  material,  very  closely 
woven,  may  be  incapable  of  holding  as  much  moisture  without  im- 
parting the  sensation  of  distinct  wetness,  as  one  of  a  loosely  woven 
substance  of  low  hygroscopicity. 

Materials. 

The  materials  employed  in  the  making  of  clothing  come  mainly 
from  the  animal  and  vegetable  worlds  ;  from  the  former  are  derived  the 


716  PERSONAL  HYGIENE. 

wools  of  various  kinds,  silk,  furs,  feathers  and  down,  and  leather ; 
from  the  latter,  the  principal  derivatives  are  cotton  and  flax  (linen), 
and,  of  lesser  importance,  straw,  hemp,  jute,  and  rubber. 

Wool. — Wool  of  various  kinds  is  yielded  by  a  number  of  different 
genera  of  animals.  That  in  commonest  use  and  to  which  the  name 
is  very  generally  restricted  is  derived  from  the  sheep.  Other  kinds 
include  mohair  from  the  Angora  goat ;  kashmir,  or  cashmere,  from 
the  Thibet  goat ;  camel's  hair  and  alpaca,  from  Auchenia  pacos,  a 
cameloid  ruminant  of  South  America.  But  the  terms  mohair,  cash- 
mere, and  alpaca  commonly  refer  to  cotton  and  sheep's  wool  imitations 
containing  no  trace  of  either  of  these  more  expensive  wools. 

Under  the  microscope,  the  fibers  of  wool  are  seen  to  be  cylindrical 
and  translucent,  and  covered  with  small  imbricated  scales  which,  like 
those  of  a  fish  or  the  feathers  of  a  bird,  run  all  in  the  same  direction. 

Fig.  109. 


Woollen  fibers. 

They  are  sharpest  and  smallest,  and  hence  most  numerous,  in  the 
finest  sorts  ;  as  many  as  2800  and  as  few  as  500  to  the  inch  have  been 
counted  respectively  in  the  best  and  very  inferior  kinds.  They  give 
to  the  fibers  the  tenacity  with  which  they  cling  together  when  woven, 
and  the  readiness  with  which,  when  wet  and  subjected  to  pressure,  as 
rubbing  or  wringing,  they  mat  together  and  cause  shrinking  of  the 
fabric.  They  are  shown  in  Fig.  109,  which  is  drawn  from  a  specimen 
of  fine  Saxony  crewel. 

Woollen  goods,  being  poor  conductors  and  containing  much  enmeshed 
air,  are  the  most  valuable  of  all  textiles  for  general  purposes  in  all 
climates,  and  particularly  in  those  in  which  abrupt  wide  changes  in 
temperature  occur.  In  very  hot  climates,  they  are  inferior  as  outer 
garments  to  cotton  and  linen,  which,  being  better  conductors  and  re- 
flectors, assist  more  in  keeping  the  body  comfortably  cool.  But  for  un- 
dergarments, wool  is  much  better  as  a  protection  against  chilling  after 


SILK. 


ni 


active  exercise,  on  account  of  its  hygroscopic  properties ;  the  vapor 
from  the  body  is  condensed  and  absorbed,  and  the  heat,  which  becomes 
latent  when  the  moisture  is  vaporized,  is  set  free,  and  the  evapora- 
tion from  the  fabric  to  the  external  air  proceeds  slowly  and  without 
the  chilling  effect  observed  when  one  sits  in  clinging  wet  cotton  or 
linen,  which  feels  cold  in  proportion  to  the  rapidity  with  which  it  dries. 

Woollen  fabrics  are  much  subject  to  adulteration  w^th  cotton  and 
other  cheaper  materials.  What  are  known  as  flannelettes  are  very 
commonly  made  wholly  of  cotton  or  with  a  very  small  percentage  of 
wool,  although  the  name  is  intended  to  convey  the  idea  that  wool  is 
the  sole  or  chief  material  used.  What  some  are  pleased  to  designate 
"sanitary  flannel"  is  often  largely  or  wholly  cotton.  Shoddy  is  a 
fabric  made  with  varying  proportions  of  old  ravelled  woollen  and  other 
cloths  with  a  minimum  of  new  wool.  It  has,  as  may  be  supposed,  a 
much  inferior  tensile  strength  and  less  uniformity  of  texture  than  wool- 
len of  good  quality. 

Silk. — Silk  is  the  spun  fiber  produced  by  a  number  of  species  of 
insects,  especially  the  larvae  of  the  bombycid  moths,  called  silkworms, 

Fig.  110. 


Silk  fibers. 


to  form  cocoons  or  protective  coverings  when  about  to  assume  the 
chrysalis  stage.  The  cocoon  in  which  the  chrysalis  is  killed  yields  an 
exceedingly  fine  thread,  consisting  of  two  agglutinated  filaments.  This 
thread,  when  unwound,  measures  more  than  two  miles  in  length,  and 
when  spun,  yields  in  the  neighborhood  of  500  yards  of  silk  thread. 
The  outer  part  of  the  cocoon  is  of  inferior  quality,  and  is  known  as 
floss. 

Silk  is  very  hygroscopic.  It  is  a  poor  heat  conductor  and  a  perfect 
non-conductor  of  electricity.  It  has  great  affinity  for  anilin  and 
other  dyes. 

Under  the  microscope,  the  fibers  appear  as  structureless  tubes,  and 
show  no  scales  or  surface  markings,  such  as  are  seen  on  wool.  They 
are  represented  in  Fig.  110.  Before  being  woven  into  fabrics,  silk  is 
commonly  weighted  with   salts  of  tin  and  iron,  with  which  it  forms 


718 


PERSONAL  HYGIENE. 


stable  chemical  compounds.  Weighted  silk,  subjected  to  the  action  of 
a  Bunsen  flame,  parts  with  its  organic  constituents,  but  retains  its 
structural  appearance. 

Silk  is  very  subject  to  adulteration  with  other  fibers  and  to  complete 
substitution  by  artificial  preparations.  One  form  of  artificial  silk,  in- 
vented, in  1884,  by  a  Frenchman,  Count  Chardonnet,  is  made  from 
prepared  cotton  or  wood  fiber.  It  possesses  a  very  silky  luster,  and  was 
at  first  very  inflammable  and  even  explosive,  being  practically  nitro- 
cellulose ;  but  later,  the  product  was  subjected  to  further  chemical 
process  and  made  harmless.  Another  form,  invented  by  Fremery  and 
Urban,  is  made  from  cotton  waste,  and  is  produced  much  more  cheaply. 
Still  another  form,  invented  by  Professor  Hummel,  of  Leeds,  is  made 
from  gelatin  at  an  expense  of  about  $1.15  per  pound.  It  has  a  low 
tensile  strength,  but  may  be  employed  in  a  mixture  with  genuine  silk 
or  fine  linen  or  cotton  thread  to  make  a  durable  fabric. 

Silk  is  used  chiefly  in  the  manufacture  of  silks,  satins,  velvets,  crape, 
and  plush. 

Cotton. — Cotton  is  the  soft  woolly  fibers  appendant  to  the  seeds  of 
the  cotton  plant  {Gossypium),  consisting  of  cellulose,  and  varying  in 

Fig.  111. 


Cotton  fibers. 


length  from  a  half  to  two  inches.  It  is  contained  with  the  seeds  within 
the  boll,  which,  when  ripe,  bursts  and  allows  the  fibers  partially  to  es- 
cape. Microscopically,  the  fibers  appear  flattened  and  twisted  ;  they  have 
somewhat  thickened  borders,  and  some  show  a  central  canal.  They  are 
shown  in  Fig.  111.  They  are  freed  from  the  seeds  by  the  cotton-gin, 
then  cleaned  and  spun  into  thread,  and  woven  into  fabrics  of  various 
kinds,  including  what  is  known  commouiy  as  "  cotton  cloth,"  sheeting, 
towelling,  jean,  drill,  and  others.  For  the  purpose  of  giving  weight, 
stiffness,  and  improved  appearance,  starch  aud  other  materials  are  com- 
monly employed  in  finishing.     Cotton  is  employed  also  with  wool  and 


LINEN-R  VBBER.  71 9 

other  materials  as  an  adulterant  or  to  combine  the  useful  properties  of 
each,  as,  for  example,  in  merino,  which  is  much  used  in  the  manufacture 
of  underclothing  and  stockings.  Cotton  is  very  durable  and  hard,  has 
low  hygroscopicity  and  high  heat  conductivity,  does  not  shrink  in 
washing,  and  is  particularly  adapted  as  a  material  for  outer  garments 
for  hot  weather. 

Linen. — Linen  is  a  fabric  woven  from  the  soft  silky  fiber  obtained 
from  the  outer  covering  of  the  stalks  of  the  flax  plant  {Linum  usitatis- 
simum),  which  are  allowed  to  rot  until  the  proper  stage  of  decomposition 
is  attained,  when  they  are  beaten  and  carded.  They  yield  about  a  six- 
teenth of  their  weight  of  fiber.  Microscopically,  the  fibers  appear  as 
cylinders  marked  at  regular  intervals  by  strise  indicating  cell  divisions. 
(See  Fig.  112.)  Twisted  into  thread,  they  are  used  in  weaving  various 
fabrics  known  as  linen,  cambric,  damask,  diaper,  lawn,  and  huckaback. 
Linen  goods  are  smooth  and  lustrous,  heavier  than  cotton,  durable  and 
hard,  of  low  hygroscopicity  and  high  heat   conductivity.     They  are 

Fig.  112. 


Linen  fibers. 


especially  suited  for  shirtings,  sheetings,  and  outer  garments  for  hot 
climates. 

Rubber. — India  rubber  is  a  product  derived  from  the  milky  juice 
of  various  tropical  plants.  It  is  soluble  in  ether,  naphtha,  chloroform, 
and  carbon  disulphide.  Its  elasticity  is  impaired  and  destroyed  by 
long  exposure  to  the  air  and  by  extremes  of  atmospheric  temperature, 
but  is  made  lasting  by  the  addition  of  a  small  amount  of  sulphur  in 
the  process  known  as  vulcanizing,  discovered  by  Goodyear  in  1844. 
This  process,  in  addition,  insures  increased  durability,  flexibility,  and 
impermeability  to  air  and  moisture.  To  the  latter  quality,  rubber  owes 
its  extensive  employment  in  articles  of  dress,  including  galoshes  and 
other  foot  coverings,  and  outer  garments  made  of  rubber-sheeting  or 
waterproof  cloth,  known  as  mackintosh.  The  latter  is  made  by  ap- 
plying a  solution  of  rubber  in  successive  layers  to  cotton  or  other 
fabric,  .so  that  it  shall  be  made  impermeable  to  water. 

Rubber  garments  are  a  very  useful  protection  against  wind  and  rain, 
but  are  objfctionablo  on  the  score  of  being  hot  and  confining  the  watery 
vapor  given  ofl"  by  the  skin,  thus  bringing  about  a  condition  of  great 


720  PERSONAL  HYGIENE. 

discomfort.  They  should,  therefore,  be  ventilated  as  much  as  is  prac-= 
ticable,  especially  if  worn  in  moderate  or  warm  temperatures. 

Clothing  can  be  made  waterproof  and,  at  the  same  time,  permeable 
to  air,  by  a  number  of  processes,  and  such  material  has  an  obvious 
advantage  over  ordinary  mackintosh  and  other  impermeable  fabrics. 

Leather. — Leather  is  the  skins  of  animals,  chiefly  the  ox,  calf, 
horse,  sheep,  and  goat,  prepared  by  tanning  and  tawing.  In  tanning, 
the  skin  is  soaked  in  vats  containing  an  infusion  of  oak  bark  rich  in 
tannic  acid,  which  causes  the  formation  of  tough,  insoluble  tannates  of 
the  gelatinous  and  albuminous  constituents  of  the  skin.  In  tawing, 
mineral  astringents  are  used  instead  of  oak  bark  ;  the  end  is  attained 
more  quickly,  but  the  product  is  of  inferior  quality.  After  the  proc- 
ess of  tanning  or  tawing  is  completed,  the  skin,  now  tough  and  stiff, 
is  subjected  to  a  series  of  processes,  collectively  known  as  currying, 
whereby  it  is  made  soft,  smooth,  pliable,  and  ready  for  use. 

Leather,  being  hygroscopic,  takes  up  perspiration  from  the  foot  and 
gives  it  off  to  the  outer  air ;  but  if  it  is  made  impermeable,  as  in  the 
case  of  the  so-called  "  patent  leather,"  the  latter  office  cannot  be  per- 
formed. That  the  perspiration  of  the  foot  is  given  off  through  the 
boot,  is  sufficiently  proved  by  the  dampness  and  dull  appearance  of  the 
leather  of  a  well-polished  boot  after  half  a  day's  confinement  in  a 
rubber  overshoe.  Although  permeable  to  this  extent,  leather  is  suffici- 
ently waterproof  for  ordinary  use,  and  may  be  made  more  so  by  the 
external  application  of  grease. 

Fur. — Fur  as  an  article  of  clothing  presents  the  great  advantage  of 
impermeability  to  wind  with  that  of  very  low  heat  conductivity,  due 
in  greatest  part  to  the  large  volume  of  air  retained  between  the  hairs. 
No  other  kind  of  material  is  comparable  as  a  j)rotection  against  wind 
and  cold. 

Felt. — Felts  are  made  from  the  hairs  of  various  animals,  but  the 
best,  such  as  are  used  for  hats,  both  soft  and  stiff  (the  Derby,  for  ex- 
ample), are  made  from  the  hairs  of  the  cony.  They  are  made  without 
weaving,  the  hairs  being  blown  against  a  revolving,  perforated,  metallic 
cone  of  large  size,  connected  with  an  exhaust  blower.  When  a  thin 
coating  has  formed,  a  jet  of  steam  is  directed  against  the  cone,  and  then 
the  felt  in  its  first  stage  is  stripped  off  in  a  coherent  mass,  held  together 
by  the  minute  imbrications  on  the  individual  hairs.  By  means  of  fur- 
ther processes  of  steaming  and  steeping,  the  mass  is  reduced  in  size  and 
increased  in  wall  thickness  through  shrinkage. 

Adulteration  of  Clothing. 

Fabrics  are  much  subject  to  adulteration  by  admixture  of  fibers  of 
lower  value,  as  of  cotton  or  shoddy  to  wool,  and  by  starch  and  mineral 
matters  to  give  weight.  Many  of  the  cheapest  of  cotton  fabrics  are  so 
heavily  sized  that  a  single  washing  will  convert  a  stiff,  apparently 
close-w-oven  piece  of  goods  into  a  worthless,  coarse,  flimsy  material  fit 
only  for  sieves. 


POISONOUS  DYES.  721 

Chemical  analysis  of  fabrics  is  not  always  to  be  relied  upon, 
although  fibers  of  vegetable  origin  behave  very  differently  from  those 
from  the  animal  world  ;  and  any  attempt  on  the  part  of  an  inexpe- 
rienced person  to  determine  the  percentage  of  different  kinds  of  fiber 
in  a  mixture  is  sure  to  lead  him  to  two  conclusions,  namely,  that  he  has 
wasted  his  time,  and  that  much  of  what  has  been  written  concerning 
the  behavior  of  different  fibers  when  treated  with  strong  chemicals  is 
remarkable  only  for  its  small  measure  of  truth. 

Microscopical  examination  is  a  far  simpler  and  much  more  satis- 
factory method  of  determining  the  composition  of  a  fabric.  A  few 
threads,  teased  apart  and  examined  with  a  moderately  high  power,  will 
reveal  the  nature  of  the  fibers  and  yield  approximately  accurate  quan- 
titative results.  Shoddy  commonly  shows  fibers  of  wool  of  different 
shades  of  color,  but  this  finding  is  by  no  means  to  be  accepted  as  con- 
clusive evidence  that  a  specimen  of  fabric  under  examination  is  shoddy, 
since  only  plain  goods  of  a  solid  color  yield  fibers  all  of  one  shade. 
But  if  the  fibers  show  abrupt  changes  in  diameter  and  partial  obliter- 
ation of  the  imbrications,  it  may  be  safely  concluded  that  the  specimen 
is  shoddy,  since  fresh  wool  is  fairly  regular  in  diameter  and  shows 
sharply  marked  imbrications. 

Poisonous  Dyes. — In  the  dyeing  of  textiles  and  other  articles  of 
clothing,  a  great  variety  of  substances  of  vegetable  and  mineral  origin 
are  used,  and  many  of  them  have  been  known  to  produce  serious 
results.  Among  them  may  be  mentioned  potassium  dichromate,  zinc 
chloride,  compounds  of  arsenic  and  antimony,  and  certain  of  the 
anilius.  An  outbreak  of  34  cases  of  acute  dermatitis,  occurring  among 
a  number  of  workmen  who  had  just  donned  new  overcoats,  is  reported 
by  Taunton.^  On  the  first  wet  day,  when  the  coats  were  worn,  the 
wrists,  where  they  came  in  contact  with  the  edges  of  the  wet  sleeves, 
became  inflamed.  In  1  case,  the  legs  were  similarly  affected,  the 
trousers  being  wet  and  rubbed  against  by  the  skirt.  In  3  cases,  the 
arms  were  affected.  On  soaking  the  cloth  in  water,  it  yielded  free 
zinc  chloride. 

According  to  U.  S.  Consul  Hughes,  of  Coburg,  in  a  communication 
to  the  Department  of  State,  under  date  of  April  23,  1901,  Dr.  Adolph 
JoUes  has  demonstrated  before  the  Vienna  Medical  Society  the  harm- 
ful effects  of  wearing  pearl-gray  silk  stockings,  colored  by  repeated 
baths  in  a  solution  of  zinc  chloride.  It  was  shown  that  a  large  amount 
of  the  salt  was  present  in  the  finished  goods  when  packed  for  the 
market,  and  that  the  danger  therefrom  by  absorption  was  very  great. 

A  serious  case  of  poisoning  by  anilin  black  is  quoted  by  Cartaz,^ 
from  a  report  of  Landouzy  and  Brouardel  to  the  Academy  of  Medicine 
of  Paris.  A  child  of  seventeen  months  became  suddenly  unconscious 
and  apparently  asphyxiated,  and,  although  restored,  remained  very  ill 
for  forty-eight  hours.  Then  the  brother  oi'  the  child  and  a  number  of 
other  children  were  seized  in  the  same  way.  All  of  the  victims  wore 
shoes  which  gave  off  a  peculiar  penetrating  odor,  and  were  found  to 
'  Lancet,  December  6,  1898.  ^  La  Nature,  August  4,  1900. 

46 


722  PERSONAL  HYGIENE. 

have  been  dyed  with  aniliu  black.  Animal  experimentation  proved 
that  absorption  of  this  by  the  skin  is  favored  by  heat  and  moistnre, 
which  conditions  are  present  in  a  tightly  laced  shoe,  and  may  bring 
about  alteration  of  the  blood  corpuscles  and  asphyxia. 

Another  case  is  reported  by  Besson/  of  a  child  of  six  years,  M^ho, 
after  wearing  a  pair  of  new  shoes  during  the  forenoon  while  at  play, 
became  cold  and  cyanosed  in  the  afternoon,  but  was  relieved  by  heat 
and  stimulants  within  twenty-four  hours.  The  shoes  had  been  pol- 
ished with  a  preparation  which  had  a  distinctly  nauseating  odor,  and 
contained  91   per  cent,  of  anilin. 

Laurent  and  Guillemin^  report  still  another,  in  which  six  children, 
all  of  one  family,  were  seized,  after  wearing  new  shoes  upon  which  the 
anilin  polish  had  not  completely  dried,  with  sudden  symptoms  of 
poisoning,  which  included  pallor  of  the  face,  bluish  discoloration  of  the 
lips  and  nails,  dilated  pupils,  headache,  vertigo,  albuminuria,  great 
muscular  weakness,  slow  pulse,  slight  convulsive  movements,  and 
unconsciousness.      Recovery  occurred  in  from  one  to  three  days. 

It  is  commonly  believed  that  arsenic  in  dyed  and  printed  textiles  is 
present  as  an  accidental  impurity  of  various  anilins,  but  this  is  far  from 
being  the  truth,  since  white  arsenic  itself  is  used  in  several  processes  for 
the  purpose  of  adding  brilliancy  to  the  colors.  Thus,  in  the  so-called 
arsenite  of  aluminum  process,  the  dye,  dissolved  in  acetic  acid  or  water, 
is  mixed  with  acetate  of  aluminum  and  white  arsenic  in  glycerin,  and 
the  mixture  is  employed  in  printing  the  pattern  ;  next,  the  printed 
fabric  is  subjected  to  moist  heat,  and  the  anilin,  in  combination  with 
the  arsenite  of  aluminum  formed,  is  fixed  iu  the  fibers  in  an  insoluble 
form. 

Selection  of  Clothing. 

The  properties  of  the  various  materials  used  in  the  manufacture 
of  textiles  have  already  been  given  in  some  detail,  and  further  con- 
sideration of  underclothing  and  outer  garments,  beyond  a  word  of 
caution  against  unnecessary  weight  of  clothing  and  undue  constric- 
tion of  any  part  of  the  body  is,  therefore,  unnecessary.  In  the 
matter  of  constriction,  no  part  of  the  human  body  is  so  abused 
as  the  foot,  especially  that  of  woman.  Boots,  shoes,  and  stockings 
should  fit  the  foot,  and  there  should  be  no  such  thing  as  the  agony 
which  many  people  expect  as  a  matter  of  course  in  the  process  of 
"  breaking  in."  The  toe  should  be  neither  pointed  nor  cut  square,  and 
the  whole  sole  should  follow  the  natural  outline  of  the  foot.  The  sole 
should  project  a  reasonable  distance  from  the  upper,  in  order  to  give 
firmer  support  and  increased  ])rotection  to  the  soft  parts  from  contact 
with  loose  stones  and  other  objects.  The  heels  should  be  low  and 
broad.  High  heels  are  worn,  not  for  comfort  in  walking,  but  to  in- 
crease the  height  of  the  body  and  diminish  the  apparent  length  of  the 
foot.     For  purposes  of  successful  deception,  they  take  about  equal  rank 

^Journal  des  Sciences  medicales  de  Lille,  1901,  No.  10. 
^  Journal  des  Praciciens,  March  2,  1901. 


SELECTION  OF  CLOTHING.  723 

with  hair  dyes  and  artificial  complexions.  Their  use  conduces  to 
weakness  of  the  arch,  atrophy  of  the  muscles  of  the  leg,  and  a  variety 
of  other  abnormalities.  The  heel  of  the  foot  should  fit  snugly  in  its 
place  within  the  shoe,  but  the  toes  should  have  sufficient  room  for 
freedom  of  movement,  yet  not  enough  to  cause  chafing  and  excoriations. 
The  upper  should  fit  snugly,  but  not  too  tightly,  about  the  ankle  and 
over  the  instep ;  otherwise,  the  foot  will  drive  forward  and  cramp  the 
toes. 


CHAPTER    XVI. 
INFECTION,  SUSCEPTIBILITY,   IMMUNITY. 

Exciting  Causes  of  Disease. — The  exciting  causes  of  infectious 
diseases  are  parasites  belonging  to  both  the  animal  and  the  vegetable 
kingdoms.  They  gain  access  to  the  system,  and  if  the  individual  be 
receptive  or  "  susceptible,"  proceed  to  bring  about  disturbance  of 
function,  some  by  mechanical  obstruction,  some  by  destroying  the  blood 
corpuscles  which  they  invade,  some  by  methods  still  unknown ;  but 
mostly  through  highly  toxic  substances  which  they  produce  and  which 
act  locally  or  generally,  as  the  case  may  be.  Most  of  those  which  have 
been  discovered  belong  to  the  vegetable  kingdom  (bacteria) ;  some  are 
animal  organisms  (protozoa).  Of  many  of  the  common  diseases,  nota- 
bly the  exanthemata,  the  still  undiscovered  causes  belong  probably  to 
the  latter  class,  if  we  may  reason  by  analogy  from  the  discoveries 
relative  to  smallpox  by  Councilman  and  concerning  the  cause  of 
scarlet  fever  by  Mallory. 

Disease  germs  are  endowed  with  life  ;  and  for  its  continuance  and  for 
multiplication  within  the  tissues,  certain  favoring  conditions  are  nec- 
essary ;  invasion  of  a  system  offering  hostile  conditions  begets  no 
disease.  Introduced  in  sufficient  numbers,  and  finding  their  environ- 
ment favorable,  they  multiply,  as  a  rule,  and  eventually  make  their 
presence  manifest  through  the  symptoms  produced  by  their  toxic  prod- 
ucts or  because  of  their  power  to  obstruct  or  destroy.  They  differ 
essentially  from  poisons  in  the  ordinary  sense ;  for  poisons,  although 
causing  disturbance  of  function,  resulting  likewise  even  in  death,  do 
not  reproduce  themselves  within  the  tissues.  An  injection  of  aconitine, 
or  of  morphine,  or  of  tetanus  toxin,  or  of  snake-venom  does  not  grow  in 
the  system,  and  hence,  if  not  sufficiently  powerful  to  cause  disturbance  of 
function,  it  will  not  become  so  with  lapse  of  time ;  but  the  introduction 
of  a  few  streptococci,  for  example,  may  be  followed  by  rapid  multiplica- 
tion in  geometrical  progression  and  result  eventually  in  a  fatal  sep- 
ticaemia. 

Channels  of  Infection. — Of  the  various  channels  of  infection,  the 
most  important  are  the  respiratory  and  alimentary  tracts  (tuberculosis, 
influenza,  diphtheria,  typhoid  fever,  cholera,  dysentery,  etc.) ;  but  some 
of  the  most  devastating  of  human  scourges  are  spread  through  inoculation 
into  the  skin  (malaria,  yellow  fever,  etc.).  Invasion  of  the  tissues  by 
disease  germs  may  be  followed  by  localized  infection  with  general  dis- 
turbance of  the  system  due  to  their  toxic  products  (as  in  diphtheria  and 
tetanus),  or  by  general  infection  and  disturbance  (as  in  the  septicaemias). 

724 


SUSCEPTIBILITY.  725 

Infection  and  Contagion. — The  terms  infectious  and  contagious 
have  given  rise  to  much  confusion.  Properly  speaking,  the  one  includes 
the  other,  for  all  contagious  diseases,  that  is  to  say,  those  communicated 
by  direct  contact  with  the  patient  or  with  fomites  (as  scarlet  fever  and 
smallpox),  are  infectious  ;  but  many  infectious  diseases  that  are  spread 
through  the  agency  of  contaminated  water  or  food  (as  typhoid  fever  and 
cholera),  or  by  the  bites  of  insects  (as  yellow  fever  and  malaria),  are  not 
contagious,  but  are  communicated  from  man  to  man  indirectly. 

Susceptibility. — When  the  exciting  cause  of  an  infectious  disease 
either  directly  or  indirectly  communicable  is  introduced  into  a  com- 
munity, not  all  of  those  whose  systems  are  invaded  become  stricken 
with  the  disease,  even  though  they  may  receive  the  same  dose  of  the 
organisms.  Of  a  dozen  children  exposed  at  the  same  time  and  for  a 
like  period  to  a  pre-existing  case  of  scarlet  fever,  perhaps  one,  or  three, 
or  six,  or  none  at  all  may  be  seized ;  of  a  hundred  consumers  of 
typhoid-infected  milk,  perhaps  a  dozen  may  be  infected  ;  in  an  entire 
community  of  a  hundred  thousand  persons,  all  drinking  water  from  a 
common  supply,  a  few  hundreds  or  thousands  may  be  stricken  with 
cholera  in  the  event  of  extensive  specific  pollution  of  the  supply,  the 
rest  of  the  population  escaping  with  no  symptoms  whatever.  The 
reason  for  this  lies  largely  in  differing  susceptibility :  one  person  may 
be  very  susceptible  and  others  wholly  resistant,  regardless  of  the  extent 
of  exposure  or  of  the  number  of  exposures ;  some  may  resist  a  few 
exposures  and  later  succumb.  Some  may  be  exposed  without  any 
resulting  invasion.  Whether  or  not  a  given  individual  will  be  attacked 
may  depend  also  upon  the  number  of  organisms  which  enter  his  sys- 
tem ;  for  while  a  few  disease  germs  may  be  overcome  and  destroyed,  a 
larger  dose  may  secure  a  foothold  and  cause  injury.  On  the  other  hand, 
what  might  be  an  overwhelming  dose  to  one  may  be  doubled  and  trebled, 
and  yet  be  ineffective  against  another. 

Susceptibility  is  influenced  by  a  number  of  conditions,  including  age, 
race,  family  predisposition,  cold,  fatigue,  etc.  A  person  who  to-day 
is  insusceptible  may,  a  few  days  hence,  acquire  susceptibility  through 
any  one  of  a  number  of  causes  which  bring  about  a  depressed  condition 
of  the  system,  such  as  lack  of  proper  food,  exposure  to  cold  or  extreme 
heat,  exhaustion  from  overexertion,  mental  disturbance,  loss  of  sleep, 
abuse  of  alcohol,  overcrowding,  mechanical  injury,  and  constitutional 
disease.  A  person  may  carry  virulent  pneumococci  in  the  respiratory 
tract  and  not  be  affected,  because  of  the  natural  defensive  properties  of 
his  cells ;  he  may  for  the  same  reason  escape  an  attack  of  Asiatic 
cholera,  although  large  numbers  of  the  specific  organisms  have  gained 
access  to  his  intestinal  tract ;  and  yet,  in  the  former  case,  a  bad  cold, 
and  in  the  latter,  a  derangement  of  digestion,  may  overcome  his  defence 
and  he  falls  a  victim. 

An  individual  who  is  insusceptible  to  the  influence  of  a  particular 
pathogenic  organism  is  said  to  be  immune,  or  to  enjoy  immunity.  Im- 
munity may  be  either  natural  or  acquired,  and  acquired  immunity  may 
be  active  or  passive.     Natural  inununity  is  the  inherent  ability  to  resist 


726  INFECTION,   SUSCEPTIBILITY,   IMMUNITY. 

infection  when  the  system  is  invaded  by  disease  germs  :  for  example, 
the  insusceptibility  of  man  to  hog  cholera  and  rinderpest ;  of  carnivora 
to  tuberculosis  ;  of  rats,  dogs,  and  birds  to  anthrax  ;  of  horses  and  cattle 
to  typhoid  fever  and  cholera.  In  these  and  in  many  other  instances 
that  might  be  given,  the  respective  organisms,  on  being  introduced,  find 
themselves  opposed  by  conditions  which  are  inimical  to  their  existence 
and  multiplication,  and  they  soon  succumb  to  the  hostile  influences. 
This  form  of  immunity  is,  however,  not  always  absolute  :  it  can  be 
overcome  in  various  ways.  Thus,  while  birds  are  naturally  immune  to 
anthrax,  it  has  been  shown  that  certain  species  may  be  rendered  sus- 
ceptible by  starvation  or  cold  ;  and  rats  lose  their  immunity  to  the  same 
disease  when  they  are  fed  wholly  on  a  vegetable  diet. 

Acquired  immunity  is,  as  stated,  of  two  kinds  :  active  and  passive. 
Active  acquired  immunity  follows  recovery  from  an  attack  of  a  disease 
which,  except  in  rare  instances,  occurs  but  once  in  the  same  person  (as 
yellow  fever,  scarlet  fever,  smallpox  and  chicken  pox) ;  or  from  a 
disease  of  an  allied  nature  (as  immunity  to  smallpox  after  cow  pox) ; 
or  it  can  be  induced  artificially  by  the  injection  of  increasing  doses  of 
bacterial  toxins  or  of  bacteria  which  have  been  killed  by  heat  or  dimin- 
ished in  virulence.  It  can  be  acquired  not  only  against  diseases,  but 
against  certain  p.roteid  vegetable  poisons  (ricin  and  abrin)  and  snake 
venoms  (rattlesnake)  ;  but  it  cannot  be  acquired  against  the  numerous 
alkaloidal  poisons.  In  but  few  diseases  does  one  attack  confer  a  lasting 
immunity  ;  and  even  in  these,  second  and  even  third  attacks  may  some- 
times occur,  but  their  severity  is,  as  a  rule,  much  diminished ;  thu,-<, 
smallpox  and  measles.  With  some  diseases  a  single  attack  confers  a 
temporary  immunity  {e.  g.,  pneumonia,  la  grippe,  and  diphtheria),  but 
subsequent  attacks  may  be  of  equal  or  greater  severity.  With  other 
diseases,  notably  malaria,  immunity  may  be  acquired  with  such  extreme 
slowness  that  increased  susceptibility  may  appear  to  become  established. 

Passive  acquired  immunity  is  that  which  is  brought  about  by  the 
injection  of  serum  obtained  from  the  blood  of  an  animal  that  has 
acquired  an  active  immunity,  the  serum  containing  antitoxin  ;  and  it 
may  be  acquired  also  through  the  milk  of  an  immune  mother,  the  anti- 
toxin being  secreted  therein.  Passive  immunity  is  acquired  rapidly  and 
with  practically  no  danger  or  discomfort,  but  the  protection  conferred 
is  only  transient.  On  the  other  hand,  active  immunity  is  a  matter  of 
much  less  rapid  appearance,  but  its  protective  influence  is  much  more 
lasting. 

The  tolerance  which  the  system  develops  tow^ard  a  specific  poison 
becomes  established  as  a  result  of  certain  processes  concerning  which 
we  have  practically  no  actual  knowledge.  While  we  know  that  certain 
means  employed  produce  certain  results,  the  various  changes  which 
occur  within  the  system  during  the  process  are  matters  concerning  which 
thus  far  we  can  only  theorize.  We  are  met  at  the  outset  by  the  fact 
that  protoplasm  is  a  substance  of  extraordinarily  complex  composition, 
which  defies  exact  analysis,  and  the  products  which  it  elaborates  are, 
so  far  as  we  know,  of  equally  complex  nature.     It  combines  with  and 


EHRLICH'S  THEORY.  727 

is  acted  upon  by  various  materials,  which,  according  to  their  nature, 
promote  or  disturb  metabolism ;  e.  g.,  nutritive  matters  and  toxins. 
It  is  with  the  latter  that  problems  of  immunity  have  to  deal,  for 
although  under  some  conditions  protoplasm  is  by  them  destroyed  or 
disturbed  in  its  functions,  under  others  it  is  able  not  only  to  withstand 
their  influence,  but  to  develop  antagonistic  products,  which  overcome 
them  completely  and  thus  prevent  disease  or  promote  recovery. 

All  our  knowledge  of  what  occurs  in  the  establishment  of  immunity 
and  all  the  therapeutical  applications  based  upon  this  knowledge  we  owe 
to  animal  experimentation  of  an  exceedingly  ingenious  and  interesting 
nature,  which  has  given  rise  to  several  theories.  Of  these,  the  "  reten- 
tion theory "  of  Chauveau  and  the  "  exhaustion  theory "  of  Pasteur 
have  long  since  been  disproved  and  possess  now  merely  an  historical 
interest ;  and  the  only  ones  which  have  withstood  the  test  of  time  and 
investigation  are  the  "  humoral  theory  "  of  Ehrlich  and  the  "  cellular 
theory  "  of  Metschnikofi^,  both  of  which  will  be  considered  below. 

EHRLIOH'S    THEORY. 

Ehrlich's  humoral  or  side-chain  theory,  which  had  its  inception  in 
1897,  explains  first  the  action  of  the  soluble  bacterial  toxins  and  their 
antitoxins,  then  deals  with  immunity  against  these  poisons  and  the 
bacteria  which  secrete  them,  and  finally  embraces  the  far  more  com- 
plicated question  of  immunity  against  those  pathogenic  organisms  which 
liberate  no  soluble  toxins,  but  bring  about  results  which  in  some  way 
are  dependent  upon  the  actual  presence  of  the  bacterial  cell.  The 
analogy  between  bacteriolysis  and  haemolysis  has  made  the  experimental 
work  much  less  laborious,  since  the  latter  can  be  employed  to  solve  the 
problems  of  the  former. 

Toxins  and  Antitoxins. — In  their  interference  with  metabolism, 
different  species  of  pathogenic  bacteria  act  in  very  different  ways  ;  they 
produce  different  kinds  of  poisons  whose  actual  nature  is  as  yet  but 
little  known,  and  these  interfere  with  the  cell  functions,  each  in  its  own 
manner.  They  appear  to  possess  certain  definite  chemical  affinities,  like 
the  far  simpler  inorganic  compounds  ;  they  are  precipitated  by  certain 
agents  and  redissolved  by  others ;  they  combine  with  other  complex 
compounds  and  form  more  or  less  stable  inert  substances.  Whether 
the  bacteria  are  within  the  tissues  elaborating  the  poisons  and  sending 
them  to  distant  parts  of  the  body,  or  are  grown  in  artificial  culture 
media  outside,  the  poisons  which  a  given  species  produces  appear  to 
possess  the  same  properties,  so  far  as  they  can  be  studied. 

Bacterial  diseases  may  be  divided  into  two  classes  :  (1)  those  in  which 
the  infective  agents  are  localized  and  produce  their  effects  through  soluble 
poisons  which  they  secrete  and  send  through  the  system  in  the  blood 
stream  ;  and  (2)  those  in  which,  whether  localized  or  not,  the  infective 
agents  act  not  through  soluble  poisons,  but  in  some  maimer  dependent 
upon  their  actual  presence  in  the  tissues  and  yet  not  ex])lainablc  in  all 
cases  by  mere  median ical  presence.     These  bacteria,  however,  contain 


728  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

poisons  united  with  their  protoplasm — intracellular  toxins,  some  of 
which  have  been  separated  and  subjected  to  careful  chemical  analysis ; 
and  it  may  be  that  they  become  effective  on  liberation  from  the  bac- 
terial cells  when  these  die  and  are  disintegrated.  Indeed,  we  know  that, 
in  the  autolysis  of  cultures  of  B.  typhosus,  a  toxin  is  liberated  into  the 
culture  medium  ;  and  Vaughan  and  Wheeler  ^  have  obtained,  in  soluble 
form,  highly  poisonous  material  from  the  cell  substance  of  colon,  typhoid, 
and  anthrax  bacilli.  That  the  last-named  organism  produces  an  intra- 
cellular poison  was  shown  first  by  J.  W.  Vaughan,^  all  prior  investiga- 
tion having  given  negative  results.  Intracellular  poisons  have  been 
demonstrated  also  by  Detweiler  ^  (_B.  prodigiosus,  B.  violaceus,  Sarcina 
lutea,  and  Sarcina  aurantica)  and  by  Gelston.* 

As  examples  of  the  first  class  may  be  cited  diphtheria  and  tetanus  ; 
and  of  the  second,  the  true  septicaemias,  in  which  the  bacteria  are  dis- 
tributed generally,  and  typhoid  fever  and  pneumonia,  in  which  the 
bacteria  have  a  selective  affinity  for  special  organs.  It  is  likely  that 
in  the  establishment  of  immunity  to  both  classes  of  disease,  the  general 
principles  of  the  process  are  the  same,  although  the  details  may  differ. 

In  the  diseases  of  the  first  class  (diphtheria  and  tetanus),  acquired 
immunity  depends  upon  the  formation,  within  the  system,  of  substances 
termed  Antitoxins,  which,  while  having  no  power  to  destroy  the  causative 
bacteria  themselves,  neutralize  their  toxic  products  (toxins).  In  the 
immunizing  process  a  very  small  part  of  what,  under  ordinary  circum- 
stances, would  be  a  fatal  dose  of  the  specific  toxin,  or  a  small  dose  of 
a  weakened  toxin,  is  given  subcutaneously  to  an  animal,  and  this  is  re- 
peated at  intervals  of  a  few  days.  After  a  time,  the  dose  is  increased, 
and  eventually  the  animal  is  capable  of  receiving  without  injury  a  nor- 
mally fatal  dose,  and  is  then  possessed  of  an  active  acquired  immunity.  If 
now  the  animal  be  bled  and  its  serum  be  injected  into  another,  it  will 
be  found  that  the  latter  can  resist  infection  by  the  organism  which  pro- 
duces the  toxin,  or  that  if  infected  before  treatment,  the  injection  will 
exert  a  curative  influence.  In  1890  Behring  made  this  discovery  as 
to  diphtheria,  after  he  and  Kitasato  had  found  it  to  be  true  of  tetanus. 
In  1891,  Ehrlich,  working  with  abrin  and  ricin,  found  that  these  toxins 
treated  in  vitro  with  the  serum  of  animals  immunized  therewith  became 
neutralized  and  incapable  of  causing  injury. 

The  protection  transferred  from  the  actively  immune  animal  to  the 
other  is  passive  acquired  immunity.  The  serum  of  the  immunized 
animal  difi'ers  from  that  of  the  normal  in  that  it  contains  the  specific 
antitoxin,  which  is  a  substance  believed,  with  good  reason,  to  unite  in  a 
definitely  chemical  manner  with  the  specific  toxin  to  form  an  inert 
compound. 

How  the  antitoxin  is  formed  in  the  system  is  an  interesting  question, 
which  Ehrlich  explains  in  the  following  manner :  The  bacterial  toxins 
have  special  affinities  for  special   cells,  and  if  they  are  introduced  in 

^  Journal  of  the  American  Medical  Association,  September  3,  1904. 
^  Transactions  of  the  Association  of  American  Physicians,  1902. 
^  Ibidem.  *  Ibidem. 


EHRLICH'S  THEORY. 


729 


sufficient  amounts  those  cells  are  destroyed  ;  but  if  not,  they  are  merely 
damaged  by  the  union  of  the  toxin  with  certain  atom-groups  of  the 
cell  for  which  it  possesses  the  special  affinity.  The  atom-group  with 
which  the  toxin  unites  is  called  a  Receptor  or  Side-chain.  The  cell, 
being  damaged  by  the  loss  of  this  portion  of  its  substance,  proceeds  to 
repair  itself  by  replacing  this  receptor  ;  but,  following  Weigert's  law  of 
supercompensation,  it  produces  an  excess  of  receptors,  which,  not  being 
needed,  are  cast  out  into  the  blood  stream,  where  they  are  free  to  unite 
with  any  fresh  portions  of  toxin  with  which  they  may  come  in  contact. 
These  free  receptors  are  the  antitoxin. 

The  union  of  the  toxin  with  the  receptor  of  the  cell  or  with  the  free 
receptor  (antitoxin)  is  effected  by  an  atom-group  called  the  Haptophore. 
When  the  toxin  becomes  fixed  to  the  cell  by  this  group,  it  may  proceed 
to  destroy  the  cell  by  its  poison  molecule  or  Toxophore;  but  when  it 
unites  with  the  free  receptor  and  thus  satisfies  its  only  attaching  group, 

Fig.  113. 


To: 


.Toxopborc  q-ro"up 
..HaLptbpnore  qroup 


ce 


pTc 


'^^^(.ht 


(Free   receptor) 

its  poison  molecule  has  no  cell  upon  which  to  work,  and  is  consequently 
unable  to  produce  harm.  The  receptor  thus  acts  in  two  ways  :  it  may 
attract  the  toxin  to  the  cell,  which  thus  may  suffer,  or  it  may  protect 
the  cell  when  it  is  no  longer  an  integral  part  thereof.  (See  Fig.  113.)^ 
It  has  been  shown  by  Ehrlich  and  .others  that  a  specific  proteid  toxin 
differs  in  one  very  important  respect  from  alkaloidal  and  other  common 
poisons,  namely,  that  the  latter  are  possessed  of  no  haptophore  groups 
with  which  they  can  form  chemical  combinations  with  the  body  cells 
or  with  substances  derived  therefrom.  A  dose  of  morphine,  for  exam- 
ple, no  matter  how  frequently  it  is  repeated,  is  incapable*of  causing  the 

'Figure  IIP.  and  the  succeeding  figures  in  this  cliapter  are  purely  diagrammatic ; 
and  in  order  that  no  erroneous  conception  may  be  formed  concerning  the  various  sub- 
stances which  they  represent,  sliapes  have  been  adopted  vvliich  are  not  likely  to  suggest 
actual  cellular  or  molecular  forms. 


730  INFECTION,   SUSCEPTIBILITY,   IMMUNITY. 

formation  of  a  substance  with  which  it  can  unite  to  form  an  inert  body^ 
although  it  can  establish  a  tolerance  for  larger  doses ;  in  other  words, 
no  morphine  antitoxin  can  be  produced.  If  one  should  attempt  to- 
immunize  an  animal  against  morphine,  the  serum  of  that  animal  when 
mixed  with  a  fatal  dose  of  morphine  would  not  deprive  the  latter  of 
its  power  to  poison  another,  as  will  an  antitoxic  serum  mixed  in  proper 
proportion  with  a  lethal  dose  of  its  corresponding  toxin.  Ehrlich  says 
that  the  term  toxin  should  be  applied  only  to  those  toxic  products  of 
metabolism  with  which,  by  animal  experimentation,  one  can  obtain  a 
specific  antitoxin.  As  examples  of  true  toxins  may  be  cited  those  of 
diphtheria  and  tetanus,  snake-venoms,  abrin  (from  the  jeqiiirity  bean) 
and  ricin  (from  the  castor  bean).  In  the  case  of  any  one  of  these,  a 
reaction  occurs  in  the  body,  whereby  the  toxin  becomes  bound  firmly 
to  the  cell,  instead  of  entering  into  loose  combinations  which  are  easily 
broken  up,  as  in  the  case  of  alkaloids. 

It  must  not  be  supposed  that  the  so-called  receptors  or  side-chains 
are  concerned  merely  with  toxins  and  antitoxin  formation.  The  cell 
protoplasm  is  an  exceedingly  complex  substance  and  the  cell  is  some- 
thing more  than  a  mere  molecule  :  it  is  made  up  of  many  very  complex 
molecules.  It  is  unfortunate  that  attempts  to  explain  immunity  with 
the  aid  of  diagrams  lead  many  to  conceive  that  the  words  cell  and  mole- 
cule are  in  a  sense  synonymous.  The  smallest  possible  drop  of  water 
consists  of  many  molecules,  all  of  the  same  character ;  but  a  cell  is  an 
aggregation  of  complex  molecules  of  diverse  natures  and  functions. 
The  cell  possesses  certain  atom-groups  (receptors,  side-chains)  with  affini- 
ties for  nutritive  materials  which  come  within  the  range  of  their  chemism, 
and  through  them  it  fixes  within  itself  that  which  it  needs  for  the 
carrying  on  of  its  functions.  It  possesses  affinities  also  for  the  proteid 
toxins,  which  are  believed  to  be  similar  to,  though  less  complex  in 
composition  than,  the  nutritive  materials.  Doubtless,  it  possesses  many 
other  atom-complexes  with  other  functions  ;  and  doubtless,  also,  the 
number  of  each  kind  is  such  that  the  destruction  of  a  few  does  not 
necessarily  mean  the  death  of  the  cell,  which  under  favoring  conditions 
may  proceed  to  make  good  its  loss  by  processes  of  repair.  The  side- 
chains  which  are  concerned  in  the  fixation  of  toxins  and  which  are 
cast  off  into  the  blood  stream  as  antitoxin  are  denominated  by  Ehrlich 
Uniceptors  or  Receptors  of  the  first  order,  being  of  the  simplest  kind  and 
possessing  a  single  bond  of  attachment,  the  haptophore  group.  Other 
more  complicated  receptors  than  these  will  be  considered  presently. 

That  the  ucion  of  toxin  with  antitoxin  is  a  purely  chemical  process, 
is  believed  by  Ehrlich  and  most  other  investigators,  and  as  proof  are 
cited  a  number  of  facts.  Thus,  when  a  toxin  is  mixed  with  its  cor- 
responding antitoxin  in  proper  proportions  in  a  test  tube,  it  becomes 
neutralized  and  is  then  incapable  of  acting  injuriously  any  longer. 
Like  acids  and  alkalies,  the  two  can  be  titrated  against  each  other. 
Again,  as  with  most  chemical  reactions,  the  union  of  the  two  is  has- 
tened by  warmth,  and  occurs  more  readily  when  concentrated  solutions 
are  employed.     It  appears,  however,  that  with  tetanus  toxin,  at  least, 


EHRLICII'S   THEORY.  731 

the  union  with  antitoxin  is  at  first  a  somewhat  loose  association,  which 
can  be  disrupted  ;  and  that,  as  time  goes  on,  the  combination  becomes 
fixed.  This  has  been  shown  in  an  interesting  experiment  by  A.  Was- 
sermann,  who,  having  found  that  a  mixture  of  tetanus  toxin  and  guinea- 
pig-brain  emulsion  possessed  no  toxic  action  for  guinea-pigs,  while 
mixtures  with  emulsions  of  other  oi^gans  of  the  same  animal  retained 
their  power,  concluded  that  the  toxin  has  a  special  affinity  for  the  cells 
of  the  central  nervous  system,  and  that  these  contain  normally  the  anti- 
toxic side-chains,  which  are  the  same  as  those  existing  in  the  serum  of 
an  immunized  animal.  It  is  known  that  the  tetanus  toxin  reaches  the 
cells  of  the  central  nervous  system  through  the  motor  axones,  and  that 
the  antitoxin  reaches  them  through  the  circulation.  Wassermann  in- 
jected some  neutralized  toxin  into  the  hind-foot  of  a  guinea-pig  and 
saw  no  result.  Next  he  injected  some  adrenalin  into  the  hind-foot 
of  another  guinea-pig,  and  after  this  agent  had  caused  the  capillaries 
to  contract  he  injected  some  of  the  same  neutralized  toxin,  and  the 
animal  became  tetanized.  The  circulation  being  stopped,  the  antitoxin 
could  not  rearch  the  central  nervous  system,  but  the  channel  of  absorp- 
tion of  the  toxin  was  open,  and  the  conclusion  must  be  that  the  toxin 
broke  away  from  its  combination  and  was  absorbed.  On  the  other 
hand,  when  the  mixture  of  toxin  and  antitoxin  was  allowed  to  stand 
some  hours  and  was  then  injected  into  an  animal  after  adrenalin  treat- 
ment, no  symptoms  were  produced,  since  firm  union  had  become  estab- 
lished between  the  two  substances,  and  the  toxin  could  no  longer  free 
itself. 

Toxins  are  decidedly  unstable,  their  strength  diminishing  with  age. 
Ehrlich  found  that  a  single  antitoxic  unit  saturated  very  variable  amounts 
of  different  toxins,  and  that  a  neutralized  mixture  of  one  antitoxic  unit 
and  diphtheria  toxin  often  required  the  addition  of  many  minimum 
lethal  doses  (the  amount  necessary  to  kill  a  250-gramme  guinea-pig  in 
48  hours)  of  the  toxin,  in  order  to  produce  a  fatal  result.  The  com- 
bining power  of  the  toxin  was  found  to  be  unimpaired,  but  its  toxic 
property  had  diminished,  and  from  this  fact  Ehrlich  concluded  that  the 
toxin  molecule  possesses  two  independent  groups  of  atoms,  one  of 
which,  the  toxophore,  is  prone  to  undergo  alteration  of  structure,  while 
the  other,  the  haptophore,  remains  unimpaired.  To  this  degenerated 
toxin  molecule  Ehrlich  applied  the  term  Toxoid.  By  reason  of  the 
fact  that  the  haptophores  of  the  toxoids  are  unimpaired,  an  animal 
treated  with  toxoids  can  elaborate  antitoxic  substances,  the  toxoids  at- 
taching themselves  to  the  cells  in  the  same  way  as  the  toxins.  Study- 
ing the  degenerated  toxins  further,  Ehrlich  found  in  addition  to 
Toxones,  which  are  original  products  feebly  toxic  to  the  nervous 
system,  a  number  of  modifications  possessing  weaker  affinities  for  anti- 
toxin and  for  cells  than  those  of  toxins,  but  capable  of  combining  with 
antitoxin  and  of  producing  slow  poisonous  effects,  as,  for  example, 
paralysis.  To  these  intermediate  products  he  gave  the  name  Epi- 
loxoifh.  He  found  also  other  modifications  which  possess  greater  affinity 
for  antitoxin  than  has  toxin,  and  to  these  he  gave  the  name  Profofoxoids. 


732  INFECTION,  SUSCEPTIBILITY,   IMMUNITY. 

To  still  others  possessing  the  same  degree  of  affinity  that  toxin  has  for 
antitoxin  he  gave  the  name  Syntoxoids.  Further  research  by  Madsen 
and  Dreyer  and  Ehrlich  has  demonstrated  the  existence  of  Toxonoids, 
poisonous  for  one  species  but  not  for  another,  and  of  Prototoxin,  Deu- 
terotoxin,  and  Tritotoxin,  possessing  different  affinities  for  antitoxin,  and 
also  alpha  and  beta  modifications  of  each. 

Through  the  fact  that  toxoids  are  unimpaired  as  to  their  haptophores, 
so  that  they  can  link  themselves  to  the  cells  and  yet  cause  no  ill  effects, 
Wassermann  and  Bruck  were  enabled  to  prove  experimentally  the 
increased  production  of  receptors.  They  found  that,  using  an  old 
wholly  non-poisonous  tetanus  toxin  on  a  rabbit,  they  could  get  no 
antitoxin  production,  and  this  indicated  either  that  the  material  injected 
could  produce  no  physiological  action,  or  that  if  it  caused  the  prolifera- 
tion of  receptors  they  were  not  cast  off  by  the  cells  into  the  blood. 
But  they  demonstrated  that  the  toxoid  did  act,  for  the  animal  could 
withstand  a  normally  fatal  dose  of  the  toxin,  the  toxoid  having  united 
with  the  cells  to  which  the  toxin  would  have  linked  itself.  On  wait- 
ing several  days  until  the  receptors  began  to  be  produced  in  overabun- 
dance, thus  increasing  the  number  of  points  of  attachment,  they  found 
that  the  animal  not  only  could  not  withstand  a  minimum  lethal  dose, 
but  was  killed  by  a  smaller  dose  than  is  required  to  kill  a  normal 
animal.  This  showed  that  the  receptors  were  produced,  but  not  cast 
off;  and  being  retained  by  the  cells  they  gave  the  toxin  an  extra  num- 
ber of  points  of  attachment  through  which  to  poison  the  cells,  whereas 
had  they  been  cast  off  they  would  have  linked  themselves  to  the  toxin 
in  the  blood-stream  and  thus  neutralized  it.  It  appears,  therefore,  that, 
when  the  receptors  are  overproduced  they  require  for  their  liberation 
some  stimulus  which  the  haptophore  itself  is  incapable  of  supplying, 
and  that,  under  ordinary  conditions  of  immunizing  with  toxins  instead 
of  with  wholly  non-poisonous  toxoids,  this  stimulation  comes  from  the 
toxophore  group. 

A  true  antitoxic  serum  is  obtainable  only  by  injecting  soluble  toxins, 
and  it  happens  that  the  only  pathogenic  bacteria  that  produce  them  to 
any  considerable  extent  are  those  of  diphtheria  and  tetanus,  the  others 
retaining  their  poisons  in  some  form  of  combination  with  their  proto- 
])lasm.  The  production  of  immune  serums  for  the  bacteria  of  the 
latter  class  requires  the  injection  of  the  bacterial  cells  themselves,  either 
living  or  killed,  the  latter  being  most  often  employed  for  the  first  in- 
jections. There  is  this  very  important  difference  between  the  serums 
obtained  through  the  injection  of  toxins  and  those,  caused  by  the  in- 
jection of  the  bacterial  cells  themselves  :  the  former  are  antitoxic — 
they  neutralize  the  specific  poison  ;  the  latter  are  not  antitoxic,  but  they 
act  against  the  bacteria  themselves.  While  the  experimental  work 
along  the  line  of  production  of  bactericidal  serums  has  been  enormous, 
and  while  our  understanding  of  the  processes  which  go  on  in  the  body 
is  constantly  growing,  no  such  measure  of  success  has  yet  been  achieved 
as  in  the  case  of  the  diphtheria  antitoxin. 

Bacteriolysis. — In  1888,  Nuttall  discovered  that  normal  serum  and 


HEMOLYSIS,  733 

various  body  fluids  have  the  power  to  kill  and  dissolve  v'S^rious  species  of 
bacteria,  and  that  this  property  disappears  when  the  same  are  heated  to 
55°  C.  (131°  F.)  or  allowed  to  stand  for  a  week  or  more.  This  prop- 
erty was  ascribed  by  Buchner,  in  1892,  to  the  influence  of  substances 
which  he  called  Alexins  (now  known  as  Complements).  The  living 
animal  has  the  same  power  when  the  organisms  are  injected  in  not 
excessive  numbers.  Thus,  one  can  inject  small  doses  of  cholera 
organisms  into  a  guinea-pig  without  causing  any  injury,  and  if  the  dose 
be  gradually  increased  the  animal  becomes  so  resistant  that  it  can  with- 
stand a  single  dose  of  many  times  the  amount  that,  in  an  untreated 
animal,  would  inevitably  cause  death.  In  other  words,  the  animal 
becomes  immune  to  cholera  ;  its  system  has  undergone  changes  which 
enable  it  to  destroy  the  specific  organism  in  ordinarily  overwhelming 
doses.*  If  its  serum  is  injected  in  very  small  amounts  into  other  guinea- 
pigs,  the  latter  also  acquire  the  same  immunity.  It  was  shown  by 
Pfeiffer,  in  1894,  that  animals  thus  artificially  immunized  could  receive 
without  harm  into  their  peritoneal  cavities  doses  of  cholera  germs, 
which  within  20  minutes  would  be  dissolved  by  the  peritoneal  exudate  ; 
and  he  asserted  that  the  result  was  due  to  a  substance  different  from 
Buchner's  alexins  and  produced  in  the  body  during  the  process  of 
immunization.  He  showed  also  that  a  non-immunized  guinea-pig,  which 
would  be  killed  by  the  intraperitoneal  injection  of  a  certain  dose  of 
cholera  germs,  could  withstand  the  same  if  some  heated  immune  serum 
(thus  deprived  of  its  complement)  were  introduced  at  the  same  time  ;  and 
he  concluded  therefrom  that  the  immunizing  material,  although  it  had 
been  exposed  to  heat,  had  not  lost  its  bactericidal  property,  and  that  it 
had  influenced  the  organization  in  some  way  so  that  it  could  destroy 
the  bacteria.  Later,  it  was  discovered  by  Bordet  that  the  bactericidal 
power  can  be  restored  by  the  addition  to  the  heated  serum  of  a  small 
amount  of  normal  serum  from  a  non-immunized  guinea-pig,  thus  show- 
ing that,  for  the  solution  of  the  bacteria,  two  substances  are  required, 
one  of  which  (complement)  is  a  normal  constituent  of  the  blood,  and 
the  other  (immune  body)  a  substance  called  forth  by  the  immunizing 
process.  While  the  perfectly  fresh  immune  serum,  like  fresh  normal 
serum,  has  power  to  dissolve  cholera  organisms  in  vitro,  so,  too,  on  keep- 
ing, it  loses  it ;  but  the  addition  of  some  fresh  normal  serum  or  of 
some  peritoneal  exudate  restores  the  property ;  that  is,  it  reactivates 
the  inactive  serum.  This  was  shown  by  MetschnikofP  and  by  Bordet 
(in  1896)  prior  to  the  beginning  of  experimental  work  in  haemolysis. 
It  is  thus  evident  that,  with  both  normal  and  immune  serum,  two  sub- 
stances are  involved  in  the  process  of  bacteriolysis  :  one,  the  comple- 
ment, is  thermolabile  (destroyed  at  55°  C.)  ;  the  other,  the  immune 
body,  capable  of  conferring  immunity,  is  thermostable  (resistant  to  heat). 
Haemolysis. — The  abandonment  of  transfusion  of  blood  was  caused 
so  long  ago  as  18G9  by  the  fact  that  marked  destruction  of  the  red 
cells  was  found  to  occur,  as  was  shown  by  the  hsemoglobinuria  which 
followed  the  operation  ;  but  transfusion  can  be  practised  without  injury 
between  animals  of  the  same  species  and  between  certain  animals  closely 


734  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

related,  as,  for  example,  between  the  dog  and  the  wolf;  but  not 
between  unrelated  species,  as  the  dog  and  rabbit,  or  the  dog  and  horse. 
Rabbit  serum  will  dissolve  the  red  corpuscles  of  the  horse,  ox,  pig, 
monkey,  and  man,  but  not  those  of  the  hare ;  guinea-pig  serum  acts 
against  the  corpuscles  of  rats  and  mice,  but  not  against  those  of 
rabbits  ;  human  corpuscles  are  dissolved  by  the  serum  of  the  horse, 
monkey,  ox,  sheep,  etc.  Although  transfusion  was  abandoned  at  the 
time  and  for  the  reason  stated,  the  hsemolytic  action  of  blood  serum 
attracted  but  little  attention  until  1898,  when  it  was  shown  by  Belfanti 
and  Carbone  that  the  blood  serum  of  horses  which  had  been  treated  with 
injections  of  rabbit  blood  was  poisonous  to  rabbits,  while  that  of  horses 
not  so  treated  had  no  such  property.  Later,  Bordet  announced  that 
guinea-pigs,  after  a  similar  course  of  treatment  with  rabbit  blood,  yield 
a  serum  which  will  dissolve  the  red  corpuscles  of  a  rabbit  with  great 
rapidity.  The  same  solvent  action  was  found  to  be  exerted  by  the 
serum  of  other  animals  treated  similarly  with  alien  blood,  and  it  was 
shown  that  it  is  a  specific  action  ;  that  is,  that  it  is  exerted  (with  certain 
few  exceptions)  only  against  the  red  corpuscles  of  the  particular  species 
whose  blood  is  used  for  injection.  In  other  words,  if  species  A  is 
injected  with  the  blood  of  species  B,  A's  serum  will  acquire  the  property 
of  dissolving  B's  corpuscles,  but  not  those  of  species  C  or  D,  This 
destruction  of  blood  cells  is  known  as  Hoemolysis,  and  the  agents  which 
bring  it  about  are  termed  Hceinolyslns.  The  nature  of  the  hemolytic 
substance  has  been  the  subject  of  much  investigation,  which  has  proved 
that  the  solution  is  effected  not  by  one  single  constituent  of  the  serum 
acting  alone,  but  by  two  acting  together,  each  being  powerless  in  the 
absence  of  the  other.  Ten  years  previously,  in  1888,  Nuttall  had 
pointed  out  that  many  normal  serums  possess  the  property  of  destroying 
bacteria,  and  that  this  ceases  on  exposure  of  the  serum  to  a  temperature 
of  55°  C.  (131°  F.).  Investigating  haemolysis,  Bordet  found  that  in 
this  process,  too,  the  property  disappears  at  this  temperature,  but  can  be 
restored  by  the  addition  of  a  very  small  amount  of  serum  of  another 
animal  of  the  same  species,  that  has  not  been  subjected  to  treatment ; 
that  is  to  say,  of  a  normal  animal.  Later,  it  was  discovered  that  an 
inactivated  normal  or  immune  serum  can  be  reactivated,  not  only  by 
normal  serum  from  the  same  species,  but  also  by  that  of  other  animals 
not  necessarily  nearly  related.  Thus,  goat  serum,  which  is  hsemolytic 
for  guinea-pig  and  rabbit  blood,  loses  this  property  on  being  heated  to 
55°  C,  but  gains  it  again  on  the  addition  of  horse  serum,  which  itself 
has  no  action  whatever  on  rabbit  blood. 

It  was  clear,  then,  that  at  least  two  substances  are  required  in 
haemolysis;  one  unable  to  resist  exposure  to  55°  C,  but  existing  in 
both  normal  and  immunized  animals,  and  the  other,  resistant  to  55° 
and  even  65°  and  70°  C,  and  existing  only  in  the  serum  of  those 
immunized.  To  the  former,  common  to  both  kinds  of  serum,  Bordet 
applied  the  term  Alexin,  invented  in  1892  by  Buchner  for  the  bacteri- 
cidal substances  which  Nuttall  had  shown  to  exist  in  normal  blood ;  to 
the  other,  found  only  in  the  serum  of  the  immunized  animal,  he  applied 


HJEMO  LYSIS.  735 

the  term  Substance  sensibilisatrice.  These  terms  aud  many  others  that 
have  been  coined  as  substitutes  have  been  sujDerseded  respectively  by 
Complement  (Ehrlich)and/?yi?7iit?ie  6o(ii/ (Pfeiifer)  ov  Amhoeeptor  (^^hxWch). 
The  actual  solvent  substance  is  the  complement,  but  it  cannot  act  unless 
the  immune  body  (amboceptor)  prepares  the  red  corjjuscles  through  some 
means  of  its  own,  fixing  itself,  according  to  Ehrlich  and  Morgenroth, 
in  the  red  cells  themselves.  The  complement  is  not  only  less  resistant 
to  heat  than  the  immune  body,  but  is  less  persistent  on  storage  of  the 
serum.  Investigation  by  Ehrlich  and  Morgenroth  of  the  power  of 
normal  blood  serum  to  dissolve  alien  corpuscles  demonstrated  that  this, 
too,  does  not  depend  upon  a  single  substance,  as  was  maintained  by 
some,  but  upon  two  substances  acting  together,  as  had  been  proved  to 
be  the  case  with  immune  serum.  The  second  substance  analogous  to 
the  immune  body  is  now  known  as  the  Interbody,  Go-between,  or 
Zwischeiikorper.  Ehrlich  and  Morgenroth  proved  also  that  a  normal 
serum  which  will  destroy  the  red  cells  of  more  than  one  animal  species 
possesses  an  interbody  for  each  species,  and  different  complements  as 
well. 

A  hsemolytic  serum  is  intensely  poisonous  to  the  animal  species 
whose  blood  has  been  employed  in  its  production,  injections  of  a  few 
cubic  centimetres  causing  destruction  of  the  blood  cells  in  corpore. 
It  acts  like  a  toxin,  and  similarly  an  artificial  immunity  to  its  action 
can  be  produced,  an  antihsemolysin  being  formed  instead  of  an  anti- 
toxin. 

In  attempting  to  discover  the  relationship  of  the  active  constituents 
of  hsemolytic  serum  to  the  blood-cells  which  it  dissolves,  and  to  deter- 
mine upon  what  its  specific  action  depends,  Ehrlich  and  Morgenroth 
had  recourse  to  a  most  ingenious  experiment,  by  which  they  proved 
that  the  immune  body  combines  with  the  corpuscles,  and  that  the 
combination  is  of  a  chemical  nature  and  resists  attempts  to  break  it 
apart.^  The  specificity  of  the  union  was  shown  by  the  fact  that  the 
combination  does  not  occur  when  blood  is  used  other  than  that  for 
which  the  serum  is  hsemolytic.  They  proved  also  that  a  similar  com- 
bination between  the  blood  corpuscles  and  complement  does  not  occur, 
and  that  the  immune  body  possesses  two  affinities  ;  one,  very  strong, 
for  the  corpuscle,  and  one,  less  strong,  for  the  complement.  Since  the 
latter,  as  proved,  has  no  combining  affinity  for  the  red  corpuscle,  its 
action  must  be  dependent  upon  the  interposition  of  some  agent  which 
has ;  and  this  is  the  immune  body,  with  its  two  combining  groups. 
Therefore,  it  is  plain  that  the  function  of  the  immune  body  is  to  enable 

^  They  destroyed  the  complement  of  a  goat  serum  that  was  hsemolytic  for  sheep  blood 
by  heating  it  for  a  half-hour  at  55°  C,  then  added  4  volumes  of  a  6  per  cent,  mixture 
of  sheep  blood  in  0.75  per  cent,  salt  solution,  and  after  letting  the  mixture  stand  for  15 
minutes  at  40°  C.  they  caused  all  the  corpuscles  to  .separate  as  a  sediment  by  centrifu- 
gation.  That  none  of  the  immune  body  was  present  in  the  supernatant  fluid  they 
proved  by  adding  to  the  latter  some  more  sheep  blood  and  normal  serum  (containing 
coiMpleinent)  and  finding  that  tlie  cory)nscles  were  not  dLssolved,  as  they  would  have 
bff-n  in  the  ))resencft  of  the  inirnune  body.  The  sediment  of  corpuscles  which  had  com- 
bined witli  the  iiimiune  body  was  mixed  with  normal  (complement-containing)  serum, 
and  after  a  time  the  corpuscles  were  dissolved. 


736 


INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 


the  complement  to  attack  and  dissolve  the  corpuscle,  and  this  it  does 
by  acting  as  a  coupling-link  between  the  two.  Its  r6le  is  the  same  in 
bacteriolysis,  binding  the  complement  to  the  bacterial  cell  in  the  same 
way.  Diagrammatically,  it  may  be  shown  as  in  Figure  114.  It  will 
be  seen  that  the  same  relations  exist  between  the  immune  body  and  the 
blood  corpuscle  or  bacterial  cell  as  between  a  toxin  and  its  antitoxin. 
Both  the  immune  body  and  the  antitoxin  possess  haptophores,  which 
fit  respectively  the  receptors  of  the  blood  corpuscle  and  the  haptophore 
of  the  toxin.     They  are  analogous  products — free  side-chains. 


c 


IB 


Fig.  114. 
Symotoxic   group 
-COMPLEMENT 


^^_^S-|-j^p^o  pbore 


-Complementophile  qrotira 
-IMMUNE    BODY 

J^eceptors 


The  importance  of  the  study  of  the  phenomena  of  haemolysis  lies  in 
the  fact  that  analogous,  if  not  identical,  processes  occur  in  bacteriolysis  ; 
and  it  happens,  too,  that  experiments  with  blood  cells  are  more  simple 
and  convenient  in  several  respects,  among  which  is  the  fact  that  they 
can  be  carried  out  in  vitro,  and  they  are  also  better  adapted  to  accuracy. 
Although  the  study  of  bacteriolysis  antedates  that  of  haemolysis  by  ten 
years,  it  is  to  the  latter  that  our  knowledge  of  immunity  is  especially 
due. 

The  side-chain  theory,  which  originally  applied  to  the  production  of 
specific  antitoxins  and  was  then  extended  to  the  formation  of  specific 
bacteriolysins  and  haemolysins,  was  finally  broadened  so  as  to  apply  as 
well  to  the  production  of  all  other  antibodies  of  whatever  nature 
caused  by  the  introduction  of  any  substance  which  can  combine  with 
receptors  in  the  body  and  bring  about  the  overproliferation  and  setting 
free  of  the  same.  It  is  not  to  be  supposed  that  the  body  cells  are  of 
such  simple  structure  that  they  have  affinities  for  only  nutritive  mate- 
rials, toxins,  alien  bloods,  and  pathogenic  bacteria.  As  has  been  pointed 
out,  the  living  cells  are  enormously  complex  aggregations  of  exceed- 
ingly complex  molecules,  and  Ehrlich  holds  that  the  atom-complexes 
have  a  great  diversity  of  functions  and  combine  with  whatever  sub- 
stances, and  only  those,  for  which  they  have  receptors  ;  and  these  sub- 
stances naturally  must  possess  atom  groups  (haptophores)  which  can 
link  themselves  to  the  cell  receptors.  The  haptophores  of  the  im- 
munizing substances  are  quite  distinct  from  the  atom  complexes  which 


COMPLEMENTS.  737 

have  functional  peculiarities  ;  for  example,  the  toxophore  groups  of 
toxins,  and  the  zymophore  groups  of  ferments. 

Illustrative  of  the  complex  nature  of  body  cells  and  of  the  multi- 
plicity of  atom  groups  which  they  possess,  may  be  cited  the  production 
of  various  other  cytotoxins.^  Thus,  the  injection  of  alien  spermatozoa 
causes  the  production,  in  the  serum  of  the  animals  injected,  of  specific 
substances  termed  Spennotoxins,  which  have  the  power  to  immobilize, 
if  they  do  not  dissolve,  the  spermatozoa  of  the  species  from  which 
they  are  derived,  and  also  to  hsemolyze  its  red  corpuscles.  Again,  in 
the  same  way,  a  serum  can  be  obtained  by  injection  of  ciliated  e])ithe- 
lium  from  the  trachea  of  the  ox  which  will  have  a  similar  action  on 
this  form  of  cells,  and  this  serum  also  is  hsemolytic  [Trichotoxins).  By 
injecting  material  from  the  central  nervous  system,  from  the  liver,  from 
the  kidneys,  from  the  mesenteric  glands,  and  from  bone  marrow,  specific 
serums  have  been  obtained  which  are  poisonous  respectively  to  the  nerve 
cells  (^Neurotoxins),  liver  substance  (Hepatotoxins),  kidney  substance 
(Nephrotoxins),  and  leucocytes  (^Leucotoxins).  Each  of  all  these  pos- 
sesses a  thermolable  complement  (destroyed  by  exposure  to  55°  C.) 
and  a  thermostable  immune  body.  But  this  is  not  all.  The  study  of 
the  production  of  antibodies  has  gone  much  farther,  and  it  has  been 
proved  that,  proceeding  in  the  same  way  as  in  immunizing  animals 
against  toxins,  a  variety  of  antibodies  can  be  pi'oduced.  Thus,  by  be- 
ginning with  very  small  doses  of  specific  hsemolysin  and  gradually  in- 
creasing the  amount  of  the  injection,  an  antihsemolytic  serum  can  be 
produced,  which,  when  added  to  the  hsemolytic  serum,  will  inhibit  the 
latter's  action.  Investigation  has  demonstrated  the  existence  in  anti- 
hsemolytic "serums  of  anticomplement  and  anti-immune  bodies,  both  of 
which  are  specific.  In  the  same  way  can  be  produced  antispermo- 
toxins,  antileucotoxins,  and  even  antibodies  to  these  antibodies.  An 
enormous  amount  of  research  work  of  a  most  complicated  and  ingen- 
ious nature  is  going  on  constantly,  having  for  its  object  the  solution  of 
the  many  problems  of  immunity,  and  these  few  facts  are  given  merely 
as  examples,  for  a  general  survey  of  the  subject  in  all  its  branches  is 
beyond  the  scope  of  a  work  of  this  nature,  particularly  until  a  wider 
practical  application  can  be  made  of  the  numerous  discoveries. 

Complements. — The  elements  of  blood  serum,  which,  through  the 
intermediation  of  the  immune  body,  bring  about  the  destruction  of 
alien  blood  cells  or  bacteria,  are  not  produced  as  a  result  of  an  immun- 
izing process,  but  are  normal  constituents  of  the  blood.  As  stated 
elsewhere,  Ehrlich  has  demonstrated  that  the  blood  contains  not  one, 
but  a  multiplicity  of  complements,  and  that  they  may  differ  in  their 
resistance  to  heat.  Thus,  the  serum  of  a  goat  immunized  with  sheep 
blood  lost,  on  being  heated  to  55°  C,  the  power  which  it  possesses 
normally  to  dissolve  rabbit  corpuscles,  but  was  hsemolytic  for  sheep 

^"  Cytotoxin  is  used  for  any  substance  in  serum,  venom,  or  bacterial  cultures,  or  of 

[)]ant  orif^in,  wbich  destroys  cellular  elements,  eitlier  animal  or  vegetable.  The  haemo- 
ysins  and  other  tfixic  substances  which  kill  but  do  not  dissolve  cellular  elements  are 
included  under  (Motoxins,  also  the  bacteriolysins  ( bactericidal  substance,  alexin)." 
Nuttiill,  Blood  Immunity  and  Relationship,  p.  14. 


738  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

blood  until  it  was  heated  to  65°  C.  Most  complements,  however, 
are  destroyed  at  the  former  temperature.  The  multiplicity  of  comple- 
ments is,  however,  a  matter  of  disagreement  between  Ehrlich  and  Mor- 
genroth  and  others,  on  the  one  hand,  and  Gruber,  Bordet  and  their 
followers,  on  the  other ;  but  the  weight  of  experimental  evidence  ap- 
pears to  be  with  the  former,  who  maintain  that  a  different  complement 
is  required  to  link  itself  to  immune  bodies  that  are  specifically  haemo- 
lytic  for  different  kinds  of  blood  corpuscles. 

Complements  are  believed  to  exert  a  sort  of  digestive  fermentative 
action  upon  the  cells  (blood  or  bacteria)  to  which  they  are  linked  by 
the  immune  body.  They  lose  this  property,  as  a  rule,  when  they  are 
heated  to  55°  C.  They  are  believed  to  contain  two  important  atom 
complexes  :  one,  the  haptophore,  with  an  affinity  for  a  similar  group  in 
the  immune  body  ;  the  other,  the  zymotoxic  group,  is  the  functional 
(digestive)  part.  It  is  the  latter  that  is  affected  by  exposure  to  55°  C, 
the  former  still  possessing  the  power  of  combining  with  the  immune 
body  and  of  stimulating  the  production  of  anticomplement  when  the 
heated  normal  serum  is  injected.  Complements  that  have  been  deprived 
of  their  zymotoxic  groups  are  analogous  to  toxoids,  and  are  known  as 
oomplementoids. 

An  immune  serum,  while  it  acquires  a  large  amount  of  immune 
body,  does  not,  as  a  rule,  gain  any  additional  amount  of  complement ; 
and  inasmuch  as  the  two  work  together,  it  cannot  exert  its  full  power 
in  test-tube  experiments  without  the  addition  of  a  sufficiency  of  com- 
plement, which  can  be  supplied  in  such  experiments  by  the  addition  of 
normal  serum.  In  the  practical  therapeutical  application,  however,  of 
a  bactericidal  serum,  the  necessary  complement  may  exist  already  in  the 
blood  of  the  patient ;  and  inasmuch  as  such  a  serum  may  contain 
many  thousand  times  as  much  immune  body  as  complement,  it  follows 
that  a  relatively  small  dose  will  be  sufficient  to  furnish  an  enormous 
number  of  linking  bodies  to  enable  the  complement  of  the  blood  to 
perform  its  office ;  but,  as  will  appear,  there  may  be  an  insufficient  sup- 
ply of  complement  for  the  attainment  of  the  desired  result,  and  in 
practice  the  deficiency  cannot  easily  be  made  up.  Moreover,  an  excess 
of  immune  body,  as  also  will  appear,  may  act  to  the  disadvantage  of 
the  subject.     (See  page  746.) 

As  to  the  source  of  the  complements,  there  is  considerable  disagree- 
ment. By  some  they  are  believed  to  be  secretory  products  of  the 
leucocytes  and  of  other  kinds  of  cells,  many  of  which  have  been  shown 
to  have  phagocytic  properties  ;  Metschnikoff  believes  that  they  are  not 
secretory,  but  decomposition,  products  of  the  leucocytes  ;  Pfeiffer  and 
others  believe  that  the  leucocytes  are  in  no  way  concerned  in  their  pro- 
duction, and  Wassermann  asserts  that  these  are  practically  their  only 
source. 

While  the  process  of  immunization  appears  to  have  no  influence  in 
increasing  the  amount  of  complement,  it  is  doubtless  the  case  that 
their  amount  in  normal  serum  is  subject  to  more  or  less  fluctuation  in 
the  same  individual  from  day  to  day  under  varying  conditions  of  health 


IMMUNE  BODIES. 


739 


Fig.  115. 

COMPLE- 
HENT 


AINTICOMPLEriEINT 


and  disturbance  of  the  body  function.s.  Thus,  Ehrlich  and  Morgenroth 
have  proved  the  disappearance  of  complement  in  poisoning  by  phos- 
phorus, and  MetschnikofF  its  diminution  following  suppuration.  It  is 
possible  that  reduced  resistance  to  infection  may  depend  upon  the 
reduction  of  complement  by  the  spontaneous  production  of  anticom- 
plement  in  the  system.  Although  this  spontaneous  production  has 
not  yet  been  demonstrated,  it  has  been  proved  by  Wassermann  that 
the  injection  of  anticomplements  increases  susceptibility  to  infection. 
Anticomplement  can  be  produced  (Bordet)  by  injection  of  complement 
(normal  serum  of  another  species),  thus  causing  the  production  of  a 
serum  which  is  antagonistic  to  haemolysis  and  bacteriolysis,  since  the 
anticomplement  possesses  a  haptophore  group,  which  links  itself  to  the 
corresponding  group  of  the  complement  and 
thus  prevents  a  similar  union  of  the  com- 
plement and  immune  body.  This  action  is 
shown  diagrammatically  in  Figure  115. 

Except  in  those  cases  in  which  the  com- 
plements of  the  two  species  possess  identical 
combining  groups,  the  anticomplements  are 
specific  bodies ;  that  is,  they  combine  only 
with  their  specific  complements.  The  union 
of  complement  and  anticomplement  is  very 
firm,  as  has  been  shown  by  Bordet,  who 
found  that  it  cannot  be  broken  up  by  heat. 

Immune  Bodies. — The  immune  bodies, 
believed  by  the  Ehrlich  school  to  originate 
through  the  saturation  of  some  particular 
atom  complexes  (side-chains)  of  some  par- 
ticular cells,  are  specific  bodies  ;  for  exam- 
ple, that  which   links   complement    to    one 

kind  of  blood  cell  will  not  act  for  that  of  another  species  ;  that  which 
makes  possible  the  destruction  of  a  cholera  germ  will  exert  no  action 
against  the  bacillus  of  typhoid  fever.  That  they  exist  in  one  form  and 
another  in  the  system  under  normal  conditions  is  generally  admitted, 
for  in  the  normal  metabolism  of  the  cells  it  is  assumed  that  various 
substances — nutritive  substances,  for  example — stimulate  the  over- 
production and  liberation  of  side-chains,  among  which  may  be  some 
that  are  identical  with  those  which  originate  in  consequence  of  the 
introduction  of  alien  bloods,  bacteria,  and  other  foreign  substances. 

Whether  each  immune  body  is  a  single  definite  substance  or  a  com- 
l)inati()n  of  substances  having  special  affinities  for  different  materials  is  a 
matter  in  dispute,  the  former  view  being  held  by  Bordet  and  Metschni- 
koff  and  t|ie  latter  by  Ehrlich  and  Morgenroth,  who  bring  forward 
certain  experimental  proof  of  the  correctness  of  their  view. 

It  has  l)een  shown  that  different  kinds  of  blood  cells  possess  some 
similar  receptors,  and  that  each  cell  appears  to  have  these  atom  com]')lexes 
in  great  variety,  so  that  a  given  cell  may  be  able  to  link  itself  to  the 
receptor  of  this  or  that  immune  body  and  not  to  that  of  some  other ; 


740  jyFECTIOX,   SUSCEPTIBILITY,   IMMUNITY. 

and  Ehrlich  and  Morgenroth  regard  the  immnne  body  of  a  serum  as  the 
sum  total  of  its  affinities  for  different  cells,  each  corresponding  to  one 
partial  immune  body.  A  particular  kind  of  blood  cell  or  species  of 
bacteria  introduced  into  an  animal's  system  may  or  may  not  find  corre- 
sponding receptors  for  each  of  its  many  different  combining  atom 
complexes  or  haptophores.  If  it  should  not  find  them,  then  only  a 
part  of  the  possible  number  of  partial  immune  bodies  will  be  produced 
by  the  animal.  In  another  species  of  animal,  other  receptors  may  be^ 
and  are,  present ;  and  in  consequence  the  immune  bodies  produced  by 
the  two  must  differ  to  some  extent  in  their  composition,  each  containing 
certain  atom  groups  or  partial  immune  bodies  that  the  other  lacks,  and 
each  differing  in  similar  respects  from  those  produced  by  other  species 
of  animals  subjected  to  the  same  and  to  different  stimuli.  If  Ehrlich 
and  Morgenroth  are  correct — and  the  weight  of  experimental  evidence 
appears  to  indicate  that  they  are — the  employment  of  bacteriolytic 
serums  made  by  combining  a  number  of  serums  derived  from  different 
species  of  animals  ought  to  give  better  therapeutical  results  than  one 
derived  from  one  species,  and  hence  containing  a  smaller  assortment  of 
possible  combining  groups.  The  greater  the  variety  of  these  groups, 
the  greater  the  possibility  for  the  human  system  to  bring  its  complements 
into  action  ;  and  these  cannot  exercise  their  functions  unless  they  find 
the  necessary  intermediary  agents — the  immune  or  partial  immune 
bodies.  Indeed,  it  appears  certain  that  in  many  experiments  with 
lysins  a  number  of  different  immune  bodies  or  partial  immune  bodies 
are  concerned.  Inasmuch  as  the  atom  complexes  or  combining  groups 
of  the  molecules  that  make  up  the  bacterial  cell  may  not  be  absolutely 
alike  in  different  races  of  the  same  bacterial  species,  it  is  reasonable  to 
believe  that  an  immune  serum  produced  through  the  employment  of 
one  particular  culture  will  not  affect  all  different  cultures  of  that 
organism  equally.  In  fact,  that  is  what  often  is  seen  in  actual  prac- 
tice :  a  bactericidal  serum  is  active  in  a  certain  number  of  cases  and 
of  no  value  in  others.  Hence,  as  pointed  out  by  Wassermann,^  the  way 
out  of  the  difficulty  is  to  employ,  not  a  single  culture,  but  a  number  of 
different  cultures  of  the  same  bacterium  in  the  preparation  of  a  serum, 
in  this  way  securing  a  very  large  number  and  variety  of  partial  groups. 
Such  a  serum  Wassermann  would  call  multipartial. 

In  the  same  way  that  anticomplement  can  be  produced  by  the  injection 
of  normal  serum,  so,  also,  can  one  bring  about  the  formation  of  anti- 
immune  body  by  injecting  an  immune  serum  into  an  animal  in  small 
and  gradually  increasing  doses,  after  the  method  followed  in  immuni- 
zation. The  resulting  serum  will  contain  both  anti-immune  body  and 
anticomplement. 

Agglutinins. — It  was  observed  so  long  ago  as  1869  by  Creite,  and  in 
1875  by  Landois,  that  the  blood  serum  of  an  animal  when  mixed  with 
the  red  corpuscles  of  many  other  species  causes  them  to  come  together 
in  clumps.  In  his  experiments  in  haemolysis,  Bordet  observed  that  in 
a  hemolytic  serum  this  property  is  increased  ;  that  the  agglutination 
'  New  York  Medical  Journal  and  Philadelphia  Medical  Journal,  October  15,  1904. 


AGGLUTININS.  741 

precedes  the  solution  of  the  cells  ;  and  that  the  increase  in  agglutinating 
property  is  specific — that  is  to  say,  it  is  increased  with  respect  to  the 
kind  of  blood  corpuscles  that  have  been  employed  in  the  process  of 
producing  the  hsemolytic  serum,  and  also  to  some  extent  for  that  of 
closely  related  species.  The  substance  which  brings  about  this  phenom- 
enon is  called  an  Agglutinin.  It  is  not  destroyed  by  exposure  to  55°  C, 
and  it  may  resist  even  70°  C.  ;  and  so  a  hsemolytic  serum  which  has 
been  heated  to  that  temperature,  while  it  loses  its  hsemolytic  property, 
is  still  capable  of  causing  agglutination.  The  exciting  cause  of  its 
genesis  is  supposed  to  reside  in  the  stroma  of  the  injected  corpuscles. 
According  to  Stewart,^  the  injection  of  the  stroma  of  an  alien  blood 
stimulates  the  production  of  agglutinins,  while  the  cell  contents  stimu- 
late more  especially  the  production  of  hsemolysins. 

The  same  agglutinating  power  is  possessed  by  some  normal  serums 
for  bacteria,  and  similarly  it  is  specifically  increased  in  bacteriolytic 
serums.  The  agglutination  with  which  we  are  most  familiar  is  that 
which  is  employed  as  a  means  of  diagnosis  in  suspected  typhoid  fever 
— the  Gruber-Widal  reaction.  The  serum  of  a  person  ill  with  that 
disease,  diluted  with  bouillon  and  mixed  with  a  culture  of  typhoid  germs 
will  cause  the  latter  to  clump  together.  This  happens  whether  the 
bacilli  are  living  or  dead.  The  agglutinin  may  persist  in  the  system 
for  many  months  or  years  after  an  attack  of  typhoid  fever,  suggesting 
a  persistence  also  of  the  specific  bacilli,  which  we  know  to  be  often  the 
case,  since  they  may  be  discharged  in  the  urine  continuously  for  many 
months  after  recovery. 

The  bacterial  agglutinins  were  studied  first  byGriiberwho  concluded 
that  in  some  way  they  affect  the  bacteria,  so  that  they  can  be  killed 
and  dissolved  ;  but  experimental  evidence  tends  to  show  that  they  are 
not  necessarily  injured,  and  that,  on  the  contrary,  they  can  even  continue 
to  multiply,  even  though  agglutinated.  It  has  been  shown  by  Bordet 
and  Malkoflf  that  the  bacterial  agglutinins  and  the  haemagglutinins 
combine  with  the  bacterial  cells  or  blood  cells  in  the  same  way  as  the 
go-betweens  (Zwischenkdrper)  of  normal  serum. 

The  agglutinins  are  complex  substances  possessed  of  haptophores, 
which  combine  with  haptophores  in  the  blood  cells  and  bacteria,  and 
other  atom  groups  which  cause  the  clumping.  The  cells  upon  which 
they  act  (blood  corpuscles  and  bacteria)  contain  what  is  called  "agglutin- 
able  substance,"  which  also  is  made  up  of  at  least  two  atom  complexes, 
one  of  which  is  a  haptophore,  as  mentioned  above,  and  the  other  is 
sensitive  to  the  atom  group  which  causes  the  clumping.  Thus,  the 
})henomenon  of  agglutination  is  analogous  to  the  chemism  of  haemolysis 
an<l  bacteriolysis  ;  but  the  one  is  apparently  not  dependent  upon  the 
other,  for  haemolysis  and  bacteriolysis  may  occur  without  agglutination, 
and  agglutination  may  occur  without  subsequent  solution.  Thus,  dog 
serum  will  agglutinate  but  not  destroy  anthrax  bacilli,  and  rat  serum 
will  destroy  but  not  agglutinate  them. 

'  Arnorican  .Journal  of  Physiolojry,  XL,  No  3.,  .June,  1904,  p.  250. 


742  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

Ehrlich  regards  the  agglutinins  as  special  products  in  an  immune 
serum,  analogous  to  the  bacteriolysins  and  hsemolysins. 

The  atom  complex  that  causes  agglutination  is  very  susceptible  to 
the  action  of  acids  and  other  substances,  and  when  it  is  deprived  of  its 
functional  power,  the  result  is  the  same  as  with  toxins  that  have  lost 
their  toxophore  groups :  the  agglutinin  retaining  its  haptophore  group 
is  converted  to  an  agglutinoid,  just  as  a  toxin  becomes  a  toxoid  ;  it  still 
can  combine,  but  it  cannot  agglutinate. 

Precipitins. — If  the  serum  of  one  species  of  animal  be  injected  into 
an  animal  of  another  not  closely  related  species,  the  serum  of  the  latter 
will  acquire  the  property  of  precipitating  part  of  the  proteid  material 
of  that  of  the  former  when  the  two  are  mixed  together.  For  example, 
if  we  mix  normal  rabbit  serum  and  horse  serum,  we  observe  no  reac- 
tion ;  but  if  we  inject  a  rabbit  with  horse  serum  at  proper  intervals, 
after  a  time  its  serum  will  acquire  the  property  of  causing  a  precipitate 
when  it  is  mixed  with  horse  serum.  The  substance  which  is  developed 
in  this  process  of  immunization  and  which  brings  about  the  reaction  is 
known  as  a  Precipitin.  Precipitins  are  not  wholly  specific  in  their 
action.  A  serum  obtained  by  immunizing  with  the  serum  of  species  A 
may  precipitate  the  latter  and  also  that  of  some  other  closely  related 
species.  This  was  pointed  out  first  by  Nuttall,^  whose  extraordinarily 
extensive  researches,  conducted  with  hundreds  of  diflPerent  kinds  of 
blood  and  involving  the  making  of  many  thousands  of  tests,  have  been 
very  rich  in  results  valuable  alike  to  students  of  zoology,  physiology, 
and  immunity,  and  also  to  those  who  have  to  do  with  medico-legal 
investigation  of  suspected  blood  stains. 

Precipitins  have  been  found  in  certain  normal  serums.  Thus,  ox 
serum  will  precipitate  that  of  man  and  also  that  of  a  number  of  other 
species,  and  the  same  is  true  of  the  serum  of  dogs,  goats,  and  other 
animals.  They  have  been  found  also  in  the  serum  of  animals  immu- 
nized with  bacterial  cultures  ;  these  are  known  as  bacterio-precipitins, 
and  are  specific  for  the  culture  filtrates  of  the  germs  employed  and  for 
solutions  of  the  material  within  the  bacterial  cell. 

Precipitins,  like  agglutinins,  are  far  more  resistant  to  heat  than  the 
other  immune  substances,  their  functional  property  being  not  com- 
pletely destroyed  under  70°  C.  They  combine  in  a  definite  chemical 
way  with  the  substances  precipitated,  but  the  reaction  is  prevented  by 
acetic  acid.  They  are  believed  to  contain  two  essential  atom  groups  : 
one,  unstable  and  functional ;  the  other,  a  stable  combining  (hapto- 
phore) group.     Precipitoids  analogous  to  agglutinoids  are  known. 

There  is  another  form  of  precipitin,  called  Coagulin,  which  is  de- 
veloped in  the  process  of  immunizing  animals  with  other  albuminous 
substances.  Thus,  by  employing  milk,  there  is  developed  an  immune 
body  that  will  coagulate  milk  of  the  same  kind  as  used.  These  lacto- 
serums  are,  in  some  instances,  also  specifically  hsemolytic  and 
spermotoxic. 

The  agglutinins  and  the  precipitins  are  more  complex  than  the 
^  Blood  Immunity  and  Blood  Eelationship,  Cambridge,  1904. 


PRECIPITINS. 


743 


toxins  and  less  so  than  the  hsemolysins  and  bacteriolysins.  Ehrlich 
conceives  of  the  individuals  of  this  group  of  immune  substances  as 
possessed  of  two  atom-complexes,  one  of  which,  the  haptophore,  holds 
the  substance  acted  upon,  and  the  other,  the  zymophore,  exerts  a  fer- 
mentative action  which  brings  about  the  change.  (See  Fig.  116.) 
They  are  called  by  Ehrlich  Receptors  of  the  second  or-der.  The  receptors 
of  the  first  and  second  orders  are  known  also  as  Uniceptors. 

Fia.  116. 


_.ZuwopV7or&  gyoup 


The  immune  bodies  concerned  in  hsemolysis,  bacteriolysis,  and  other 
lyses  are  more  complicated  than  the  antitoxins  (receptors  of  the  first 
order)  and  the  precipitins  and  agglutinins  (receptors  of  the  secood 
order).  In  this  third  kind,  one  haptophore  group  fixes  the  bacterium, 
blood  cell,  epithelium  cell,  food  material  or  other  substance  concerned 
by  the  corresponding  group  in  the  latter,  while  another  haptophore, 
represented   usually    as   another  arm,  links  to  itself  the  complement 


Fia.  117. 


ZTtjwotoxic/   group 


Haptop\7oye 


Hekpfopbor? 
"orpple  wentopbile 

CjYOUp 


through  the  mutual  attraction  of  the  complementophile  (haptophore) 
group  of  the  immune  body  and  the  haptophore  group  of  the  complement. 
Both  are  held  separately  by  the  same  kind  of  affinities,  and  the  comple- 
ment can  proceed  to  exercise  its  digestive  function  upon  its  companion 
in  captivity.  This  is  shown  diagram matically  by  Figure  117,  in  the 
use  of  which  and  of  the  others  presented  in  this  chapter,  it  must  be 
borne  in  mind  that  the  action  is  not  mechanical,  but  purely  chemical, 
and  that  the  figures  are  mere  diagrams  and  represent  bodies  which 
never  have  been  seen.  Figure  117  is  but  another  way  of  expressing 
the  same  idea  as  Figure  114. 


744  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

The  immune  bodies  of  this  class  are  known  as  Receptors  of  the 
third  order.  When  they  are  formed  and  thrust  out  like  the  antitoxins 
into  the  blood  stream  in  consequence  of  some  immunizing  process,  they 
are  known  as  Amboceptors ;  and  those  which  are  not  so  caused,  but 
exist  normally  in  the  serum,  are  termed  Intermediary  bodies,  Zwischen- 
korper,  and  Go-betweens. 

From  the  fact  that  all  receptors  of  whatever  order  possess  hapto- 
phore  groups,  Ehrlich  calls  all  free  receptors  Haptins.  There  are 
doubtless  many  more  varieties  of  haptins  than  have  yet  been  conceived 
of,  and  an  infinite  number  of  sub-varieties  of  each  kind. 

Metschnikoff 's   Theory. 

Metschnikolf 's  theory  of  Phagocytosis,  which  dates  back  to  1884, 
holds  that  bacterial  invasion  of  the  system  is  followed  by  either  attrac- 
tion or  repulsion  of  the  leucocytes  and  other  phagocytic  cells  by  the 
bacteria,  which  in  the  former  case  become  absorbed  and  destroyed. 
In  case  the  phagocytes  are  repelled,  or  if  the  attraction  is  only  partial, 
so  that  some  bacteria  escape,  multiplication  of  the  invaders  occurs, 
with  consequent  lesions.  The  property  of  being  attracted  or  repelled 
is  known  as  Chemiotaxis,  which  is  respectively  positive  or  negative. 
In  case  of  natural  immunity,  the  chemiotaxis  is  positive  and  the  cells 
move  toward  the  bacteria  and  englobe  them  ;  in  susceptibility,  it  is 
negative  or  only  partially  positive,  or  the  phagocytes  may  not  possess 
the  requisite  phagocytic  power.  In  the  acquirement  of  immunity,  the 
negative  chemiotaxis  is  converted  to  the  positive  form  by  the  introduc- 
tion of  very  small  numbers  of  the  specific  bacteria  or  of  weakened 
cultures,  which  bring  about  a  tolerance  on  the  part  of  the  phagocytes, 
which  eventually  are  enabled  to  attack  and  destroy  the  organisms  in 
numbers  which  ordinarily  would  cause  death.  The  phagocytes  include 
the  mononuclear  and  polymorphonuclear  leucocytes,  certain  cells  in  the 
serous  cavities,  connective-tissue  spaces,  lymph  nodes,  neuroglia,  splenic 
pulp,  and  in  the  lining  of  small  bloodvessels,  and  elsewhere ;  but  those 
chiefly  engaged  are  the  leucocytes. 

The  destruction  of  bacteria  by  the  phagocytes  is  attributed  to  the 
presence  of  digestive  ferments,  which  Metschnikoff  calls  Cytases,  and 
which  in  their  function  correspond  to  the  complements  of  Ehrlich. 

Metschnikoff  believes  that  what  the  Ehrlich  school  calls  immune 
bodies  and  complements  are  produced  within  the  phagocytic  cell,  and 
that,  in  natural  immunity,  they  are  retained  within  the  cell ;  while  in 
the  artificial  form,  the  immune  body,  but  not  the  complement,  is  liber- 
ated into  the  plasma.  He  explains  the  presence  of  the  two  substances 
in  an  immune  serum  as  a  consequence  of  disintegration  of  phagocytes 
(Phagolysis) ;  but  Wassermann  has  demonstrated  that  complement  exists 
naturally  in  the  free  state  in  the  blood.  He  believes  that  under  ordi- 
nary conditions  the  bacterium  is  englobed  by  the  cell,  which  produces 
both  substances  necessary  for  the  process  of  destruction.  In  what  is 
known  as  "  Pfeiffer's  phenomenon  "  (see  page  733),  Metschnikoff  asserts 


PRACTICAL  APPLICATIONS  OF  STUDIES  IN  IMMUNITY.      745 

that  the  phagocytes  are  broken  up  in  consequence  of  the  operation  on 
the  animal,  and  thus  the  cytase  (complement)  is  liberated ;  but  this 
alleged  phagolysis  is  denied  and  disproved. 

The  Metschuikoif  school  asserts  that  not  only  the  process  of  bac- 
teriolysis, but  also  that  of  haemolysis,  is  carried  on  by  the  leucocytes ; 
that  they  also  absorb  and  destroy  the  soluble  toxins  ;  that  anticomple- 
ments  do  not  neutralize  complements,  but  merely  paralyze  the  leucocytes  ; 
and  that  the  circulating  blood  has  no  bactericidal  power. 

Both  the  Ehrlich  and  the  Metschnikoff  schools  agree  that,  in  acquired 
imnaunity,  two  substances,  immune  body  and  complement,  are  necessary  ; 
the  former  insists  that  these  exist  in  a  free  state  in  the  blood  ;  the  latter, 
that  they  are  contained  within  the  phagocytic  cells.  Both  agree  that 
the  immune  bodies  are  wholly  specific,  but  the  Metschnikoff  school  insists 
upon  two  common  complements  (^Macroeytase  and  Microcytase).  The 
Ehrlich  school  recognizes  the  importance  of  the  leucocytes,  but  does 
not  affree  as  to  their  role. 


Practical  Applications  of  the  Results  of  Studies  in  Immunity. 

While  it  is  true  that,  in  spite  of  the  vast  amount  of  experimentation 
on  the  subject,  the  practical  application  of  what  has  been  thus  far  dis- 
covered to  the  prevention  and  cure  of  disease  has  made  comparatively 
little  progress,  it  must  be  borne  in  mind  that  the  problems  of  biochemis- 
try are  exceedingly  complex  ;  that  the  work  of  solving  them  is  of  quite 
recent  origin  ;  that  the  pursuit  of  methods  for  their  solution  has  neces- 
sitated the  investigation  of  many  points  of  apparently  indirect  relation 
to  the  main  question  ;  and  that  one  is  obliged  to  reason  largely  from 
phenomena  which  are  the  outcome  of  processes  which  do  not  occur  in 
nature.  It  may  be  said  that  the  whole  subject  is  still  in  its  infancy, 
and  that  only  a  small  part  of  the  foundation  of  the  final  structure  has 
yet  been  laid.  Thus  far  the  only  really  brilliant  results  achieved  in  the 
practical  application  of  the  discoveries  in  immunity  are  limited  to  one 
disease — Diphtheria — the  toxic  material  of  which,  being  soluble  and 
extracellular,  makes  easily  possible  the  production  of  an  immune  serum 
which  can  be  used  either  as  a  prophylactic  or  as  a  curative  agent.  The 
pathogenic  organisms  other  than  those  of  diphtheria  and  tetanus  retain 
their  toxins  within  their  ceil  substance,  and  the  immune  serums  produced 
by  their  introduction  into  living  animals  are  not  antitoxic,  but  bac- 
teriolytic, and  exert  only  temporary  protection  and  but  slight  curative 
action. 

The  lack  of  success  in  the  treatment  of  diseases  caused  by  this  class 
of  bacteria  is  due  probably  to  the  disparity  in  the  amount  of  ambo- 
ceptor and  complement  in  the  immune  serum.  As  has  been  pointed 
out,  a  bacteriolytic  immune  serum  contains  an  enormous  increase  in  the 
amount  of  specific  amboceptor  (sometimes  100,000  times  as  much), 
Vjut  no  increase  in  complement.  Inasmuch  as  the  conjoint  action 
of  both  is  necessary  for  thc^  destruction  of  the  l)acterial  cells,  it  follows 
that,  unless  the  patient  can  furnish  the  necessary  amount  of  complement, 


746  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

the  treatment  must  fail.  To  supply  the  needed  additional  complement 
is  not  an  easy  matter,  even  if  normal  serum  be  injected,  on  account  of 
the  multiplicity  of  complements  ;  for,  according  to  Ehrlich  and  Mor- 
geuroth,  each  kind  of  amboceptor  requires  a  different  specific  comple- 
ment ;  and  hence  they  recommend  the  immunization  of  different  species 
of  animals  with  the  same  kind  of  bacteria  and  the  utilization  of  a 
mixture  of  the  several  serums,  thus  bringing  into  action  amboceptors 
and  complements  which,  although  differing  according  to  the  species  in 
which  they  are  produced,  are,  nevertheless,  specific  against  the  same 
organism,  and  some  of  them,  at  least,  may  satisfy  the  needs  of  the 
human  system.  Not  only  does  a  deficiency  of  complement  in  itself 
present  an  insuperable  obstacle  to  successful  treatment,  but  the  excess 
of  amboceptor  may  also  work  injuriously  by  preventing  the  available 
complement  from  exercising  its  function,  as  has  been  shown  by  Neisser 
and  Wechsberg,  who  proved  that  it  may  unite  directly  with  the  com- 
plement, which  has  a  greater  affinity  for  free  amboceptor  than  for  that 
which  has  linked  itself  to  the  bacteria ;  whereas,  in  the  absence  of  an 
excess,  the  complement  will  unite  with  that  which  already  has  engaged 
the  bacteria.  Thus  it  happens  that  successful  treatment  depends  upon 
the  very  difficult  problem  of  bringing  together  in  the  diseased  system 
the  proper  amounts  of  amboceptor  and  complement  to  cope  with  the 
specific  bacteria.  An  excess  of  complement  is  not  to  be  thought  of, 
but  a  material  excess,  either  of  amboceptor  on  the  one  hand  or  of 
specific  bacteria  on  the  other,  is  fatal  to  success. 

DIPHTHERIA. 

As  has  been  stated,  the  disease  iu  which  the  most  brilliant  results  have 
been  achieved  in  the  application  of  an  immune  serum  is  Diphtheria, 
against  which  the  agent  may  be  employed  either  as  a  means  of  cure  or 
as  a  prophylactic.  Its  introduction  as  a  curative  agent,  in  1894,  met 
at  first  with  much  adverse  criticism,  but  its  value  was  soon  firmly 
established,  and  statistics  of  cases  to  the  number  of  hundreds  of 
thousands  testify  that  the  mortality  has  been  reduced  from  about  40 
per  cent,  to  about  15  per  cent,  or  lower.  The  statistics  of  the  Boston 
City  Hospital  show  that  of  3067  cases  treated  during  the  period  1888— 
1894,  43  per  cent,  resulted  fatally  ;  while  with  antitoxic  treatment  the 
death-rate  of  14,910  received  during  the  period  1895-1904  was  but 
11.84  per  cent.  During  the  year  ending  December  31,  1904,  the 
death-rate  was  9.57  per  cent.,  and  if  those  cases  which  ended  fatally 
within  twenty-four  hours  of  admission  are  eliminated,  this  figure  is 
reduced  to  6.95  per  cent.  Preventive  treatment  has  been  practised  exten- 
sively in  schools,  hospitals,  and  other  institutions  for  children,  but  the 
immunity  thus  conferred  is  but  transient.  In  a  children's  hospital  in 
which  an  outbreak  of  diphtheria  occurred,  Lohr^  immunized  460 
inmates  and  the  outbreak  was  checked,  no  cases  occurring  within  three 
weeks  of  the  operation.     Later,  a  few  cases  occurred,  which  illustrated 

^  Jahrbuch  fiir  Kinderheilkunde  und  physiscbe  Erziehung,  September,  1896. 


DIPHTHERIA.  747 

the  temporary  nature  of  the  immunity.  Of  99  patients  with  measles, 
treated  because  of  the  special  danger  of  diphtherial  supervention,  not 
one  was  attacked.  Similar  outbreaks  in  children's  institutions  have 
repeatedly  been  checked,  but  since  the  protection  conferred  is  so  tran- 
sient, reappearance  of  cases  is  likely  to  occur,  as  in  the  instance  cited ; 
and  to  guard  against  this,  it  is  advisable  to  remove  the  inmates  long 
enough  to  give  the  premises  a  thorough  disinfection. 

According  to  Netter,^  immunity  begins  after  24  hours  and  wears  off 
within  3  or  4  weeks.  He  recommends  that,  when  a  case  of  the  dis- 
ease occurs  in  a  school,  hospital,  or  other  institution  for  children,  the 
other  inmates  be  treated.  The  treatment  is  advised  also  in  measles  and 
scarlet  fever  wards  as  a  preventive  of  possible  diphtherial  complication. 
An  instance  is  given  in  which  the  disease  was  a  frequent  complication 
in  a  measles  ward,  2  to  4  cases  occurring  during  each  of  4  months,  and 
19  in  the  next  succeeding  6  weeks,  after  which  period  each  child  was 
treated  on  entrance  and  no  further  cases  occurred.  The  employment 
of  the  immunizing  treatment  as  a  routine  practice  is  advocated  by  Caille  ^ 
for  young  schoolchildren,  for  the  purpose  of  preventing  primary  infec- 
tion and  diphtherial  complication  of  scarlet  fever  and  measles.  He 
recommends  two  treatments  during  the  school  year. 

The  serum  employed  acts  upon  the  toxins,  but  it  is  not  bactericidal, 
and  hence  does  not  act  upon  the  bacilli  which  secrete  them ;  but  Was- 
sermann  ^  has  brought  to  notice  a  serum  which  acts  upon  the  bacilli 
themselves.  It  is  the  result  of  the  inoculation  of  the  specific  bacilli  in 
large  numbers,  rather  than  of  the  toxin,  and  causes  changes  in  the  in- 
tracellular substance  of  the  bacilli,  and  agglutination.  Schwone  having 
shown  that  such  a  serum  obtained  by  the  inoculation  of  a  single  culture 
acts  upon  only  a  limited  number  of  other  cultures,  the  experiment  was 
tried  of  treating  the  same  animal  with  a  large  number  of  cultures,  and 
in  this  way  there  have  been  obtained  "  multipartial "  serums  which 
agglutinate  all  cultures  subjected  to  their  action.  Wassermann  has 
made  the  important  discovery  that  with  such  a  serum  it  is  possible  to 
overcome  the  bacilli  that  so  often  remain  for  a  long  time  in  the  naso- 
pharynx, and  thus  prevent  the  patient  from  being  liberated  from  house 
quarantine.  A  strongly  agglutinating  serum  is  evaporated  to  dryness 
in  vacuo,  mixed  with  sugar  of  milk,  and  made  into  tablets,  which  on 
being  dissolved  in  the  mouth  confer  upon  the  fluids  of  the  same  the 
property  of  agglutinating  the  bacilli,  which  then  can  be  removed  by 
spraying  or  gargling.  A  tablet  is  dissolved  every  two  hours,  and  after 
fifteen  minutes  the  clumped  bacteria  are  removed  by  the  spray  or  gargle. 
By  this  treatment  the  nasopharynx  has  in  many  cases  been  freed  from 
the  Ijacilli  within  a  few  days. 

'  Bullf-tin  (le  I'Arademie  de  Mddedne,  March  18,  1902. 

^  Archives  of  Paediatrics,  October,  1903. 

^  New  York  Medical  Journal  and  Philadelijhia  Medical  Journal,  October  15, 1904. 


748  INFECTION,  SUSCEPTIBILITY,   IMMUNITY. 

TETANUS. 

Like  diphtheria,  tetanus  is  due  to  extracellular  toxins  which  are 
produced  by  the  localized  bacilli.  They  are  conveyed  in  the  blood 
stream  to  the  cells  of  the  central  nervous  system,  for  which,  as  has  been 
shown,  they  have  a  selective  affinity,  and  with  Avhich  they  form  a  very 
close  union.  Although  it  is  possible  to  })roduce  an  antitoxic  serum 
which,  in  test-tube  experiments,  acts  equally  well  with  the  diphtheria 
antitoxin  in  neutralizing  the  specific  toxins,  the  antitoxic  treatment  of 
the  disease  has  failed  signally  in  fulfilling  expectations.  This  is  because 
before  the  diagnosis  can  be  established,  the  injury  to  the  cells  has  been 
effected  beyond  the  possibility  of  repair.  The  antitoxin  is,  however, 
valuable  in  aborting  possible  attack,  and  its  injection  has  become  a 
routine  practice  in  cases  of  gunshot  wounds  and  similar  accidents, 
especially  after  the  annual  observance  of  Independence  Day. 

HAY   FEVER. 

In  hay  fever  we  have  a  true  intoxication,  but  the  toxin  is  not 
of  bacterial  origin.  The  discovery  of  the  cause  of  this  exceedingly 
annoying  condition  is  due  to  the  investigations  of  Professor  William 
Dunbar,  of  Hamburg,  who  proved  that  the  disease  is  due  not  to 
bacteria,  but  to  the  poison  contained  in  the  pollen  grains  of  various 
grasses.  In  his  first  communication  ^  he  showed  the  difference  in  the 
way  susceptible  and  non-susceptible  persons  react  to  the  dissolved 
toxin  ;  9  of  the  former  subjected  to  its  influence  developed  typical 
symptoms,  and  20  of  the  latter  were  in  no  way  aifected.  In  a  later 
paper  ^  he  showed  that  the  autumnal  catarrh,  which  is  peculiar  to  this 
continent,  is  caused  by  the  pollen  of  goldenrod,  ragweed  and  other 
weeds  not  indigenous  to  Europe.  In  the  same  way  that  diphtheria 
antitoxin  is  produced,  Dunbar  obtains  a  horse  serum  which  neutralizes 
the  pollen  toxin  completely.  This  toxin  is  so  powerful  that  one-forty- 
thousandth  part  of  a  milligram  (corresponding  to  2  or  3  pollen  grains) 
is  sufficient,  when  placed  in  the  conjunctival  sac  of  a  susceptible  per- 
son, to  cause  an  attack  lasting  several  hours,  but  it  will  yield  readily 
to  the  antitoxin.  Although  the  toxin  of  the  grass  pollens  differs  from 
those  of  the  pollens  of  goldenrod,  ragweed,  etc.,  the  grass-pollen  anti- 
toxin neutralizes  them  all.  Statistics  collected  by  various  writers 
abroad  and  in  this  country  show  most  favorable  results  of  treatment. 
Unlike  diphtheria  antitoxin,  Dunbar's  preparations  (liquid  and  pow- 
dered forms)  cannot  be  employed  subcutaneously,  but  are  applied 
locally.  The  serum,  evaporated  to  dryness  and  converted  to  a  fine 
powder  with  sugar  of  milk,  is  administered  as  a  snuff  in  very  small 
doses.  It  does  not  confer  lasting  immunity,  and  must  be  resorted  to 
during  the  season  at  intervals  of  a  day  or  two,  or,  if  the  outdoor  air  be 
unusually  rich  in  pollen,  at  intervals  of  a  few  hours.     For  application 

^  Deutsche  medicinische  Wochenschrift,  Februarv  26,  1903. 
^  Berliner  klinische  Wochenschrift,  June  15,  22,  and  29,  1903. 


TYPHOID  FEVER.  749 

to  the  eyes,  the  serum  itself  is  preferred.  It  is  said  that  in  the  majority 
of  unsuccessful  cases  either  the  antitoxin  is  not  used  sufficiently  often 
or  is  taken  in  excessive  amounts,  which  aggravate  the  difficulty.  In 
some  cases  the  mucous  membranes  are  in  such  swollen  condition  as  not 
to  permit  absorption. 

DYSENTERY. 

The  exciting  causes  of  dysentery  (Shiga's  and  Kruse's  bacilli)  elab- 
orate toxins  which  appear  to  be  approximately  identical,  and  which 
can  be  used  for  the  production  of  antitoxic  serums.  Shiga  claims  for 
his  serum  a  diminution  in  mortality  amounting  to  about  50  per  cent. 
Rosenthal  ^  isolated  a  toxin  from  bouillon  cultures  of  the  bacillus,  with 
which  he  succeeded  in  obtaining  an  antiserum,  which  is  said  to  have  had 
about  the  same  measure  of  success  that  Shiga  claims.  The  extensive 
researches  made  in  this  country  during  1903  and  1904  into  antidysen- 
teric  serum  have  led  to  the  conclusion  that  it  is  not  a  success. 

TYPHOID   FEVER. 

Numerous  attempts  have  been  made  to  produce  an  antityphoid 
sernm  for  the  treatment  of  the  disease  when  it  has  become  estab- 
lished, but  as  yet  the  results  have  been  very  disappointing,  although 
Chantemesse^  claims  that  in  the  treatment  of  765  cases  with  his  serum 
during  a  period  of  three  and  a  half  years,  a  very  low  mortality  has 
been  observed.  During  the  same  period,  the  cases  treated  in  other 
Paris  hospitals  yielded  an  average  mortality  of  18  per  cent.,  the  lowest 
shown  by  any  one  of  the  institutions  being  12.8  per  cent.  The  765 
cases  treated  with  his  serum  showed  a  mortality  of  but  4  per  cent. 

For  Jez's  antityphoid  extract,  obtained  from  the  organs  of  animals 
inoculated  with  typhoid  bacilli,  is  claimed^  that  it  reduces  the  tempera- 
ture, strengthens  the  pulse,  and  shortens  the  attack.  It  is  given  at  first 
in  doses  of  15  c.c.  once  or  twice  an  hour,  and,  after  the  first  remission, 
at  intervals  of  three  hours.  When  the  morning  temperature  falls  to 
about  100°  F.,  the  extract  is  given  thrice  daily. 

By  grinding  typhoid  bacilli  frozen  by  means  of  liquid  air,  Macfad- 
yen  and  Rowland  ^  succeeded  in  obtaining  their  intracellular  toxins, 
which  they  injected  in  small  repeated  doses  into  animals,  which  then 
yielded  a  serum  which  proved  to  be  both  antitoxic  and  bactericidal, 
neutralizing  the  isolated  intracellular  toxins  and  destroying  the  bacilli. 

That  the  toxins  of  the  typhoid  bacillus  are  not  wholly  intracellular 
is  asserted  by  Rodet,  Lagriffiaul  and  Wahby,*^  who  found  that,  while  the 
bacilli  secrete  toxic  products,  these  are  largely  adherent  to  the  exterior 
of  the  cell-substance,  and  are  of  vmstable  character.  Nevertheless, 
experimenters  believe  them  to  be  the  cause  of  the  systemic  disturbance. 

'  Deutsche  mccliriniflchc  Woclicnschrift,  1904,  No.  7. 

*  PresHG  MM'icnU;  1904,  No.  HO,. 
3Th<;rapeuliHclie  Monafsliofte  XV.,  1001,  No.  9. 

*  Ontralhlatt  fiir  Hakt<Tiolot;ie,  etc.,  XXXIV.,  p   filR. 

^  Arcliives  de  Mwl.  Kxper.  et  d' Ariat.  I'athologique,  July,  1904. 


750  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

The  preventive  inoculation  of  sterilized  cultures  of  typhoid  bacilli 
appears  to  have  been  very  successful.  Among  the  favorable  reports 
the  following  may  be  cited:  Wright^  reports  that  of  11,295  men 
of  the  British  Indian  army  under  observation  for  nine  months,  0.95 
per  cent,  of  those  inoculated  (2,835)  and  2.5  per  cent,  of  those 
not  inoculated  (8,460)  acquired  the  disease.  Of  a  smaller  number 
of  susceptible  persons,  Wright^  reports  that  1  in  77  of  the  inoculated 
(541)  and  1  in  4  of  the  non-inoculated  (114)  were  seized. 

In  the  beleaguered  garrison  of  Ladysmith,  South  Africa,  there  was 
much  typhoid  fever.  Between  November  2,  1899,  and  February  2, 
1900,  there  were  1,489  cases  among  the  10,529  who  were  not  inocu- 
lated, and  only  35  among  the  1,705  who  had  been  inoculated,  instead 
of  250,  which  would  have  been  the  probable  number  otherwise.  The 
death-rates  of  the  two  groups  were  respectively  3.12  and  0.047.  Later 
statistics  published  by  Wright  ^  deal  with  a  much  larger  number  of 
men  of  the  Indian  and  South  African  armies.  In  India  there  were 
744  cases  of  the  disease  with  199  deaths  among  55,955  non-inoculated 
soldiers — an  attack-rate  of  1.33  and  a  death-rate  of  0.36  per  thou- 
sand ;  but  among  4,883  who  were  inoculated,  there  were  but  32  cases 
with  3  deaths — an  attack-rate  of  0.66  and  a  death-rate  of  0.06  per 
thousand.  In  South  Africa  the  attack-rates  for  the  non-inoculated  and 
inoculated  soldiers  were  respectively  2.3  and  1  per  thousand. 

Crombie,^  in  a  consideration  of  the  effects  of  antityphoid  inoculation 
in  South  Africa,  lays  particular  emphasis  on  the  influence  of  age.  In 
persons  under  30  the  advantage  of  inoculation  is  marked,  the  incidence 
among  the  inoculated  being  about  half  that  among  the  non-inoculated  ; 
but  beyond  that  age  the  reverse  is  the  fact,  the  incidence  among  the 
non-inoculated  being  about  half  that  among  those  who  had  undergone 
one  treatment.  He  suggests  that  as  the  period  of  greatest  susceptibility 
(20  to  25  years)  passes,  inoculation  tends  rather  to  increase  the  prob- 
ability of  becoming  infected.  Wright^  emphasizes  the  fact  that  in 
preventive  inoculation  there  is  danger  if  the  subject's  natural  resistance 
is  reduced,  as  is  often  the  case,  by  a  previous  attack,  and  when  an 
excessive  dose  is  given  or  reinoculation  is  performed  after  too  short  an 
interval,  and  also  when  a  full  dose  is  given  in  actually  infected  sur- 
roundings. 

Besredka "  asserts  that  he  has  succeeded  in  producing  a  means  of 
immunization  which  is  free  from  the  disadvantage  of  local  and  general 
reaction,  and  produces  immunity  which  is  much  more  lasting.  An 
emulsion  of  the  living  organisms  is  mixed  with  immune  serum  that 
has  been  heated  so  as  to  destroy  the  complements  but  not  the  ambo- 
ceptors, and  is  allowed  to  stand  for  a  number  of  hours,  during  which 
time  union  occurs  between  the  latter  and  the  bacteria.     The  mixture  is 

*  British  Medical  Journal,  January  20,  1900. 

2  Ibidem,  October  26,  1901. 

3  British  Medical  Journal,  October  10,  1903. 

*  The  Lancet,  August  16,  1902. 

^  British  Medical  Journal,  August  16,  1902. 
^  Annales  de  I'lnstitut  Pasteur,  XVI.,  No.  12. 


BUBONIC  PLAGUE.  751 

then  heated  on  a  water-bath  to  60°  C,  and  the  organisms  are  thereby 
killed.  After  thorough  washing  the  organisms  with  the  antibodies 
which  have  united  with  them  are  used  as  an  injection,  Besredka 
claims  that  immunity  is  produced  within  24  hours  ;  that  it  lasts  at 
least  five  and  a  half  months ;  and  that  neither  local  nor  general 
symptoms  follow  the  injection. 

Wassermann/  believing  that  immunity  is  dependent  upon  the  use 
of  a  culture  which  will  fit  the  patient's  receptors  rather  than  upon  the 
degree  of  virulence  of  the  culture,  recommends  the  employment  of  a 
number  of  races  of  the  specific  organism  in  the  preparation  of  a  true 
polyvalent  agent.  The  mixed  cultures  are  killed  by  heat  and  allowed 
to  undergo  autolysis,  and  then  the  liquid  is  evaporated  in  vacuo  and 
the  residue  reduced  to  a  powder,  which  may  be  kept  unchanged.  Such 
an  immunizing  agent  may  be  prepared  also  for  Asiatic  cholera. 

ASIATIC    CHOLERA. 

Preventive  inoculation  against  Asiatic  cholera  actually  antedates  the 
antitoxic  treatment  of  diphtheria,  since  it  was  in  1890  that  Haffkine, 
inspired  by  Pasteur's  discovery  in  1880  that  chickens  could  be  ren- 
dered immune  to  chicken  cholera  by  preventive  inoculation,  discovered 
that  the  same  was  true  of  human  beings  in  respect  to  Asiatic  cholera. 
First  he  experimented  upon  himself,  and  then  made  70,000  injections 
of  living  cholera  germs  into  40,000  people  in  India  within  a  period  of 
two  years.  By  inoculating  only  a  part  of  any  given  population  where 
cholera  was  raging,  he  was  sure  of  a  control  by  which  he  could  judge 
of  the  value  of  his  work.  The  rate  of  attack  among  those  inoculated 
fell  to  about  one-twentieth,  and  the  mortality  in  about  the  same  pro- 
portion. 

Experimental  work  by  Kolle  led  to  the  conclusion  that  sterilized 
cultures  possess  the  same  immunizing  power,  and  on  his  recommendation 
that  such  be  used  in  place  of  the  living  organisms,  Murata^  adopted 
this  means  of  conferring  immunity  and  employed  it  most  extensively. 
Of  every  10,000  persons  so  inoculated,  6  contracted  the  disease,  against 
13  of  the  same  number  not  treated.  This  difference  in  the  number  of 
seizures  is,  however,  hardly  large  enough  to  be  regarded  as  having 
much  probative  force,  but  it  is  worthy  of  note  that  the  mortality  among 
the  inoculated  was  considerably  lower  and  the  severity  of  the  attack 
■was  less  marked.  Besredka  prepares  an  anticholera  injection  in  the 
same  way  that  the  antityphoid  injection  above  described  is  produced, 
and  claims  for  it  the  same  advantages. 

BUBONIC    PLAGUE. 

It  is  to  ITaffkine  also  that  the  prophylactic  treatment  for  bubonic 
plague  is  due.  He  discovered  tliat  imnumity  could  be  attained  by 
injecting  sterilized  cultures  of   t])c  specific  l)acilli  (treated  at  70°  C. 

'  Festichrift  ziir  seclizif^stori  (jcbiirtstiiffc  von  R.  Koch,  1903,  p.  526. 
'■*  Centi-dlblatt  fur  I}akteri(jlogie,  etc.,  1904,  XXXV.,  No.  5. 


752  INFECTION,  SUSCEPTIBILITY,  IMMUNITY. 

for  an  hour  or  longer).  The  injection  causes  slight  fever,  with 
enlargement  of  the  nearest  lymphatic  glands,  but  all  evidence  of 
reaction  disappears  in  from  2  to  3  days.  While  the  treatment  con- 
fers some  degree  of  immunity,  the  duration  thereof  is  very  uncer- 
tain :  it  may  be  two  days  or  several  months.  Haffkine  asserts  that  it 
lasts  from  4  to  6  months  and  sometimes  for  as  long  as  2  years,  but  the 
weight  of  evidence  tends  to  indicate  that  it  is  not  safe  to  count  upon  a 
more  lasting  immunity  than  3  months,  and  hence  that  reinoculation 
every  3  mouths  is  -advisable.  Calmette  has  called  attention  to  the  fact 
that  inoculation  of  persons  in  whom  the  infection  is  already  present  in 
the  incubative  stage  will  hasten  the  appearance  of  the  disease  and  con- 
duce to  a  fatal  result.  Personal  investigation,  in  India,  of  the  results 
obtained  led  B.  R.  Slaughter  ^  to  conclude  that  the  treatment  acts  within 
24  hoars  and  renders  the  subject  immune  for  3  months  ;  that  when 
applied  during  the  stage  of  incubation,  it  frequently  aborts  the  disease ; 
that  it  has  no  eifect  on  other  diseases  excepting  eczema,  which  appears 
to  derive  benefit  therefrom  ;  and  that  the  chances  of  recovery  are  greatly 
increased  in  case  of  attack  in  spite  of  the  inoculation. 

According  to  a  report  of  the  Plague  Commissioners  in  India,  of 
4,296  persons  inoculated  once,  only  45  contracted  the  disease,  and  of 
3,387  inoculated  twice,  2  were  seized.  Fifteen  of  the  former  and  1 
of  the  latter  died.  At  the  same  time,  among  the  non-inoculated  persons, 
no  less  than  657  per  thousand  died  in  a  single  week  (the  third  week 
of  September,  1899).  At  Kirkee  (India)  the  plague  broke  out 
in  a  small  camp ;  671  persons  were  inoculated  and  859  were  left 
unprotected.  Thirty-two  cases  occurred  among  the  inoculated  and  143 
among  the  uninoculated.  The  mortality  among  the  inoculated  was 
2.05,  and  among  the  uninoculated,  11.40,  per  cent.  In  another  camp, 
324  persons  were  inoculated  and  300  left  unprotected.  Fourteen  cases 
occurred  among  the  uninoculated  and  none  among  those  protected. 

From  further  statistics  which  demonstrate  the  value  of  the  treat- 
ment, the  following  may  be  quoted  :  In  the  Bombay  Presidency,  in  one 
community,  among  365  persons  who  were  inoculated  there  were  13 
cases  with  3  deaths,  while  among  413  not  inoculated,  there  were  48 
cases  with  36  deaths.  In  another  community  there  were  7  deaths 
among  5,184  inoculated,  and  177  among  8,146  not  inoculated.  At 
Lanowli,  among  323  who  were  inoculated,  there  were  14  cases  with 
7  deaths,  and  among  377  not  inoculated,  78  cases  with  58  deaths. 

Immunity  appears  to  be  prolonged  by  a  second  inoculation  within 
ten  days  of  the  first,  as  is  shown  by  the  following  figures  :  At  Shawar, 
among  5,614  persons  not  inoculated,  there  were  957  cases  with  756 
deaths;  among  5,712  who  were  inoculated  but  once,  there  were  69 
cases  with  31  deaths  ;  but  among  3,349  who  were  inoculated  twice, 
there  were  only  9  cases  with  5  deaths. 

Prior  to  the  discovery  of  the  Haffkine  prophylactic,  Yersin's  anti- 
pest  serum,  which  is  the  only  known  remedy  for  the  cure  of  the  disease, 
was  employed  as  an  immunizing  agent,  but  the  duration  of  immunity 
^  Bulletin  of  the  Johns  Hopkins  Hospital,  November,  1908. 


ANTISTREPTOCOCCUS  SERUMS.  753 

was  found  rarely  to  exceed  two  weeks,  and  hence  the  treatment  must 
be  repeated  every  fourteen  days  in  order  to  insure  protection.  It  is 
claimed  by  Calmette  that  the  serum  confers  an  immunity,  certain  and 
effective,  ahiiost  immediately  after  the  injection  ;  that  the  injection  is 
not  painful  and  is  never  harmful ;  and  that  the  serum,  properly  pre- 
pared, retains  its  power  almost  indefinitely.  On  the  other  hand,  the 
disadvantages  are  the  short  duration  of  immunity,  the  great  cost  of 
production,  the  difficulty  of  obtaining  a  supply  sufficient  for  the 
repeated  treatment  of  entire  populations,  and  the  difficulty  of  inducing 
the  natives  to  submit  even  once  to  the  operation.  It  takes  from  seven 
months  to  a  year  to  immunize  a  horse  to  the  point  that  his  serum 
acquires  preventive  and  curative  properties,  and  many  of  the  horses 
die  before  the  process  of  immunization  is  completed.  According 
to  Assistant  Surgeon-General  Greenleaf,  protective  inoculation  by 
means  of  the  Yersin  serum  is  not  practical  for  the  following  reasons  : 
The  enormous  plant  necessary  for  the  production  of  the  material ;  the 
large  working  force  necessary  for  conducting  the  inoculations ;  the 
opposition  of  the  people  to  the  treatment ;  and  the  short  duration  of 
the  benefit  conferred. 

Cairns,^  who  used  the  serum  with  some  success  in  the  treatment  of 
cases  at  Glasgow,  concludes  that  it  is  both  antitoxic  and  bactericidal, 
and  that  it  produces  its  best  effects  when  the  injection  is  made  early 
and  both  subcutaneously  and  intravenously,  the  total  initial  dose 
ranging  from  150  to  300  cc,  according  to  the  circumstances  of  the 
case. 

Besredka's  prophylactic  is  prepared  in  the  same  way  and  has  the 
same  advantages  as  those  which  he  prepares  for  typhoid  fever  and 
cholera,  but  the  organisms  are  first  killed  by  heating  to  60°  C.  for  an 
hour  on  the  water  bath,  before  being  mixed  with  the  antiserum. 

Both  the  Yersin  serum  and  the  HaiFkine  prophylactic  are  very  un- 
popular with  the  natives  of  India.  The  Hindoos  suspect  that  the 
materials  are  of  animal  origin,  and  the  injection  of  such  matters  into 
the  body  constitutes  an  offence  against  their  religion. 

ANTISTREPTOCOCCUS    SERUMS. 

Antistreptococcus  serums  of  various  kinds  have  been  employed  in  the 
treatment  of  Erysipelas,  Puerperal  Sepsis,  Malignant  Endocarditis  and 
other  streptococcic  infections  and  Scarlet  Fever,  but  thus  far  they  have 
not  given  results  that  indicate  that  they  are  of  much  value.  They  have 
been  prepared  by  inoculating  with  living  cultures  of  streptococci  and 
with  the  intracellular  substance  of  killed  cultures,  and,  on  account  of 
the  asserted  differences  in  the  organisms  according  to  the  nature  of  the 
pathologic  processes  in  which  they  are  a  factor,  with  cultures  obtained 
from  a  number  of  subjects  with  different  diseases,  and  also  with  cul- 
tures taken  directly  from  a  number  of  individuals  with  the  same  disease, 
as  is  the  method  followed  by  Moscr  in  the  preparation  of  his  poly- 

'  Therapeutische  Monatshefte,  May,  1904. 
48 


754  INFECTION,   SUSCEPTIBILITY,   IMMUNITY. 

valent  serum  for  scarlet  fever.  They  have  been  prepared  also  by 
inoculating  with  organisms  rendered  unusually  virulent  by  being  passed 
through  a  series  of  animals. 

How  these  various  serums  produce  such  results  as  have  been  observed 
is  a  matter  of  some  disagreement.  It  is  believed  by  some  that  they 
are  bactericidal,  but  this  is  denied  by  others,  who  believe  that  they  act 
as  stimuli  to  the  phagocytic  cells.  However  they  may  act,  the  hoped- 
for  results  have  not  been  attained,  and  immunity  to  streptococcic 
invasion  is  evidently  a  very  complex  problem. 

TUBERCULOSIS. 

In  the  treatment  of  tuberculosis,  Maragliauo's  serum,  for  which  are 
claimed  both  antitoxic  and  bactericidal  properties,  and  Marmorek's, 
which  is  antitoxic  only,  have  failed  thus  far  to  yield  other  than  disap- 
pointing results,  although  the  principal  advocates  of  each  have  asserted 
otherwise.  No  progress  worthy  of  note  has  been  made  in  the  serum 
treatment  of  Pneumonia ;  indeed,  it  has  scarcely  entered  the  laboratory 
stage  of  experimentation. 


CHAPTER    XVII. 
VACCINATION  AND  SMALLPOX. 

Prior  to  the  discovery  of  vaccination  by  Jenner,  toward  the  close 
of  the  eighteenth  century,  smallpox  was  one  of  the  principal  scourges 
of  the  world.  It  killed,  on  an  average,  nearly  half  a  million  people 
in  Europe  alone,  and  about  once  in  three  years  was  more  than  ordi- 
narily severe.  In  England,  Germany,  France,  Sweden,  and  other 
countries  of  Europe,  the  yearly  mortality  from  smallpox  was  about 
two  thousand  per  million  inhabitants.  More  than  half  the  cases  of 
blindness  throughout  Europe  were  attributed  to  the  disease,  and  about 
a  third  of  the  population  showed  in  their  faces  evidences  of  having 
had  it. 

It  was  well  known  that  those  who  recovered  enjoyed  protection  from 
recurrence  of  the  disease,  and  consequently  it  had  long  been  the  prac- 
tice to  produce  immunity  by  causing  the  disease  intentionally  by  inocu- 
lation when  it  prevailed  in  a  modified  form,  favorable  to  recovery. 
For  more  than  a  thousand  years,  the  Chinese  and  other  Eastern  peoples 
had  produced  the  disease  by  blowing  dried  smallpox  matter  in  pow- 
dered form  into  the  nostrils.  The  discovery  that  the  inoculation  of 
material  from  a  smallpox  pustule  was  more  certain  and  quick  in  its 
results  led  to  the  widespread  practice  of  inoculation.  This  was  begun 
in  England  in  1721,  and  toward  the  end  of  the  century  was  em- 
ployed very  extensively ;  and  even  after  the  discovery  of  the  beneficent 
results  of  vaccination,  was  practised  to  a  certain  extent,  until,  in  1840, 
it  was  prohibited  by  law. 

The  first  successful  vaccination  M^as  performed  by  Benjamin  Jesty,  a 
Dorsetshire  farmer,  who  inoculated  his  wife  and  two  sons  from  the 
teats  of  cows  afflicted  with  cowpox.  The  inoculation  was  successful 
in  all  three  cases,  although  the  wife  had  a  badly  inflamed  arm.  Fif- 
teen years  later,  the  two  sons  were  inoculated  with  smallpox,  but  noth- 
ing resulted.  It  is  said  that  Heim^  had  noted  as  early  as  1763  that 
the  accidental  inoculation  of  cowpox  was  followed  by  smallpox 
immunity.  The  practice  of  vaccination  is,  however,  due  to  the  M'ork 
of  Jenner,  who,  on  May  14,  1796,  performed  his  first  successful 
opfjration.  After  some  very  strong  opposition,  intelligent  people  began 
to  a<lo))t  the  ])ractice,  and  the  uneducated  classes  began  to  fall  gradually 
into  line.  The  ])ractice  was  adojited  in  America,  France,  Germany, 
and,  in  fact,  tlu;  entire  civilized  world,  and  everywhere  proved  to  be  of 
the  greatest  benefit.     In  1802,  the  English  Parliament  awarded  Jenner 

*  Nothnagel's  .Si)eciolIo  Patliolof^ne  und  Tlierapie,  IV.,  IT.  2. 

755 


756  VACCINATION  AND  SMALLPOX. 

4,000  pounds  sterling,  and  later,  a  still  larger  grant  was  made.  But 
the  j)ioneer,  Jesty,  was  not  lost  sight  of,  and  in  1805  he  was  the 
honored  guest  of  the  Jennerian  Society. 

The  practice  was  introduced  into  this  country  by  Dr.  Benjamin 
Waterhouse,  Professor  of  Physick  in  Harvard  University,  who,  on 
July  8,  1800,  vaccinated  his  seven  children,  with  six  positive  results. 
About  the  same  time  it  was  introduced  into  Philadelphia  by  John 
Redman  Coxe,  who  vaccinated  his  eldest  child  and  then  exposed  him 
to  smallpox  without  result.  In  Boston,  in  August,  1802,  19  boys 
were  vaccinated  successfully  at  a  temporary  hospital  on  Noddle  Island 
(now  East  Boston),  and  in  November,  these  and  one  other,  who  had 
been  vaccinated  two  years  previously,  were  inoculated  with  smallpox, 
but  in  no  case  was  the  disease  produced.  Two  unvaccinated  boys  were 
inoculated  at  the  same  time,  and  both  developed  the  disease.  In  1806, 
Thomas  Jefferson,  who  was  the  first  to  introduce  the  practice  in  the 
South,  wrote  to  Jenner  :  ^'  You  have  erased  from  the  calendar  of  human 
aiSictions  one  of  its  greatest.  Yours  is  the  comfortable  reflection  that 
mankind  can  never  forget  that  you  have  lived.  Future  nations  will 
know  by  history  alone  that  the  loathsome  smallpox  has  existed,  and  by 
you  has  been  extirpated." 

The  beneficent  results  of  the  introduction  of  vaccination  into  this 
country  are  well  shown  by  a  couiparison  of  the  conditions  obtaining  in 
the  early  part  of  the  eighteenth  century  and  in  the  corresponding  period 
of  the  nineteenth  in  Boston.  In  1721,  Boston,  with  a  population  of 
about  11,000,  had  5,989  cases  of  smallpox  with  850  deaths.  In  1730, 
in  a  population  of  about  15,000,  there  were  about  4,000  cases  with 
509  deaths  ;  but  between  1811  and  1830,  in  a  very  much  larger  popu- 
lation, there  were  but  14  cases  of  the  disease. 

In  London,  during  the  third  quarter  of  the  seventeenth  century,  the 
average  annual  mortality  from  smallpox  per  million  was  4,000.  A 
hundred  years  later,  between  1770  and  1780,  it  was  more  than  5,000  ; 
in  the  first  years  of  vaccination,  it  was  more  than  2,000  ;  by  the  mid- 
dle of  the  nineteenth  century  it  fell  to  about  500,  and  in  the  last  decade 
of  the  century,  to  less  than  75.  In  the  whole  of  England,  during  the 
peroid  of  optional  vaccination,  the  mortality-rate  fell  from  about  2,000 
to  417,  and  after  the  practice  was  made  compulsory  in  1850,  it  fell  to 
53.  In  August,  1898,  the  "conscientiously  believes"  clause  was  en- 
acted in  deference  to  the  anti-vaccinationists,  and  by  December  31, 
230,147  persons  were  exempted.  The  result  of  this  modification  of 
the  law  has  recently  been  shown  in  extensive  epidemics  in  London 
and  elsewhere. 

In  Sweden,  where  very  accurate  records  have  been  kept  since  1774, 
the  average  mortality  per  million  of  population,  between  1774  and  1801, 
was  2,045.  During  the  years  of  optional  vaccination,  1802—1816, 
it  fell  to  480.  In  1817,  when  vaccination  was  made  obligatory,  the 
rate  began  to  fall  still  lower,  and  up  to  1893  the  average  mortality  was 
155.  During  the  last  nine  years  of  this  period,  under  more  stringent 
regulations,  it  was  never  more  than  5,  and  in  one  year  it  was  as  low  as  0.2. 


VACCINATION  AND  SMALLPOX.  757 

In  Prussia,  duriug  the  period  of  optional  vaccination,  the  mortality 
rate  fell  from  more  than  2,000  to  about  300.  During  the  Franco- 
Prussian  War,  there  were  among  the  million  well-vaccinated  German 
troops  but  459  deaths,  while  in  the  smaller,  imperfectly  vaccinated 
French  army  there  were  no  less  than  23,400.  Between  1874,  when  vac- 
cination was  made  obligatory,  and  1896,  there  was  but  one  death  from 
smallpox  in  the  whole  German  army.  In  1899,  the  total  deaths  in 
285  German  cities  and  towns,  with  a  population  of  nearly  16,000,000, 
amounted  to  only  4.  In  the  same  year,  in  France,  where  vaccination 
is  not  universal,  there  were  600  deaths  in  116  communities  with  a 
population  of  8,500,000. 

In  Austria,  Hungary,  and  Belgium,  where  the  practice  is  not  re- 
quired, the  death-rates  were,  in  1886,  respectively  81,  687,  and  48  times 
that  which  obtained  in  Germany.  In  Spain,  where,  also,  the  practice 
is  optional,  the  death-rate  in  six  provinces,  iu  1889,  was  12,050  per 
million  against  one  of  4  per  million  in  Germany, 

In  Denmark,  where  vaccination  was  made  obligatory  in  1816,  not  a 
single  case  was  known  up  to  1826. 

In  Porto  Pico,  before  the  Spanish  War,  the  annual  mortality  from 
smallpox  was  about  600 ;  but  since  the  wholesale  vaccination  by  the 
United  States  authorities,  the  disease  has  virtually  disappeared. 

In  all  countries  where  vaccination  has,  at  different  periods,  been 
optional  and  then  required,  a  remarkable  drop  has  occurred  both  in 
morbidity-  and  mortality-rates,  and  those  countries  in  which,  to-day, 
vaccination  is  not  compulsory,  suffer  periodical  visitations  of  the  dis- 
ease and  lose  thousands  of  lives.  In  1889,  for  instance,  the  death- 
rate  from  smallpox  in  Spain  was  nearly  as  great  as  obtained  a  century 
before  in  the  principal  countries  of  Europe,  while  in  the  same  year,  in 
Germany,  the  disease  was  practically  non-existent.  In  France,  in  the 
twenty -five  years  from  1870  to  1895,  more  than  20,000  people  died 
from  smallpox  in  Paris  alone,  the  epidemics  of  1871  and  1872  being 
exceptionally  severe  and  fatal.  No  epidemic  has  occurred  in  Germany 
since  1871,  when  the  disease  Avas  brought  in  by  French  prisoners, 
although  a  few  scattered  cases  have  appeared  occasionally. 

In  spite  of  the  remarkable  testimony  concerning  the  value  of  vac- 
cination in  making  a  rarity  of  what  was  once  one  of  the  principal 
scourges,  there  are  in  this  country  and  in  others  where  laws  compelling 
vaccination  have  been  enacted,  numerous  misguided  individuals  who 
band  themselves  together  into  anti-vaccination  leagues  and  attempt  to 
create  a  popular  antagonism  to  the  practice  and  to  effect  repeal  of 
existing  laws.  In  England,  as  has  been  noted,  they  have  been 
partially  successful  in  compelling  the  passage  of  a  law  which  exempts 
parents  who  have  "conscientious  scruples"  against  having  their  chil- 
dren vaccinated.  In  jirogressive  Ja]ian,  where  the  government  has 
decided  to  compc;!  vaccination  before  the  age  of  ten  months,  and  revac- 
cination  at  the  age  of  six  and  again  at  twelve,  the  anti-vaccinationist 
is   unknown. 

TIk;   following  tiiblc   shows    the   sii)alli)()x    mortality  of  the   several 


758 


VACCINATION  AND  SMALLPOX. 


countries  named,  in  which  vaccination  is  either  not  compulsory  or  im^ 
perfectly  performed,  as  compared  with  that  of  Germany,  which  in  each 
year  is  represented  by  1  : 


Switzerland 
England 

France    .  . 

Austria   .  . 
Belgium 

Holland.  . 

Germany  . 


1893. 

1894. 

1895. 

1896. 

1897. 

1898. 

8 

96 

3 

17 

25 

24 

108 

19 

23 

ie 

4 

34 

261 

201 

1,176 

123 

22 

67 

132 

28 

177 

247 

121 

158 

145 

25 

57 

21 

86 

640 

81 

147 

7 

5 

1 

1 

1 

1 

1 

1 

42 
231 

67 
174 

i 


It  cannot  be  claimed  that  vaccination  confers  absolute  immunity 
against  smallpox,  but  it  is  true  that  those  who  have  been  vaccinated 
and  then  acquire  the  disease  have  it  in  a  much  milder  form  and  are 
more  likely  to  recover  than  those  who  have  not  been  vaccinated.  In- 
vestigation of  11,0-36  cases  of  smallpox  in  England  showed  that,  for 
unvaccinated  and  vaccinated  cases,  the  rates  of  mortality  were  respec- 
tively 36.6  and  5.2  per  cent.,  and  that  for  all  cases  in  children  under 
ten,  the  rates  were  respectively  36.2  and  2.7  per  cent.  Among  those 
stricken  during  the  epidemic  at  "Warrington,  England,  in  1891-92, 
21.8  per  cent,  of  the  cases  in  vaccinated  persons  were  confluent,  while 
among  the  unvaccinated  cases,  the  percentage  was  70.6.  In  the  Shef- 
field epidemic  of  1887-88,  1.55  per  cent,  of  vaccinated  and  9.7  of 
unvaccinated  persons  were  attacked.  Among  the  former,  the  death-rate 
was  0.7,  and  among  the  latter,  48  per  thousand.  Among  children 
under  ten,  the  rate  of  attack  was  5  and  101  per  thousand,  respectively, 
for  vaccinated  and  unvaccinated,  and  the  death-rate  was  0.09  and  44. 

The  protection  conferred  by  vaccination  is  greatest  during  the  year 
succeeding  the  operation,  and  appears  to  diminish  gradually  during  the 
succeeding  five  or  six  years ;  but  the  modifying  power  does  not  di- 
minish equally  fast.  The  protective  influence  can  be  reestablished  by 
a  repetition  of  the  operation,  and  during  epidemics,  or  when  about  to 
visit  countries  where  vaccination  is  not  practised  and  smallpox  is 
endemic,  revaccination  is  always  advisable.  If  the  operation  is  negative 
in  its  results,  the  individual  is  regarded  as  immune  or  partially  pro- 
tected; but  in  the  case  of  a  first  vaccination,  it  is  customary  to  repeat 
the  operation  until  success  is  attained.  In  most  civilized  countries, 
vaccination  is  not  postponed  until  an  outbreak  of  smallpox  occurs, 
but    is  attended  to  in  the  first  few  months  of  life. 

Successful  primary  vaccination  within  three  days  after  exposure  to 
existing  cases  of  smallpox  will  prevent  the  development  of  the  disease, 
and  as  late  as  the  fifth  or  sixth  day  will  either  prevent  or  modify  an 
attack.  This  fact  has  been  utilized  in  many  cases  where  smallpox  has 
broken  out  among  unprotected  people  with  a  prospect  of  unlimited 
spread,  and  has  been  the  means  of  ending  epidemics  with  some  sud- 
denness. Thus,  for  example,  at  Gloucester,  England,  in  1895,  after 
eight  years  of  practical  abandonment  of  compulsory  vaccination,  that 


VACCINATION  AND  SMALLPOX.  759 

is  to  say,  of  neglect  on  the  part  of  the  authorities  to  enforce  the  law, 
an  epidemic  of  smallpox  occurred  in  what  was  practically  an  unvac- 
cinated  community.  The  cases  increased  at  such  a  rate  that  great 
alarm  was  felt  and  extensive  measures  were  taken  for  general  vaccina- 
tion. In  the  closing  weeks  of  1895,  31  cases  occurred.  In  January, 
28  more  were  reported.  In  February,  the  number  increased  suddenly 
to  146,  and  during  March,  to  644.  Toward  the  last  of  that  month, 
the  authorities  gave  directions  for  enforcement  of  the  law,  and  work 
was  begun ;  but  during  the  following  month,  no  less  than  744  cases 
occurred.  During  the  last  days  of  April,  a  committee  undertook  general 
vaccination  of  the  city,  and  within  a  very  few  days,  every  house  had 
been  visited ;  by  the  end  of  June,  the  city  had  been  converted  from  a 
practically  unvaccinated  city  to  the  best  vaccinated  in  the  country. 
Nearly  36,000  persons  were  operated  upon ;  the  epidemic  began  at 
once  to  decline,  and  before  August  had  disappeared.  Xearly  450  per- 
sons, however,  had  died,  and  1,600  others  who  survived,  bore  the 
usual  lasting  evidence  of  the  disease  in  their  faces. 

As  showing  the  influence  of  re  vaccination,  the  following  figures 
from  a  study  of  the  statistics  of  the  Sheffield  epidemic  are  presented  : 

Rates  of  attack  per  1,000  persons. 

Persons  not  vaccinated      94 

Persons  once  vaccinated 19 

Persons  twice  vaccinated 3 

Death-rates  per  1,000  persons. 

Persons  not  vaccinated       51 

Persons  once  vaccinated 1 

Persons  twice  vaccinated 0.08 

Similar  facts  are  yielded  by  investigation  of  all  epidemics  where 
there  is  a  large  class  of  vaccinated  and  another  of  unvaccinated 
persons,  and  yet  anti-vaccinationists  still  agitate  and  find  sympathetic 
listeners  to  their  arguments.  One  of  their  favorite  charges  is  that 
vaccination  not  only  has  had  nothing  to  do  with  the  decline  in  the 
amount  of  smallpox,  but,  on  the  contrary,  gives  rise  to  other  diseases. 
It  is,  indeed,  true  that  syphilis  has  been  conveyed  from  one  to  another 
through  the  practice  of  vaccination,  but  at  the  present  time  the  danger 
is  practically  nil,  since  arm-to-arm  vaccination  has  fallen  into  disuse ; 
but  while  the  arm-to-arm  practice  was  continued,  there  were  occasional 
instances  of  grave  injury.  Thus,  some  years  since,  it  happened  that  a 
company  of  French  infantry,  prior  to  being  sent  to  Algiers,  was 
vaccinated  by  the  arra-to-arm  method,  and  very  many  of  the  men 
were  thereby  inoculated  with  syphilis. 

Parents  are  prone  to  ascribe  to  vaccination  every  disturbance  which 
a  child  may  suffer,  particularly  if  there  be  any  cutaneous  eruption. 
Sometimes  a  vesicular  or  pustular  rash  may  occur  and  spread  from  the 
vaccinated  arm  to  other  parts  of  the  body  ;  sometimes,  erysipelas  and 
other  infections  occur  at  the  point  of  vaccination  ;  but  these  are  no 
more  likely  to  occur  as  a  result  of  vaccination  than  of  any  other  inter- 
ference with  the  integrity  of  the  skin.     Persons  of  dirty  habits,  living 


760  VACCINATION  AND  SMALLPOX. 

in  unclean  surroundings,  are  more  likely  than  others  to  suffer  from 
ulceration  of  the  vesicle  and  from  other  local  disturbances  not  due  to 
the  influence  of  the  virus  itself. 

With  regard  to  the  assertion  that  the  three  weeks  following  vaccina- 
tion are  a  period  of  unusual  danger  from  the  various  zymotic  diseases, 
the  results  of  extensive  study  by  Dr.  Voight,  Director  of  Vaccination 
at  Hamburg,  are  of  interest.  According  to  his  records,  the  reverse  of 
this  assertion  is  true,  for  the  process  appears  to  exert  a  restraining 
influence  upon  the  development  of  practically  all  of  the  infectious  dis- 
eases. According  to  Dr.  J.  M.  Mackenzie,^  scarlet  fever,  whooping 
cough,  influenza,  and  syphilis  are  favorably  influenced,  tuberculosis 
and  enteritis  may  be  unfavorably  influenced,  and  latent  eczema  and 
impetigo  may  be  excited. 

In  revaccination,  if  the  individual  has  become  again  wholly  sus- 
ceptible, the  local  manifestations  occur  earlier  than  in  the  primary  vac- 
cination, and  the  general  symptoms  are  usually  much  more  marked. 

^  British  Medical  Journal,  August  15,  1903. 


CHAPTER   XVIII. 
QUARANTINE. 

QuAEANTiNE  IS  a  term  of  wide  signification.  Derived  from  the 
French  quarante,  forty,  its  original  meaning  had  reference  to  the  num- 
ber of  days'  detention  to  which  vessels  and  their  personnel,  arriving 
from  places  infected  or  suspected  of  being  infected  with  the  plague, 
Avere  subjected  in  places  set  apart  for  the  purpose,  to  insure  against  the 
introduction  of  the  disease  into  the  country  or  port  of  arrival. 

The  usual  definitions  of  the  term  which,  in  a  composite  form,  may 
be  given  as,  "The  enforced  detention  of  vessels,  their  personnel,  and 
cargoes,  arriving  from  infected  ports,  or  having,  or  being  supposed  to 
have,  cases  of  certain  infectious  diseases  on  board,  and  interdiction  for 
a  fixed  period  of  time  of  all  communication  therewith,"  are  wholly  in- 
adequate under  present  conditions.  Far  more  accurate  and  compre- 
hensive is  that  given  by  Dr.  Walter  Wyman,  U.  S.  P.  H.  and 
M.-H.  S.  :  "  The  adoption  of  restrictive  measures  to  prevent  the  intro- 
duction of  diseases  from  one  country  or  locality  into  another,"  for  the 
original  meaning  is  now  quite  lost.  To-day,  we  speak  of  port  quaran- 
tine, land,  interstate,  railroad,  municipal,  house,  and  room  quarantine. 
Restrictive  measures  are  not  adopted  solely  against  human  diseases, 
but  also  against  those  of  the  lower  animals  (cattle  quarantine),  and 
even  of  certain  fruits  and  other  important  crops. 

The  necessity  of  restrictive  measures  in  certain  cases  has  long  been 
recognized  ;  in  fact,  in  the  case  of  leprosy,  from  earliest  times.  The 
first  enactment  providing  for  the  detention  and  isolation  of  travellers 
from  infected  places  dates  back  to  the  fifteenth  year  of  the  Emperor 
Justinian  (a.  d.  542),  but  quarantine  in  the  modern  sense  had  its 
origin  in  the  fourteenth  century  in  Italy,  where,  on  account  of  the 
ravages  of  the  plague,  local  authorities  at  different  times  adopted  pre- 
ventive measures.  Thus,  Florence  and  Venice,  in  1348  ;  Lombardy, 
1374;  Milan,  1399. 

The  first  maritime  quarantine  was  instituted,  in  1403,  at  Venice. 
A  lazaret,  the  house  of  St.  Lazarus,  was  founded  on  a  small  island, 
and  all  jicrsons  from  the  Levant  were  there  detained  for  forty  days 
before  admission  to  +he  city.  The  restrictive  measures  enforced  at 
Mediterranean  ports  and  elsewhere,  were  for  many  years,  and  at  some 
jilaces  now  are,  unreasonable,  harsh,  useless,  and  a  great  injury  to 
trade.  Most  of  the  leading  countries  have,  for  a  long  time,  been 
strongly  opposed  to  the  oppressive,  arbitrary,  and  irrational  quaran- 
tine measures,  and  have  now  ado])ted  rules  and  regulations,  which, 
while  effectiv'c  as  far  as  can  be  hoped  for  or  expected,  impose  the  least 

761 


762  ■  QUARANTINE. 

possible  restrictions  upon  personal  liberty  and  trade.  The  danger  is 
estimated  according  to  the  condition  of  health  of  the  port  of  depar- 
ture, and  this,  with  the  sanitary  history  of  the  vessel,  up  to  the  time 
of  arrival,  determines  what  measures,  if  any,  are  to  be  taken. 

The  periods  of  detention  are  fixed  with  reference  to  the  probable  in- 
cubative period  of  the  disease  in  question,  and  questions  of  necessity 
of  disinfection,  and  of  methods  to  be  followed  in  carrying  out  the  same, 
are  determined  by  the  circumstances  of  each  individual  case.  Quar- 
antines administered  with  reason  do  invaluable  work  in  sifting  out 
infection  and  protecting  the  public  health  from  exotic  diseases,  which, 
in  the  absence  of  precautionary  measures,  might  easily  gain  access. 
At  the  same  time,  they  act  in  restraint  of  trade  to  the  slightest  possible 
extent,  since  uninfected  vessels  are  not  unnecessarily  detained. 

Unfortunately,  not  all  quarantines  are  administered  with  reason, 
and  it  often  happens  that  great  injustice  and  unnecessary  expense  are 
caused  by  absurdly  tenacious  adherence  to  exploded  theories  and  routine 
practice.  As  au  example,  may  be  cited  the  case  of  the  Helene,  a  Ger- 
man vessel,  which,  arriving  in  an  English  port  in  August,  1893,  with 
two  cases  of  cholera,  was  disinfected  and  given  free  pratique ;  nine 
mouths  later,  she  was  refused  pratique  at  a  South  American  port, 
because  in  England  she  had  not  been  held  for  a  definite  period  at  quar- 
antine. As  an  example  of  quarantine  absurdity  of  a  minor  character, 
but  indicative  of  what  might  be  imposed  in  case  opportunity  presented 
itself,  may  be  cited  an  experience  with  the  municipal  authorities  at  a 
Southern  port,  who  required  thorough  disinfection  of  a  barrel  of  car- 
bolic acid  before  it  was  allowed  to  be  landed. 

Far  more  and  almost  incredibly  absurd  is  the  following  instance  :  On 
November  3,  1893,  the  steamship  Cabo  Machichaco,  laden  in  part  with 
dynamite,  blew  up  at  her  dock  at  Santander,  Spain,  after  having  been 
on  fire  for  some  hours.  The  burning  cargo  was  thrown  about  in  all 
directions  and  started  a  general  conflagration.  It  happened  that  the 
entire  fire  department  was,  at  the  time  of  the  explosion,  engaged  in 
attempting  to  overcome  the  fire  raging  in  the  ship's  hold,  and  in  the 
explosion  was  completely  wrecked.  Word  was  sent  to  Bilbao,  and  aid 
was  urgently  requested.  Two  steamships  were  sent  with  fire  engines, 
firemen,  surgeons,  nurses,  laborers,  and  others,  and  arrived  in  six 
hours.  The  provisional  governor  refused  to  permit  the  vessels  to  dock 
and  discharge  the  much-needed  apparatus  and  other  aid,  because  quar- 
antine had  not  been  observed,  and  he  insisted  that  they  should  comply 
with  the  regulations,  which  would  involve  several  days'  detention  out- 
side the  harbor.  It  was  several  hours  before  a  way  was  found  to 
overcome  the  strict  interpretation  of  the  rules. 

The  first  action  taken  by  any  official  organization  in  this  country 
looking  to  the  establishment  of  a  uniform  system  of  quarantine  regu- 
lations was  at  a  conference  of  boards  of  health  at  Philadelphia  in  1857, 
called  on  account  of  the  excitement  caused  by  the  breaking  out  of  yellow 
fever  at  Bay  Ridge  in  the  previous  year ;  but  in  spite  of  this  and  other 
attempts,   the  various  quarantines  of  the  country  were  administered 


QUARANTINE  LAW   OF  1893.  763 

with  no  uniformity  until  after  the  passage  of  the  Act  of  February  15, 
1893,  entitled  "An  Act  granting  additional  quarantine  powers  and 
imposing  additional  duties  upon  the  Marine  Hospital  Service."  This 
act  established  a  national  system  of  quarantine,  but  in  no  way  limited 
State  and  municipal  authorities  in  their  right  to  prescribe  and  enforce 
additional  measures ;  and,  indeed,  it  is  beyond  the  power  of  Congress 
to  interfere  with  local  authorities  so  long  as  the  minimum  requirements 
of  the  national  law  are  complied  with. 

Quarantine  Law  of    1893. 

Section  1  makes  it  unlawful  for  a  vessel  from  a  foreign  port  to  enter 
any  port  of  the  United  States,  except  in  accordance  with  the  provisions 
of  the  act  and  with  such  rules  and  regulations  of  State  or  municipal 
health  authorities  made  in  pursuance  of  or  consistent  therewith,  under 
penalty  of  not  exceeding  $5,000. 

Section  2  provides  that  a  vessel  at  a  foreign  port,  clearing  for  any 
port  in  the  United  States,  shall  obtain  from  the  consular  or  medical 
officer  of  the  United  States  at  that  place  a  bill  of  health  in  duplicate, 
in  the  form  prescribed  by  the  Secretary  of  the  Treasury,  setting  forth 
its  sanitary  history  and  condition,  and  that  it  has  complied  with  the 
rules  and  regulations  prescribed  for  securing  the  best  sanitary  condi- 
tion of  the  vessel  and  its  cargo,  passengers,  and  crew.  Penalty  for 
clearing  and  sailing  without  such  bill  of  health  and  entering  any  port 
of  the  United  States,  not  exceeding  $5,000.  By  an  amendment 
approved  August  18,  1894,  it  is  provided  that  the  provisions  of  this 
section  shall  not  apply  to  vessels  plying  between  foreign  ports  on  or 
near  the  frontiers  of  the  United  States  and  ports  of  the  United  States 
adjacent  thereto.  But  the  Secretary  of  the  Treasury  is  authorized, 
when,  in  his  discretion,  it  is  expedient  for  the  preservation  of  the 
public  health,  to  establish  regulations  governing  such  vessels. 

Section  3  directs  the  Supervising  Surgeon-General  of  the  U.  S. 
Public  Health  and  Marine-Hospital  Service  to  cooperate  with  and  aid 
State  and  municipal  boards  of  health  in  the  execution  and  enforcement 
of  the  rules  and  regulations  of  such  boards  and  of  those  made  by  the 
Secretary  of  the  Treasury  to  prevent  the  introduction  of  contagious  or 
infectious  diseases  into  the  United  States  and  into  one  State,  Territory, 
or  the  District  of  Columbia  from  another. 

It  provides  that  all  rules  and  regulations  made  by  the  Secretary  of 
the  Treasury  shall  operate  uniformly  and  in  no  manner  discriminate 
against  port  or  place.  Where  no  State  or  municipal  quarantine  regu- 
lations exist,  and  in  the  opinif)n  of  the  Secretary  of  the  Treasury  are 
necessary  to  prevent  the  introduction  of  such  diseases,  and  where 
(!xistiiig  regulations  are  in  his  o])inion  insufficient,  he  shall  make  such 
additional  rules  and  regulations  as  he  may  deem  necessary,  and  they 
shall  be  enforced  by  the  respective  sanitary  authorities ;  failing  which, 
the  President  shall  execute  and  enforce  the  same  and  adopt  such  meas- 
ures  as    in    his  judgment   are  necessary,  and    may  detail  or  a])point 


764  QUARANTINE. 

officers  for  that  purpose.  The  Secretary  of  the  Treasury  shall  make 
such  rules  and  regulations  as  are  necessary  to  be  observed  by  vessels 
at  the  port  of  departure  and  on  the  voyage,  to  secure  the  best  sanitary 
condition  of  themselves,  their  cargoes,  passengers,  and  crews. 

Section  4  makes  it  incumbent  on  the  Supervising  Surgeon-General 
to  perform  all  the  duties  in  respect  to  quarantine  and  quarantine  regu- 
lations, and  to  obtain  information  through  consular  officers  of  the  sani- 
tary condition  of  foreign  ports  and  places  from  which  contagious  and 
infectious  diseases  are  or  may  be  imported  into  the  United  States.  The 
Secretary  of  the  Treasury  is  required  to  obtain  through  all  available 
sources,  including  State  and  municipal  sanitary  authorities  throughout 
the  United  States,  weekly  reports  of  the  sanitary  condition  of  ports 
and  places  within  the  United  States,  to  transmit  to  collectors  of  cus- 
toms and  to  State  and  municipal  health  officers  and  other  sanitarians 
weekly  abstracts  of  the  consular  sanitary  reports  and  other  pertinent 
information  received  by  him,  to  procure,  through  all  available  sources, 
public  or  private,  information  relating  to  climatic  and  other  conditions 
affecting  the  public  health,  and  to  make  an  annual  report  to  Congress, 
with  such  recommendations  as  he  may  deem  important  to  the  public 
interests. 

Section  5  provides  for  the  issuance  from  time  to  time  to  the  United 
States  consular  and  medical  officers  at  the  various  foreign  ports,  of  the 
rules  and  regulations  made  by  the  Secretary  of  the  Treasury  to  be 
used  and  complied  with  by  vessels  in  foreign  ports  for  securing  the 
best  sanitary  conditions  before  departure  for  the  United  States,  and  in 
course  of  the  voyage,  and  of  all  other  rules  and  regulations  as  shall  be 
observed  in  inspection  on  arrival  at  any  quarantine  station  and  for  dis- 
infection and  isolation,  and  treatment  of  cargo  and  persons  on  board,  so 
as  to  prevent  the  introduction  of  cholera,  yellow  fever,  and  other  con- 
tagious or  infectious  diseases.  No  vessel  shall  enter  a  port  or  dis- 
charge its  cargo  or  land  its  passengers  except  upon  a  certificate  of  the 
health  officer  at  such  quarantine  station  that  the  rules  and  regulations 
have  in  all  respects  been  observed  and  complied  with  both  by  him  and 
by  the  master  in  respect  to  the  vessel  and  its  cargo,  passengers,  and 
cre^^^  The  master  is  required  to  deliver  to  the  collector  with  the 
other  papers  of  the  vessel,  the  bills  of  health  obtained  at  the  port  of 
departure  and  the  certificate  above  mentioned. 

Section  6  provides  that  on  the  arrival  of  an  infected  vessel  at  any 
port  not  provided  with  proper  facilities  for  treatment,  the  vessel  shall 
be  remanded  at  its  own  expense  to  the  nearest  national  or  other  quar- 
antine station  where  accommodations  and  appliances  are  provided  for 
the  necessary  disinfection  and  treatment  of  vessel,  passengers,  and 
cargo.  After  treatment  of  such  vessel  and  after  certification  by  the 
United  States  quarantine  officer  that  vessel,  cargo,  and  passengers  are 
free  from  infectious  disease  or  danger  of  carrying  the  same,  the  vessel 
shall  be  admitted  to  entry  at  any  port  of  the  United  States  named  in 
the  certificate.     But  at  ports  where  sufficient  quarantine  provision  has 


QUARANTINE  LAW  OF  1893.  765 

been  made  by  State  or  local  authorities,  the  Secretary  of  the  Treasury 
may  direct  the  undergoing  of  quarantine  at  said  station. 

Section  7  provides  that  whenever  the  President  is  satisfied  that  by 
reason  of  the  existence  of  cholera  or  other  infectious  diseases  in  a 
foreign  country  there  is  serious  danger  of  the  introduction  of  the  same 
into  the  United  States,  and  that  notwithstanding  the  quarantine  defence 
this  danger  is  so  increased  by  the  introduction  of  persons  or  property 
from  such  country  that  a  suspension  of  the  right  to  introduce  the  same 
is  demanded  in  the  interest  of  the  public  health,  he  shall  have  power  to 
prohibit,  fn  whole  or  in  part,  the  introduction  of  persons  and  jDroperty 
from  such  countries  or  places  as  he  may  designate,  and  for  such  period 
of  time  as  he  may  deem  necessary. 

Sections  8  and  9  are  of  no  sanitary  interest. 

In  accordance  with  the  provisions  of  this  act,  certain  rules  and  regu- 
lations to  be  observed  at  foreign  ports  and  at  sea  and  at  ports  and  on 
the  frontiers  of  the  United  States  have  been  adopted  and  amended  and 
added  to  as  occasion  has  made  it  necessary  or  advisable.  These  rules 
are  subject  to  very  material  modifications  or  additions,  based  on  a  wider 
knowledge  of  the  causes  of  disease,  modes  of  infection,  etc.,  and  thus 
what  may  be  law  today  may  be  superseded  tomorrow.  Thus  the  very 
strongest  regulations  with  regard  to  yellow  fever,  which  were  made 
before  the  method  of  its  dissemination  was  known,  and  with  the 
idea  that  infection  could  be  conveyed  by  fomites,  merchandise,  bag- 
gage, etc.,  will  undoubtedly  be  changed  completely  in  consequence  of 
the  discovery,  by  Reed  and  his  associates,  that  infection  cannot  thus  be 
conveyed.  It  is  only  reasonable,  in  view  of  their  work,  that  quaran- 
tine restrictions  upon  passengers  and  cargoes  from  non-infected  ports 
should  be  very  greatly  modified,  and  that,  in  each  instance  of  vessels 
from  infected  ports,  the  incubative  period  of  the  disease,  the  possibility 
of  the  presence  of  infected  mosquitoes  on  board,  and  the  length  of  time 
a  mosquito  requires  for  the  acquirement  of  dangerous  properties,  should 
be  kept  in  mind.  Reed  believes  that  a  vessel  at  an  infected  port  can 
be  loaded  in  midstream  by  lighters,  and  can  then  become  infected  only 
by  persons  who  have  been  exposed  on  shore,  since  the  probability  of 
mosquitoes  reaching  the  ship  by  flying  or  by  lighters  is  very  slight. 
If,  then,  a  vessel  thus  loaded  arrives  at  its  destination  free  from  dis- 
ease, the  non-immunes  aboard  should  be  quarantined  not  longer  than 
five  days,  and  the  time  consumed  by  the  voyage  should  be  included  in 
this  period.  The  cargo  may  be  allowed  to  be  discharged  without  treat- 
ment or  delay.  But  if  the  disease  should  occur  while  between  ports, 
the  sick  should  be  removed,  the  sleeping  quarters  disinfected  with 
sulphur  dioxide  in  order  to  destroy  all  mosquitoes,  and  then  the  vessel 
should  be  allowed  to  dock.  Under  some  circumstances,  it  may  be 
necessary  to  fumigate  the  hold,  for  mosquitoes  may  be  there  in  an 
active  condition  ;  although,  unless  they  have  access  to  moisture,  they 
will  not  liv(;  longer  than  five  or  six  days.  Rosenau  has  kept  them 
aliv<-   ill   trunks  for  ten  days  and  longer,  but  moisture  was  provided. 

li'  iiK.-fjiiitoes  are  found  on  board  a  vessel  from  an  infected  port,  the 


766  QUARANTINE. 

Don-immunes  should  be  detained,  unless  more  than  twenty  days  have 
already  elapsed  smce  clearing.  This  period  will  be  sufficient  to  demon- 
strate the  presence  of  infection  in  the  mosquitoes,  by  the  occurrence  of 
cases  during  the  voyage.  If  more  than  twenty  days  have  elapsed,  there 
can  be  no  danger,  and  neither  passengers  nor  cargo  should  be  detained. 

Since  the  publication  of  Reed's  results  and  views,  many  cases  have 
been  cited  in  the  medical  press  in  opposition  to  the  view  that  the  dis- 
ease cannot  be  spread  by  baggage,  fomites,  and  cargoes,  but  in  no 
instance  which  has  thus  far  fallen  under  the  author's  observation  can 
the  mosquito  be  ignored.  Indeed,  in  many  of  the  cases,  the  disease 
has  broken  out,  after  an  uneventful  voyage  and  the  formalities  of 
quarantine,  in  places  where  tlie  specific  yellow  fever  mosquito  is  known 
to  be  indigenous.  In  some  cases,  mention  is  made  of  the  fact  that,  in 
spite  of  the  v^ery  numerous  mosquitoes  present  where  a  case  of  the  dis- 
ease has  been  brought,  no  extension  of  the  fever  has  been  produced ; 
but  it  is  not  stated  that  the  mosquitoes  were  Stegomyla  fasciata,  which 
is  a  vital  point  in  the  argument. 

In  view  of  the  probable  extensive  changes  in  the  rules,  it  is  deemed 
best  not  to  reproduce  here  existing  rules  in  extenso,  but  advise  one  to 
apply,  as  occasion  arises,  to  the  Treasury  Department  for  a  printed  copy 
thereof. 

As  they  stand  at  present,  the  regulations  prescribe  forms  for  bills 
of  health,  methods  of  inspection  of  passengers,  crew,  baggage,  cargo, 
food  and  water  supplies,  and  of  the  vessel  itself;  requirements  as  to 
cleanliness  of  vessels,  and  as  to  ventilation ;  methods  of  disposal  of 
bedding  ;  location  and  arrangement  of  the  "  sick  bay  "  ;  what  may  not 
be  taken  on  board  at  ports  infected  with  certain  diseases  ;  what  must 
be  disinfected,  and  how ;  what  persons  may  not  be  shipped,  and 
periods  of  detention  according  to  the  nature  of  the  disease  to  which 
they  have  been  exposed ;  and  general  and  particular  rules  to  apply  in 
certain  cases.  The  regulations  prescribe,  also,  requirements  as  to  clean- 
liness and  ventilation  at  sea ;  isolation  of  the  sick ;  disinfection  and 
disposal  of  the  dead ;  and  give  in  detail  the  methods  to  be  followed  in 
disinfection  of  all  parts  of  a  ship,  of  various  kinds  of  cargoes,  and  of 
personal  effects. 

The  regulations  to  be  observed  at  ports  and  on  the  frontiers  of  the 
United  States  providie  for  the  establishment  of  quarantine  stations  at 
or  convenient  to  the  principal  ports  of  the  country,  and  prescribe 
methods  of  inspection  according  to  the  circumstances  of  each  case,  as, 
for  instance,  for  vessels  from  healthy  or  infected  ports,  and  for  vessels 
suopected  of  being  infected  with  plague  or  yellow  fever.  Quaran- 
tinable  diseases  are  named  as  follows  :  cholera  and  cholerine,  yellow 
fever,  smallpox,  typhus,  leprosy,  and  plague ;  and  rules  are  laid  down 
for  the  government  of  vessels  on  which  any  of  these  diseases  have 
occurred  during  the  voyage,  and  for  the  treatment  and  detention  of 
passengers,  crew,  baggage,  and  cargo. 

Following  the  passage  of  the  quarantine  law  of  1893  and  the 
promulgation  of  the    regulations   made    in   accordance    therewith,   at 

47 


STATE   QUARANTINE.  767 

many  ports  the  quarantine  service  was  surrendered  voluntarily  to  the 
national  government,  and  at  others  it  was  taken  over  by  the  same  au- 
thority, because  of  non-compliance  with  the  regulations.  At  others, 
the  regulations  have  been  adopted  and  efficiently  enforced  by  the  local 
authorities,  but  these  and  all  others  are  inspected'  regularly  by  the 
Public  Health  and  Marine-Hospital  Service,  to  insure  efficiency  of 
administration  and  correction  of  faults  in  methods  and  defects  in 
appliances. 

In  1900,  there  were  in  the  United  States  no  less  than  120  quaran- 
tine and  inspection  stations,  of  which  number,  81  were  on  the  Atlantic 
coast,  17  on  the  Pacific  coast,  and  22  on  the  Gulf  of  Mexico.  They 
vary,  naturally,  very  widely  in  importance  and  equipment,  the  most 
important  one  being  that  of  New  York,  the  chief  gate  of  entrance  of 
immigrants  and  of  foreign  commerce,  and  the  least  important  being 
several  with  practically  no  arrivals  of  vessels  from  foreign  ports. 
Only  a  small  proportion  are  equipped  with  extensive  disinfecting  ap- 
pliances, and  but  8  are  provided  with  quarters  for  the  detention  of 
persons   held  for  observation. 

Interstate  Quarantine. 

To  prevent  the  introduction  of  contagious  diseases  from  one  State  to 
another.  Congress,  on  March  27,  1890,  passed  an  Act  providing  that 
whenever  the  President  is  satisfied  that  cholera,  yellow  fever,  small- 
pox, or  plague  exists  in  any  part  of  the  United  States,  and  that  there 
is  danger  of  the  spread  thereof  into  other  States,  Territories,  or  the 
District  of  Columbia,  he  is  authorized  to  cause  the  Secretary  of  the 
Treasury  to  promulgate  such  preventive  rules  and  regulations  as  he 
may  deem  necessary,  and  to  employ  such  inspectors  and  other  persons 
as  may  be  necessary  to  enforce  them. 

These  rules  and  regulations  shall  be  prepared  by  the  Supervising 
Surgeon-General  of  the  Public  Health  and  Marine-Hospital  Service, 
under  the  direction  of  the  Secretary  of  the  Treasury,  and  any  violation 
thereof  entails  a  fine  of  not  exceeding  $500,  or  imprisonment  for  not 
more  than  two  years,  or  both,  in  the  discretion  of  the  Court.  In  the 
case  of  any  officer  or  other  person  employed  to  prevent  the  spread  of 
said  diseases,  wilful  violation  of  any  of  the  quarantine  laws  of  the 
United  States  or  of  any  of  the  rules  and  regulations  made  and  promul- 
gat€d  as  above,  or  of  any  lawful  order  of  his  superior  officer  or  officers, 
the  penalty  is  a  fine  not  exceeding  |300  or  imprisonment  for  not 
exceeding  one  year,  or  both,  in  the  discretion  of  the  Court.  Any 
common  carrier  or  servant  thereof  who  shall  wilfully  violate  any  of  the 
same,  shall  be  liable  to  a  fine  of  not  exceeding  $500,  or  imprisonment 
for  not  exceeding  two  years,  or  both,  in  the  discretion  of  the  Court. 

State  Quarantine. 

■^FIk'  natioDiil  (juarantine  law  and  the  rules  and  regulations  made 
tlici-'Miiidcr   an^,  as   has  been   said,  iiifcndcd  only  as  miniruuiu    require- 


768  QUARANTINE. 

ments,  to  Avhich  State  or  municipal  autbority  may  make  such  additions 
as  may  be  deemed  necessary  for  the  preservation  of  the  health  of  the 
people  within  its  jurisdiction.  Such  additional  requirements  may  be 
established  for  specific  periods  or  without  limit  of  time,  and  to  meet 
general  conditions  or  a  special  class  of  cases.  As  an  example  of 
special  regulations  made  for  a  limited  period,  the  following,  adopted  by 
the  State  Board  of  Health  of  Louisiana,  with  reference  to  vessels  en- 
gaged in  the  tropical  fruit  trade  during  the  season  of  1899,  may  be 
cited. 

"All  vessels  engaged  in  the  tropical  fruit  trade  between  Central 
American,  South  American,  and  West  Indian  ports  and  New  Orleans 
will  be  allowed  to  pass  the  Mississippi  River  Quarantine  Station  with- 
out detention  longer  than  is  necessary  for  a  thorough  inspection  by  day 
by  the  quarantine  officers,  so  long  as  a  properly  accredited  medical 
agent  of  this  board  certifies  that  such  ports  and  places  are  free  from 
contagious  or  infectious  disease,  and  provided  said  vessels  shall  strictly 
conform  to  the  following  conditions  : 

"  1 .  They  shall  not  be  allowed  to  bring  to  this  port  bedding  or 
household  effects  of  any  kind. 

"2.  After  leaving  New  Orleans,  said  vessels  may  take  on  board 
passengers  during  any  part  of  their  trip,  and  briug  passengers  to  this 
port  as  herein  provided. 

"  Cabin  passengers  only  will  be  allowed  at  the  discretion  of  the  med- 
ical officer.  This  officer  must  satisfy  himself  that  the  applicant  has 
not  been  in  any  infected  locality  in  the  past  thirty  days,  and  that  none 
of  his  effects  have  been  exposed  to  infection,  and  further  such  effects 
shall  have  been  fumigated  or  disinfected  before  going  on  board. 

"  Passengers  may  be  taken  on  board  from  one  healthy  port  to  another, 
each  of  said  ports  having  a  medical  officer  representing  this  board ; 
under  the  same  restrictions  said  passengers  may  be  brought  to  New 
Orleans.  Personal  effects  of  passengers  are  restricted  to  personal 
wearing  apparel,  and  should  as  much  as  possible  consist  only  of  clean, 
recently  laundered  clothing,  and  such  effects,  together  with  passengers' 
trunks,  bags,  valises  or  baskets,  must  be  fumigated  before  being  brought 
on  board. 

"  The  medical  officer  will  refuse  to  permit  the  bringing  of  any  un- 
usual or  unnecessary  amount  of  baggage,  it  being  the  purjDOse  of  the 
board  of  health  to  facilitate  the  affairs  of  commerce  by  permitting 
passenger  communication  whereby  business  may  be  transacted  in  a  safe 
manner,  holding  highest  the  health  of  the  community  ;  and  it  is  insisted 
that  material  capable  of  carrying  any  possible  infection  should  be 
limited  to  the  least  possible  amount.  Woollen  bags  or  carpet  sacks 
will  be  prohibited.  Trunks  should  be  of  metal,  wood,  or  paper ; 
valises  of   leather  or  paper. 

"  The  medical  officer  will  make  a  personal  inspection  of  all  passengers 
and  of  every  member  of  the  crew  just  prior  to  the  departure  of  the 
vessel,  and  give  a  certificate  to  the  master  of  the  vessel  of  the  con- 
dition of  such  persons  examined,  marking  opposite  the  name  of  each 


MUNICIPAL   QUARANTINE.  769 

person  on  the  list  furnished  him  by  the  officers  of  the  vessel  of  every 
person  on  board  such  observations  as  may  seem  to  him  to  be  advisable 
concerning  the  condition  of  said  person's  present  or  previous  state  of 
health. 

"  Medical  officers  will  invariably  assist  masters  of  vessels  in  treat- 
ment of  members  of  crew  or  j^assengers  taken  sick  on  board  vessels 
and  should  make  notes  of  such  treatment  in  writing  to  be  sent  to  the 
quarantine  officer  at  home  ports. 

"3.  Vessels  shall  not  touch  at  any  infected  port  or  have  any  com- 
munication with  any  vessel  during  their  voyage  except  in  case  of  dis- 
tress. 

"  4.  They  shall  not  touch  at  such  ports  or  stations  as  are  not  men- 
tioned in  their  schedule,  which  latter  shall  be  communicated  to  the 
board  of  health. 

"  5.  They  shall  be  required  to  make  a  full  disclosure  when  arriving  at 
quarantine  station  of  all  ports  and  places  they  have  visited  on  their  voyage. 

"  6.  They  may  take  on  board  a  crew  of  laborers  after  inspection  by 
the  medical  officer  and  disinfection  of  clothing  of  such  crew  for  such 
healthy  point  where  they  j)ermanently  reside  and  remain,  the  crew 
being  as  nearly  as  possible  composed  of  the  same  men.  The  captain 
or  other  officer  may  go  ashore  only  for  the  purpose  of  entering  or  clear- 
ing vessels.  Any  further  communication  with  shore  or  natives  will  be 
considered  a  violation  of  regulations,  and  vessels  in  default  will  be 
treated  accordingly. 

"7.  These  vessels  shall  be  cleansed,  and,  when  necessary,  disinfected 
in  the  city  of  New  Orleans  after  discharge  of  cargo." 

Sanitary  Cordon. 

What  is  known  as  a  sanitary  cordon  (''cordon  sanitaire")  consists 
of  an  extended  line  of  guards  thrown  about  a  district  to  prevent  access 
thereto  or  egress  therefrom  of  any  person  or  thing  which  may  act  as  the 
carrier  of  infection.  The  object  is,  in  other  words,  to  protect  the  dis- 
trict from  infection  from  the  surrounding  country  or  to  protect  the  lat- 
ter from  infection  from  the  district.  Sometimes  a  double  line  is  estab- 
lished, the  territory  intervening  being,  perhaps,  only  suspected  of  being 
infected.  Cordons  are  not  uncommonly  established  in  the  South  against 
yelloAv  fever,  but  are  practically  unknown  in  the  North.  In  California, 
in  1900,  a  cordon  was  maintained,  for  a  short  time  only,  against  a 
district  in  which  cases  of  bubonic  plague  were  believed  to  be  concealed. 

Municipal  Quarantine. 

Municipal  quarantine  comprehends  measures  for  isolating  those  sick 
with  certain  of  the  infectious  diseases,  such  as  scarlet  fever,  diphtheria, 
and  small ))0x,  keeping  others  under  observation,  and  disinfecting  rooms 
and  houses  and  objects  contained  therein  which  may  be  capable  of  har- 
boring infection.  It  is  beyond  dis]Hite  that  public  safety  requires  that 
certain  sick  shr)uld  be  shut  off  from  free  communication  with  the  out- 
side world.  This  isolation  is  most  complete  and  entails  less  hardship 
49 


770  QUARANTINE. 

when  it  can  be  carried  out  at  a  special  hospital  for  contagious  diseases, 
but  generally  it  is  enforced,  if  at  all,  at  the  patient's  home.  Room  and 
house  quarantines  are  commonly  difficult  or  impossible  of  enforcement, 
especially  in  tenement  districts  among  the  very  poor,  for  it  is  among 
this  class  that  danger  of  infection  is  least  understood  and  mutual  help 
and  neighborly  visiting  most  extensively  practised,  and  thus  the  foci 
of  infection  may  become  increased  indefinitely.  In  hospitals,  on  the 
other  hand,  where  indiscriminate  egress  and  ingress  are  under  control 
and  facilities  for  the  disinfection  of  discharges  are  at  hand,  the  danger 
of  spread  is  reduced  to  a  minimum. 

Especially  difficult  and  productive  of  hardship  is  the  isolation  not 
only  of  the  patient,  but  also  of  the  other  members  of  his  family.  This 
is  commonly  practised  in  the  case  of  smallpox,  but  is  unnecessary  if 
the  other  members  have  undergone  recent  successful  vaccination,  and 
their  clothing  and  other  effects  are  disinfected  and  they  are  then  sepa- 
rated from  all  possible  contact  and  communication  with  the  patient. 
But  even  then,  they  should  be  kept  under  surveillance  for  a  time  equal 
to  the  period  of  incubation.  In  times  of  epidemics  of  yellow  fever  in 
the  South,  house  quarantine  of  entire  families  has  proved  to  be  the 
cause  of  much  hardship  and  anything  but  an  unqualified  success.  It 
causes  great  popular  dissatisfaction,  leads  to  concealment  of  cases,  and 
tends,  therefore,  to  spread  rather  than  restrict  the  disease.  Treatment 
of  the  sick  in  isolation  hospitals  and  removal  of  those  who  have  been 
exposed  to  infection  to  camps  of  detention  for  five  full  days  have  been 
found  to  give  far  better  results. 

In  some  outbreaks  of  infectious  diseases,  it  is  necessary  or  advisable 
to  conduct  a  house-to-house  inspection  for  the  discovery  and  isolation 
of  unreported  cases.  When  such  a  course  is  undertaken,  the  visits 
should  be  repeated  at  intervals  equal  to  the  period  of  incubation. 

The  making  of  regulations  for  municipal  quarantine  and  inspection 
is  subject  to  no  general  rule,  each  local  authority  being  a  law  unto 
itself.  In  some  cities,  the  rules  governing  notification,  isolation,  and 
disinfection  are  exceedingly  thorough  and  strictly  enforced ;  in  others, 
they  are  inadequate  in  varying  degrees  and  enforced  with  laxity. 

Camps  of  Detention. — Camps  of  detention  are  places  set  apart 
for  the  reception  and  observation  of  persons  who  have  been  exposed 
or  who  are  under  suspicion  of  having  been  exposed  to  the  contagion 
of  smallpox  or  other  quarantinable  disease.  They  should  be  under 
strict  surveillance  and  governed  by  inflexible  rules.  Every  person 
should  be  examined  before  admission,  and  such  effects  as  he  may  be 
permitted  to  bring  in  should  be  disinfected  thoroughly,  for  above  all 
things,  it  is  necessary  to  guard  against  the  introduction  of  infection. 
The  entire  personnel  should  be  mustered  in  quarters  and  examined  at 
least  twice  daily,  and  such  as  are  beginning  to  show  symptoms  must 
be  promptly  isolated.  Indiscriminate  ingress  and  egress  must  be 
strictly  prevented.  At  the  expiration  of  the  proper  period,  in  each 
case  the  clothing  and  other  personal  effects  should  be  thoroughly  dis- 
infected before  discharge. 


CHAPTER   XIX. 
DISPOSAL  OF  THE  DEAD. 

The  public  health  requires  that  the  bodies  of  the  dead  shall  be 
disposed  of  in  such  a  way  as  not  to  be  a  menace  to  the  living,  and 
as  soon  as  possible,  with  due  consideration  of  the  feelings  of  those 
bereaved.  In  the  case  of  those  dead  of  infectious  diseases,  disposal 
should  not  be  delayed  by  sentimental  considerations,  but  should  be 
accomplished  with  as  little  delay  as  possible,  on  account  of  the 
risk  to  which  the  living  may  be  subjected  by  the  retention  of  the 
body  in  the  home. 

Concerning  methods  of  disposal,  consideration  may  be  limited  to  the 
two  in  use  by  most  civilized  peoples  and  by  most  others  as  well ; 
namely,  earth-burial  and  cremation. 

Earth-burial. — Interment  of  the  dead  has  ever  been  the  principal 
mode  of  disposal  among  Christians,  Jews,  and  Mussulmans.  Within 
comparatively  recent  years,  the  results  of  overcrowding  of  ancient 
churchyards  and  cemeteries,  and  the  necessity  of  dedicating  great 
areas  of  valuable  land  to  be  held  in  perpetuity  for  the  accommodation 
of  the  dead,  have  brought  about  an  economic  sentiment  against  the 
practice,  and  to  it  has  been  added  a  feeling  of  danger  to  the  public 
health  from  the  decomposing  tissues,  particularly  of  those  who  have 
died  of  infectious  diseases. 

Buried  in  soil  of  suitable  character,  a  body  gives  off  for  a  number 
of  months — six  to  nine  may  be  regarded  as  reasonable  limits — foul 
gases  of  decomposition  which  are  not  evolved  in  the  later  stages.  The 
rate  of  decomposition  is  influenced  not  alone  by  the  nature  of  the  soil, 
its  pore  volume,  and  its  degree  of  moisture,  but  also  by  the  character  of 
the  coffin,  the  depth  of  interment,  and  the  processes  to  which  the  body 
has  been  subjected  before  burial.  After  some  years,  the  period  varying 
within  very  wide  limits  according  to  circumstances,^  decomposition  is 
cf)mplete  and  l)ut  little  remains  besides  bones,  more  or  less  crumbly  in 
character. 

It  is  charged  against  earth-burial,  that  the  places  used  for  the  pur- 
pose are  offensive ;  that  the  air  becomes  poisoned  ;  that  the  soil  be- 
comes laden  with  disease  germs  of  all  descriptions,  which  are  pre- 
served indefinitely,  and  that  water  supplies  are  converted  to  dilute 
poisons  of  great  potency ;  that  is  to  say,  cemeteries  predispose  to 
and  act  as  direct  causes  of  disease.  As  proof,  numerous  cases  which 
will  not  bear  close  scrutiny  are  cited,  but  the  whole  mass  of  what  is 
1  See  case  cited  on  pnge  293. 

771 


772  DISPOSAL   OF  THE  DEAD. 

regarded  as  evidence  of  the  connection  of  cemeteries  with  the  outbreak 
of  disease  has  but  little  real  weight  and  is  unconvincing.  It  has 
been  said,  for  example,  that  typhus  and  other  fevers  were  prevalent  in 
the  immediate  neighborhood  of  old,  overcrowded  churchyards  in  Lon- 
don when  it  was  customary  to  keep  disturbing  the  soil  for  new 
interments,  regardless  of  the  number  and  condition  of  those  already 
buried.  Even  though  the  supposed  connection  were  anything  more 
than  mere  coincidence,  it  may  be  said  that  nothing  of  the  sort  has  been 
noticed  within  recent  years,  and  never  anywhere  except  in  densely 
populated  neighborhoods,  in  which  densely  crowded  cemeteries  happen 
to  be  located. 

Cases  of  cholera,  yellow  fever,  scarlet  fever,  and  other  diseases  have 
been  attributed  to  the  opening  of  old  graves.  In  one  case,  often  quoted 
in  all  seriousness,  a  number  of  persons  were  seized  with  scarlet  fever 
supposedly  from  digging  up  the  surface  of  a  burial  ground  where, 
no  less  than  thirty  years  before,  a  number  of  victims  of  that  disease 
had  been  buried.  Sir  Henry  Thompson  has  said  :  "  The  poisons  of 
scarlet  fever,  enteric  fever,  smallpox,  diphtheria,  malignant  cholera, 
are  undoubtedly  transmissible  through  earth  from  the  buried  body  by 
more  than  one  mode.  And  thus  by  the  act  of  interment  we  literally 
sow  broadcast  throughout  the  laud  innumerable  seeds  of  pestilence ; 
germs  which  long  retain  their  vitality,  etc.,  many  of  them  destined  at 
some  future  time  to  fructify  in  premature  death  or  ruined  health  to 
thousands." 

Such  broad  statements  are  easy  to  make,  but  exceedingly  difficult  or, 
indeed,  impossible  to  substantiate.  If  true,  it  would  appear  that  the 
earth,  instead  of  being  the  great  natural  resolvent  and  disinfectant  of 
all  forms  of  dead  organic  matter  deposited  below  the  surface,  is  a  mine 
of  septic  matter,  in  spite  of  which,  the  world  at  large  continues  to 
increase  in  health  and  the  average  length  of  life  to  extend  little  by 
little  with  every  decade. 

It  is  said  also  that  the  spores  of  all  known  species  of  pathogenic 
bacteria  are  very  resistant  and  retain  their  virulence  indefinitely.  But 
even  if  this  were  true,  and  it  is  not  true,  it  is  not  shown  that  the  spore- 
bearers  in  the  body  form  spores  after  death  occurs.  As  a  matter  of  fact, 
the  basis  of  the  bacterial  scare  concerning  the  dangers  of  earth-burial 
rests  on  no  more  solid  foundation  than  the  instance,  quoted  in  the 
chapter  on  Soils,  of  anthrax  spores  supposed  to  have  been  brought 
to  the  surface  by  earthworms  that  had  acquired  them  from  a  cow  buried 
two  meters  below,  which  instance  has  no  value  as  evidence  for  reasons 
already  explained. 

Coming  to  a  consideration  of  the  actual  dangers  arising  from 
earth-burial  and  from  the  proximity  of  cemeteries,  it  must  be 
admitted  at  the  outset  that  merely  stinking  gases  are  incapable  of 
transmitting  disease,  and  are,  moreover,  absorbed  and  deodorized  by 
the  soil  itself.  The  same  class  of  foul  odors  are  borne  without  injury 
by  those  engaged  in  the  numerous  offensive  trades.  There  is  no 
ground   for  supposing  that    the  emanations    from  graveyard  soil  are 


CREMATION.  773 

dangerous  to  health,  for  if  they  were,  their  eifects  should  be  most 
marked  among  grave-diggers,  a  class,  who,  like  the  workmen  in 
sewers,  are  obstinately  healthy  in  spite  of  all  a  priori  reasoning  to  the 
contrary. 

Whether  the  soil  becomes  seriously  polluted,  is  a  question  which  bears 
on  the  possible  contamination  of  the  ground-water.  This  possibility 
may  exist,  but  it  is  as  nothing  in  comparison  with  the  pollution 
of  the  soil  and  its  contained  water  by  leaching  cesspools,  into  w^hich 
man  casts  yearly  several  times  his  weight  of  liquid  and  solid  excreta 
from  his  own  body,  and  there  is  recorded  no  single  well-authenticated 
case  of  outbreak  of  disease  due  to  water  contaminated  by  the  drainage 
of  a  graveyard. 

On  general  principles,  the  drainage  of  a  cemetery  should  not  be 
allowed  to  run  into  streams  used  as  water  supplies,  and  wells  should 
not  be  located  in  close  proximity  to  the  boundaries  of  land  used  for 
interments. 

While  burial  too  near  the  surface  should  be  avoided  on  account  of 
the  possibility  that  the  body  may  be  exhumed  by  dogs  and  other 
animals,  it  is  to  be  borne  in  mind  that  the  nearer  the  body  is  to  the 
surface,  the  more  rapid  will  decomposition  occur.  In  order  to  shorten 
as  much  as  possible  the  time  required  for  complete  resolution,  the  coffin, 
which  should  not  be  of  too  permanent  material,  should  be  placed  in 
immediate  contact  with  the  earth,  and  not  in  a  bricked  enclosure  or 
vault.  The  use  of  wicker  coffins  is  urged,  since  they  offer  less  obstacles 
to  the  natural  processes  of  resolution  than  any  other.  Metallic  coffins 
which  retain  the  j^roducts  of  decomposition  indefinitely  should  be 
prohibited.  The  top  of  the  grave  should  be  a  mound  of  earth  capable 
of  supporting  a  fairly  luxuriant  growth  of  vegetation,  which  assists  in 
draining  the  soil  and  makes  use  of  the  products  of  decay. 

Sites  for  Cemeteries. — In  the  selection  of  a  site  for  a  cemetery, 
particular  attention  should  be  given  to  the  nature  of  the  soil.  This 
should  be  dry  and  permeable  to  air ;  the  ground- water  level  should 
normally  be  well  below  the  bottom  of  the  deepest  grave ;  the  surface 
should  be  of  rich  loam,  which  acts  as  a  powerful  deodorant  and  provides 
for  an  abundant  growth  of  vegetation.  Clay  soils  are  objectionable  on 
account  of  dampness  and  impermeability,  which  prevent  rapid  decom- 
position of  the  bodies.  Rocky  soils  are  objectionable  on  account  of 
their  drainage  and  the  obstacles  to  the  digging  of  graves. 

Much  has  V)een  written  concerning  the  danger  of  pollution  of  water 
supjjlies  by  the  drainage  of  cemeteries,  and  this  danger  should  be  kept 
in  mind,  but  it  is  unlikely  that,  with  proper  locations  well  away  from 
habitations,  serious  pollution  will  occur.  Where  land  is  abundant  and 
cheap,  the  immediate  neighborhood  of  cemeteries  for  purposes  of  resi- 
dence is  generally  avoided,  but  it  is  always  well  to  pay  attention  to  the 
proper  drainage  of  lands  devoted  to  burial  purposes,  and  to  consider 
the  possibility  of  the  fouling  of  any  wells  already  present  or  likely  to 
}k'  sunk  in  tli(!  surrounding  .soil. 

Cremation. — Disposal  of  the  dead  by  burning  was  practised  in  very 


774  DISPOSAL    OF  THE  DEAD. 

early  times  as  a  mark  of  respect  by  some,  or  of  dishonor  by  others,  or 
from  motives  of  expediency  after  great  slaughter  in  warfare ;  but  the 
practice  of  incineration,  based  on  economic  and  sanitary  considerations, 
is  of  quite  recent  origin  among  Christian  peoples.  The  arguments 
urged  in  its  favor  from  an  economic  standpoint  are  indisputable,  for 
not  only  can  the  dead  be  thus  disposed  of  much  more  cheaply,  but  the 
necessity  of  devoting  large  tracts  of  valuable  land  for  purposes  of 
burial  is  done  away  with. 

From  a  sanitary  standpoint,  the  arguments  are  not  so  strong  and,  in 
fact,  are  easy  of  refutation.  It  is  urged  that  earth-burial  is  a  menace 
to  public  health,  and  a  number  of  supposedly  convincing  instances  are 
cited  as  proof  of  this  statement ;  but  these  cannot  withstand  the  test 
of  careful  examination  and  weighing  of  evidence,  and  it  must  be  ad- 
mitted, even  by  the  strongest  advocates  of  cremation,  that  there  is  no 
definite  statistical  evidence  that  the  general  death-rate  or  any  special 
death-rate  has  ever  been  influenced  by  earth-burial. 

It  is  urged  also  that  earth-burial  is  repulsive  in  idea  and  horrible  in 
practice,  and  while,  in  the  minds  of  many,  this  statement  is  true, 
it  is  to  be  said,  on  the  other  hand,  that  in  the  minds  of  far  more,  the 
argument  applies  with  greater  force  to  the  practice  of  incineration. 
From  the  time  of  the  early  Christians,  who  practised  interment  by 
stealth,  earth-burial  has  ever  been  the  one  method  of  disposal,  and  the 
sentiment  in  its  favor,  fostered  through  nineteen  centuries  of  practice, 
is  a  powerful  obstacle  to  the  general  adoption  of  cremation,  and  can 
only  slowly  be  overcome.  A  strong  feeling  that  cremation  is  opposed 
to  Christian  doctrine  concerning  the  resurrection  of  the  body  can  only 
be  overturned  by  the  influence  of  the  clergy,  many  of  whom,  including 
Protestants  and  Roman  Catholics  of  eminence,  have  already  done  much 
in  advocacy  of  the  practice  as  a  rational,  economic,  and  sanitary  means 
of  disposal. 

Aside  from  religious  feeling,  the  strongest  argument  urged  against 
cremation  is  the  destruction  thereby  of  evidence  of  poisoning  in  cases 
in  which,  after  disposal  of  the  body,  suspicion  of  foul  play  may  arise ; 
but  when  one  considers  the  very  great  infrequency  of  exhumations  on 
this  ground,  and  the  still  greater  infrequency  of  positive  results  there- 
from, this  objection  can  hardly  be  regarded  as  entitled  to  much  weight. 
In  the  case  of  the  metallic  poisons,  the  evidence  would  still  be  present 
in  most  cases  in  the  ashes  ;  in  the  case  of  the  organic  compounds,  it 
must  be  borne  in  mind  that,  under  most  favorable  conditions,  begin- 
ning the  analysis  before  the  onset  of  putrefaction,  their  detection  in 
the  small  amounts  commonly  employed  is  by  no  means  easy,  and 
afterward  is  extremely  difficult  and  more  often  impossible. 

Furthermore,  it  must  be  borne  in  mind  that,  unless  suspicion  arises 
before  or  immediately  after  death,  chemical  analysis  is  commonly  viti- 
ated by  the  universal  practice  of  embalming  the  body  with  strong  solu- 
tions containing  the  very  substances  sought.  In  every  case  of  doubt 
as  to  the  cause  of  death,  the  body  should  be  subjected  at  once  to  proper 
examination.      In  some  States,  legal  provision  has  been  made,  forbid- 


HISTORY  OF  MODERN  CREMATION. 


lib 


ding  embalming  in  case  of  death  by  violence,  until  the  body  has  been 
"  viewed  "  by  the  proper  authority,  and  providing  for  proper  certifica- 
tion before  incineration. 

History  of  Modern  Cremation. — According  to  Japanese  authori- 
ties, cremation,  as  at  present  practised  among  civilized  nations,  had  its 
origin  in  their  country  many  years  ago.  Until  1871,  however,  no 
special  crematories  were  installed,  the  body  in  its  coffin  being  placed  on 
stones  surrounded  by  wood  or  other  inflammable  material.  In  that  year, 
crematories  were  erected  ;  and  since  then,  the  practice  of  incineration 
has  increased  to  such  an  extent  that,  in  1897,  in  Tokio,  of  34,000  per- 
sons who  died,  15,000,  or  44  per  cent.,  were  cremated.  In  1898,  the 
percentage  was  about  the  same. 

In  this  country,  the  first  movement  in  favor  of  cremation  occurred 
in  New  York,  in  1873,  but  the  first  crematory  was  not  erected  until 


Fig.  118. 


1876-'83  '84  '85  '8B  '^7  '88  '89  '90  '91  '92  -'93  '91  '95  '96  '97  '98 
YEAR 

Curve  showing  number  of  cremations  in  the  United  States.    (After  Abbott.) 


1876.  This  was  built  at  Washington,  Pa.,  by  Dr.  J.  T.  LeMoyne, 
f(jr  the  disposal  of  his  own  body,  and  was  the  only  one  in  the  country 
until  1884,  when  another  was  established  at  Lancaster,  Pa.  During 
this  interval  of  eight  years,  the  use  of  his  crematory  was  allowed  by 
Dr.  LeMoyne  for  others,  and  25  incinerations  were  performed.  Be- 
tween 1884  and  1900,  the  number  of  crematories  increased  to  26, 
which  growth  indicates  a  steady  increase  in  public  sentiment  in  favor 
of  the  process.  The  number  of  cremations  performed  in  the  United 
States  from  1884  to  1899  is  shown  in  Figure  113  from  the  monograph 


776 


DISPOSAL   OF  THE  BEAD. 


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HISTORY  OF  MODERN  CREMATION.  777 

by  Dr.  Samuel  "W.  Abbott/  contributed  by  the  Commonwealth  of 
Massachusetts  to  the  United  States  Social  Economy  Exhibit  at  the 
Paris  Exposition.     During  this  period,  8,885  cremations  occurred. 

The  first  table  on  page  776,  from  the  same  monograph,  shows  the 
progress  of  the  movement  in  the  United  States.  The  second  table 
shows  the  growth  of  the  movement  in  Great  Britain  to  1899. 

Next  to  the  United  States  in  the  number  of  crematories  stands  Italy, 
where,  in  1901,  22  were  in  operation.  The  movement  began  in  Italy 
in  1857,  but  nothing  was  accomplished  until  1897,  three  years  after 
legal  sanction  was  obtained.  Germany  had,  in  1901,  7  establishments, 
the  first  of  which  was  installed  at  Dresden  in  1874;  Great  Britain 
had  7,  the  first  of  which  was  established  in  London  in  1885  ;  France 
had  2,  Switzerland  had  3,  Sweden  had  2,  and  Denmark  had  1. 

According  to  Sir  Henry  Thompson,^  there  were  in  the  United  States 
during  1901,  no  less  than  2,605  incinerations;  in  Germany,  693;  in 
England,  445  ;  in  Paris,  297  ;  in  Italy,  at  12  of  the  22  institutions, 
243  ;  in  Switzerland,  at  2  of  the  3  institutions,  144. 

In  the  destruction  of  the  body,  the  apparatus  is  so  constructed  that, 
while  reduction  to  ashes  is  complete  within  three  hours,  no  oflPensive 
fumes  are  given  off.  Commonly,  the  body,  inclosed  in  a  simple 
wooden  coffin,  is  placed  in  the  retort,  which  is  then  intensely  heated 
by  an  oil  flame,  with  which  air  under  pressure  is  mixed  by  a  blower. 

^  The  Past  and  Present  Condition  of  Public  Hygiene  and  State  Medicine  in  the 
United  States,  Boston,  1900. 
2  The  Lancet,  July  5,  1902. 


INDEX. 


AT)    f^  process   for   sewage   disposal, 
.  JD.  \J.     495 

Abdominal  bands,  579 
Absinthe,  201 
Abyssinian  wells,  340 
Acetylene,  450 
Acid  albumins,  20 

boric,  use  of,  in  foods,  213 

carbolic,  532 

citric,  in  fruits,  etc.,  23 

malic,  in  fruits,  etc.,  22 

oxalic,  in  fruits,  etc.,  23 

salicylic,  use  of,  in  foods,  216 

tartaric,  in  fruits,  etc.,  23 
Acids,  mineral,  disinfection  by,  532 
in  air,  235 

organic,  in  foods,  22 

vegetable,  22 
Actinomycosis,  43 

character  of  milk  in,  99 
Adulteration  of  beer,  180 

of  butter,  125 

of  cheese,  135 

of  chocolate,  175 

of  clothing,  720 

of  cocoa,  175 

of  coffee,  172 

of  flour,  143 

of  honey,  167 

of  milk,  94 

of  tea,  170 

of  vinegar,  203 

of  wines,  192 
Aerobioscope,  269 
AggUitinable  substance,  741 
Agglutinins,  740 
Agglutinoids,  742 
Ague,  brassfounders',  673 
Air,  224 

acids  in,  235 

ammonia  in,  230 

amount  of,  necessary  for  ventilation, 
425 

analysis  of,  251 

aqueous  vapor  in,  231 

argon  in,  227 

bacteria  in,  233 

bacteriological  e.xamination  of,  268 

carbon  dioxide  in,  227 
monoxide  in,  235 

composition  of,  224 

conveyance  of  infection  by,  244 

disinfectant  prof)erties  of,  522 

disinfection  of,  560 


Air,  dust  in,  233 

filtration  of,  443 

hydrogen  in,  227 

peroxide  in,  230 

methods  of  moistening,  441 

nitrogen  in,  226 
acids  in,  230 

organic  matters  in,  240 

oxygen  in,  224 

ozone  in,  229 

permeability  of  bricks,  etc.,  to,  428 

respired,  toxicity  of,  242 

sewer,  237 

soil,  283 

vitiated,  effects  of,  240 
Air-testers,  264 
Albuminates,  20 
Albuminoid  ammonia,  328 
Albuminoids,  20 
Albumins,  20 
Albumoses,  20 

Alcohol,    advisability   of   inclusion   of,  in 
soldiers'  ration,  589 

deteimination  of,  181 

disinfectant  properties  of,  537 

tables,  182 

use  of,  in  the  tropics,  631 
Ale,  175 
Alewife,  36 
Alexins,  733 
Algse,  destruction  of,  in  water,  363 

presence  of,  in  water,  322 
Alkaline  soils,  272 
Alkaloidal  beverages,  168 
Allspice,  206 
Almonds,  152 
Alum  in  baking-powders,  208 

use  of,  in  purification  of  water,  351 
in  wines,  193 
Aluminum  chloride,  disinfectant  properties 
of,  529 

ware,  223 
Amboceptors,  735 

"Amines"  process  for  sewage  disposal,  495 
Ammonia,  albuminoid,  328 

determination  of,  395 

free,  determination  of,  395 
presence  of,  in  water,  326 

influence  of  fumes  of,  on  health,  670 

presence  of,  in  air,  230 
Amyloids,  20 
Anaemia,  miners',  304 
Anilin  colors  in  wines,  194 

influence  of  vapors  of,  on  health,  672 

r79 


7«0 


INDEX. 


Anilin  orange,  detection  of,  in  milk,  120 
Animal  foods,  23 
Ankylostomiasis,  304 
Ankylostomum  duodenale,  304 

spread  of,  by  water,  392 
Annatto,  detection  of,  118 
Anopheles,  642 

Anthrax,  cause  of,  destroyed  by  cooking, 
42,  43 
connection  of  soil  with,  303 
spread  of,  by  flies,  637 

by  ^vater,  375 
Anticholera  inoculation,  751 
Anticomplements,  737 
production  of,  739 
Antihsemolytic  serums,  737 
Anti-immune  bodies,  737 

production  of,  740 
Antileutfotoxins,  737 
Antiplague  inoculation,  751 
Antiseptics,  511 
Antispermotoxins,  737 
Antistreptococcus  serums,  753 
Antitoxic  treatment  of  diphtheria,  746 

of  dysentery,  749 

of  hay  fever,  748 

of  tetanus,  748 
Antitoxins,  727 
Antityphoid  serum,  749 
Apples,  159 
Apricots,  160 
Aqueous  vapor,  determination  of,  252 

presence  of,  in  air,  231 
Argand  burners,  448 
Argol,  190 
Argon,  227 
Arrowroot,  152 
Arsenic  in  beer,  179 

influence  of  dust  of,  on  health,  675 
uses  of,  in  the  arts,  675 
Arseniuretted  hydrogen,  poisoning  by,  673 
Artesian  wells,  342 
Artichokes,  157 
Ascaris  lumbricoides,  spread  of,  by  water, 

391 
Ashland,  Wisconsin,  epidemic  of  typhoid 

fever  at,  381 
Asiatic  cholera,  see  Cholera. 
Asparagus,  158 
Asterionella,  323 

BABCOCK  method  of  determining  fat,114 
Bacillol,  536 
Bacillus  coli,  detection  of,  by  neutral-red, 
415 
significance  of,  in  water,  334 
Bacon,  29 

poisoning  by,  68 
Bacteria  filter,  502 

growth  of,  in  milk,  88 

kinds  of,  concerned  in  meat-poisoning, 

54 
presence  of,  in  air,  233 
in  milk,  89 
in  oysters,  52 
in  water,  332 


Bacteria,  resistance  of,  to  low  temperatures, 

393 
Bacteriolysis,  732 
Baking  powders,  206 
Ball-traps,  463 
Bananas,  162 
Barley,  144 

malt,  178 

pearl,  144 
Barracks,  599 
Bass,  36 
Bathing,  706 
Baths,  706 
Bath-tubs,  482 
Beans,  150 

broad,  150 

kidney,  150 

soja,  150 

string,  150 

canned,  150 
Bedbugs,  transmission  of  disease  by,  640 
Bed-linen,  disinfection  of,  559 
Beef,  26 

canned,  29 

composition  of,  28 

corned,  29 

poisoning  by,  59,  70 
Beefsteak,  composition  of,  28 
Beer,  175 

adulteration  of,  180 

analysis  of,  181 

arsenical,  poisoning  by,  179 

colonial  laws  concerning,  177 

composition  of,  180 

detection  of  preservatives  in,  188 

exti-act,  determination  of,  188 

manufacture  of,  177 

neuritis  caused  by,  179 

preservatives  in,  181 

use  of,  in  the  tropics,  632 
Beerwort,  177 
Beet  sugar,  1 63 

tops,  158 
Beets,  157 
Bell-traps,  464 
Berkefeld  filter,  356 
Berries,  162 
Beverages,  alcoholic,  175 

alkaloidal,  168 

distilled,  197 

fermented,  175 
Bilge-water,  624 
Bilharzia  hsematobia,  392 
Birds,  meat  of,  26 
Birth-rates,  693 
Biscuits,  142 
Blackberries,  162 
Black  sti-ap,  165 
Blankets,  waterproof,  580 
Blueflsh,  36 
Blue-green  algae,  322 
Boiling,  disinfection  by,  619 

purification  of  watei'  by,  355 
Bologna  sausage,  32 
Books,  disinfection  of,  564 
Boots,  578 


INDEX. 


781 


Boots,  fit  of,  722 

Borax,  action  of,  on  digestion,  93 
on  the  system,  214 

detection  of,  in  milk,  120 

use  of,  in  foods,  213 

in  preserving  milk,  93 
Boric  acid,  detection  of,  in  milk,  120 
use  of,  in  foods,  213 

in  preserving  milk,  93 
Bothrioceplialus  latus,  37 
Bottle-traps,  462 
Botulism,  55 
Boyle,  law  of,  261 
Brandy,  198 
Bread,  140 

pulled,  142 
Brickmakers'  disease,  304 
Bromine,  disinfectant  properties  of,  526 

influence  of,  on  health,  670 

use  of,  in  purification  of  water,  353 
Brussels  sprouts,  158 
Bubonic  j^lague,  inoculation  against,  751 
Buckwheat,  148 
Burgundy,  191 
Butler,  Pa.,  epidemic  of  typhoid  fever  at, 

384 
Butter,  124 

analysis  of,  128 

artificial,  125 

character  of  fat  of,  125 

composition  of,  124 

"process,"  127 

rancid,  124 

"renovated,"  127 

spread  of  disease  by,  127 

tubercle  bacilli  in,  127 

use  of  glucose  in,  125 
preservatives  in,  125 
Butterfish,  36 
ButterinC;  125 
Butyric  ferments,  88 
Butyrin,  21 
Butyrorefractometer,  131 

nABBAGE,  158 
\J  Caffeine,  168 
Caisson  disease,  682 
Calcutta,  Black  Hole  of,  241 
Calories,  17 
Calves'  liver,  30 
Cameron's  septic  tank,  504 
Camps,  597 

detention,  770 

inspection  of,  606 

sanitation  of,  607 

sewerage  of,  604 

water-supply  of,  604 
Candy,  167 
Cane-sugar,  163 
Canned  beef,  29 

foods,  209 

metallic  contamination  of,  221 

meats,  210 
Canning,  preservation  of  foods  by,  209 
Capillarity  of  soil,  determination  of,  312 
Capillai-y  water,  278,  286 


Caprin,  21 
Caproin,  21 
Caprylin,  21 
Capsicum,  206 
Caramel,  163 

detection  of,  119 
Carbohydrates,  amount  of,  necessary,  18 
classification  of,  21 
function  of,  22 
Carbolic  acid,  532 
powders,  534 
soaps,  541 
Carbon  dioxide,  amount  of,  in  water,  325 
determination  of,  in  air,  257 

in  soil  air,  313 
increase  of,  during  fogs,  251 
permissible  amount  of,  in  air,  229 
presence  of,  in  air,  227 
sources  of,  in  air,  227 
disulphide,  influence  of,  on  health,  671 
monoxide,  235 

amount   of,    in   illuminating  gas, 

449 
determination  of,  in  air,  265 
influence  of,  on  health,  670 
poisoning  by,  236 
sources  of,  235 
Carlsbad  water,  331 
Carrots,  157 
Caseins,  20 
Cassia,  206 

Cats,  use  of,  as  food,  23 
Catsup,  202 
Cauliflower,  158 
Celery,  158 
Cellulose,  22 
Cemeteries,  drainage  of,  773 

sites  for,  773 
Census,  687 
Cereals,  137 
Cerebro-spinal  meningitis,  transmission  of, 

through  air,  249 
Chalk,  adulteration  of  milk  with,  95 
Chamberland-Pasteur  filter,  356 
Champagne,  192 
Chaptalizing  of  wines,  193 
Charles,  law  of,  261 
Chauveau's  retention  theory,  727 
Cheese,  132    _ 

adulteration  of,  135 
analysis  of,  135 
composition  of,  134 
"faults"  in,  133 
"  filled,"  135 
manufacture  of,  133 
poisoning  by,  88,  136 
varieties  of,  134 
Chemiotaxis,  744 
Cherries,  160 
Chestnuts,  153 
Chicken,  31 
Chicory,  172 
(Jhigoe,  634 

Children,  employment  of,  685 
Chloride  of  lime,  disinfectant  properties  of, 
524 


782 


INDEX, 


Chloride  of  lime,  use  of,  in  purification  of 

water,  352 
Chlorinated  soda,  disinfectant  properties  of, 
526 
use  of,  in  purification  of  water,  352 
Chlorine,  determination  of,  in  water,  402 

disinfectant  properties  of,  524 

influence  of,  on  health,  669 

presence  of,  in  soils,  272 
in  water,  330 

use  of,  in  purification  of  water,  353 
Chocolate,  174 

Cholera,  Asiatic,   connection  of  soil  with, 
300 

belt,  579 

epidemics  of,  due  to  water,  386 

infantum,  spread  of,  by  milk,  108 

preventive  inoculation  against,  751 

propagation  of,  in  India,  388 

transmission  of,  by  flies,  637 
through  air,  249,  250 
milk,  105 
ovsters,  49 
water,  375,  386 
Chromates,  detection  of,  in  milk,  122 
Cider,  196 

vinegar,  202 
Cinnamon,  206 
Cisterns,  336 

Citric  acid,  presence  of,  in  milk,  85 
Clams,  37 

sewage  pollution  of,  52 
Claret,  191 

Clark's  process  for  removal  of  hardness,  364 
Clay  soils,  270 
Clothing,  714 

adultei-ation  of,  720 

disinfection  of,  559 

heat  conductivity  of,  715 

hygroscopicity  of,  715 

influence  of  color  of,  577,  714 
of  texture  of,  714 

kind  of,  necessary  in  the  tropics,  633 

materials  used  in,  715 

selection  of,  722 
Cloves,  205 
Coagulin,  742 

Coal-gas,  composition  of,  449 
Coal-tar  coloi-s,  detection  of,  194 

presence  of,  in  wine,  194 
Cocoa,  173 

flake,  174 

shells,  175 

soluble,  174 
Cocoanuts,  152 

Cockles,  sewage  pollution  of,  51 
Codfish,  36 

salt,  37 
Coffee,  171 

adulteration  of,  172 

composition  of,  172 
Coffins,  744 
Cold,  antiseptic  action  of,  519 

preservation  of  food  by,  209 
Collagens,  20 
Colostrum,  87 


Complementoids,  738 
Complementophile  groups,  743 
Complements,  737 

source  of,  738 
Condensed  milk,  95 
Condiments,  202 
Conduction,  436 
Confectionery,  167 
Contagious  diseases,  725 
Convection,  436 
Cooked  milk,  detection  of,  122 
Cooking,  action  of,  on  meats,  25 
Copper,  addition  of,  to  foods,  219 

sulphate,  disinfectant  properties  of,  530 
purification  of  water  by,  363 
Cordials,  201 
Cordon  sanitaire,  769 
Corn,  146 

flint,  146 

pop, 146 

meal,  146 

sweet,  146 

varieties  of,  146 
Corned  beef,  poisoning  by,  72 
Cotton,  718 

clothing,  properties  of,  576 

dust,  influence  of,  on  health,  679 

workers,  diseases  of,  679 
Cottonseed  oil,  154 
Cowls,  ventilating,  429 
Crabs,  37 
Crackers,  142 
Cranberries,  162 
Cream,  96 

detection  of  gelatin  in,  123 

of  tartar,  207 
Cremation,  773 

history  of,  775 

statistics  of,  776 
Crenothrix  Kiihniana,  326 
Creolin,  535 
Cresols,  534 
Cresses,  158 

Crustaceans,  digestibility  of,  35 
Cucumber,  159 
Culex  fasciatus,  654 
Currants,  162 

dried,  161 
Cusk,  36 

Cutlery  grinding,  dangere  of,  678 
Cyanide  of  mercury,  disinfectant  properties 

of,  532 
Cysticercus  bovis,  37 

cellulosse,  37 
Cytases,  744 

DALMATIAN   POWDER,   destruction 
of  mosquitoes  by,  656 
Dampness,  occupations  involving  exposure 
to,  682 
soil,  connection  of,  with  disease,  296 
Dandelions,  158 
Dead,  disposal  of  the,  771 
Death-rates,  695 

correction  of,  701 
infantile,  698 


INDEX. 


783 


Death-rates,  influence  of  age  on,  695 
of  density  on,  697 
of  race  on,  696 
of  sex  on,  695 

standard,  702 

weekly,  698 

zymotic,  698 
Dececo  closet,  477 
Dengue,   transmission   of,   by   mosquitoes, 

659 
Deniti-ification,  329 
Denitrifying  bacteria,  329 
Deodorants,  511 

Destructors  for  swill  disposal,  508 
Detention,  camps  of,  770 
Deuterotoxins,  732 
Dextrin,  21 
Dextrose,  22,  164 
Dhobie  itch,  634     _ 

Diarrhoea,    epidemic,    connection    of   soil 
with,  307 
spread  of,  by  milk,  108 
Diarrhoeal     diseases,     prevalence     of,    in 

armies,  616 
Diastase,  145 
Dibdin's  filter,  502 
Diet,  regulation  of,  708 

selection  of,  in  the  tropics,  629 
Dietaries,  standard,  18 

tropical,  595 
Diphtheria,  antitoxic  treatment  of,  746 

connection  of  soil  with,  301 
of  water-supply  with,  374 

preventive  treatment  of,  746 

spread  of,  by  milk,  105 

transmission  of,  through  air,  249,  250 
Disinfectants,  511 
Disinfecting  stations,  518 
Disinfection,  511 

practical,  557 
Disposal  of  the  dead,  771 
Distillation,     purification     of    water    by, 

355 
Distilled  liquors,  197 
Distomiasis,  transmission  of,  by  mosquitoes, 

660 
Dogmeat,  inspection  of,  23 
Dogs,  use  of,  as  food,  23 
Dracunculus    medinensis,    spread    of,    by 

water,  391 
Drainage,  influence  of,  on  soil,  297 
Di-iven  wells,  340 
Dunbar's  hay-fever  antitoxin,  748 
Dust,  a  constituent  of  air,  233 

B.  tuberculosis  in,  245 

determination  of,  in  air,  267 

effects  of,  in  inhabited  rooms,  242 

infective,  680 

influence  of,  in  transmission  of  disease, 
248 
on  liealth,  674 

irritating,  677 

poisonous,  674 
Dyes,  poisonous,  721 
Dysentery,  antitoxic  treatment  of,  749 

connection  of  water-sujjply  with,  374 


EARTH  burial,  771 
supposed  danger  from,  771 
Eels,  36 
Egg-plant,  159 
Eggs,  78 

composition     of     brown-shelled     and 

white-shelled,  80 
digestibility  of,  80 
influence  of  feed  on  flavor  of,  80 
proteids  of,  79 
Egyptian  chlorosis,  304 
Ehrlich's  theory,  727 
Elastins,  20 
Electric  lighting,  452 
Elutriating  apparatus,  308 
Enamelled  ware,  223 
Enzymes,  20 
Epidemic   diarrhoea,   spread   of,  by  milk, 

108 
Epitoxoids,  731 
Erysipelas,   transmission   of,   through   air, 

249  _  _ 

Essential   oils,   disinfectant   propeities  of, 

538 
Eucalyptol,  538 
Exercise,  709 

amount  of,  required,  712 
effect  of,  on  weight,  711 
kinds  of,  713 

F^CES,  disinfection  of,  558 
Farinaceous  seeds,  137 
Fat,  amount  of,  necessary,  18 

Babcock  method  of  determining,  114 
character  of,  in  butter,  125 
Werner-Schmidt  method  of  determin- 
ing, 113 
Fats,  21 

composition  of,  21 
function  of,  21 
vegetable,  153 
Fatty  seeds,  152 

Feet,  care  of,  during  marching,  585 
Felt,  720 

Ferric  chloride,  disinfectant  properties  of, 
529 
sulphate,   disinfectant    properties    of, 
529 
Ferrous  sulphate,  disinfectant  properties  of, 

528 
Figs,  162 

Filaria   sanguinis   hominis,  spread  of,  by 
water,  392 
transmission   of,  by  mosqui« 
toes,  657 
File-makers,  diseases  of,  676 
Filled  cheese,  135 
Filter  beds,  358 

galleries,  346 
Filters,  Berkefeld,  356 

Chamberland-Pasteur,  536 
domestic,  355 
sand,  358 
Filtration,  intermittent,  362 
"  mechanical,"  363 
purification  of  water  hy,  355 


784 


INDEX. 


Filtration,  sewage,  500 
Fish,  34 

composition  of,  35 

connection  of,  with  leprosy,  34 

digestibility  of,  35 

keeping  qualities  of,  35 

poisoning  by,  54 

spread  of  parasites  through,  37 

transmission  of  disease  through,  42 

value  of,  as  food,  34 
Fitz's  method  of  detennining  COj  in  air, 

264 
Flake  cocoa,  174 

Flax  dust,  influence  of,  on  health,  679 
Fleas,  transmission  of  disease  by,  640 
Flies,   transmission  of  disease  by,  637 
Flounder,  36 
Flour,  adulteration  of,  143 

"  bakers',"  139 

Graham,  139 

"  mixed,"  143 

"patent,"  139 

wheat,  139 
Flukes,  41 
Fluorides,  use  of,  in  foods,  219 

detection  of,  in  beer,  188 
Flushing  apparatus,  478 
Fogs,  influence  of,  on  health,  251 
Fomites,  relation  of,  to  spread  of   yellow 

fever,  653 
Food,  amount  of,  necessary,  17 

definition  of,  17 
Foods,  animal,  23 

canned,  209 

cereal,  137 

chemical  preservatives  of,  211 
-  composition  of,  19 

contamination  of,  by  metals,  219 

lead  in,  221 

lead-poisoning  from,  221 

nickel  in,  222 

nutritive  value  of,  17 

preservation  of,  208 

salted,  209 

smoked,  209 

tin  in,  210 

use  of  copper  in,  219 

vegetable,  136 

zinc  in,  222 
Foot-and-mouth  disease,  character  of  milk 
in,  98 
harmlessness  of  meat  of  animals 
dead  of,  43 
Forecastles,  621 
Fore-milk,  84 
Formaldehyde,  542 

action  of,  against  mosquitoes,  556 
in  foods,  217 

conditions  favoring  disinfection  by,  553 

detection  of,  in  milk,  120 
in  wines,  196 

disinfection  by,  543 

power  of  penetration  of,  552 

toxicity  of,  554 

use  of,  in  preserving  milk,  93 
Formalin,  543 


Formochloral,  544 
Fowls,  composition  of,  31 
Frankfort  sausage,  32 
Fruits,  159 
Fungi,  edible,  163 
Fur,  720 

Furnaces,  hot-air,  439 
Fusel  oil,  197 

GAITERS,  577 
Galactose,  22 
Galleries,  filter,  346 
Gallizing  of  wines,  193 
Garbage,  disposal  of,  507 
Garget,  99 

Gas  burners,  kinds  of,  448 
Gas-leaks,  detection  of,  452 
Gas-poisoning,  449 
Gasolene  gas,  451 

Gelatin,  detection  of,  in  cream,  123 
Germicides,  511 
Gin,  201 
Ginger,  206 
Glaisher's  table,  254 
Glanders,  spread  of,  by  water,  375 
Glass-grinding,  dangers  of,  679 
Globulins,  20 
Glucose,  164 

arsenical,  179 

use  of,  in  beer,  178 

use  of,  in  butter,  125 

wholesomeness  of,  178 
Gluten,  138 
Go-betweens,  735 
Glycoproteids,  20 
Goitre,  connection  of  soil  with,  306 

of  water  with,  372 
Golf,  713 
Goose,  31 

liver,  31 
Gooseberries,  162 
Graham  flour,  139 
Grape  sugar,  22 
Grapes,  161 
Grease  traps,  464 
Green  turtle,  37 
Ground-water,  287,  818 

movement  of,  320 

supplies,  338 
Gruber-Widal  reaction,  741 
Guinea-worms,  391 

HABITATIONS,  420 
Haddock,  36 
Hsemagglutinins,  741 
Haemoglobins,  20 
Hsemolysins,  734 
Hemolysis,  733 
Hsemosporidia,  645 
Hake,  36 
Halibut,  36 

smoked,  37 
Halteridium,  647 
Ham,  29 

poisoning  by,  66,  69 
Hamburg,  epidemic  of  cholei-a  at,  386 


INDEX. 


785 


Hamburg  steak,  preservation  of,  217 
Hammocks,  621 
Hands,  disinfection  of,  560 
Haptins,  744 
Ilaptophores,  729 

Hardness,  determination  of,  in  water,  403 
of  water,  331 

permanent,  332 
removal  of,  364 
temporary,  332 
Play  fever,  antitoxic  treatment  of,  748 
Heat,  disinfection  by,  514 

exposure  to  extreme,  682 
Heating,  423 

Hermite  process  for  sewage  disposal,  495 
Herring,  36 

smoked,  37 
Herrings,  poisoning  by,  61 
Hog  cholera,  spread  of,  by  water,  375 
Hominy,  146 
Honey,  165 

adulteration  of,  167 
poisoning  by,  166 
Hookworm  disease,  304 
Hopper  closets,  475 
Hops,  176 

substitutes  for,  179 
Horse  meat,  26 

amount  of,  eaten,  31 
composition  of,  31 
poisoning  by,  73 
detection  of,  33 
use  of,  in  sausage,  32 
Hospital  tents,  601 
Hot-water  heating,  439 
Huckleberries,  162 
Humidifier,  442 
Humidity,  absolute,  232,  252 
excess  of,  in  tropics,  627 
relative,  232,  252 
Humus,  271 
Huts,  soldiers',  603 
Hydric  trap,  469 
Hydrocliloric  acid,  influence   of  fumes  of, 

on  health,  669 
Hydrogen,  a  constituent  of  air,  227 

peroxide,  action  of,  as  a  food  preserva- 
_  tive,  218 
disinfectant  power  of,  523 
Hygroscopic  water,  278,  286 

f  CE,  393 

i      artificial,  394 

cream,  poisoning  by,  88 
transmission  of  typhoid  fever  through, 
394 
Illuminating  gas,  kinds  of,  449 

poisoning  by,  236 
Immune  bodies,  739 
partial,  740 

disadvantage  of  excess  of,  746 
Inimuiiity,  724 
af()iii]-ed,  725 
active  acquired,  726 
natural,  725 
passive  ac(juired,  726,^ 


j  Immunity,  practical  applications  of  studies 

in, 745 
j  India,  propagation  of  cholera  in,  388 
I  Indian  corn,  146 

meal,  146 
'  Infantile  diarrhoea,  transmission  of,  through 
I  air,  250 

j  through  milk,  108 

j  Infection,  channels  of,  724 

conveyance  of,  by  air,  244 
Infectious  diseases,  725 
causes  of,  724 
Inosite,  22 

Insects,  relation  of,  to  human  diseases,  636 
Inspection  of  meat,  76 
Interbodies,  735 
Intermediary  bodies,  744 
Intermittent  filtration,  363 
Interstate  quarantine,  767 
Iodine,  disinfectant  i^roperties  of,  526 
Iron,  action  of  water  on,  369 
detection  of,  in  water,  409 
presence  of,  in  soils,  272 
removal  of,  from  water,  365 
use  of,  in  purification  of  water,  353 
Irrigation,  sewage,  496 

Waring  system  of,  499 
Ithaca,   N.  Y.,  epidemic  of  typhoid  fever 
at,  384 

JAMS,  168 
d     Jellies,  168 
Jiggers,  634 

KEFIE,  95 
Kid  meat,  poisoning  by,  76 
Kidneys,  composition  of,  29,  30 
Kieselguhr,  356 
Kingfish,  36 
Kitchen  refuse,  disposal  of,  507 

utensils,    metallic,     contamination    of 
foods  by,  222 
KJeldahl  process  for  nitrogen,  117 
Koumiss,  95 
Kummerbund,  580 

T  ABAEEAQUE'S   solution,  disinfectant 

iJ     properties  of,  526 

Lactalbumin,  85 

Lactodensimeter,  110 

Lactometer,  110 

Lactoscope,  110 

Lactose,  84 

determination  of,  116,  117 

Lifivulose,  22 

Lager  beer,  175 

Lamb,  composition  of,  30 

Lard,  81 

Latrines,  605 

description  of,  612 

Lausen,  epidemic  of  typhoid  fever  at,  379 

Lead,  action  of  water  on,  365 

contamination  of  foods  by,  221 
determination  of,  in  water,  406 
influence  of  dust  of,  on  health,  675 
uses  of,  in  the  arts,  675 


786 


INDEX. 


Leather,  720 
Leavening  of  bread,  140 
Leeks,  158 
Leggings,  577 
Legumes,  148 
Legumin,  148 
Lemon  juice,  204 
Lentils,  151 

Leprosy,  Hutchinson's  fish  theory  concern- 
ing, 34 

ti-ansmission  of,  by  flies,  639 
Lettuce,  158 
Leucotoxins,  737 
Life,  dui-ation  of,  703 

expectation  of,  703 

mean  duration  of,  708 

probable  dui-ation  of,  703 

tables,  704 
Lightmg,  445 

Lime,   chloride  of,  use  of,  in  purification 
of  water,  352 

disinfectant  properties  of,  527 

juice,  204 

milk  of,  527 
Linen,  719 

clothing,  properties  of,  576 

workei-s,  diseases  of,  679 
LiqueuiB,  201 

Liquid  air,  disinfectant  action  of,  520 
Liquors,  distilled,  197 

malt,  175 
Liver,  composition  of,  29,  30,  31 
Loam,  271 
Lobster,  37 
Luneburg,    epidemic   of   typhoid  fever  at, 

382 
Lysofomi,  536 
Lysol,  536 

MACARONI,  142 
Mace,  206 
Mackerel,  36 

canned,  37 

Spanish,  36 
Macrocytase,  745 
Madeiiu  wine,  192 
Maize,  146 
Malaria,  connection  of  soil  with,  302 

prevalence  of,  in  armies,  615 

preventive  measures  against,  651 

the  parasites  of,  645 

transmission  of,  by  mosquitoes,  642 

water  as  a  cause  of,  374 
Malignant  oedema,  connection  of  soil  with, 

303 
Malt,  barley,  178 

substitutes  for,  178 

liquoi^s,  175 

vinegar,  203 
Maltose,  22 

Manganese,  presence  of,  in  soils,  272 
Manihot,  151 
Maple  sugar,  164 

syrup,  164 
Maranta,  152 
Margarine,  125 


Marching,  instances  of  long-distance,  581 
Marine  hygiene,  618 
Marl,  271 

Marriage-rates,  692 
Match-making,  dangei-s  of,  672 
Mattresses,  disinfection  of,  563 
Measles,  prevalence  of,  in  armies,  616 
Measly  meat,  37 

pork,  38 
Meat  and  disease,  42 

bases,  24 

canned,  209 

characteristics  of  good,  26 

consumption  of,  in  the  tropics,  594 

digestibility  of,  24,  26 

dried,  209 

effects  of  cooking  on,  25 

extracts,  32 

flavor  of,  21 

inspection,  76 

powder,  32 

"  red  "  and  "  white,"  27 

salted,  209 

smoked,  209 

spread  of  parasites  through,  37 

texture  of,  25 

transmission  of  disease  by,  42 

tuberculous,  43 

infectivity  of,  44 
Meat-poisoning,  53 

bacteria  concerned  in,  56 

character  of  meats  which  cause,  58 

identity  of,  with  paratyphoid,  56 

onset  and  symptoms  of,  57 

postmortem  appearances  in,  58 
Melons,  161 
Menthol,  538 

Mercuric  chloride,  disinfectant  properties 
of,  530 

cyanide,  disinfectant  properties  of,  532 
Mercurv,  influence  of  fumes  of,  on  health, 

672 
Metschnikoff''s  theory,  744 
Mycrocytase,  745 
Military  hygiene,  565 
Milk,  82 

abnormal  colors  produced  in,  85 

action  of  formaldehyde  on,  93 

adulteration  of,  94 

alcohol  in,  86 

analysis  of,  110 

antiseptics  in,  92 

bacteria  in,  88 

bitter,  86 

causes  of  bitterness  of,  86 

chalk  in,  95 

changes  produced  in,  by  bacteria,  88 
by  boiling,  87 

character  of,  in  actinomycosis,  99 
in  anthrax,  99 

in  foot-and-mouth  disease,  98 
in  garget,  99 
in  rinderpest,  98 

colored,  95 

composition  of,  82 

condensed,  95 


INDEX. 


787 


Milk,  cooked,  methods  of  detecting,  122 

dirty,  88 

fat  of,  83 

flavor  of,  affected  by  feed,  86 
how  modified,  86 

growth  of  bacteria  in,  89 

mineral  matter  of,  85 

of  lime,  527 

pasteurization  of,  91 

physical  examination  of,  110 

poisoning  by,  109 

poisonous,  96 

preservation  of,  91 
by  chemicals,  92 
by  cold,  91  _ 
by  sterilization,  91 

proteids  of,  84 

reaction  of,  85 

ropy,  86 

skimmed,  94 

specific  gravity  of,  85 

spread  of  Asiatic  cholera  by,  105 
of  cholera  infantum  by,  108 
of  diphtheria  by,  105 
of  epidemic  diarrhoja  by,  108 
of  scarlet  fever  by,  106 
of  septic  sore  throat  by,  98 
of  tuberculosis  by,  100 
of  typhoid  fever  by,  107 

standards,  94 

sterilization  of,  91 

streptococci  in,  99 

sugar  of,  84 

tubercle  bacilli  in,  91,  100 

zymases  in,  92 
Miners'  anaemia,  304 
Molasses,  165 
Molasses-vinegar,  203 
Mollusks,  digestibility  of,  35 
Moselle  wines,  191 
Mosquitoes,  destruction  of,  651 

species  of,  in  the  United  States,  642 

transmission  of  diseases  by,  641 
Mother  of  vinegar,  202 
Muck,  271 
Mulberries,  162 
Multipartial  serums,  740,  747 
Municipal  quarantine,  769 
Muscle  sugar,  22 
Mushrooms,  163 
Muskellunge,  36 
Mussels,  37 

poisoning  by,  60 
Mustard,  205 
Mutton,  26 

composition  of,  30 
Mycoderma  aceti,  202 

NAPHTHA,   influence  of  fumes   of,  on 
health,  671 
Naval  hygiene,  618 
Nephrotoxins,  737 
Nesslej-'s  reagent,  395 
Neurotoxins,  737 

Neutral-red,  detection  of  B.  coli  with,  415 
Nickel,  contamination  of  food  by,  223 


Nickel,  greening  of  peas  with,  222 

Nickelware,  223 

Nitrates,  determination  of,  in  water,  401 

in  water,  328 
Nitrification  (in  water),  360 
Nitrites,  determination  of,  in  water,  400 

in  water,  328 
Nitrobenzol,  influence  of,  on  health,  671 
Nitrogen,  absorption  of,  by  plants,  226 

acids  in  air,  230 

forms  of,  in  soils,  272 

function  of,  in  air,  226 
Nitrous  fumes,  influence  of,  on  health,  670 
Norton  tube  wells,  340 
Nucleins,  20 
Nucleo-albumins,  20 
Nutmeg,  206 
Nuts,  152 

OATMEAL,  145 
Oats,  145 
Occupation,  diseases  of,  662 

fallacies  of  statistics  concerning,  663 

hygiene  of,  661 
Occupations,  classification  of,  666 

dusty,  674 
Offensive  trades,  681 
Ogdensburg,  N.  Y.,   outbreak  of  typhoid 

fever  at,  394 
Oil,  cottonseed,  154 

fusel,  197 

of  wine,  198 

olive,  153 

virgin,  153 
Oils,  essential,   disinfectant  properties  of, 

538 
Olein,  21 
Oleomargarine,  125 

detection  of,  129 

frauds  in  the  sale  of,  126 

tubercle  bacilli  in,  128 
Oleo-oil,  125 
Onions,  158 
Open  fires,  437 

Ophthalmia,  transmission  of,  by  flies,  639 
Oranges,  160 

Organic  acids  in  foods,  22 
Oyster  beds,  sanitation  of,  54 

plant,  157 
Oysters,  37 

bacteria  in,  52 

composition  of,  37 

poisoning  by,  63 

sewage  pollution  of,  49 

transmission  of  typhoid  fever  by,  49 
Oxygen,  disinfectant  properties  of,  522 

proportion  of,  in  air,  224 

I'equired,    determination  of,  in  water, 
404 
Oxyuris  vennicularis,  spread  of,  bv  water, 

391 
Ozone,  a  constituent  of  air,  229 

action  of,  on  the  system,  230 

determination  of,  in  air,  266 

disinfectant  properties  of,  522 

use  of,  in  purification  of  water,  354 


788 


INDEX. 


PAIL  system  of  sewage  disposal,  493 
Palmitin,  21 
Faraform,  543 
Paraformaldehyde,  542 
Parasites  in  fish  and  meat,  37 

in  water,  391 
Pasteur  filter,  356 
Pasteur's  exhaustion  theory,  727 
Pasteurization  of  milk,  91 

of  wines,  193 
Patent  flour,  139 
Peaches,  160 
Peanuts,  153 
Pearl  barley,  144 
Peai-s,  160 
Peas,  149 

canned,  150 

green,  149 

greening  of,  by  copper,  220 
by  nickel,  222 
Peat,  271 

bactericidal  properties  of,  493 
Pectin,  22 
Pectose,  22 
Peppei-,  205 

Cayenne,  206 
Peppermint  test  for  plumbing,  487 
Perch,  36 
Permanganate,  use  of,    in    j^ni'lfication  of 

water,  351 
Permeability  of  soils,  determination  of,  309 
Peroxide  of  hydrogen,  a  constituent  of  air, 

230 
Perry,  197 
Person,  care  of  the,  706 

in  the  tropics,  634 
Personal  hygiene,  706 
Pfeifiei-'s  phenomenon,  733,  744 
Phagocytosis,  744 
Phagolysis,  744 
Phenol,  532 

Phosphorus,    influence    of    fumes    of,    on 
health,  672 

presence  of,  in  soils,  272 
Pickerel,  36 
Pimento,  206 
Pinworms,  391 
Piquette,  193 
Plague,  connection  of  soil  with,  300 

inoculation  against,  751 

transmission  of,  bv  fleas,  640 
by  flies,  639  " 
through  air,  249 
Plantains,  162 
Plastering  of  wines,  193 
Plug  closets,  474 
Plumbing,  452 

methods  of  testing,  487 
Plums,  160 
Plunger  closets,  474 
Plymouth,  Pa.,  epidemic  of  typhoid  fever 

at,  380 
Pneumonia,  serum  treatment  of,  754 

transmission  of,  through  air,  249 
Poisoning  by  anilin  black,  721 

by  arsenic  in  beer,  179 


Poisoning  by  arsenic  in  the  arts,  675 

by  arseniuretted  hydrogen,  673 

by  bacon,  68 

by  beef,  59,  70 

by  carbon  disulphide,  671 
monoxide,  236 

by  cheese,  88,  136 

by  corned  beef,  72 

by  fish,  54 

by  ham,  66,  69 

by  herrings,  61 

by  honey,  166 

by  horse  meat,  73 

by  ice  cream,  88 

by  illuminating  gas,  236 

by  kid  meat,  76 

by  meat  and  fish,  63 

bv  mercury,  672 

by  milk,  109 

by  mussels,  60 

by  naphtha,  671 

by  nitroleenzole,  671 

by  oysters,  63 

by  phosphorus,  672 

by  pork,  66 

by  potatoes,  156 

by  salmon,  63 

by  sausage,  60,  74 

by  tea,  170 

bv  tvrotoxicon,  97 

by  veal,  59,  64  ' 

by  wood  alcohol,  674 
Poisonous  dyes,  721 

fish,  53 

milk,  96 
Pom  pa  no,  36 

Pollution,  detection  of,  by  fluorescein,  349 
Popcorn,  146 
Population  constitution,  690 

estimated,  689 

increase  of,  690 
Pore  volume  of  soils,  273 
Pork,  composition  of,  29 

measled,  38 

salt,  29 
Pork-poisoning,  66 
Port,  192 
Porter,  175 
Posts  and  camps,  597 

Potassium  permanganate,  disinfectant  prop- 
erties of,  5o0 
presence  of,  in  soil,  272 
Pot-traps,  462 
Potato-poisoning,  156 
Potatoes,  154 

antiscorbutic  value  of,  126 

sweet,  157 
Potential  energy  of  foods,  17 
Potters,  diseases  of,  676 
Poultry,  31 
Precipitins,  742 
Precipitoids,  742 
Preservation  of  milk,  91 
Preservatives,  detection  of,  in  beer,  188 
in  milk,  120 
in  wine,  195 


INDEX. 


789 


Preservatives,  food,  212     • 

Prismatic  glass,  action  of,  in  lighting,  446 

Proof  spirit,  200 

Proteids,  amount  of,  necessary,  18 

classification  of,  20 

determination  of,  117 

function  of,  19 

nature  of,  19 
Proteosoma,  647 
Prototoxins,  732 
Prototoxoids,  731 
Psychrometer,  253 
Ptomain-poisoning,  54 
Ptomains,  55 
Pumpkin,  159 
Pumps,  340 

Purification  of  water,  349 
Puttees,  577 

Pyrethrum    powder,    destruction   of    mos- 
quitoes by,  656 

QUAKANTINE,  761 
house,  770 
interstate,  767 

instances  of  absurd  application  of,  762 
law  of  1893,  763 
municipal,  769 
probable  modification  of,  765 
state,  767 
Quick-process  vinegar,  203 

RADIATION,  436 
Radishes,  157 
Eags,  influence  of,  on  health,  680 
Earn,  316 

stored,  3.' So 
Eaisins,  161 
Easpberries,  162 
Eation,  alcohol  in  the,  589 

Austrian  army,  592 

British  army,  59 1 

emergency,  588 

French  army,  592 

German  army,  592 

Italian  army,  592 

naval,  619 

Eussian  army,  592 

Spanish  army,  592 

travel,  588 

U.  S.  army,  adequacy  of,  591 

suitability  of,  to  the  tropics. 
593 
Eations,  587 
Eeceptors,  729 

first  order  of,  730 

second  order  of,  743 

third  oi'der  of,  744 
Eecreation,  708 
Eecruits,  examination  of,  572 

grounds  for  rejection  of,  574 

naval,  618 

qualifications  of,  567 
Eed  meat,  27 

snappei',  36 
Registnirs'  returns,  69] 
Relative  humidity,  232 


Eeservoirs,  338 

Respirators,  668 

Respiratory   disease,    increase    of,    during 

fogs,  251 
Rest,  708 
Reverdissage,  219 
Rhine  wines,  191 

Ribbed  glass,  action  of,  in  lighting,  446 
Rice,  147 
Rinderpest,  character  of  milk  in,  98 

harmlessness  of  meat  of  animals  dead 
of,  42 
Room  disinfection,  561 
Roots,  edible,  154 
Round-pipe  traps,  462 
Round  worms,  391 
Rowing,  714 
Rubber,  719 
Rum,  200 
Running  traps,  461 
Rusks,  142 
Rye,  144 

q  ACCHAROMYCES  cerevisise,  202 
kJ     Sago,  151 
Sailors,  diseases  of,  622 
Salicylic  acid,  action  of,  as  a  food  preserva- 
tive, 216 
detection  of,  in  beer,  188 
in  milk,  120 
in  wine,  195 
Salmon,  composition  of,  36 

poisoning  by,  63 
Salt,  204 

soils,  272 
Salting,  preservation  of  food  by,  209 
Salts  in  foods,  23 
Samp,  146 

Sand  filtration  of  water,  357 
Sanitary  cordon,  740 
Sanitas  closet,  478 

trap,  469 
Saprol,  536 

Sausage-poisoning,  53,  60,  74 
Sausages,  32 
Sauterne,  191 
Scallops,  37 

Scarlet  fever,  spread  of,  by  milk,  106 
Sobering  paraform  lamp,  546 
School  furniture,  422 
Schools,  420 
Scott-Moncrieflf  system  of  sewage  disposal, 

507 
Sea-water,  influence  of,  on  pathogenic  bac- 
teria, 52 
Seeds,  fatty,  152 
&elf-purification  of  water,  349 
Septic  tank,  Cameron's,  504 
Sewage,  action  of,  on  fish  life,  496 

chemical  treatment  of,  493 

composition  of,  488 

disposal  of,  488 

by  biological  processes,  502 
by  pail  system,  493 

farming,  496 

filtration,  500 


790 


INDEX. 


Sewage,  irrigation,  496 

manurial  value  of,  489 
methods  of  disposal  of,  491 
purification  of,  by  filti-ation,  500 
Sewer  air,  bacteria  in,  237 

gas,  237 
Shad,  36 
Sheep  rot,  41 
scab,  43 
Sheepshead,  36 
Sherry,  192 

Ships,  general  hygiene  of,  624 
ventilation  of,  623 
water-supply  of,  620 
Shoddy,  576,  717 
Shrimps,  composition  of,  37 
vSickness,  registration  of,  702 
Side-chains,  729 
Side-chain  theory,  727 
Silk,  717 

Silt  cylinder,  Knop's,  308 
Sinks,  484 

company,  605 
Siphon  closets,  476 
Slaughtering,  76 
Slop  sinks,  485 
Smallpox,  755 
Smelts,  36 
Smoked  meats,  209 

Smoking,  preservation  of  food  by,  209 
Soap,  carbolic,  541 
Soaps,  disinfectant  properties  of,  538 

medicated,  541 
Sodium  bisulphate,  use  of,  in  purification 
of  water,  354 
fluoride,  action  of,  as  a  food  preserva- 
tive, 219 
hypochlorite,    disinfectant    properties 
of,  525 
use  of,  in  purification  of  water, 
352 
presence  of,  in  soils,  272 
Soil,  270 

action  of  worms  on  character  of,  282 
air,  283 

bacteria  of,  294 

bacteriological  examination  of,  315 
classification  of,  270 
connection  of,  with  anthrax,  303 
with  cholera,  300 
with  diphtheria,  301 
with  epidemic  diarrhcea,  307 
with  goitre,  306 
with  malaria,  302 
with  malignant  oedema,  303 
with  plague,  300 
with  tetanus,  303 
with  tuberculosis,  297 
with  typhoid  fever,  297 
with  uncinariasis,  304 
with  yellow  fever,  302 
constituents  of,  272 
determination  of  capillarity  of,  312 
of  permeabilty  of,  309 
of  water  capacity  of,  312 
examination  of,  307 


Soil  moisture,  influence  of  vegetation  on, 
290 

pathogenic  bacteria  in,  295 

permeability  of,  274 

physical  properties  of,  273 

pipes,  454 

pollution  of,  292 

by  dead  bodies,  744 

pore  volume  of,  273 

self-purification  of,  282 

temperature  of,  280 

efiect  of  vegetation  on,  291 

water,  286 

sources  of,  289 

water-retaining  capacity  of,  278 
Soja-bean,  150 
Solanin,  poisoning  by,  156 
Soldier,  clothing  of  the,  576 

diseases  of  the,  613 

food  of  the,  587 

hygiene  of  the,  575 
Soldiers,  care  of,  in  the  tropics,  627 
Solutol,  537 
Solveol,  536 
Sorghum,  163 
Spaghetti,  142 
vSpanish  mackerel,  36 
Spermotoxins,  737 
Spices,  202 
Spinach,  158 

oxalic  acid  in,  23 
Spirit,  proof,  200 

vinegar,  203 
Spirits,  197 
Springs,  338 
Sprouts,  158 

Sputum,  disinfection  of,  559 
Squash,  159 
Standard  diets,  18 
Starches,  21 
Steam,  disinfection  by,  515 

heating,  439 
Stearin,  21 

Steel-grinding,  dangers  of,  678 
Stegomyia  mosquitoes,  654 
Sterilization  of  milk,  91 
Sterilized  milk,  objections  to,  92 
Stockings,  578 
Stout,  175 
Stoves,  437 
Strangles,  43 
Strawberries,  162 
String-beans,  150 
"  Strippings,"  84  ' 
Sturgeon,  36 

Substance  sensibilisatrice,  735 
Sucrose,  21 
Sugar,  163 

beet,  163 

cane,  163 

invert,  164 

maple,  164 

milk,  22,  84 
Sugars,  classification  of,  21 
Sulphites,  action  of,  as  food  preservatives, 

217 


INDEX. 


791 


Sulphites,  detection  of,  in  wine,  196 
Sulphur  dioxide,  destruction  of  mosquitoes 
by,  651 
disinfectant  properties  of,  526 
influence  of,  on  health,  670 
presence  of,  in  soils,  272 
production  of,  from  illuminating  gas, 

Sunlight,  disinfectant  action  of,  511 
Sunstroke,  616 

forms  of,  630 
Surface-waters,  317,  337 
Susceptibility  to  disease,  725 
Sweet  potatoes,  157 
SwilJ,  disposal  of,  507 
Syn  toxoids,  732 
Syrup,  maple,  164 


TABES  mesenterica,  47,  103 
Taenia  saginata,  37 
solium,  37 

transmission  of,  by  fleas,  640 
Tanks,  house-service,  485 
Tapeworm,  37 

life  cycle  of,  38 
Tapioca,  151 
Tartar,  cream  of,  207 
Tea,  168 

adulteration  of,  170 
composition  of,  169 
"facing"  of,  170 
poisoning  by,  170 
Tennis,  714 
Tents,  601 

Terra  alba  in  candy,  167 
Terrapin,  composition  of,  37 
Terne  plates,  210 
Tetanus,  antitoxic  treatment  of,  748 

connection  of  soil  with,  303 
Theine,  168 
Theobromine,  168 
Thymol,  538 
Tin,  action  of  water  on,  370 

as  adulterant  of  molasses,  165 
contamination  of  food  by,  222 
detection  of,  in  water,  4u9 
Toast,  142 

Tobacco- workers,  diseases  of,  680 
Tokay,  192 
Tomato,  159 
Tomcod,  36 
Toxins,  727 
Toxoids,  731 
Toxones,  731 
Toxonoids,  732 
Toxophores,  729 
Trades,  dangerous,  662 

offensive,  681 
Ti-aps,  460 
ball,  463 
bell,  464 
bottle,  462 
grease,  464 
hydric,  469 
inteicepting,  457 
noii-sij)li()Mir]g,  468 


Traps,  pot,  462 

round-pipe,  462 

running,  461 

sanitas,  469 
Trembles,  96 
Trichina  spiralis,  38 
Trichinosis,  39 

frequency  of,  in  Germany,  39 

in  United  States,  40 

Trichocephalus  dispar,  spread  of,  by  water. 
392  *     '   i  1   J  > 

Trichotoxins,  737 
Trillat's  autoclave,  544 
Tripe,  29 
Tritotoxins,  732 
Tropical  hygiene,  627 
Tropics,  care  of  the  person  in  the,  634 
clothing  in  the,  633 
diet  in  the,  630 
diseases  of  the,  634 
use  of  alcohol  in  the,  631 
Trout,  composition  of,  36 
Truffles,  163 

Tubercle  bacilli  in  butter,  127 
in  milk,  91, 100 
in  oleomargarine,  128 
Tuberculosis,  bovine,  43 

connection  of  soil  with,  297 
frequency  of,  in  domestic  animals,  43 
German  Commission  on,  47 
identity  of  human  and  bovine  bacilli 

of,  46 
in  fish,  47 
interim  report  of   Eoyal  Commission 

on,  48 
prevalence  of,  among  sailore,  622 

in  armies,  613 
rarity  of,  in  Western  beeves,  44 
reciprocal   transmissibility  of  human 

and  bovine,  46 
serum  treatment  of,  754 
transmission  of,  by  bedbugs,  640 
by  butter,  127 
by  flies,  639 
by  inoculation,  48 
by  meat,  45 
by  milk,  100 
through  air,  245 
Tuberculous  meat,  43,  48 
Tube  wells,  340 
Tunnel  disease,  304 

Turbidity,  determination  of,  in  water,  406 
Turbot,  36 
Turkey,  31 
Turnips,  167 
Turtle,  37 

Typhoid  fever,  connection  of  soil  with,  297 
examples  of  epidemics  of,  379 
inoculation  against,  750 
prevalence  of,  in  armies,  614 
serum  treatment  of,  749 
transmission  of,  by  air,  248 
by  clams,  62 
by  cockles,  51 
by  flies,  639 
by  ice,  394 


792 


INDEX. 


Typhoid  fever,  transmission  of,  by  milk, 
107 
by  oysters,  49 
by  water,  375 
Tyrotoxicon,  88,  136 

cases  of  poisoning  by,  97 

TTNCINAEIA,  304 
U      Americana,  304 
duodenalis,  304 
Uncinariasis,  304 
Underclothing,  579 
Uniceptors,  730 
Urinals,  480 

Urine,  disinfection  of,  559 
Uroglena,  323 

TIACCINATION,  755 
V     Veal,  composition  of,  30 
Yeal-poisoning,  59,  64 

(cases  of) ,  64 
Vegetable  casein,  148 

fats,  153 

foods,  136 

marrow,  159 
Vegetables,  137 

Vegetation,  effects  of,  on  soil  temperature, 
•291 

influence  of,  in  purification  of  water, 
350 
on  soil  moisture,  290 
Venereal  diseases,  prevalence  of,  in  armies, 

617 
Ventilation,  423 

detej'minatioti  of  rates  of,  443 

effect  of,  on  phthisis  rates,  240 

flues  for,  434 

inlets  and  outlets  for,  432 

mechanical,  435 

natural,  431 

forces  in,  426 

of  ships,  623 

space  required  for,  425 
Vermicelli,  142 
Vermuth,  201 
Vinegar,  202 

mother  of,  202 
Vital  statistics,  o86 

WALNUTS,  152 
Waring  svstem  of  irrigation,  499 
Wash-basins,  480 
Wash-down  closets,  476 
Wash-out  closets,  475 
Waste  pipes,  459 
Water,  316 

action  of,  on  iron,  369 
on  lead,  365 
on  tin,  370 
on  zinc,  369 
aeration  of,  325 
albuminoid  ammonia  in,  328 
ammonia  in,  326 
analysis  of,  394 
appeai-ance  of,  321 
bacteria  in,  332 


W'ater,  bacteriological  examination  of,  412 
capacity    of    soils,    determination    of, 

312 
capillary,  278,  286 
carbon  dioxide  in,  325 
Carlsbad,  331 
cause  of  taste  in,  324 
chemical  examination  of,  394 
chlorine  in,  330 
classification  of,  316 
color  of,  321 
connection  of,  with  anthrax,  375 

with  cholera,  375,  386 

with  dij^htheria,  374 

with  dysentery,  374 

with  glanders,  375 

with  goitre,  372 

with  hog  cholera,  375 

with  malaria,  374 

with  typhoid  fever,  375 

with  yellow  fever,  374 
gases  in,  324 
ground-,  287,  318 
hygroscopic,  278 
instances  of    finding  B.  tvphosus  in, 

419 
mineral  matters  in,  330 
nitrates  in,  328 
nitrites  in,  328 
odor  of,  322 
organic  matters  in,  325 
parasites  and,  391 
purification  of,  349 

by  alum,  351 

by  boiling,  355 

by  bromine,  353 

by  chlorine,  353 

by  chlorinated  soda,  352 
lime,  352 

by  copper  sulphate,  363 

by  distillation,  355 

by  filtration,  355 

by  iron,  353 

by  ozone,  354 

by  permanganate,  351 

by  sodium  bisulphate,  354 
reaction  of,  322 
removal  of  hardness  from,  364 

of  iron  from,  365 
self  purification  of,  349 
significance  of  B.  coli  in,  334 
spread  of    Ankvlostomum   duodenale 
by,  392    ' 

of  Ascaris  lumbricoides  by,  391 

of  Bilharzia  hsematobia  by,  392 

of    Dracunculus    medinensis    by, 

391  _ 

of  Filaria  sanguinis  hominis  by, 

392  _        \ 

of  Oxyuris  vermicularis  by,  391 

of   Strongyloides    intestinalis   bv, 
392 

of  Trichocephalus  dispar  by,  392 
substances  found  normally  in,  324 
supplies,  335 

filtration  of,  357 


INDEX. 


793 


AVater  supplies,  typhoid  infection  of,  376 

surt'uce,  317 
Water-closets,  470 

disinfection  of,  5G4 
"Water-gas,  composition  of,  449 
Water-hammer,  486 
AVater-proofing,  580 
AVatermelons,  162 
Weakfish,  36 
AVells,  339 

Abyssinian,  340 

Artesian,  342 

bored,  341 

drainage-area  of,  344 

driven,  340 

Norton,  340 

pollution  of,  344 
AA'elsbach  burner,  448 
AA^heat,  137 
AVheaten  bread,  141 

flour,  139 
AVheeling,  714 
AVhip-worms,  392 
AVhiskey,  199 
AVhite  meat,  27 
AVhite-wine  vinegar,  202 
AVhitefish,  36 
AVidal  reaction,  741 
AVind,  action  of,  in  ventilation,  429 
AVine,  oil  of,  198 

vinegar,  202 
AAlnes,  189 

adulteration  of,  192 

alum  in,  193 

analysis  of,  194 

anilin  colors  in,  194 

artificial,  193 

chaptalizing  of,  193 

classification  of,  191 

composition  of,  191 

detection  of  preservatives  in,  195 


AVines,  dry,  191 

fortified,  193 

gallizing  of,  193 

low,  199 

manufacture  of,  190 

pasteurization  of,  193 

plastered,  193 

preservatives  in,  195 

salicylic  acid  in,  195 

sparkling,  191 

sweet,  191 
Wolpert's  method  for  CO2  in  air,  263 
Women,  employment  of,  685 
AVood  alcohol,  dangers  to  health  from,  674 
AA'ool,  716 

Wool-sorters'  disease,  680 
Woolf  process  for  sewage  disposal,  495     • 
Woollen  clothing,  680 
Worms,  action  of,  on  soils,  282 

guinea-,  spread  of,  by  water,  391 

hook-,  spread  of,  by  soil,  304 

pin-,  spread  of,  by  water,  391 

round-,  spread  of,  by  water,  391 

whip-,  spread  of,  by  water,  392 

YEAST,  action  of,  in  bread-making,  140 
Yellow  fever,  connection  of  soil  with, 
302 
of  water-supply  with,  374 
prophylaxis  against,  656 
transmission    of,  by    mosqui- 
toes, 652 

ZINC,  action  of  water  on,  369 
chloride  of,  as  disinfectant,  529 
contamination  of  foods  by,  222 
detection  of,  in  water,  408 
Zwischenkorper,  735 
Zymases,  92 
Zymophores,  743 
Zymotoxic  groups,  738 


.         '    .  V    ■.      .i  ,^'.  .     V       't       'l„. 


RA426 


Harrington 


H23 

1906 


Manual  of  practical  hygiene 


'^: 


